Download Revision PowerPoint B2 Topic 3

Process 3 – Impression fossils
A dead plant or animal sinks into mud leaving its shape.
The body decays, leaving a mould. Eventually, all that is left is an organism‐shaped hole or mould in the rock
What conditions are needed for fossils to form? What happens if those conditions are not there? • Certain conditions slow down the decaying process, helping to preserve the tissues. Examples are:
• Low / no oxygen, eg when an organism becomes trapped in amber
• Low temperatures, eg when an organism becomes frozen in a glacier
• High soil acidity, eg when an organism falls into a peat bog
• If these conditions are not present, the remains will not be fossilised. What is the fossil record?
The fossil record provides a record of organisms that lived a long time ago. They also provide evidence that animal and plant species can change over long periods of time.
Why are there gaps in the fossil record?
Soft‐ bodied organisms usually decay without leaving fossils. Many fossils may exist but have yet to be found. Many organisms don’t form fossils – the conditions are not always right to preserve them.
Earthquakes can break apart fossils. The problems with the fossil record gaps. • This makes the story of evolution of any one species challenging. • In most cases there are big gaps in fossil records, making it like a jigsaw puzzle with half the pieces missing. • Problems also arise as soft tissues decay resulting in scientists having to estimate what the organism was like. • Finally, there are also lots of fossils that we haven't yet found.
Discuss why scientists have problems interpreting fossil records.
Some fossils will have been damaged or destroyed in the many years since they were formed, and others exist but have not been found yet. All of this means that scientists have to work from incomplete data that is often open to much interpretation when piecing together the fossil record.
Explain how the anatomy of the pentadactyl limb provides evidence for evolution.
Evolution is the change over time of organisms. If organisms are related, they have evolved from the same ancestor a long time ago. So they will have similar features which they have inherited from that ancestor . Many vertebrates have a similar bone structure despite their limbs looking very different on the outside. This structure is known as the pentadactyl limb – five fingered. This suggests that many vertebrates descended from the same common ancestor.
Starter ‐ True or False? Justify your answers.
1. Growth is an increase in mass

2. Growth occurs because cells divide

3. Growth occurs because of meiosis X
4. Mitosis produces 2 non‐identical cells X
5. Mitosis produces diploid cells 
6. Meiosis produces gametes 
7. Meiosis produces 4 identical cells X
Starter ‐ True or False? Justify your answers.
Growth is an increase in dry mass
How else do you know if something has grown?
Increase in size
Growth
Increase in length
Increase in mass
How do plants grow?
• Plants continually grow.
• Plants have meristems in tips of roots or shoots.
• Cells in the meristem area keep dividing and then elongate.
• Older meristems differentiate into any cell eg a cell in a shoot can become a cell in a leaf. Animal Growth
Animal cells also divide but animals stop growing when they become adults. Animals have stem cells that can differentiate and become different specialised cells. Eg In an embryo the stem cells differentiate into every specialised cells eg muscle cells, needed in the body. These cells then form tissues eg muscle tissue. Different tissues form organs etc. Adults don’t have many stem cells, and adult stem cells are limited in the cells they can become (they cannot change into every type of cell). This is why we cannot re‐grow a damaged body part but a plant can continually grow new leaves, roots etc. Now take turns to annotate the text to help compare the growth in plant cells with that of animal cells. Which important bits will you pull out?
Growth in both plants and animals involves cell division and cell growth. Plant cell division is followed by elongation and then differentiation. There are constant regions of cell division (meristems) where cells divide to form undifferentiated cells, so plants grow throughout their lives. In animals, cell division is immediately followed by differentiation and there is no elongation. Once cells have differentiated they can only form more of the same type of cell. Growth stops at adulthood in animals and so can not continue to regenerate as only a limited number of cells can differentiate and so cannot develop into a new organism.
Yellow = B grade / Green = A grade
Percentile Charts
Boys
Percentile: the value below which a percentage of data falls. The heart pumps blood around the body
ALL: Outline the composition of blood (Grade D)
MOST: Establish the functions of each part (Grade C)
SOME: Analyse the adaptations of a red blood cell and link this to its function (GradeB)
FEW: Explain in detail how all the cells in the blood are adapted to their function.(Grade A)
Your blood carries oxygen and food
around your body
ALL: Outline the composition of blood (Grade D)
MOST: Establish the functions of each part (Grade C)
SOME: Analyse the adaptations of a red blood cell and link this to its function (GradeB)
FEW: Explain in detail how all the cells in the blood are adapted to their function.(Grade A)
There are 4 main parts in the blood:
Plasma
Red blood cells
White blood cells
Platelets
These have all differentiated and become specialised from blood stem cells. Model – Blood Soup
ALL: Outline the composition of blood (Grade D)
MOST: Establish the functions of each part (Grade C)
SOME: Analyse the adaptations of a red blood cell and link this to its function (GradeB)
FEW: Explain in detail how all the cells in the blood are adapted to their function.(Grade A)
what’s in
digested food
red blood cells
white blood cells
oxygen
waste (urea)
platelets
carbon dioxide
plasma
hormones
ALL: Outline the composition of blood (Grade D)
MOST: Establish the functions of each part (Grade C)
SOME: Analyse the adaptations of a red blood cell and link this to its function (GradeB)
FEW: Explain in detail how all the cells in the blood are adapted to their function.(Grade A)
Red Blood Cells – carry oxygen
No nucleus – contains more haemoglobin to carry more oxygen
Biconcave disc shape – increases surface area– for fast diffusion of oxygen in to the cell. Contain haemoglobin, a molecule that holds oxygen and carries it to body cells.
Small and can flexible, it squeezes in single file through the capillaries.
