Download The body in action 1/ Movement 1-What are the 3 main roles of the

The body in action
1-What are the 3 main roles of
the skeleton?
2-Describe the range of
movements allowed by a ball and
socket joint and by a hinge joint.
3-State the functions of
ligaments (2) and cartilage at a
joint (2).
4 (C)-Describe the structure of
the synovial joint and state the
function of its parts
5-What is bone composed of?
(2)
6-(C) What is bone formed by
7-How are muscles attached to
bones?
8-Why are tendons inelastic?
9-Describe how movement is
brought about by muscle
contraction.
10-(C) Explain the need for a
pair of opposing muscles at a
joint.
1/ Movement
it provides - a framework for support against the
force of gravity and muscle attachment
- protection for the heart (ribcage), lungs
(ribcage), brain (skull) and spinal cord (vertebrae of
the backbone).
Ball and socket: e.g. hip and shoulder, movement in
all directions
Hinge: e.g. knee and elbow; movement in one plane
only
Ligaments: tough fibrous tissues: hold bones
together at a joint and prevent dislocation (ligaments
are very slightly elastic)
Cartilage: smooth, slippery and rubbery: reduce
friction at the end of bones and acts as a shock
absorber
1- Capsule: surrounds and protects the joint
2- Cartilage: cushions the joint
3- Synovial sac: secretes synovial fluid
4- Ligament: holds bones together
5- Synovial fluid: liquid that lubricates the joint
(reduce friction)
Bone is composed of flexible fibres (living cells) and
hard minerals (calcium phosphate).
Bone is formed by living cells.
Muscles are attached to bones by tendons. Tendons
are inelastic.
To allow fast and precise movement. Needed for the
transfer of muscle forces.
One end of a muscle is usually attached to a rigid part
of the skeleton whereas the other end is attached to
a bone which can be moved. When the muscle
contracts, it becomes shorter thereby pulling the
moveable bone it is attached to.
Muscle can contract but they cannot elongate of
their own accord. To be pulled back to their original
length, they need the contraction of a muscle in the
opposite direction (e.g. biceps: flexor muscle/
triceps: extendor muscle). A pair of opposite muscles
are also called an antagonistic pair.
Body in action
1-State the effects of an
imbalance between energy input
and energy output. (2)
2-State what sort of gas
exchange take place during
breathing
3- Describe the internal
structure of the lungs. (name
and role in breathing)
Larynx
2
3
1
3
4
2/ The need for energy
1- Energy input more than energy output: extra
energy stored as fat → gain weight
2- Energy input less than energy output: body gets
extra energy needed from stored body fat → loose
weight
Oxygen (needed to release the energy from food
during aerobic respiration) is absorbed and carbon
dioxide (waste product of aerobic respiration) is
released
1- Trachea: the air passes through the larynx and
through the trachea (1).
2- Bronchus (plu. bronchi): after the trachea, the air
flow is divided within the 2 bronchi which connect to
each lung.
3- Bronchioles: bronchi which have divided many
times and are smaller in size
4- Air sacs
5- Blood capillaries surrounding the air sac where gas
exchange takes place.
5
4-(C) Describe the mechanism
of breathing in humans
5- (C) Explain the function of
mucus, cilia and cartilage in the
trachea and bronchi
6- (C) Describe the features
which make the lungs efficient
gas structures (4)
Air is drawn in when the diaphragm muscles pull the
diaphragm downwards + the intercostals muscles
contract
which lifts the ribcage upwards
Air is squeezed out of the lungs when both
intercostals and diaphragm muscles relax
Mucus: lines the trachea and the bronchi; it is thick
and traps germs and dust in the passing air
Cilia in the trachea: push mucus upwards towards the
throat and the oesophagus. Once in the stomach,
germs are destroyed by stomach acids.
Cartilage in the trachea and bronchi: prevent the
collapsing (and closing…) of the airways during
breathing
- very large surface area: maximises gas exchange
- very thin gas exchange surface (air sacs): allow
quick passage of gases
- moist gas exchange surface: allows diffusion of
gases
- many capillaries: excellent blood supply to air sacs
7- (C) Describe gas exchange
between the air sacs and the
surrounding blood vessels
8- Identify the four chambers
of the heart
1
In the capillaries, the blood has low levels of oxygen
and high levels of carbon dioxide. In the air sacs,
fresh air has a higher concentration of oxygen and
lower concentration of carbon dioxide. As result,
diffusion takes place so that oxygen passes diffuses
from the air to the blood and carbon dioxide from
the blood to the air.
1- Right atrium (Plural atria)
2- Right ventricle
3- Left atrium (Plural atria)
4- Left ventricle
3
2
2
4
9- Describe the path of blood
flow through the heart and
blood vessels connected to it.
6
8
4
5
7
3
1
3
2
4
10- Describe the positions and
functions of the heart valves.
V2
2
Blood return from organs via the vena cava (5) and
enters the right atrium (1). When the right atrium is
full, the blood is squeezed into the right ventricle (2).
The muscular wall of the right ventricle contracts
and pushes the blood through to the pulmonary
artery (6) towards the lungs.
Blood return from the lungs via the pulmonary vein
(7) and enters the left atrium (3). When the left
atrium is full, the blood is squeezed into the left
ventricle (4). The muscular wall of the left ventricle
contracts and pushes the blood through to the aorta
(8).
When the atria are full, the blood is squeezed into
the ventricle and valves (V1) prevent its return to
the atria.
When the ventricles are full, the blood is squeezed
towards the arteries (pulmonary artery and aorta)
and valves (V) prevent its return to the ventricles.
