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B2 Topic 3
-The structure of the Heart
-Blood
-The Circulatory System
- Aerobic and Anaerobic Respiration
In past foundation papers from 2011 to
2015, 24 questions have been about this
topic = Really important that you know
it!!!!
Starter: Stick in the heart diagram
Structure of the
Heart
Questions in the past have asked:
-Label the structure in the heart
-Describe how blood travels through the heart
- Where the blood flows into and out of the heart
Structure of the
Heart
Right= Blood without
oxygen
(deoxygenated)
Left= Blood with oxygen
(oxygenated)
Where does blood enter the heart?
NEED TO KNOW: Both are Veins
How does blood flow through the heart?
1
1
Step 1: Enters the atrium
How does blood flow through the heart?
2
2
Step 2: Pumped into ventricles
How does blood flow through the heart?
3 3
Step 3: Pumped out of ventricles
Which blood vessels transport blood away
from the heart?
To lungs
To rest of body
Both are arteries
What stops blood flowing backwards in the
heart?
Valves stop blood flowing backwards
Why is the heart called a double pump?
Heart pumps blood to two places;
left side pumps blood to the rest of the body
and right side pumps blood to the lungs
Why do the ventricle walls have different
thicknesses?
Left ventricle has a thicker wall
= Stronger so can pump blood further round the
body
Now try this
(i) Name the parts of the heart labelled A, B and C. (3)
(ii) Describe the direction of the flow of blood through the left
side of the heart. (2)
6 mark question- Model answer
Explain how the structures of the heart are related to their
function. (6)
Valves - prevent backflow of blood.
Right side- pumps blood to the lungs
Left side- pumps to the rest of the body
Two sides- stops blood mixing
Thicker left ventricle wall- pump blood around the
body.
1-2 marks= One structure of heart linked to its function.
3-4 marks= Two structure linked to their function.
5-6 marks= Three structures linked to their function.
Why do we have a heart?
To transport gases, glucose, nutrients and water
around the body. These are carried by the blood.
Key words:
Components- What something is made up of, i.e. the
components of blood
What are the components of blood?
What do they do?
Carry
Oxygen
Clot the
blood
Liquid to carry the
substances
Answer is always:
DESTROY
PATHOGENS
Red blood cells carry oxygen in the blood.
Explain how one feature of a red blood cell helps it to carry
oxygen around the body.
(3)
An explanation including three the following points
• small cells (1)
• to squeeze through capillaries (1)
• to reach all cells (1)
OR
• no nucleus (1)
• so more haemoglobin (1)
• to carry more oxygen (1)
OR
• biconcave shape (1)
• so large surface area (1)
• for faster movement of oxygen into / out of cell (1)
Why does the blood transport
substances around the body?
• Respiration
• Blood transports oxygen and glucose to
cells so they can make energy in
respiration.
• Blood transports carbon dioxide and
waste away from cells.
At the cells
Aerobic Respiration = Lots of oxygen available
Come from blood
Anaerobic Respiration = No oxygen
Exam questions on this topic often involve graphs.
What does it mean?
More exercise
More oxygen
needed by the
cells for
respiration
Heart rate and
breathing rate
will increase
Now try these
Explain why the breathing rate of a person changes during
exercise. (2)
Now you try
Explain why the breathing rate of a person changes during
exercise. (2)
Another example
Some athletes train at high altitudes (over 2000 m above sea level).
There is less oxygen in the air at high altitudes.
The graph shows the number of red blood cells in the blood of an athlete
training at high altitudes, over a ten-week period.
graph
(i) Describe the change in the number of red blood cells during this ten-week
training period.
(2)
(ii) Suggest the minimum training period this athlete needs to produce the highest
number of red blood cells. (1)
(iii) State the function of red blood cells. (1)
(b) When athletes train, the size of their hearts can increase.
Suggest how an increase in the size of the heart is an advantage to an athlete. (2)