Download Body in Action

Body in Action
 revision
 Sub-topic (a) Movement
 State the functions of the skeleton.
 To protect vital organs. For example the
ribcage protects the heart and lungs.
 To provide support.
 To provide a framework for muscle
attachment.
 Describe the range of movement allowed by
the hinge and ball and socket joints.
 A hinge joint (knee) can only move in one
plane.
 A ball and socket joint (hip) can move in three
planes.
 State the functions of ligaments and cartilage.
 The ligament attaches bone to bone across a
joint.
 The cartilage acts as a shock absorber (soft
cushioning) at the end of a bone at a joint.
 Describe the composition of bone.
 Bone is composed of living cells which make
up flexible fibres and hard minerals such as
calcium phosphate.
 Describe how muscles are attached to bones.
 Muscles are attached to bone by inelastic
tissues called tendons.
 Describe how muscles bring about
movement.
 To bend an arm, for example, the bicep
would contract while at the same time the
tricep would relax bending the arm. To
straighten the arm the bicep would relax while
at the same time the tricep would contract.
Air sac
Blood capillaries
 Describe the features that make capillary
networks efficient at gas exchange.
 Capillaries are very narrow tubes which
branch repeatedly, forming such a dense
network that that every living body cell is
close to a capillary.
 The combined surface area of the capillary
network is enormous and the capillary walls
are only one cell thick.
 These properties of the capillary network will
allow efficient gas exchange to occur
between the bloodstream and the body cells.
 Describe the function of the components of
the blood.
 Plasma
 Contains dissolved substances (amino acids,
glucose etc.) and blood cells.
 Red Blood Cells
 Carry oxygen around the body.
 White Blood Cells
 Fight infection.
 Platelets
 Clot blood to stop bleeding at a wound.
 Describe the exchange of gases between
body cells and capillaries.
 As oxygenated blood flows through a
capillary close to a body cell, oxygen diffuses
out of the capillary into the surrounding cells.
 During respiration the cells produce carbon
dioxide. The carbon dioxide diffuses out of
the cells and into the capillary.
 Carbon dioxide is then transported to the
lungs in the blood.
 Sub-topic (c) Coordination
 State the benefit of having two eyes and two
ears.
 Two eyes allow accurate judgement of
distances.
 Two ears allow accurate judgement of the
direction of sound.
 Identify the parts of the eye and state their
function.
 Cornea
 Allows light to enter the eye.
 Iris
 Coloured part containing muscle. Controls
amount of light entering the eye.
Iris
Cornea
Optic nerve
Pupil
Lens
 Sub-topic (c) Coordination
 Describe how the structure of semi-circular
canals is related to their function.
 The three liquid filled canals are situated at
right angles to one another.
 Each contains an ampulla containing a
receptor which is stimulated by movements of
the liquid in the canal.
 These are caused by the canal being rotated
in its respective plane by movements of the
head.
 Messages are carried by a branch of the
auditory nerve to a region of the brain that
controls muscular activity for balance.
Nerves throughout the
body
Relay nerve
Sensory nerve
Motor nerve
Cerebrum
Cerebellum
Medulla
 Sub-topic (d) Changing levels of
performance
 Explain muscle fatigue in terms of anaerobic
respiration.
 Under normal circumstances the energy
needed for contraction of muscles comes
from aerobic respiration (glucose and
oxygen).
 During vigorous exercise the supply of
oxygen cannot meet the demand.
 Muscles will continue to use glucose
anaerobically producing lactic acid and a little
energy.
 Oxygen debt is required to remove the lactic
acid so that muscles can work properly.
 Explain the relationship between the effects
of training and recovery time.
 Recovery time is the time it takes for the heart
rate, breathing rate and the lactic acid levels
to return to normal resting values.
 A person who is in training will notice that the
factors above will return to normal resting
values quicker than a person who is not in
training.
 It can therefore be used as an indicator of
fitness.
 State the effects of training on the lungs and
circulation.
 Training involves vigorous exercise over a
period of several weeks.
 The lungs of an athlete are more efficient able
to take in larger volumes of oxygen in each
breath.
 During training the heart muscle tissue
gradually increases in strength and efficiency.
 As a result the same volume of blood can be
supplied to the muscles using fewer
heartbeats.
 Therefore the athlete’s circulation is more
efficient.