Download S1 – Body Systems Summary Notes

S1 – Body Systems Summary Notes
The Respiratory System – The Lungs
LI
1 – We are learning about the role of the lungs
Breathing is the process by which oxygen passes from the lungs to the
blood stream and carbon dioxide passes from the blood stream to the
lungs.
They are therefore known as the organs of gas exchange.
When we breathe the following process takes place:
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Air enters through mouth or nose.
It passes down the WINDPIPE (trachea).
The windpipe splits into two BRONCHI.
The bronchi split, again and again, into BRONCHIOLES.
The bronchioles end in tiny AIR SACS, millions in each lung.
The exchange of oxygen and carbon dioxide between the air and
the blood takes place in the air sacs or alveoli.
The Respiratory System - Breathing
LI
2 – We are learning about the differences between inhaling
and exhaling.
Inhale
Exhale
Ribs move up and out
Ribs move in and down
Diaphragm moves down
Diaphragm moves up
Chest cavity gets bigger
Chest cavity gets smaller
Air goes in
Air goes out
The Respiratory System – Vital Capacity and Tidal Volume
LI
3 – We are learning about vital capacity and tidal volume.
The volume of air that you move in and out of your lungs while breathing
normally is called TIDAL VOLUME. This volume of air provides enough
oxygen for a person who is resting.
It is possible to inhale and exhale more forcefully - the maximum volume
of air moved in and out of the lungs is called the VITAL CAPACITY.
We can measure our vital capacity by taking a deep breath and
breathing into a balloon then measuring the diameter of the balloon.
The Respiratory System - Smoking
LI
4 – We are learning to describe some of the health risks
associated with smoking.
Cigarettes contain approximately 7000 chemicals, many of them toxic.
Some of them are shown below along with alternative uses of each
chemical.
There are many health risks associated with smoking:
Chronic lung disease is a dangerous long-term effect of smoking. Two
types of chronic lung disease are:
– Chronic Bronchitis: this is where chemicals from tobacco
build up in the lungs and make it difficult to breath.
– Emphysema: this is where chemicals from tobacco destroy
air sacs in the lungs and stop the lungs getting enough
oxygen.
Smoking affects more than just your health:
The Digestive System – Food
LI
5 – We are learning about the importance of a
balanced diet.
The three main food groups are carbohydrates, proteins and fats.
Vitamins and minerals are also required to keep the body healthy, but
are not strictly a food group. A balanced diet is needed to obtain all the
nutrients we require.
Food Type
Examples
Importance
Carbohydrates (sugars
and starches)
Pasta, bread,
potatoes
Energy
Protein
Meat, fish, eggs
Fats
Dairy products e.g.
milk and cheese
Growth and repair of
body tissues
Insulation i.e. to keep
heat in the body. Fats
do not produce heat
energy
All of the cells in our body need food so that they can do their jobs and
keep us functioning.
Our bloodstream acts as a transportation system to carry food around
the body to the places it is needed.
Food must be broken down before it can enter the bloodstream.
This process is called digestion.
There are two types of digestion
- mechanical (e.g. teeth)
- chemical (e.g. digestive juices)
The Digestive System – Food
LI
6 – We are learning about the importance of digestion.
Mechanical digestion occurs in the mouth where we chew our food in
order to break it down into smaller pieces. We have different types of
teeth for this purpose.
Molar
Canine
Incisors
 Molars are used for grinding and crushing food
 Canines are used for tearing food or killing prey
 Incisors are used for biting
Chemical Digestion
As we chew our food a chemical called saliva is produced in the mouth.
Saliva in our mouth mixes with food and helps break it down into
substances that can be used by our bodies.
Saliva also makes swallowing easier.
The Digestive System – The Alimentary Canal
LI
7 – We are learning to investigate the journey of food
through the digestive system.
The digestive system consists of: - the alimentary canal
associated organs
The alimentary canal is a long tube that carries food from the mouth all
the way to the anus.