ALL: Outline the composition of blood (Grade D)
MOST: Establish the functions of each part (Grade C)
SOME: Analyse the adaptations of a red blood cell and link this to its function (GradeB)
FEW: Explain in detail how all the cells in the blood are adapted to their function.(Grade A)
White Blood Cells – engulf and ingest microbes
White blood cells contain a big nucleus ‐
contain DNA to make proteins. . Some white blood cells make
antibodies – these are proteins.
They destroy microbes.
Some white blood cells engulf and ingest
micro‐organisms . Therefore they have a flexible cell membrane. Some contain enzymes that destroy the microbe once it has been ingested. ALL: Outline the composition of blood (Grade D)
MOST: Establish the functions of each part (Grade C)
SOME: Analyse the adaptations of a red blood cell and link this to its function (GradeB)
FEW: Explain in detail how all the cells in the blood are adapted to their function.(Grade A)
Platelets – stick together to form scabs (clots). This stops blood loss and prevents entry of microbes. Platelets are sticky and produce fibres to form a scab to stop bleeding/ prevent entry of microbes. ALL: Outline the composition of blood (Grade D)
MOST: Establish the functions of each part (Grade C)
SOME: Analyse the adaptations of a red blood cell and link this to its function (GradeB)
FEW: Explain in detail how all the cells in the blood are adapted to their function.(Grade A)
Composition of blood
A straw‐coloured
liquid that carries the cells and the platelets which help blood clot. Also carries dissolved substances such as glucose and hormones. ALL: Outline the composition of blood (Grade D)
MOST: Establish the functions of each part (Grade C)
SOME: Analyse the adaptations of a red blood cell and link this to its function (GradeB)
FEW: Explain in detail how all the cells in the blood are adapted to their function.(Grade A)
Group quiz
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5.
6.
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8.
9.
10.
11.
What is the liquid part of the blood that carries dissolved substances. What part of the blood carries oxygen?
Name the 4 components of the blood. Which part of the blood destroys microbes and forms your immune system. What do platelets do?
Which type of cell has no nucleus so it can carry more oxygen?
Give one adaptation of a red blood cell.
Explain how this adaptation helps it do its job. Give one adaptation of a white blood cell.
Explain how this adaptation helps it do its job. Which type of cell has a flexible cell membrane so it can engulf and ingest microbes. ALL: Outline the composition of blood (Grade D)
MOST: Establish the functions of each part (Grade C)
SOME: Analyse the adaptations of a red blood cell and link this to its function (GradeB)
FEW: Explain in detail how all the cells in the blood are adapted to their function.(Grade A)
Group quiz ‐ Answers
1.
2.
3.
4.
5.
6.
7.
8.
9.
What is the liquid part of the blood that carries dissolved substances (Plasma)
What part of the blood carries oxygen? (Red blood cells)
Name the 4 components of the blood. (Red blood cells, white blood cells, platelets, plasma).
Which part of the blood destroys microbes and forms your immune system. (White blood cells). What do platelets do? (Form scabs)
Which type of cell has no nucleus so it can carry more oxygen? (Red blood cells)
Give one adaptation of a red blood cell. Small and flexible Explain how this adaptation helps it do its job. , it squeezes in single file through the capillaries. Give one adaptation of a white blood cell. White blood cells contain a big nucleus –
10. Explain how this adaptation helps it do its job. contain DNA to make proteins such as antibodies and enzymes. 11. Which type of cell has a flexible cell membrane so it can engulf and ingest microbes. White blood cell. ALL: Outline the composition of blood (Grade D)
MOST: Establish the functions of each part (Grade C)
SOME: Analyse the adaptations of a red blood cell and link this to its function (GradeB)
FEW: Explain in detail how all the cells in the blood are adapted to their function.(Grade A)
Cells, tissues, organs and organ systems. Your heart is an organ. This is because it is made up of different tissues that work together to perform a function. (Eg, muscle tissue, fat tissue). Each tissue is made of similar cell working together. Eg muscle tissue is made up lots of muscle cells.
Cells are the building blocks of life.
The heart is not able to pump blood around the body on its own – it has other organs that help it and so is part of an organ system (the circulatory system). •
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
So which is the correct order and definition?
Tissues
Organ Systems
Cells
Different tissues working together
These are the building blocks of life
Groups of similar cells working together
Different organs working together
Organs
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
Heart Dissection The right side of your heart pumps blood to your lungs.
The left side of your heart pumps blood to the rest of your body. This is why it is called a double pump. •
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
The heart
The ventricles fill with blood and then the muscles contract which squeezes the blood out (this is felt as your heart beat)
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
Your pulse is the number of times your
heart beats in a minute; it's your heart
rate.
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
How does the Heart work?
STEP ONE
blood from the
body
blood from
the lungs
The heart beat begins when the
heart muscles relax and blood
flows into the atria.
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
How does the Heart work?
STEP TWO
The atria then contract and
the valves open to allow blood
into the ventricles.
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
How does the Heart work?
The valves close to stop blood flowing backwards.
STEP THREE
The ventricles contract forcing the blood to leave
the heart.
At the same time, the atria are relaxing and once
again filling with blood.
The cycle then repeats itself.
The heart is sometimes called a double pump. One side
collects blood from the body and pumps it to the lungs,
while the other side collects blood from the lungs and
pumps it to the body. The two sides act as two separate
pumps.
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
The heart is a pump.
It will continually contract and relax throughout the rest of your life to pump blood to the lungs and around the rest of the body.
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
ALL: Label the structures of the heart (Grade C)
MOST: Establish
the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain
how the structure of the heart is related to its function. (Grade A‐A*)
The journey of blood Deoxygenated blood brought back from body tissues –
inferior Vena cava
from the lower
body, superior vena
cava from the
upper body. This
feeds into the right
atrium.
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
The journey of blood Blood flows from inferior and superior vena cava into the right atrium.
