Download Body In Action Notes

Movement
State that the skeleton provides a framework for skeleton and muscle attachment
State that the skeleton protects the heart, lungs, brain and spinal cord
The spine protects the spinal cord.
The skull protects the brain.
The rib cage protects the lungs.
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Describe the range of movements allowed by a ball and socket joint and by a hinge joint
Where bones of the skeleton meet, joints are formed. Joints allow the skeleton to
bend and move in different ways.
There are 2 kinds of joint, ball and socket joints and hinge joints.
Ball and socket
Type of joint
Ball and socket
Hinge
Hinge joint
Examples
Hip, shoulder
Elbow, knee
Type of movement
move in all three dimensions
In one plane only
State the functions of ligaments and cartilage at a joint
At a joint, the bones are held
together by ligaments.
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Cartilage is found at the ends of the bones and
acts as a shock absorber and allows smooth
movement.
Describe the structure of a synovial joint and state the functions of its parts
Part of the joint
Function
Ligament
Holds bones together
Synovial membrane
Secretes synovial fluid
Synovial fluid
Lubricates the joint
Cartilage
Acts as a shock absorber
State that bone is formed by living cells
These cells are supplied with food and oxygen by blood vessels. That is why if you break
a bone it will bleed.
State that bone is composed of flexible fibres and hard minerals
Roasting removes the flexibility of bone. The acid removes the hardness from the bone
and it now bends easily.
State that muscles are attached to bones by tendons
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Explain why tendons are inelastic
Tendons are inelastic i.e. they do not stretch very much so that the movement of the
muscle will be passed on to the bone.
Describe how movement is brought about by muscle contraction
When a muscle contracts (gets shorter),
the tendons pull on the bones and the arm moves.
Explain the need for a pair of opposing muscles at a joint
Muscles can only contract and relax. Therefore most muscles work against each other
in pairs. If one muscle straightens the arm, the other muscle bends it.
The tricep contracts
The bicep relaxes
The arm straightens
The bicep contracts
The tricep relaxes
The arm bends
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The Need for Energy
State the effects of the imbalance between energy input and output
The amount of energy needed by a person will vary according to their age, gender, job
and lifestyle. We get our energy from our food.
If you take in more
energy in food than
you use, your
body will store fat.
If you take in less energy in
food than you require, your
body will lose fat.
State that oxygen is absorbed and carbon dioxide released in breathing
You need oxygen to release the energy from your food. In doing this a waste gas,
carbon dioxide, is produced. You obtain oxygen and get rid of carbon dioxide by
breathing. Your lungs are the organs that allow you to do this.
Describe the internal structures of the lungs
Air passes in to the body through the mouth and
nose. It then passes down the trachea. The
trachea branches into 2 bronchi which divide into
smaller tubes called bronchioles. Each bronchiole
ends in an air sac or alveoli.
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The lungs have a very large surface area. They feel spongy and will float in water
because they have air in them. They are pinky red in colour because they have a good
blood supply.
Describe the mechanism of breathing in humans
Movements of the chest wall help us to inhale (take in air) and exhale (give out air).
The diaphragm and the intercostal muscles between the ribs are used to help us
breathe.
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To breathe in:
o The muscles of the diaphragm contract causing the diaphragm to move
down
o The intercostal muscles between the ribs contract causing the ribs to
move up and out
o The volume of the chest increases and the pressure in the lungs decreases
o Air is drawn in.
To breathe out:
o The muscles of the diaphragm relax causing the diaphragm to move up
o The intercostal muscles between the ribs relax causing the ribs to move
down and in
o The volume of the chest decreases and the pressure in the lungs increases
o Air is forced out.
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Describe gas exchange between the air sacs and the surrounding blood vessels
The bronchi divide into smaller and smaller tubes called
bronchioles. Each bronchiole ends in an air sac which is
lined in moisture. Oxygen dissolves in this moisture and
diffuses from the lungs into the blood because there
is a higher concentration in the air sac than in the
blood. Carbon dioxide diffuses in the opposite
direction because there is a higher concentration in
the blood than in the air sac.
Describe the features which make lungs efficient gas exchange structures
1
The air sacs are thin to let gases through easily.
2
The air sacs have many blood capillaries in close contact with them.
3
Because there are so many air sacs, they make a large surface area.
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The air sacs are lined with mucus which is moist so that gases can dissolve.
Explain the function of cilia, cartilage and mucus in the trachea and bronchi
Mucus
secreting
cell
Air contains dust and germs which could damage your
lungs. The air you breathe is cleaned by cells lining the
air tubes.
These cells have small hairs or cilia which move in
waves up to the mouth. A slippery liquid called mucus is
made by the cells and this traps dirt. The mucus acts
like a conveyor belt which is moved by the beating
cilia. In this way dirt and germs are moved up to the
mouth where they are swallowed.
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Cartilage rings are found around the trachea
and bronchi to prevent them from closing.