The associated organs produce digestive juices that are added to the
food as it passes along the alimentary canal.
Food moves along the alimentary canal by the contraction of muscles
behind the food and the relaxation of muscles in front of the food.
The Digestive System - The Associated Organs
LI
8 – We are investigating the role of the organs of the
digestive system.
The Stomach
The stomach is a bit like a muscular bag that contracts and relaxes to
mix food with the gastric juices it produces.
This process is called churning.
The Liver
The liver produces bile.
The gall bladder
The gall bladder stores
the bile.
The Pancreas
The pancreas
produces enzymes.
The Small Intestine
Digested food passes through
the wall of the small intestine
into the bloodstream.
The small intestine is lined with many
finger-like projections.
This increases the surface area of small
intestine in contact with the digested food.
This means that digested food can be
quickly absorbed into the bloodstream
The Large Intestine
The large intestine
absorbs excess water
from digested food into
the bloodstream.
Once digestion is complete, the leftover materials pass through the large
intestine into the rectum as faeces. Faeces are temporarily stored in the
rectum before being expelled through the anus – at an appropriate time.
The Reproductive System – The Reproductive Organs
9 – We are learning about the organs of the reproductive
system.
LI
The male sex cells are called sperm. They are produced in the testes.
The testes are held by the scrotum. The sperm tube carries sperm from
the testes to the penis. The penis is the organ that carries sperm out of
the body.
Sperm
Tube
Testes
Scrotum
Penis
The female sex cells are called eggs. They are produced in the ovaries.
The oviduct carries the egg to the uterus (womb). The uterus is where a
fertilised egg develops and grows into a baby. The vagina is the part of
the female reproductive system that receives the sperm.
Oviduct
Ovary
Uterus
Cervix
Vagina
Male Reproductive System
Part
Testes
Scrotum
Sperm tube
Penis
Function
Produces sperm
Holds the testes
Carries sperm to the penis
Carries sperm out of the body
Female Reproductive System
Part
Uterus
Ovaries
Egg tube (oviduct)
Cervix
Vagina
Function
Where the baby grows
Produces eggs
Carries egg to the uterus
Opening to the vagina
Receives the sperm
The Reproductive System – The Sex Cells
LI
10 – We are learning about sex cells.
The male sex cell
The female sex cell
 The sperm have a tail to swim to
the egg
 Approximately 250 million sperm
are released from the penis
 Only one sperm can fuse with the
egg and fertilise it
The Reproductive System – Fertilisation
LI
11 – We are investigating the process of fertilisation
Fertilisation
The sperm from the testes are deposited into the vagina during sexual
intercourse. The sperm then swim up the cervix and uterus and along
the oviduct where it meets the egg.
Fertilisation takes place in the oviduct. Fertilisation is the fusing together
of the sperm nucleus and the egg nucleus.
The fertilised egg divides into a ball of cells as it passes along the
oviduct.
When the embryo passes into the uterus it becomes attached to the
uterus wall which has developed a spongy lining. It is attached by its
umbilical cord to the placenta.
The Reproductive System – Development of the Embryo
LI
12 – We are learning about the development of the embryo.
The developing embryo is connected to its mother by the umbilical cord.
The baby’s blood passes through the cord to the placenta. In the
placenta the mother’s blood and the baby’s blood come into close
contact but do not mix.
Food and oxygen pass from the mother’s blood into the baby’s blood
and waste products pass from the baby’s blood to the mother’s blood.
Usually harmful substances in the mother’s blood cannot reach the baby
but there are some exceptions:
German Measles is not really a serious illness in adults but it can have
serious consequences for a developing foetus. If the virus that causes
the illness passes through the placenta to the baby’s blood it can cause
babies to be born blind, deaf and with other mental and physical
problems.
Nicotine, alcohol and other drugs can also pass to the baby’s blood.