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
The journey of blood When full right atrium contracts and blood
flows through the
open valve from right atrium to right ventricle.
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
The journey of blood When full right
ventricle contracts
sending the blood
into the pulmonary
artery.
This will take the deoxygenated blood to the lungs.
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
The journey of blood Oxygen diffuses from the alveoli into the haemoglobin in the red blood cells.
What is this and what does it do?
Pulmonary veins take the blood from the lungs back to the heart.
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
The journey of blood Blood goes into the left atrium. •
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•
ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
The journey of blood Blood flows through the valve into left ventricle.
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
The journey of blood When full left
ventricle
contracts. Blood
goes in to the
aorta (the largest
blood vessel).
This will take the oxygenated blood to the body tissues.
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•
ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
Important to remember ‐
The heart is a double pump – the right side of the heart pumps blood to the lungs.
The left side of the heart pumps blood to body tissues. When the right side is contracting and pumping blood the lungs, at the same time the left side pumps blood to the body. •
•
•
ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
Adaptations of the heart – how do these help it carry out its function
• Valves (Close so blood flows forwards and not backwards).
• Tendons (Attached to the valves, stop the valves from turning inside out).
• Septum (Separates the left and right sides of the heart so deoxygenated and oxygenated blood do not mix).
• Left ventricle has thicker muscular wall. (Contracts with more force than the right to push blood all around the body and head. Right side only has to force blood to the lungs). •
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•
ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
Assess the differences between modern ideas about the heart with ideas many years ago. (Grade A*)
• For almost 1500 years most of society followed the teachings of a Greek doctor called Galen. Galen believed there were two independent types of blood that ebbed and flowed to the upper and lower parts of the body and eventually “evaporated.” The venous blood (blood in veins) was filled with nutrients, while the arterial blood was infused with the “vital spirit” by a mixture of air from lungs, chemicals, and heat from the heart. The former was formed within the liver and the latter in the left ventricle. He also thought the blood flowed between the two ventricles through invisible holes in the septum, and the heart did not act as a pump. This blood was not recycled but was either evaporated or consumed by the organs.
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ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
•
•
•
ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
Tissues
Systems
Cells
Organs
Different tissues working together
These are the basic units of life
Groups of similar cells working together
Different organs working together
The heart pumps
blood around the
body so that oxygen
and glucose can get
to all of the body’s
cells.
What other organs
are needed in the
circulatory system?
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•
•
ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
Blood vessels are tube shaped organs that carry blood around the body.
The three kinds are:
Arteries
Veins
Capillaries
Each have structures (adaptations) that help them with their functions.
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•
•
ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
• I will project a statement
• Tell me whether it refers to arteries, veins or capillaries then how it helps do its job.
Vein
Wide passage
Capillary
Thin walls – one cell thick
Artery
Tough connective tissue on outside
Veins
Valves
Artery
Thick muscle layer
Capillaries
Really small
Veins
Thin muscle layer
The ARTERY
Arteries carry blood away from the heart. Arteries
carry blood that is under high pressure.
Strong, thick muscle
walls that can cope
with high pressure
blood. The thick muscle
can contract to push the
blood along.
Tough connective tissue that
stops the artery from bursting
due to the pressure that is
exerted on the walls by blood
flow.
The VEIN
Veins carry blood towards the heart. The blood flowing
through veins is under low pressure.
Veins have valves which act to stop the blood from going in the wrong direction as the blood is under low pressure.
Thin muscle and
elastic fibres as
blood is pumped
under low
pressure (Thick
wall not needed).
Wide passage to allow more blood flow as blood flows quite slow under low pressure. Capillaries
Capillary walls are thin for easy diffusion of oxygen, carbon dioxide and glucose.
Capillaries are so small that red blood cells can only travel through them in single file to maximise oxygen uptake. 7 Describe the route of a small volume of blood from
a capillary in your muscle where it has just given up
its oxygen until it returns to the same place loaded
with oxygen again. Include in your answer what
substances pass into or out of the blood at each
stage.
next
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A: Oxygen moves into muscle by ..................... Blood moves
through network of .........................into vein. Travels back to
……………… and enters ………………through vena cava.
Moves into....................., then right ventricle, and
then........................ Carried to ................. and travels
through capillaries in ...................where oxygen moves into
........................ by diffusion. Moves through capillaries into
........................... and is taken back to heart. Enters
……………………, then left ventricle, then……………….
Moves through arteries into capillaries ready to give up the
...................by diffusion again.
pulmonary artery lungs Heart
Capillaries right atrium diffusion
aorta
heart oxygen
lungs
left atrium red blood cells pulmonary vein Explain the process of giving blood using our modern ideas about giving blood. (Grade A*)
Hint: Highlight the main parts of the whole process – why do you think this is done?
Clues: Muscle contraction helps blood to flow through veins
Red blood cells need to be collected whole
So red blood cells are not destroyed
Vein – blood under lower pressure so less chance of blood loss
increase the blood flow through the vein.
Stop blood loss
Stop microbes entering the wound site
You have lost red blood cells that need to be replenished.
Complete the C grade outcome in your books..
Cells are............................. The building blocks of life are cells. A group of similar cells working together are called a tissue. Different tissues working together are called an organ. Different organs working together are called an organ system.
Eg A muscle cell
Lots of muscle cells working together are muscle tissue.
Muscle tissue and fat tissue are different tissues working together in the heart
which is an organ.
The heart, arteries and veins are different organs working together to form an
organ system.
ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
Starter: The heart pumps blood around the body so that body cells receive the oxygen and nutrients they need. Do you know how the blood travels around the body?
ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
Circulatory System: Is a transportation system by which oxygen and nutrients reach the body's cells, and waste materials are carried away. Parts of the Circulatory System
• Divided into three major parts:
– The Heart – The Blood – The Blood Vessels (arteries, veins and capillaries). ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
Circulation
• Travels through pulmonary arteries to lungs where it gets fresh oxygen and becomes bright red. • Blood from lungs through pulmonary veins back to the heart's left side pump
• Pumped out into the body in arteries – the arteries get thinner and thinner until they form capillaries, a network of tiny blood vessels near all of your cells. Blood in arteries and veins
Blood is pumped under high pressure in arteries and so flows faster in arteries. Blood in arteries is being taken away from the heart.
Blood is pumped under low pressure in veins and so flows slower. Blood in veins flows towards the heart. ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
Which is the artery, vein and capillary? Why do you think that? ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
Which is the artery, vein and capillary? Why do you think that? Artery: takes oxygenated blood at high pressure around the body to tissues. Capillaries: tiny blood vessels that carry blood near to cells so substances can diffuse into and out of the blood into the cells. Veins: Bring deoxygenated blood at low pressure back to the heart. ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
Task: Use the diagram to fill in the table giving info about each . blood vessel
ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
Decide on the which blood vessel, what the adaptation is and how it help the blood vessel fulfil its function Eg – lets do one together
Valves are located it these vessels. The valves prevent the back flow of blood as the blood is under low pressure. Have thick, muscular walls to cope with high pressure blood and can contract to push blood along to reach all body parts.
One cell thick wall for easy diffusion of oxygen into the cells and waste substances out of the cells.
Tough connective tissue so the vessel does not burst due to high pressure blood. Very thin and branched – allowing single file red blood cells to travel through allowing maximum exchange of substances (CO2, oxygen, glucose).
Smooth inner layer so that the blood can flow easily Connect arteries & veins – once the red blood cells have given up their oxygen they will need to return to the heart via the veins. Body muscles surround these vessels so that when they contract to move the body, they also squeeze the blood vessel and push the blood along the vessel.
ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
The aorta takes blood around the body to the small capillaries. The oxygen (in a high concentration in the red blood cell) diffuses into nearby tissue cells (where oxygen is in a low concentration). Waste materials then diffuse from the cell into the blood plasma. https://www.youtube.com/watch?v=HKC‐eMyStXk
ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
Have strong, muscular walls to cope with high pressure blood and
can contract to push blood along (Blood has to be under high
pressure in the arteries as it has to each all parts of the body).
The inner layer is very smooth so that the blood can flow easily
Tough connective tissue so the artery does not burst due to high
pressure blood. Has elastic tissue that stretches under pressure.
The CAPILLARY
A collection of capillaries is known as a capillary bed.
artery
vein
capillaries
body cell
ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
Capillaries
• Very thin and branched – allowing single file red blood cells to travel through allowing maximum exchange of materials (CO2, oxygen, glucose).
• Wall only one cell thick – allowing easy diffusion of oxygen into the cells and waste substances out of the cells back into the capillary. • Connect arteries & veins – once the red bloods have given up their oxygen they will need to return to the heart via the veins. ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
Valves are located inside the veins. The valves only allow blood to
move in one direction (so it doesn’t go backwards) as the blood is
under low pressure.
Body muscles surround the veins so that when they contract to
move the body, they also squeeze the veins and push the blood
along the vessel.
Veins take blood to the heart.
• This is how the circulatory system works. ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
7 Determine the route of a small volume of blood
from a capillary in your muscle where it has just
given up its oxygen until it returns to the same
place loaded with oxygen again. Include in your
answer what substances pass into or out of the
blood at each stage.
Artery vein capillary diffusion Concentration gradient oxygen glucose Carbon dioxide heart ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
A grade model answer
Deoxygenated blood move through the capillaries into a vein. Travels back to heart and enters heart through vena cava into the right atrium, through valves into the right ventricle then pumped to the lungs to pick up oxygen. Oxygenated blood comes back to the heart into the left atrium, then left ventricle. The blood is pumped through the aorta to be taken to cells in the body. Blood containing oxygen and glucose moves into a capillary near muscle cells. They will travel in single file. Oxygen and glucose moves into muscle cells by diffusion from a high concentration in the blood to a low concentration in the cells to be used for respiration. Carbon dioxide moves from the cells where it is in high concentration into the blood where it is in a low concentration by diffusion. What happens then???
ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
So which is the correct order and definition?
Tissues
Organ Systems
Cells
Different tissues working together
These are the building blocks of life
Groups of similar cells working together
Different organs working together
Organs
•
•
•
ALL: Label the structures of the heart (Grade C)
MOST: Establish the journey of the flow of blood in the correct order through the heart (Grade B). SOME: Explain how the structure of the heart is related to its function. (Grade A‐A*)
ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
6 mark question practice
• Explain how the 3 types of blood vessels in the circulatory system are adapted to their function. • What is the question asking??
6 mark question practice
Arteries take high pressure blood
Away from the heart to the body tissues / cells.
Has thick muscular wall as it carries high pressure blood
Has smooth inner layer so blood flows easily
Capillaries are where the oxygen diffuses into the cells.
Have one cell thick wall for easy diffusion of substances into and out of the cell.
Are branched and small so red blood cells go through in single file allowing for maximum diffusion of substances. Veins take blood back to the heart under low pressure. Have valves so blood flows forwards and not backwards.
Large central hole to allow more blood to flow.
Surrounded by muscles which contract ad squeeze blood through the veins. Why do body cells need oxygen? What happens to our heart and breathing rate when we exercise? Why does this happen? ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
Your muscles are contracting more – this needs more energy. Energy is made by respiration – respiration requires both oxygen and glucose. Breathing rate increases to get more oxygen into the blood. Heart rate increases to pump blood with oxygen and glucose in it quicker to muscle cells, then carry away more carbon dioxide. ALL: Recall how systems, organs, tissues and cells are organised in the human body. (Grade C)
MOST: Establish the adaptations of different blood vessels and relate them to their function (Grade B)
SOME: Discuss in detail how blood is transported around the body to take oxygen and glucose to respiring cells and transport waste materials away (Grade A)
Starter: The digestive tract – Alimentary Canal – Can you label the parts you know. Mouth
Bolus of food
Oesophagus
Liver
Stomach
Gall Bladder
Pancreas
Small intestine
Large Intestine
Anus
Grade C
Can you state which organs are involved in digestion and establish their function?
