Body in Action

General Objectives

Sub-topic (a) MovementState 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.

Sub-topic (b) The need for energyState the effects of an inbalance between

energy in and energy out.Physical life style: need to put enough kJ of

energy into the body to provide enough energy for this life style. If too little energy was put in the individual would begin to lose weight and feel lethargic and weak.

Light work/ office work: again the individual would have to consume enough energy to live this life style. In this situation and individual could over eat resulting in weight gain and health problems.

Describe the movement of gases during breathing.

Breathing in: oxygen enters the mouth/nose, trachea, bronchus, bronchioles and the air sacs. The oxygen then passes across into the blood by diffusion. The blood carries oxygen to the cells to carry out respiration. Oxygen passes into the cells by diffusion.

Breathing out: cells produce carbon dioxide during respiration. From here carbon dioxide takes the same route in reverse.

There is a higher concentration of oxygen in inhaled air compared to exhaled air.

Describe the internal structures of the lungs.The lungs are a mammal’s organs of gaseous

exchange. Air entering by the nose or mouth passes via the larynx, trachea, bronchus and bronchioles which end in tiny air sacs called alveoli.

Name and label on a diagram the four chambers of the heart.

Be able to label the left atrium and the right atrium.

Be able to label the left ventricle and the right ventricle.

Describe the path taken by blood as it travels through the heart and the body.

Deoxygenated blood enters the right atrium through a vein.

It the enters the right ventricle and leaves the heart through the pulmonary artery.

Blood travels to the lungs and picks up oxygen.

Oxygenated blood then enters the left atrium of the heart through the pulmonary vein.

It then enters the left ventricle and leaves the heart through the aorta.

Blood travels around the rest of the body.

Describe the position and function of the heart valves.

Valves are situated between the atria and ventricles and between the ventricles and the arteries leaving the heart. Their function is to ensure blood flows in the correct direction.

Explain why the thickness of the ventricle walls is different.

The thickness of the right wall is significantly thinner than the left wall as it has only has to pump blood to the lungs. The right wall has to pump blood around the rest of the body so will require increased muscle power.

State the source of the heart’s own blood supply.

The first branch of the aorta is called the coronary artery. This artery supplies the heart with oxygenated blood. If this vessel becomes blocked, blood flow to the heart wall is prevented and the person suffers a heart attack.

State what is indicated by the pulse.Each time the heart beats, blood is forced

along an artery at high pressure and this can be felt as a pulse beat.

Describe the function of the components of the blood.

PlasmaContains dissolved substances (amino acids,

glucose etc.) and blood cells.Red Blood CellsCarry oxygen around the body.White Blood CellsFight infection.PlateletsClot 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) CoordinationState 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.CorneaAllows light to enter the eye. IrisColoured part containing muscle. Controls

amount of light entering the eye.

PupilActivity of iris controls the diameter of the

pupil. Prevents damage to the retina.LensFocuses light on to retina.RetinaConverts light to nerve impulses.Optic nerveCarries nerve impulses from retina to brain.

Lens

Optic nerve

Pupil

Cornea

Iris

Identify the parts of the ear and state their function.

Auditory canalDirects sound waves to the ear drum.Ear drumSet vibrating by sound waves which it passes

on to the middle ear bones.Middle ear bonesAmplify and transmit sound vibrations from

ear drum to cochlea.

CochleaContains liquid and sound receptor cells with

hair like endings. Stimulated hairs convert sound vibrations in the liquid to nerve impulses.

Auditory nerveCarries nerve impulses from cochlea to the

brain.Semi-circular canalsThree tubes containing liquid that move in

response to movements of the head. Messages sent to part of the brain which controls muscular activity for balance.

Name the main components of the nervous system.Brain,spinal cord and nerves.State the functions of the nerves.The CNS is connected to all parts of the body by

the nerves which lead to and from all organs and systems. They carry information ensuring all parts work together as a coordinated whole.

Sensory nerve: carries nerve impulses from the sense organs to the CNS.

Relay nerve: transmits a nerve impulse from sensory to motor neurone.

Motor nerve: carries nerve impulses from the CNS to muscles and glands.

Nerves throughout the body

Sub-topic (d) Changing levels of performance

State how muscle fatigue can be produced and what causes it.

During continuous exercise the person will eventually have to stop due to muscle fatigue. Causing discomfort and pain.

This results from a lack of oxygen to the muscle cells and the build up of a chemical called lactic acid.

Explain why heart and breathing rate increase with exercise.

Working muscles demand more energy and therefore more oxygen.

The breathing rate increases to get more oxygen into the bloodstream.

Pulse rate increases to deliver blood to the muscles.

Describe the effects of training on the changes produced by exercise.

Training reduces the rise in pulse rate, breathing rate and lactic acid production during exercise.