Biopsychology:
The nervous system:
Two main functions
To co-ordinate the different organs and cells in the body
To collect, process and respond to information in the environment
CNS – made up of the brain and spinal cord
brain – Centre of conscious awareness, has two hemispheres, cerebral cortex is important for
development
Spinal cord – responsible for reflex actions, passes messages from the brain to the pns
PNS – transmits messages to and from the nervous system
Autonomic – governs vital functions in the brain e.g. breathing, digestion
Somatic – governs muscle movement and receives information from sensory receptors
The endocrine system – works alongside the nervous system and controls vital functions in the
body through the actions of the hormones. It works more slowly than the nervous system, but
it has more powerful and widespread effects.
Glands are organs in the body that produce hormones. The ‘master gland’ is called the pituitary
gland located in the brain which controls the release of hormones and other endocrine glands
in the body.
Hormones are secreted in the bloodstream which affect cells that have receptors for that
hormone. For example, thyroxine produced by thyroid gland affects heart cells but also the rest
of the body which increases metabolic rate, affecting the growth rate.
Fight or flight response: endocrine and ANS work together
Stressor perceived by hypothalamus which activates the pituitary
The sympathetic nervous system is now aroused
Adrenaline is secreted from adrenal medulla into the bloodstream which delivers the aroused
state causing changes in target organs in the body – flight or fight
e.g. increased heart rate, breathing rate and dilated pupils
This is automatic and immediate – happens as soon as threat is perceived
, The parasympathetic nervous system takes over once the threat has passed and now the body
is at its resting state. This reduces the actions that was increased in the sympathetic branch –
rest and digest
e.g. reduced heart rate, breathing rate, constricts pupils
Types of neurons:
Sensory neurons carry messages from PNS to CNS. They have long dendrites and short axons.
Relay neurons connect sensory to motor neuron. They have short dendrites and short axons.
Motor neurons connect the CNS to effectors e.g. muscle and Glands. They have short dendrites
and long axons.
The structure of a neuron:
Cell body – nucleus which contains genetic material
Dendrites – carry nerve impulses from other neurons to the cell body
Axon – carries electrical impulses away from the cell body
It has myelin sheath that protects the axon
Gaps are called nodes that speed up the transmission of the impulse
Terminal buttons – communicate with the next neuron through the synapse
Electrical transmission:
Resting = negative
Activated = positive causing an action potential which creates an electrical impulse to travel
down
Synaptic transmission:
Presynaptic – neurotransmitters – vesicles – adrenaline (positive – exhibitory), serotonin
(negative – inhibitory), dopamine (can be both) - through the synapse – bind to receptor cites –
post synaptic – summation, action potential (exhibitory – fire, inhibitory – no fire)
Localisation of function: specific areas for specific functions
Holistic – all parts of the brain are involved through all actions
Lateralisation – some functions are controlled by a particular hemisphere, LH – analyser, RH –
synthesiser, right controls left vice versa
The nervous system:
Two main functions
To co-ordinate the different organs and cells in the body
To collect, process and respond to information in the environment
CNS – made up of the brain and spinal cord
brain – Centre of conscious awareness, has two hemispheres, cerebral cortex is important for
development
Spinal cord – responsible for reflex actions, passes messages from the brain to the pns
PNS – transmits messages to and from the nervous system
Autonomic – governs vital functions in the brain e.g. breathing, digestion
Somatic – governs muscle movement and receives information from sensory receptors
The endocrine system – works alongside the nervous system and controls vital functions in the
body through the actions of the hormones. It works more slowly than the nervous system, but
it has more powerful and widespread effects.
Glands are organs in the body that produce hormones. The ‘master gland’ is called the pituitary
gland located in the brain which controls the release of hormones and other endocrine glands
in the body.
Hormones are secreted in the bloodstream which affect cells that have receptors for that
hormone. For example, thyroxine produced by thyroid gland affects heart cells but also the rest
of the body which increases metabolic rate, affecting the growth rate.
Fight or flight response: endocrine and ANS work together
Stressor perceived by hypothalamus which activates the pituitary
The sympathetic nervous system is now aroused
Adrenaline is secreted from adrenal medulla into the bloodstream which delivers the aroused
state causing changes in target organs in the body – flight or fight
e.g. increased heart rate, breathing rate and dilated pupils
This is automatic and immediate – happens as soon as threat is perceived
, The parasympathetic nervous system takes over once the threat has passed and now the body
is at its resting state. This reduces the actions that was increased in the sympathetic branch –
rest and digest
e.g. reduced heart rate, breathing rate, constricts pupils
Types of neurons:
Sensory neurons carry messages from PNS to CNS. They have long dendrites and short axons.
Relay neurons connect sensory to motor neuron. They have short dendrites and short axons.
Motor neurons connect the CNS to effectors e.g. muscle and Glands. They have short dendrites
and long axons.
The structure of a neuron:
Cell body – nucleus which contains genetic material
Dendrites – carry nerve impulses from other neurons to the cell body
Axon – carries electrical impulses away from the cell body
It has myelin sheath that protects the axon
Gaps are called nodes that speed up the transmission of the impulse
Terminal buttons – communicate with the next neuron through the synapse
Electrical transmission:
Resting = negative
Activated = positive causing an action potential which creates an electrical impulse to travel
down
Synaptic transmission:
Presynaptic – neurotransmitters – vesicles – adrenaline (positive – exhibitory), serotonin
(negative – inhibitory), dopamine (can be both) - through the synapse – bind to receptor cites –
post synaptic – summation, action potential (exhibitory – fire, inhibitory – no fire)
Localisation of function: specific areas for specific functions
Holistic – all parts of the brain are involved through all actions
Lateralisation – some functions are controlled by a particular hemisphere, LH – analyser, RH –
synthesiser, right controls left vice versa