Grade B
Can you discuss the role of the liver and pancreas in digestion. Grade A
Can you explain the role of the gall bladder and bile in digestion. When you eat, you eat large molecules of food. The whole point of digestion is to break down these large molecules of food into small molecules of food. What are the three large nutrients that need breaking down? Mini whiteboards ‐ Identify the wrong words in these sentences. What is the correct word? 1.
2.
3.
4.
5.
6.
7.
8.
The liver makes the enzymes (carbohydrase, protease and lipase) that break down the large food molecules. The mouth contains saliva that chews food into smaller pieces. The oesophagus is a muscular tube that takes food from the mouth to the small intestine. Bile breaks protein into small pieces, giving them a larger surface area for protease to break it down further. Most of the large food molecules are broken down into small molecules by enzymes in the large intestine, where they are absorbed into the blood. The stomach contains sulphuric acid that kills microbes in food. Saliva contains the enzyme called amylase which breaks down fats into sugar (glucose). The rectum removes excess water from faeces. Food is squeezed through the oesophagus, stomach, small intestine and large intestine by a process called peristalsis. • https://www.youtube.com/watch?v=Ujr0UAb
yPS4
• Peristalsis: muscular contractions that move or squeeze food along the gut. Effect of bile
https://www.youtube.com/watch?v=TZOCQko8i
Dg
STARTER
There are three main nutrients your body needs. They are large molecules that need to be broken down. These are:
Carbohydrates
Protein Fat
Question: What kinds of foods contain each nutrient?
What am I?
I am about 5 m long and 2.5 cm wide.
I am a tube
I am found in the human body
If my inside surface was smooth my surface area would only cover 0.5m2 Luckily, the inside of me is covered in millions of finger‐like projections called villi that make the surface area much bigger (about 200m2 – the size of a tennis court approx). This aids the absorption of nutrients into the blood. I am....
The small
intestine
The small Intestine is where large food molecules are broken down into small food molecules. These are then absorbed into the blood. C Grade
Enzymes are catalysts because the speed up they rate of chemical reactions, they are called biological catalysts because they do this in the body. Enzymes are made of proteins.
B Grade
Enzymes are catalysts because the speed up the rate of chemical reactions, they are called biological catalysts because they do this in the body. Enzymes are made of proteins and remain unchanged after they have speeded up the rate of reaction. They can build substances up or break them down.
Establish what an enzyme is Compare the uses of by explaining why it is called a enzymes inside and biological catalyst. (Grade C)
outside of cells. (Grade B)
Justify why enzymes are needed in the body by explaining the consequences if we didn’t have them. (Grade A)
A Grade
As B grade but also……………… if we didn’t have enzymes in the body then the chemical reactions would still occur but at a much slower rate and not quick enough for the body to function. Digestion would be too slow to provide glucose for respiration. Proteins would not be built quick enough. This would eventually lead to death. Establish what an enzyme is Compare the uses of by explaining why it is called a enzymes inside and biological catalyst. (Grade C)
outside of cells. (Grade B)
Justify why enzymes are needed in the body by explaining the consequences if we didn’t have them. (Grade A)
The role of digestive enzymes. You need to be in groups of 4. (I will decide this). You will need to become experts in one particular type of digestive enzyme. (I will give you a number). You will need to explain how insoluble food molecules are broken down by enzymes into small soluble molecules so that can be absorbed into the blood. To do this you need to:
State the name of the enzyme
Where it is produced in the body
Explain what kind of nutrient it breaks down, and what it is broken into. EXTENSION: Bile is not an enzyme but is very important in helping with digestion. Explain the role of bile. Use the info to fill in your table. 6 mins
The role of bile.
True / False (Circle the correct answer)
1.
2.
Amylase is a carbohydrase enzyme that breaks down carbohydrates such as starch. T / F Fats (lipids) are broken down by lipase enzymes into amino acids. T / F
3. Pepsin is a protease enzyme that is produced in the stomach and breaks down proteins into amino acids. T / F 4. Nutrients are absorbed through villi in the small intestine. T / F
5. The role of bile is to break up proteins into smaller pieces so enzymes have a larger surface area to break them down further. 6. Villi and microvilli decrease the surface area of the small intestine so nutrients are absorbed fast (efficiently). T / F
7. Enzymes are made of protein, and are called biological catalysts because they speed up reactions like breaking up large nutrient molecules. T / F
8. We can test for starch by adding iodine to the food. It will go red if starch is present in the food. T / F
9 The mouth contains teeth which chew food into bigger pieces. This gives it a larger surface area for amylase to break down starch into glycerol. T / F
10. The oesophagus (gullet) is a muscular tube leading to the stomach. Muscles in the oesophagus contract so food is pushed down into the stomach. T / F
Grade C
Use the model to explain the function of the small intestine.
Grade B
Predict the results of the experiment – explain your predictions.
Grade A/A*
Evaluate the model of the small intestine.
