GCSE AQA Triple Biology Higher Tier
Paper 2
Homeostasis ANS:The regulation of the internal conditions of a cell or organism in response to internal
or external changes. E.g. the control of: blood glucose concentration, body temperature, water and ion
levels, etc.
Negative Feedback ANS:This is a type of control mechanism:
1) a receptor detects a change in a stimulus.
2) the coordination centre compares the stimulus to a set point.
3) an effector then produces a response to correct any difference from the set point.
The Thermoregulatory Centre ANS:This is in the brain and it monitors and controls body temperature,
blood temperature via impulses from temperature receptors.
Effects when Body Temperature is too High ANS:- Vasodilation.
- Swear more.
- Transfer of energy form the skin to the environment.
Effects when Body Temperature is too Low ANS:- Vasoconstriction
- Stop sweating
- Piloerection
- Shiver
The Nervous System ANS:This enables humans to react to their surroundings and coordinate their
behaviour. It stimulates a reflex arc.
Types of Neurones ANS:Sensory Neurone, Motor Neurone, Relay Neurone.
Reflex Arc ANS:1) the pain stimulus is detected by receptors.
2) impulses from the receptor pass along a sensory Neurone to the CNS.
3) an impulse then passed through a relay Neurone.
4) a motor neurone carries an impulse to the effector.
, 5) the effector (muscle or gland) responds
Synapse ANS:The connection between neurones. When an electrical impulse reaches this, a chemical is
released that diffused across the gap. This causes an electrical impulse to be generated in the second
one.
Human Reaction Time Required Practical ANS:1) the experimenter holds a meter rule from the end.
2) the subject had their finger and thumb a small distant apart either side of the ruler on the 50cm line.
3) the experimenter lets go of the ruler and the subject has to trap it.
4) the distance the ruler travels from the 50cm line is noted.
5) the experiment is repeated on the subjects that have just drunk coffee and the subjects that have not.
Parts of the brain ANS:- Medulla
- Cerebellum
- Cerebral Cortex
Medulla ANS:controls automatic actions such as heartbeat and breathing.
Cerebellum ANS:coordinates movement and balance
cerebral cortex ANS:responsible for consciousness, intelligence, memory and language.
Parts and Functions of the Eye ANS:- Retina - contains receptor cells that are sensitive to brightness and
colour of light.
- Optic Nerve - carries impulses from the retina to the brain.
- Sclera - forms a tough outer layer.
- Cornea - transport region.
- Iris - controls the size of the pupil and the amount of light reaching the retina.
- Ciliary Muscles & Suspensory Ligaments - change the shape of the lens to focus light onto the retina.
Accommodation ANS:The process of changing the shape of the lens to focus on near or distant objects.
Myopia ANS:Shortsightedness.
Hyperopia ANS:Long sightedness.
The Endocrine System ANS:This is made up of glands that secrete hormones directly into the
bloodstream.
Paper 2
Homeostasis ANS:The regulation of the internal conditions of a cell or organism in response to internal
or external changes. E.g. the control of: blood glucose concentration, body temperature, water and ion
levels, etc.
Negative Feedback ANS:This is a type of control mechanism:
1) a receptor detects a change in a stimulus.
2) the coordination centre compares the stimulus to a set point.
3) an effector then produces a response to correct any difference from the set point.
The Thermoregulatory Centre ANS:This is in the brain and it monitors and controls body temperature,
blood temperature via impulses from temperature receptors.
Effects when Body Temperature is too High ANS:- Vasodilation.
- Swear more.
- Transfer of energy form the skin to the environment.
Effects when Body Temperature is too Low ANS:- Vasoconstriction
- Stop sweating
- Piloerection
- Shiver
The Nervous System ANS:This enables humans to react to their surroundings and coordinate their
behaviour. It stimulates a reflex arc.
Types of Neurones ANS:Sensory Neurone, Motor Neurone, Relay Neurone.
Reflex Arc ANS:1) the pain stimulus is detected by receptors.
2) impulses from the receptor pass along a sensory Neurone to the CNS.
3) an impulse then passed through a relay Neurone.
4) a motor neurone carries an impulse to the effector.
, 5) the effector (muscle or gland) responds
Synapse ANS:The connection between neurones. When an electrical impulse reaches this, a chemical is
released that diffused across the gap. This causes an electrical impulse to be generated in the second
one.
Human Reaction Time Required Practical ANS:1) the experimenter holds a meter rule from the end.
2) the subject had their finger and thumb a small distant apart either side of the ruler on the 50cm line.
3) the experimenter lets go of the ruler and the subject has to trap it.
4) the distance the ruler travels from the 50cm line is noted.
5) the experiment is repeated on the subjects that have just drunk coffee and the subjects that have not.
Parts of the brain ANS:- Medulla
- Cerebellum
- Cerebral Cortex
Medulla ANS:controls automatic actions such as heartbeat and breathing.
Cerebellum ANS:coordinates movement and balance
cerebral cortex ANS:responsible for consciousness, intelligence, memory and language.
Parts and Functions of the Eye ANS:- Retina - contains receptor cells that are sensitive to brightness and
colour of light.
- Optic Nerve - carries impulses from the retina to the brain.
- Sclera - forms a tough outer layer.
- Cornea - transport region.
- Iris - controls the size of the pupil and the amount of light reaching the retina.
- Ciliary Muscles & Suspensory Ligaments - change the shape of the lens to focus light onto the retina.
Accommodation ANS:The process of changing the shape of the lens to focus on near or distant objects.
Myopia ANS:Shortsightedness.
Hyperopia ANS:Long sightedness.
The Endocrine System ANS:This is made up of glands that secrete hormones directly into the
bloodstream.