V1
11- Explain the difference in
thickness of the walls of the
ventricles
The walls of the right ventricle are thinner than that
of the left ventricle. This is because the right
ventricles only pumps the blood to the lungs which are
close to the heart whereas the left ventricle needs
to pump blood at higher pressure so that it can reach
all places in the body.
12- State where the heart
obtain its supply of energy from
13- State the path of blood in
the circulatory system
14- State what the pulse
indicates
15- Describe the function of red
blood cells and plasma in the
transport of respiratory gases
and food
The coronary artery supplies the heart with blood.
Blood leaves the heart in arteries. Arteries further
divide and become capillaries which are the tiny blood
vessels found in organs and tissues. Finally, blood
returns to the heart through veins.
The pulse indicates that blood is flowing through an
artery. This is because every time the heart beats,
blood is pushed at high pressure through arteries
which causes the artery walls to bulge.
Blood= red blood cells + white blood cells + plasma
Red blood cells
- filled with haemoglobin (carry oxygen)
- No nucleus
Function:
- transport of oxygen from lungs to the tissues
Plasma
- yellowish coloured liquid
Function:
- transports cells
- carries food (e.g. glucose and amino acids)
- carries dissolved carbon dioxide
16- (C) Explain the function of
haemoglobin in the transport of
oxygen
17- Describe gas exchange
between the body cells and the
surrounding capillaries
18- (C) Describe the features of
a capillary network which allows
efficient gas exchange
To transport oxygen
In lungs:
Haemoglobin binds oxygen to become oxyhaemoglobin
In tissues:
Oxyhaemoglobin separates into haemoglobin and
oxygen
for cells to use.
The cells in tissues have low concentration of oxygen
and high concentration of carbon dioxide.
The blood entering capillaries has a high
concentration of oxygen and a low concentration of
carbon dioxide.
This creates a concentration gradient for both
oxygen and carbon dioxide so that oxygen diffuses
from the blood to the cells and carbon dioxide
diffuses from the cells to the
blood
Arteries dividing many times so that tiny capillaries
with thin walls (one cell thick) provide a large
surface area allowing gas exchange
Body in Action
1- Explain the benefit of having
two eyes rather than one
2- (C) Explain the relationship
between judgement of distance
and binocular vision
3- Parts of the eye and their
function
3
4
1
2
5
4- Explain the benefit of having
two ears rather than one
5- Identify the different parts
of the ear and state their
function
2
1
4
3
6- (C) Explain how the
arrangement of semi-circular
canals is related to their
function
7- State the name of the three
parts that make up the nervous
system
3/ Co-ordination
Using two eyes (binocular vision) makes the
judgement of distances more accurate than using one
eye only
A slightly different image is formed on the retina of
each eye. As a result, two different images are sent
to the brain which combines them into one. The brain
uses the difference between the two images to
estimate the distance of an object
1- Cornea: allows the light to enter and start to focus
2- Iris: control the amount of light entering the eye
3- Lens: focussed the light which has passed through
the hole in the middle of the iris (called the pupil)
4- Retina: light-sensitive layer of cells where an
image is formed
5- Optic nerve: carries nerve impulse from the retina
to the brain.
Using two ears makes the judgement of direction of
sound more accurate
1- Ear drum: thin membrane which is set to vibrates
when sound waves are funnelled in it by the outer
ear.
2- Middle ear bones (Hammer, Anvil and Stirrup):
transmit and amplify vibration from the ear drum to
the cochlea (inner ear).
3- Cochlea: filled with fluid and lined with sound
receptor cells with hair-like endings which convert
sound to nerve impulse.
4- Semi-circular canals filled with fluid which moves
with head movements. Receptors detect movement of
liquid. Essential for balance.
5- Auditory nerves: carries nerve impulse from the
cochlea
to the brain.
The 3 semi-circular canals are at right angle to each
other ensuring that head movements in all 3 planes
will be detected:
Nodding head: up and down
Shaking head: left to right, right to left
Bending head towards shoulder: side to side
The brain, the spinal cord and nerves
8- State where nerves carry
information to and from.
9- State in general terms the 2
main functions of the Central
Nervous System (CNS).
10- Give three examples of
reflex actions. Describe how a
reflex action works, using the
simple model of a reflex arc.
11- Identify the cerebrum,
cerebellum and medulla. State
their function.
Sensory nerves carry information from the senses to
the Central Nervous System (CNS= brain + spinal
cord).
Motor nerves carry information from the Central
Nervous System to the muscles.
The CNS (Brain + spinal cord) sorts out information
from the senses and sends messages to those muscles
which make the appropriate response.
Some information is analysed by the brain before
conscious action is taken (seeing a cake and decide to
grab it). Other information (e.g. touching something
very hot) require rapid action (reflex action see
below) to prevent body damage.
Reflex actions are fast, automatic and involuntary
actions. They either protect the body from damage
(e.g. removing hand from heat, sneeze) or help its
normal functioning (e.g. swallowing).
Receptors (1) are stimulated (e.g. pain) and send a
nerve impulse though the sensory neurone (2).
From the sensory neurone, the message has to pass
through a synapse (junction, 3) before it reaches the
intermediate neurone or relay neurone (4) in the
spinal cord.
From the intermediate/relay neurone, it crosses
another synapse (5) and travels down a motor neurone
(6) which stimulates a muscle to contract (7) (e.g.
jerking movement of the hand).
1- Cerebrum: the largest part, divided into two
halves.
Different regions are responsible for memory,
conscious thought, reasoning, intelligence, personality.
2- Cerebellum: controls balance and co-ordination.
3- Medulla: controls automatic functions of the body:
breathing, heart beat, etc…
Watch: the last part of the topic “Changing levels of performance”
is missing.