Questions – can you answer them
•
•
•
•
•
•
•
•
•
•
1. Where is amylase made? What does it do?
2. Where is carbohydrase made and what does it do?
3. Where is pepsin made and what does it do? 4. Where is protease made and what does it do?
5. What is lipase and what does it do?
6. What do carbohydrates get broken down into?
7. What do proteins get broken down into? 8. What do fats get broken down into? 9. What does bile do? carbohydrase
protease
Bile
carbohydrase
protease
lipase
Establish what an enzyme is Compare the uses of by explaining why it is called a enzymes inside and biological catalyst. (Grade C)
outside of cells. (Grade B)
Justify why enzymes are needed in the body by explaining the consequences if we didn’t have them. (Grade A)
Rice contains starch
– a carbohydrate
starch
glucose
C
C
C
Small
BIG
starch
molecule
Explain
ase
carbohydr
glucose
molecules for
energy
113
Eggs contain
proteins
P
P
P
BIG
prote
ase
protein
molecule
Explain
114
Small
amino acids for
building cell
components
Oil is a fat
L
L
L
fatty acid and glycerol to
BIG
fat
molecule
Explain
lip
ase
build cell
membranes
and supply
energy
115
Bile – 2 jobs
https://www.youtube.com/watch?v=TZOCQko8iDg
1. Emulsifies fats (breaks them into smaller pieces). This means the lipase has a larger surface area to break the fats down further into fatty acids and glycerol.
2. Food is acidic when it leaves the stomach – the bile increases the pH of the acidic food so it is not acidic anymore. Grade C
Use the model to explain the function of the small intestine.
Grade B
Predict the results of the experiment – explain your predictions.
Grade A/A*
Evaluate the model of the small intestine.
Watch this
• http://www.kscience.co.uk/animations/duode
num.htm
Grade C
Use the model to explain the function of the small intestine.
Grade B
Predict the results of the experiment – explain your predictions.
Grade A/A*
Evaluate the model of the small intestine.
L&K Academy 4 Nutrition
SS6 L&K Academy 4 Nutrition
SS6
Fingers of flesh
The diagram shows a cut through one of your ________ .
Villi are found inside your small _______________.
They absorb nutrients more ________ than a flat surface
because they have a greater ______________
______________.
Villi also have very thin ___________ so that nutrients from
_________________ food can diffuse into
your______________ quickly. There are ____________ in the
centre of the villi. These collect nutrients and carry them
to _____________ all over your body.
Cells use glucose and fat for ___________ and
_____________ and ____________ for growth and repair.
Recap from last lesson – you were listing the features of the small intestine and how they aid the efficiency of nutrient absorption One cell thick wall
Good blood supply
Capillary network
Villi
Microvilli
Grade C
Use the model to explain the function of the small intestine.
Grade B
Predict the results of the experiment – explain your predictions.
Grade A/A*
Evaluate the model of the small intestine.
Enzymes are
crucial.
When you
eat glucose it
dissolves...
...and moves
from your intestines
to your blood quickly.
Grade C
Use the model to explain the function of the small intestine.
Explain
Grade B
Predict the results of the experiment – explain your predictions.
Grade A/A*
Evaluate the model of the small intestine.
120
glucose
Starch can’t
get out of your
intestines.
But when
it mixes with
carbohydrase,
glucose appears
in your blood.
Grade C
Use the model to explain the function of the small intestine.
Grade B
Predict the results of the experiment – explain your predictions.
glucose
Grade A/A*
Evaluate the model of the small intestine.
121
glucose
starch
glucose
glucose
Starch is a large insoluble
molecule.
It can’t pass
through the
wall of your intestine.
Glucose is a
small soluble molecule.
It can get
into your
blood.
glucose
molecules
Grade C
Use the model to explain the function of the small intestine.
part of
a starch
molecule
Grade B
Predict the results of the experiment – explain your predictions.
122
Grade A/A*
Evaluate the model of the small intestine.
Evaluating the model of the small intestine..
The strengths of the model are ……..
The weaknesses of the model are……
I could modify the model by ...
This would improve it by ... Grade C
Use the model to explain the function of the small intestine.
Grade B
Predict the results of the experiment – explain your predictions.
Grade A/A*
Evaluate the model of the small intestine.
Strengths of the model villi
Shows a thin covering / membrane.
Shows the amylase breaking down the starch.
Shows that the water represents the blood. Shows the glucose going through the tubing into the blood. However, weaknesses are …
•
•
•
•
Tubing not one cell thick
Doesn’t show microvilli
There are usually lots of them – only one.
Doesn’t show blood moving
Strengths and weaknesses
/ carbohydrase
Grade C
Use the model to explain the function of the small intestine.
Grade B
Predict the results of the experiment – explain your predictions.
Grade A/A*
Evaluate the model of the small intestine.
Strengths and weaknesses
/ carbohydrase
Grade C
Use the model to explain the function of the small intestine.
Grade B
Predict the results of the experiment – explain your predictions.
Grade A/A*
Evaluate the model of the small intestine.
How do you think we can get enzymes to work faster? What factors affect enzyme activity?
Grade C
Use the model to explain the function of the small intestine.
Grade B
Predict the results of the experiment – explain your predictions.
Grade A/A*
Evaluate the model of the small intestine.
How do you think we can get enzymes to work faster? What factors affect enzyme activity?
Temperature
pH
Substrate concentration (food concentration). Grade C
Use the model to explain the function of the small intestine.
Grade B
Predict the results of the experiment – explain your predictions.
Grade A/A*
Evaluate the model of the small intestine.
1a We say that digested food is absorbed. What does ‘absorbed’ mean?
1bWhere does absorption occur?
Grade C
Annotate a diagram to explain
the main features of the villi.
Grade B
Explain how each feature allows the villi to carry out its function.
Grade A/A*
Discuss the ways in which the
villi increases efficiency of food absorption by making reference to diffusion and concentration gradient.
Use coeliacs disease to help with your explanation (A*)
1a We say that digested food is absorbed. What does ‘absorbed’ mean?
A: It means the digested food passes through the intestine and capillary walls and enters the blood by diffusion from an area of high concentration (small intestine) to an area of low concentration (blood). 1b Where does absorption occur?
