Download Body in Action summary notes

Standard Grade Biology
Body in Action Summary Notes
SKULL
a) Movement
Skeleton Functions
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Support
Muscle attachment
Protection
o Skull protects the brain
o Ribcage protects the heart and lungs
o Spine protects the spinal cord
Bone Composition
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Hard minerals
o Removed when bone is placed in acid
Flexible fibres
o Removed when bone is roasted
Living bone cells
o Makes new bone cells
Joints
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Types of joints
o Hinge joint: moves in one direction (plane)
o Ball and socket joint: moves in three planes
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Parts of a joint
o Ligaments attach bone to bone and hold the joint together
o Cartilage is at the ends of bones to protect the bones and reduce friction
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Synovial joints
o Synovial membrane produces synovial fluid
o Synovial fluid lubricates joint and reduces friction
o Surrounded by a capsule which protects the joint
o Examples are knee, hip, shoulder, elbow and finger
RIB CAGE
SPINE
Cartilage
Synovial
fluid
BSynovial
A
Cartilage
fluid
Synovial
membrane
Ligament
Synovial
membrane
Ligament
Hinge joint
Part
Cartilage
Synovial fluid
Synovial membrane
Ligament
Ball and Socket
Function
Protects end of bone, cushions joint, reduces friction
Lubricates joint, reduces friction
Produces (secrets) synovial fluid
Holds joint together
Muscles
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Tendons
o Attach muscles to bone
o Inelastic (do not stretch)
 Passes all force from muscle to bone to make joint move
Muscles
o Muscles contract to move a joint
o Always found in pairs
 Muscles only work in one direction by pulling
 Need two muscles for full movement at a joint
 One muscle bends, one will straighten
Muscle
A
B
P
Q
R
S
Movement
Pulls arm up (bend)
Pulls arm down (straight)
Pulls leg straight
Pulls leg back (bend)
Pulls toes down (points toes)
Pulls toes up (flex feet)
b) Need for Energy
Energy
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Energy is needed for all life processes (heat, movement, chemical reactions etc)
Energy input= total energy of all food eaten in a certain time
Energy output= total energy used by body in a certain time
If energy input is greater than energy output, body will gain weight
If energy input is less than energy output, body will lose weight
Breathing and lung structure
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Oxygen is inhaled and absorbed into the blood
Carbon dioxide is released from the blood and exhaled
Larynx (voice box)
Trachea
Bronchus
Intercostal muscles
Rib
Bronchiole
Diaphragm
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Trachea and Bronchi
o Rings of cartilage keep air passages open, prevent collapse
o Produces mucus to trap dust and microbes
o Cilia sweeps mucus out of lungs
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Breathing in
Moves up and out
Contract (shorten)
Flattens (contract)
Increases
Decreases
Ribcage
Intercostals muscles
Diaphragm
Volume
Pressure
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Breathing out
Moves down and in
Relax (lengthen)
Moves up (relaxes)
Decreases
Increases
Gas exchange
o Alveoli (air sacs)
o Oxygen moves from HC in alveoli to LC in blood
capillary
o Carbon dioxide moves from HC in blood to LC
in alveoli
o Large surface area to allow maximum gas
exchange
o Good blood supply to air sacs to absorb
maximum volume of oxygen
o Moist surfaces for gases to dissolve into and
diffusion to occur
o Very thin walls allows gases to diffuse quickly
Heart
Pulmonary artery takes blood to lungs
Aorta takes blood to body
Vena cava brings blood from body
Pulmonary vein brings
blood from lungs
RA
LA
Valve
LHS of heart is
oxygenated blood
RV
RHS of heart is
deoxygenated blood
LV
LV wall is thicker so it can force blood
over a greater distance around the
body
Coronary arteries
supply blood to the
heart
Valves
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Valves
o Between the atrium and ventricles
o Between ventricle and artery leaving heart
Valves prevent the back flow of blood in the heart
o Keeps blood moving in one direction around body and lungs
Blood Vessels
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Blood is taken away from the heart in arteries
o Thick, muscular vessels which have a pulse from the heart beating
