Summary AQA A level Psychology AO1 content for Biopsychology (A*)

Biopsychology Content

The Nervous System
- Allows you to respond to changes in your environment and coordinate your actions
- Receptors detect stimuli and e ectors bring about a response to a stimulus
- E ectors include muscle cells and cells found in glands
- Receptors communicate with e ectors via the nervous or endocrine system or both

CENTRAL NERVOUS SYSTEM:
❥ Made up of the brain and spinal cord
❥ Transfers messages to and from brain to PNS

PERIPHERAL NERVOUS SYSTEM:
❥ Made up of the neutrons that connect the CNS to the rest of the body
❥ Consists of the somatic nervous system (controls conscious activity) and the autonomic
nervous system (controls unconscious activity)
❥ The ANS has two di erent divisions: sympathetic nervous system (prepares body for
ght or ight) and parasympathetic nervous system (returns body to natural state)

NEURONS
- Transmit information as electrical impulses around the body
- Dendrites receive information from other neurons
- Info passes along axon in the form of electrical impulses to axon terminal
- Myelin sheath insulates the axon to speed up nervous transmission

SENSORY NEURONS:
❥ Carry nerve impulses to CNS

RELAY NEURONS:
❥ Transmits electrical impulses between sensory neurons and motor neurons

MOTOR NEURONS:
❥ Transmit electrical impulses from CNS to e ectors

NEUROTRANSMITTERS:
❥ Chemicals that are released from the axon terminal
❥ Can be excitatory or inhibitory which are summed and if net e ect on post synaptic
neurone is inhibitory then impulse less likely to re & vice versa
❥ Excitatory - post synaptic neurone more likely to re an impulse
❥ Inhibitory - post synaptic neurone less likely to re an impulse

SYNAPSE
- A junction between two neurons or between a neuron and an e ector cell




fi ff fl ff ffff ff fi fi ffff

, SYNAPTIC TRANSMISSION:
❥ Action potential travels down axon
❥ AP reaches synaptic terminal
❥ Vesicles bind w/ the membrane on presynaptic neuron which triggers the release of
neurotransmitters
❥ Neurotransmitters di use across synaptic cleft
❥ Neurotransmitter binds w/ receptors on post synaptic membrane on adjacent neuron
❥ The stimulation of the post synaptic receptors results in excitation or inhibition

NEUROTRANSMITTERS CAN ONLY TRAVEL IN ONE DIRECTION BECAUSE:
❥ Vesicles w neurotransmitter inside are only present on presynaptic membrane
❥ Receptors for neurotransmitter only present on postsynaptic membrane
❥ Binding of neurotransmitters to receptors triggers transmission of info from next neuron
❥ Di usion of neurotrasmitters means they can only go from high to low conc areas so
can only travel pre to postsynaptic neurons


Endocrine System
- Regulates hormone production from glands which are required for essential bodily
functions
- A gland is a group of cells that are specialised to secrete a useful substance such as a
hormone
- Hormones are ‘chemical messengers’
- Hormones di use directly into the blood, then they’re taken around the body and
trigger a response in the e ectors

HYPOTHALAMUS:
❥ Controls release of hormones from pituitary gland

PITUITARY GLAND:
❥ Controls release of hormones from other glands in body

PINEAL GLAND:
❥ Releases melatonin which regulates sleep-wake cycle

ADRENAL GLAND:
❥ Releases adrenaline & noradrenaline which are responsible for ght or ight response

THYROID GLAND:
❥ Releases thyroxine which increases metabolic rate

FIGHT OR FLIGHT RESPONSE:
❥ Hypothalamus triggers activity in the sympathetic branch of the ANS
❥ ANS stimulates adrenal medulla of adrenal gland
❥ Adrenaline and noradrenaline released into the bloodstream causing physical e ects on
the body:
- increased heart rate and blood pressure get blood quickly to areas of the body where it
is needed
- muscles become more tense so that the body is physically responsive
- Pupil size increases to allow for clearer vision




ff

ff ff ff fi fl ff