Identify the four chambers of the heart
Oxygen and food are carried to all the body’s cells by the blood. Blood is pumped around
the body by the heart
The heart is made of muscle. There are four chambers in the heart.
Right atrium
Left atrium
Right ventricle
Left ventricle
Describe the path of blood flow through the heart and its associated blood vessels
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Deoxygenated blood i.e. low in
oxygen returns to the heart via the
vena cava after travelling to all
parts of the body. It enters the
heart at the right atrium. The right
atrium then pumps blood out
through the pulmonary artery to the
lungs. In the lungs the blood picks
up oxygen and loses carbon dioxide.
The oxygenated blood then returns
to the heart via the pulmonary
vein entering the left atrium. The
left ventricle pumps blood out
through the aorta to the body.
Describe the positions and functions of the heart valves
Heart valves stop blood flowing in the wrong
direction and allow blood to flow in one direction
only. Valves are found between the atria and the
ventricles and also as the blood leaves the
heart, in the aorta and the pulmonary artery.
Explain the difference in thickness of the walls of the ventricles
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The ventricles have thicker walls than the atria.
The left ventricle has a thicker wall than the
right ventricle because the left ventricle has to
pump blood right round the body and the right
ventricle only has to pump blood to the lungs.
State that the heart obtains its blood supply from coronary arteries
The coronary arteries supply food and oxygen to the
heart muscle. When these blood vessels get blocked,
you can suffer a heart attack.
State that blood leaves the heart in arteries, flows through capillaries and returns to
the heart in veins
Blood is carried away from the heart in arteries.
These arteries carry blood to the body’s organs and
tissues. In the organs the arteries split up into a
network of tiny tubes called capillaries. Substances
are exchanged between the capillaries and the
tissues. Blood leaves the tissues in vessels called
veins which carry the blood back to the heart.
Describe gas exchange between the body cells and the surrounding capillaries
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Carbon dioxide
oxygen
Oxygen diffuses from the
high concentration in the
capillary blood across into
the body cells. Carbon
dioxide diffuses from the
high concentration in the cells
into the plasma.
Describe the features of a capillary network which allow efficient gas exchange
The capillary network allows efficient exchange of gas, food and waste because
1
they are narrow and thin walled which gives a greater surface area to allow fast
diffusion of gases etc.
2
they are very long which also increases the surface area.
3
no cell is ever far away from a capillary thus ensuring easy exchange.
State that the pulse indicates that blood is flowing through an artery
The heartbeat can be felt as a pulse in arteries which lie just underneath the
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skin. Pulse can be detected at different parts of the body
Describe the function of red blood cells and plasma in the transport of respiratory
gases and food
Blood is made up of cells floating in a
liquid called plasma.
The plasma also carries dissolved
substances such as carbon dioxide,
digested food and waste products.
Red blood cells carry oxygen.
Explain the function of haemoglobin in the transport of oxygen
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A red pigment called haemoglobin is found in red blood cells. Its function is to combine
with oxygen to form oxyhaemoglobin.
At the lungs, haemoglobin combines with oxygen to make oxyhaemoglobin.
At the tissues, oxyhaemoglobin releases oxygen and becomes haemoglobin again.
at lungs
haemoglobin + oxygen
oxyhaemoglobin
at tissues
Co-ordination
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State that judgement of distance is more accurate using two eyes rather than one
As well as detecting pictures, your eye also allows you to judge distances. Having two
eyes rather than one makes judgement of distance more accurate.
Explain the relationship between judgement of distance and binocular vision
Your eyes are set in the front of your head. This gives you binocular vision which allows
you to see things in three dimensions.
Each eye sees the object slightly differently. The two messages are sent to the brain
which puts the two pictures together to form a 3-dimensional image.
Identify the cornea, iris, lens, retina, optic nerve and state their function
The eye is the sense organ that you use to detect light.
Part of the eye
Cornea
Lens
Iris
Retina
Optic nerve
Function
Tough, transparent to let light in and begins to bring it to a focus
Focuses light onto the retina
Coloured part, muscles control the size of the pupil thereby
controlling how much light enters the eye
Light is converted to nerve impulses
Carries nerve impulses from the retina to the brain
State that the judgement of direction of sound is more accurate using two ears rather
than one
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Your ears, as well as detecting sound, can also help you judge the direction from which
the sound is coming.
Two ears are better than one at detecting the direction of sound. The sound arrives
from each ear at slightly different times, thus giving an indication from where the
sound is coming.
Identify the ear drum, middle ear bones, cochlea, auditory nerve and semi-circular
canals and state their functions
The ear is the sense organ you use to detect sound.
Part of the ear
Function
Eardrum
Thin membrane set vibrating by sound
waves which it passes on to middle ear
bones
Middle ear
Amplify and transmit sound vibrations to
bones
the cochlea
Cochlea
Liquid filled tube. Converts sound
vibrations into nerve impulses
Auditory nerve Carries nerve impulses from the cochlea
to the brain
Semi circular
Contain liquid which moves in response to
canals
movements of the head
Explain how the arrangement of semi-circular canals is related to their function
Your semi-circular canals help you to balance.
