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Body In Action
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Movement
The skeleton is required for:
 Muscle
attachment
 Support
 Protection
 Heart & Lungs
 Skull  Brain
 Vertebrae  Spinal Cord
 Ribs
 Bone
is made up of:
 Hard
minerals – Calcium phosphate
 Flexible
fibres – living bone cells
 Joints

can be:
Ball & Socket  Hip / shoulder
 Allows

movement in 3 planes
Hinge 
 Allows
Knee / Elbow
movement in 1 plane
Synovial Joints - Credit

Freely movable joints
Structure
Function
Ligament
Holds BONES together
Cartilage
Reduces friction & acts
as a shock absorber
Secretes synovial fluid
Synovial Membrane
Synovial Fluid
Lubricant which reduces
friction.
Muscles & Movement

Muscles bring about movement
in the body.

Muscles can only contract or
relax – they cannot make
themselves longer.
Muscles

Muscles are attached to bones by
inelastic tendons

They must be inelastic so that when a muscle
contracts they pull on the bone!!
Antagonistic Pairs - Credit

Muscles must work in pairs.

When one muscle contracts the other
relaxes allowing the joint to move.

To straighten the joint the opposite
muscles contract and relax.
The Need for Energy
Energy In Food

Energy in food is measured in
KILOJOULES.

The amount of energy required by a
person depends on
Size
 Sex
Age
Activity levels

 Weight
Loss
Weight Gain
Energy Imbalance
Comparing Inhaled & Exhaled Air

Inhaled Air



High Oxygen
Low Carbon Dioxide
Exhaled Air



Low Oxygen
High Carbon Dioxide
During Aerobic Respiration oxygen is used up
and carbon dioxide is produced.
The Respiratory System

The trachea ( windpipe) is supported by
rings of cartilage.
Mucus catches dirt & bacteria and is
carried to the top of the trachea by cilia.
 The mucus is then swallowed.

Breathing

Breathing is brought about by the muscles
of the ribs (intercostal muscles) and the
diaphram contracting & relaxing.
During inspiration the volume of the chest
cavity increases and air rushes in to fill the
space.
 During expiration the volume of the chest
decreases and air is pushed out.

Gas Exchange

Gas exchange takes place in the alveoli
(air sacs)

To allow effiecient gas exchange the
alveoli have a:
Large surface area
 Moist surface
 Good blood supply
 Thin lining

The Circulatory System
The heart is a muscular pump
 Pumps blood around the body
 Supplies all cells with

Food
 Oxygen


Removes wastes

Carbon dioxide
Structure of the heart
Valves prevent
the backflow
of blood
The muscle on the right
side is thinner. It only pumps
blood to the lungs
The muscle of the left
side is much thicker as
it must pump blood all
around the body.
The Circulatory System – Blood
Flow
Blood Vessels

Arteries



Veins




thick, muscular walls
carry high pressure blood away
from the heart
thin, stretchy, muscular walls
return low pressure blood to the
heart
Valves prevent backflow of blood
Capillaries



tiny blood vessels
connect arteries and veins
carry blood to the cells of the body
The Coronary Artery

Leads from the aorta - supplies blood to
heart muscle.

Blockage can result in a heart attack
The Blood

Blood is made up of:

Plasma – liquid which carries
cells and dissolved substances

Red blood cells – carry oxygen

White blood cells – fight
infection

Platelets – help clot blood
Gas Exchange

As blood flows through capillaries oxygen
diffuses from the blood into the cells.
Blood high in
oxygen

Blood high in carbon
dioxide.
Carbon dioxide from the cells diffuses into
the blood and is carried away.
Capillary Networks

To allow efficient gas exchange the
capillary network has:
A large surface area
 Very thin cell walls

Haemoglobin
Red blood cells contain haemoglobin.
 This combines with oxygen in the lungs to
form oxyhaemoglobin.


As the blood passes through cells which
have low oxygen levels the
oxyhaemoglobin releases the oxygen
which can then be used by the cells.
Coordination
The Eye
The structure of the eye:






Cornea - focusing of light.
Lens - fine focuses the light onto the retina
Iris - controls the size of the pupil, controling the
amount of light entering the eye.
Retina - layer of light sensitive cells where an
image is formed.
Optic nerve - carries the nerve impulses to the
brain.
Blind spot – where the optic nerve meets the
retina – no image is formed here.
Binocular Vision

Using two eyes allows us to judge
distance.

This is called binocular vision.
The Ear
Judging Direction

Using two ears allows us to judge the
direction of sound more effectively.
Balance

The position of the head can be judged by
the position of fluid in the semi – circular
canals.
The Nervous System

The human nervous system is made up of
The brain
 The spinal cord
 The nerves


The brain & spinal cord
make up the central
nervous system (CNS).
Functions of parts of the brain

Cerebrum – conscious
thought, memory, senses,
intelligence, imagination.

Cerebellum – balance &
coordination.

Medulla (brain stem) –
breathing & heart rate.
Nerves



Sensory Neurons carry information from sense
organs to the brain.
Information is decoded in the brain.
Motor Neurons carry information back to the
body.
Reflex Reactions

Very quick.

Protect the body from harm.

Do not involve conscious thought.
Sneezing
 Blinking
 Limb withdrawal (eg from heat)

The Reflex Arc
Relay nerves
in the spinal
cord send
information
from the
sensory
neurone
straight to the
motor neurone
Changing Levels of
Performance
Muscle Fatigue

Muscle fatigue occurs due to the build up
of lactic acid in muscles that are
exercising.

Lack of oxygen results in anaerobic
respiraton which causes lactic acid to
form.
Anaerobic Respiration

Only a little energy is released.
During rest oxygen is needed to remove
the lactic acid formed.
 This is known as the ‘oxygen debt’.

Exercise

Exercise causes the heart rate &
breathing rate to increase.


Allows more blood carrying sugar &
oxygen to be supplied to muscles.
The time taken for these to return
to normal following exercise is the
RECOVERY TIME.

Fitter people have a shorter recovery time
than unfit people.

They also have lower levels of lactic acid
production.

Recovery time can be improved by regular
exercise