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Capillaries
o Where exchange of substances takes place
Have very thin walls
to allow exchange of
substances
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Blood returns to heart in veins
o Veins have valves to help return blood to heart and to stop the blood flowing
backwards
Blood
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Red blood cells transport oxygen
o Contain haemoglobin which binds to oxygen to form oxy-haemoglobin
Plasma carries:
o Dissolved food to respiring cells
o Dissolved gases to and from the lungs
o Cells (red and white blood cells)
Capillary network
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Place where exchange of substances between body cells and capillaries occurs
Oxygen and glucose move into body cells by diffusion
Carbon dioxide moves into blood by diffusion
Capillaries have very thin walls to allow easy exchange of substances
Capillary networks are dense (lots of) to increase exchange of substances
Capillary networks near to body cells allow quick diffusion
c) Co-ordination
Eye
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Judgement of distance is more accurate using two eyes
Binocular vision (2 eyes)
o Gives better depth of vision
Cornea
Retina
Lens
Optic Nerve
Iris
Part
Cornea
Function
Allows light to enter eye. Protects eye
Iris
Controls size of pupil. Controls light entering eye
Lens
Changes shape to focus light onto retina
Retina
Changes light energy into electrical impulse
Optic nerve
Carries electrical impulse from retina to brain
Ear
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Judgement of direction of sound is more accurate with two ears rather than one
Semi-circular canals
Auditory nerve
Ear drum
Cochlea
Middle ear bones
Part
Ear drum
Function
Passes sound vibrations onto middle ear bones
Middle ear
bones
Cochlea
Amplify and pass vibrations from sound onto cochlea
Converts sound vibrations into electrical impulses
Auditory nerve Carries electrical impulses to the brain
Semi-circular
canals
Involved in control of balance. Arranged at right angles to
detect movement in three planes.
Central Nervous System
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Made of
o Brain and spinal cord
Functions
o Sorting out information from the senses
o Sending messages to muscles which can make the appropriate response
Nerves
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Sensory neurone
o Carry impulses from the senses to the nervous system
Motor neurone
o Carry impulses from the senses to the muscles
Reflex Arc
o Receptor detects stimulus in sense organ
o Impulse passed along sensory nerve to spinal cord
o Impulses passes along relay nerve in spinal cord
o Impulse passes to motor nerve which causes muscle to contract
Brain
Cerebrum
Cerebellum
Medulla
Part
Cerebrum
Cerebellum
Medulla
Function
Control conscious thought
Control muscle coordination and balance
Controls breathing and heart rate
d) Changing levels of performance
Muscle Fatigue
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As muscle work load increases (continuous or repeated use), muscles switch to anaerobic
respiration
Causes muscle causes fatigue
Caused from a build up of lactic acid from lack of oxygen present
Good blood supply can increase oxygen supply to reduce lactic acid production
Oxygen debt
 Oxygen is required to remove lactic acid from muscles
 The body builds up an oxygen debt which is repaid during a rest period
Exercise and Training
 Breathing rate and heart rate increase during exercise
o To increase aerobic respiration
o More oxygen is supplied to muscle cells quickly
o Carbon dioxide is removed from muscle cells faster
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During exercise, pulse rate, breathing rate and lactic acid levels rise less in athletes than an
untrained person
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Recovery time
o The time taken to return to normal levels of pulse rate, breathing rate and lactic acid.
o The quicker the recovery time, the fitter the person
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Training
o Improves the efficiency of the heart, lungs and muscles
o Decreases recovery time
Trained Athlete
Lower resting heart rate
Lower heart rate during exercise
Quicker recovery time
Lower breathing rate
Lower level of lactic acid in muscles
Untrained person
High resting heart rate
Higher heart rate during exercise
Slower recovery time
Higher breathing rate
Higher level of lactic acid in muscles