A: In the small intestine, in the villi (singular villus).
Grade C
Annotate a diagram to explain
the main features of the villi.
Grade B
Explain how each feature allows the villi to carry out its function.
Grade A/A*
Discuss the ways in which the
villi increases efficiency of food absorption by making reference to diffusion and concentration gradient.
Use coeliacs disease to help with your explanation (A*)
Task: Match the labels to the diagram.
Get them checked and stick them in. Discuss in your groups how each feature allows the villi to carry out its function.
Villi covered in microvilli
Large molecules are not absorbed into the blood
Villi
Small Intestine
Network of capillaries
Blood Supply
Grade C
Annotate a diagram to explain
the main features of the villi.
Villi covering –
one cell thick
Grade B
Explain how each feature allows the villi to carry out its function.
Grade A/A*
Discuss the ways in which the
villi increases efficiency of food absorption by making reference to diffusion and concentration gradient.
Use coeliacs disease to help with your explanation (A*)
Network of capillaries
2
1
Small Intestine
4
Large molecules are not absorbed into the blood
Villi
3
Villi covering –
one cell thick
2
1
Blood Supply
Grade C
Annotate a diagram to explain
the main features of the villi.
Grade B
Explain how each feature allows the villi to carry out its function.
5
Villi covered in microvilli
Grade A/A*
Discuss the ways in which the
villi increases efficiency of food absorption by making reference to diffusion and concentration gradient.
Use coeliacs disease to help with your explanation (A*)
The villi covering is one cell thick so that ……………………………
……………………………
………………
Network of capillaries
Large molecules are no absorbed into the blood
Blood Supply
Grade C
Annotate a diagram to explain
the main features of the villi.
Grade B
Explain how each feature allows the villi to carry out its function.
Villi covering –
one cell thick
Villi covered in microvilli
Grade A/A*
Discuss the ways in which the
villi increases efficiency of food absorption by making reference to diffusion and concentration gradient.
Use coeliacs disease to help with your explanation (A*)
The villi covering is one cell thick so that ... there is a short distance for nutrients to be absorbed into the blood. Network of capillaries
Large molecules are not absorbed into the blood
Blood Supply
Grade C
Annotate a diagram to explain
the main features of the villi.
Grade B
Explain how each feature allows the villi to carry out its function.
Villi covering –
one cell thick
Villi covered in microvilli
Grade A/A*
Discuss the ways in which the
villi increases efficiency of food absorption by making reference to diffusion and concentration gradient.
Use coeliacs disease to help with your explanation (A*)
The villi has a good network of blood capillaries so that ……………………………
……………………………
………………
Network of capillaries
Large molecules are no absorbed into the blood
Blood Supply
Grade C
Annotate a diagram to explain
the main features of the villi.
Grade B
Explain how each feature allows the villi to carry out its function.
Villi covering –
one cell thick
Villi covered in microvilli
Grade A/A*
Discuss the ways in which the
villi increases efficiency of food absorption by making reference to diffusion and concentration gradient.
Use coeliacs disease to help with your explanation (A*)
The villi has a good blood supply and network of blood capillaries so that...
Soluble food molecules move straight into the blood.
Network of capillaries
Large molecules are no absorbed into the blood
Blood Supply
Grade C
Annotate a diagram to explain
the main features of the villi.
Grade B
Explain how each feature allows the villi
to carry out its function.
Villi covering –
one cell thick
Villi covered in microvilli
Grade A/A*
Discuss the ways in which the villi increases efficiency of food absorption by making reference to diffusion and concentration gradient.
Use coeliacs disease to help with your explanation (A*)
The villi gives the small intestine ……………………………
……………………………
………………
Network of capillaries
Large molecules are not absorbed into the blood
Blood Supply
Grade C
Annotate a diagram to explain
the main features of the villi.
Grade B
Explain how each feature allows the villi to carry out its function.
Villi covering –
one cell thick
Villi covered in microvilli
Grade A/A*
Discuss the ways in which the
villi increases efficiency of food absorption by making reference to diffusion and concentration gradient.
Use coeliacs disease to help with your explanation (A*)
The villi and microvilli gives the small intestine a large surface area so absorption can take place quicker and more efficiently. Network of capillaries
Large molecules are not absorbed into the blood
Blood Supply
Grade C
Annotate a diagram to explain
the main features of the villi.
Grade B
Explain how each feature allows the villi to carry out its function.
Villi covering –
one cell thick
Villi covered in microvilli
Grade A/A*
Discuss the ways in which the
villi increases efficiency of food absorption by making reference to diffusion and concentration gradient.
Use coeliacs disease to help with your explanation (A*)
• Coeliac disease is a common digestive condition where a person has an adverse reaction to gluten. • Eating foods containing gluten can trigger a range of symptoms, such as:
• diarrhoea
• weight loss • feeling tired all the time
• What causes coeliac disease?
• Coeliac disease is what is known as an autoimmune condition. This is where the immune system mistakenly attacks healthy tissue.
• In cases of coeliac disease, the immune system mistakes substances found inside gluten as a threat to the body and attacks them.
• This damages the villi, meaning many are lost. Use this information to explain why coeliacs may suffer the symptoms above
Grade C
Annotate a diagram to explain
the main features of the villi.
Grade B
Explain how each feature allows the villi
to carry out its function.
Grade A/A*
Discuss the ways in which the villi increases efficiency of food absorption by making reference to diffusion and concentration gradient.
Use coeliacs disease to help with your explanation (A*)
People suffering from coeliac disease have a lot of unpleasant symptoms, including serious weight loss. This shows how important a large surface area for absorption of digested food is, since without it people suffer these problems. Grade C
Annotate a diagram to explain
the main features of the villi.
Grade B
Explain how each feature allows the villi
to carry out its function.