The three semi-circular canals are three fluid-filled
tubes arranged at right angles to each other. This is
so that when the head moves, fluid in one or more of
the canals will move.
Since the canals are at right angles to each other the brain can tell us which way up we
are and use the information to control your balance.
State that the nervous system is composed of the brain, spinal cord and nerves
The nervous system is composed of the brain, the spinal cord and nerves.
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State that the nerves carry information from the senses to the central nervous system
and from the central nervous system to the muscles
The brain sorts out information.
The spinal cord sends information to and from the brain.
The brain and spinal cord make up the central nervous
system (CNS).
Describe how a reflex action works, using a simple model of a reflex arc
A reflex action is a rapid, automatic response to a stimulus. It is an involuntary action
which does not always involve the brain.
Reflex actions happen so quickly that there is often no time for the nerve impulses to
reach the brain. Often the impulse only goes to the spinal cord and the brain becomes
aware of the action only after it has happened.
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The reflex arc is an arrangement of nerve cells which make sure that you react quickly
to hazardous stimuli e.g. picking up something hot.
Sensory nerve cells send a message to the spinal cord. A relay nerve or interneurone
connects the sensory nerve to the motor nerve in the spinal cord. A signal to make a
muscle contract is then sent down a motor nerve.
State that the central nervous system sorts out information from the senses and sends
messages to those muscles which make the appropriate response
Nerves carry information from the senses to the CNS.
The CNS sorts out the information and sends information to muscles to make the
appropriate response.
Nerves carry information from the CNS to the muscles.
Information received from the sensory nerves is sorted out by the CNS.
Information from the CNS is then carried by the motor nerves to the appropriate
muscles which then contract.
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Identify the cerebrum, cerebellum and the medulla and state their functions in simple
terms
The brain is the control centre of the nervous
system.
The brain is made up of three main parts; the
cerebrum, the cerebellum and the medulla.
cerebrum
The cerebrum is responsible for memory, thought
and intelligence.
The cerebellum controls balance and muscular
co-ordination.
The medulla controls unconscious activities such as
breathing and heart rate.
Changing Levels of Performance
State that continuous or rapidly repeated contraction of muscle results in fatigue
If you exercise very hard or for a long time, eventually your muscles will ache. This is
called muscle fatigue. The muscles will stop working.
State that muscle fatigue results from a lack of oxygen and a build up of lactic acid
Muscle fatigue occurs when muscles do not receive enough oxygen and because a waste
product, lactic acid, has built up in the muscles.
Explain muscle fatigue in terms of anaerobic respiration
If not enough oxygen is available for your muscles to carry out aerobic respiration,
they are able to switch to anaerobic respiration to allow you to carry on using the
muscles for a while longer. Instead of producing carbon dioxide and water as in aerobic
respiration, your muscles produce lactic acid. This build up of lactic acid makes your
muscles fatigue.
With oxygen
glucose + oxygen  carbon dioxide + water
Without oxygen
glucose
 lactic acid
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Explain why pulse rate and breathing rate increase with exercise
After exercise the breathing rate has increased. This is so that more oxygen can be
absorbed into the lungs and blood stream.
After exercise the pulse rate has increased. This is so that more food and oxygen can
be carried to the muscles.
State that with exercise the pulse rate, breathing rate and lactic acid level rise less in
an athlete than in an untrained person
State that recovery time is the time taken to return to normal levels of pulse rate,
breathing rate and lactic acid
The graph shows the heart rate before, during and after a period of exercise.
State that training improves the efficiency of the lungs and circulation
Training allows a person to exercise more vigorously and for a much longer time before
muscle fatigue sets in.
Training improves your body’s efficiency in several ways:
Your heart is able to pump more blood every beat
The flow of blood through the muscles increases
Your lung volume is increased which means that each breath carries more oxygen
All of these provide food and oxygen to the muscles much quicker so your pulse
rate can stay lower
 Since more oxygen reaches the muscles, less lactic acid is made.
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Describe how recovery time can be used as an indication of physical fitness
In general, the longer your recovery time the less fit you may be.
A group of pupils measured their resting pulse rates. They then exercised for 3
minutes and measured their pulse rates 2 minutes, 10 minutes and 20 minutes after
exercise.
They recorded their results in the table below.
Condition
Resting
2 minutes after
exercise
10 minutes after
exercise
20 minutes after
exercise
Pulse Rate
(beats/min)
Jane
Brenda
82
65
120
130
Wilma
77
120
100
70
95
90
65
85
Brenda is the fittest as she took the shortest time to recover.
Explain the relationship between the effects of training and recovery time
If you are fit, you make less lactic acid so there is less to get rid of.
Efficient heart and lungs provide oxygen much more quickly.
All of this means that training reduces recovery time.
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