In the gut affected by coeliac
disease the villi are damaged and are no longer sticking out into the small intestine, so there is no longer a large surface area for absorption. They cannot absorb the products of digestion properly.
Grade A/A*
Discuss the ways in which the villi increases efficiency of food absorption by making reference to diffusion and concentration gradient.
Use coeliacs disease to help with your explanation (A*)
What are:
1. Probiotics
2. Prebiotics
3. Plant stanol esters
ALL: Explain the difference between a probiotic and a prebiotic (Grade C)
MOST: Analyse data to explain the effect of plant stanol esters (Grade B)
SOME: Evaluate the evidence for the benefits of functional foods (Grade A)
1. Probiotics – Foods containing live bacteria that produce lactic acid in the gut and may improve the health of your digestive system. 2. Prebiotics –Substances in food that cannot be digested by enzymes. Are food for probiotic bacteria in the intestine. Eg oligosaccharide.
3. Plant stanol esters – oily substances found in plants that appear to lower cholesterol. ALL: Explain the difference between a probiotic and a prebiotic (Grade C)
MOST: Analyse data to explain the effect of plant stanol esters (Grade B)
SOME: Evaluate the evidence for the benefits of functional foods (Grade A)
Match up – what does what
1. Mouth
A. Makes bile. 2. Oesophagus
B. Enzymes breakdown large food molecules into smaller food molecules which are absorbed into the blood. 3. Stomach
C. Contains amylase enzyme in the saliva which breaks up starch into simple sugars. 4. Small Intestine
D. Tube that uses muscular contractions called peristalsis to move food from the mouth to the stomach. 5. Large Intestine
E. Emulsifies fats to increase the surface area for lipase to work on. Also increases the pH of the food coming out of the stomach to make it more alkaline. 6. Rectum
F. Faeces egested (passed out) from here. 7. Anus
G. Churns up food. Contains hydrochloric acid and pepsin. 8. Pancreas
H. Absorbs water to produce firm faeces. 9. Liver
I. Stores the faeces.
10. Gall Bladder
J. Stores the bile. 11. Bile
K. Produces enzymes, releases them into the small intestine. 1 What is a functional food and suggest one reason why people might eat functional foods.
2 What is a probiotic and what do probiotic foods contain? What do the makers of these probiotic yoghurts claim?
3 What is a prebiotic and what do prebiotic foods contain and how do they work?
4 What are plant stanol esters? How are plant stanol esters
meant to work and how is this a benefit?
5 How would you evaluate the data given in Figure D on the impact of oligosaccharides on health? (Give a detailed discription of what you think it shows, does it prove anything?). 6 In fig C Is it worth taking the higher dose of plant stanols? Explain your answer. 7 A new functional food for toddlers is being advertised on TV, claiming to increase the numbers of ‘good bacteria’ in the gut. How would you evaluate these claims? ALL: Explain the difference between a probiotic and a prebiotic (Grade C)
MOST: Analyse data to explain the effect of plant stanol esters (Grade B)
SOME: Evaluate the evidence for the benefits of functional foods (Grade A)
Answers
• 1. A functional food is a food that claims to make you healthier.
• People may think they will help them digest food better/make their digestive system or immune system work better/to try to prevent possible health problems in the future. 2. Probiotic foods contain live bacteria such as Lactobacillus or bifidobacteria that produce lactic acid. This increases the bacteria number in your digestive system. The makers of the yoghurts claim to make you healthier by improving your digestive system, reduce disease, reduce allergies, 3. Prebiotics are substances that cannot be digested by human enzymes but which act as food for probiotic bacteria in the intestine. Oligosaccharides ( a form of prebiotic in tomatoes, bananas and onions) that cannot be digested by humans but provide nutrients for some kinds of bacteria.
They act as food for beneficial bacteria and so increase the number of beneficial bacteria in your digestive system. 4. How are plant stanol esters meant to work
and how is this a benefit?
Oily substances found in plants which are
meant to stop the small intestine absorbing
cholesterol – reducing the amount of
cholesterol which is linked to heart disease.
5. The results show that people given oligosaccharide in their
diet are much less likely to suffer from diarrhoea than people
who are given a placebo (something that looks like the
oligosaccharide but doesn't contain any). This suggests that
oligosaccharide can provide protection against diarrhoea.
A: However, the study only looked at 142 patients, which is a
small sample. And we don't know if those patients were
selected for a particular reason or are a random sample of
the population. So we cannot really extrapolate the results to
the wider population without further study.
© Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have
6d Is it worth taking the higher dose of plant
stanols? Explain your answer.
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A: The study shows that, in this group of people, blood cholesterol
is lowered. As high blood cholesterol is a risk factor for heart
disease, this suggests that including stanol esters in the diet
should help prevent heart disease. However taking the higher
dose of 2.6g a day didn’t have much of a different effect to 1.8g
a day.
Further studies for a longer period of time would be needed to
show that stanol esters did improve life expectancy by
preventing heart disease, and that it did so for all groups of
people not just those at higher risk generally.
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7 A new functional food for toddlers is being
advertised on TV, claiming to increase the
numbers of ‘good bacteria’ in the gut.
How would you evaluate these claims?
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A: You would need to see data from experiments
that clearly showed an increase in numbers of
beneficial bacteria in the guts of toddlers who ate
the food compared with those who didn't, and be
certain that the only difference in the test and
control groups was the functional food. The data
would need to come from a large study, so that
random differences between toddlers didn't mask
the overall effect.
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• Label the digestive system and explain what happens in each structure.
• Explain the functions of bile (HIGHER ONLY)
• Know what enzymes break up which nutrient and what the nutrient is broken into. • The adaptations of villi.
• Explaining the small intestine model and the strengths and weakness.
• Probiotics, prebiotics and plant stanol esters.