Biopsychology
The nervous system, the brain, the endocrine system, neurons & synaptic
transmission,
The divisions of the nervous system:
The CNS- brain & spinal chord (control behaviour & regular physiological
processes)
The PNS:
Somatic NS- transmits/receives messages from senses (eg- visual) &
directs muscles to react/move.
Autonomic NS- controls non-skeletal muscles (eg- heart). Automatic
reactions, deal with vital organs (eg- breathing & digestion).
2 parts of the ANS:
Sympathetic NS- activated for energy (eg- fight or flight). Causes- inc
heart rate, breathing rate, muscle tension, blood pressure & diverts blood
to muscles.
Parasympathetic NS- to conserve energy & store resources (rest & digest)
The endocrine system:
Network of glands that create & secrete hormones (chemical messengers that
regulate activity in cells)
The pituitary gland (the master gland):
Hypothalamus receives info from body and controls release of hormones from
pituitary gland. (Either directly cause changes in physiological processes or
stimulate other glands to produce other hormones).
Anterior pituitary gland- releases ACTH in response to stress (stimulates
adrenal glands to produce cortisol)
Posterior pituitary gland- releases oxytocin (stimulates bonding between
mother & infant)
The adrenal glands:
Adrenal cortex (outer layer- necessary for life)- cortisol (cardiovascular & anti-
inflammatory functions, also inc in response to stress)high cortisol= poor
immune function & inability to deal with stress)
, Adrenal medulla (inner layer- not necessary for life)- adrenaline &
noradrenaline (prepare body for fight or flight- inc heart rate, breathing rate,
etc)
Neurons & Synaptic transmission:
Sensory neuron- carry nerve impulses from sensory receptors to spinal
cord & brain. Convert info from receptors to neural impulses. In brain, they’re
translated into sensations. Some info only reaches spinal cord for quick reflex
reactions.
Relay neuron (interneurons) – allow sensory & motor neurons to
communicate. Found in brain & spinal cord.
Motor neuron- Send messages from brain to muscles. Form synapses
(junctions) on the muscle to control contraction. When stimulated, motor neurons
release neurotransmitters which bind to receptors on the muscle (triggering a
response).
Synaptic transmission:
Signals within neurons transmitted electrically, signals between neurons
transmitted chemically.
1. When the action potential reaches end of neuron (axon terminal) it
triggers neurotransmitters to release from vesicles.
2. Neurotransmitters diffuse across the synapse & bind to receptors on post-
synaptic neuron (dendrites of next neuron)
3. This triggers the next action potential (electrical impulse). The likelihood of
cell firing determined by excitatory/inhibitory neurotransmitter input. Eg-
high levels of dopamine (excitatory) triggers nerve impuses (action
potentials).
4. Enzymes released to break down neurotransmitters. There then taken in
by presynaptic neuron’s reuptake pumps.
5. Vesicles replenished with new & reused neurotransmitters.
Types of neurotransmitter:
Excitatory- trigger nerve impulses in the receiving neuron & stimulate brain into
action. Inc positive charge of post synaptic neuron. Make it more likely to fire.
(eg- dopamine, adrenaline)
Inhibitory- inhibit nerve impulses to calm brain/balance mood. Neuron becomes
negatively charged & less likely to fire. (eg- serotonin)
Likelihood of cell firing = synaptic imput (excitatory + inhibitoty)
The nervous system, the brain, the endocrine system, neurons & synaptic
transmission,
The divisions of the nervous system:
The CNS- brain & spinal chord (control behaviour & regular physiological
processes)
The PNS:
Somatic NS- transmits/receives messages from senses (eg- visual) &
directs muscles to react/move.
Autonomic NS- controls non-skeletal muscles (eg- heart). Automatic
reactions, deal with vital organs (eg- breathing & digestion).
2 parts of the ANS:
Sympathetic NS- activated for energy (eg- fight or flight). Causes- inc
heart rate, breathing rate, muscle tension, blood pressure & diverts blood
to muscles.
Parasympathetic NS- to conserve energy & store resources (rest & digest)
The endocrine system:
Network of glands that create & secrete hormones (chemical messengers that
regulate activity in cells)
The pituitary gland (the master gland):
Hypothalamus receives info from body and controls release of hormones from
pituitary gland. (Either directly cause changes in physiological processes or
stimulate other glands to produce other hormones).
Anterior pituitary gland- releases ACTH in response to stress (stimulates
adrenal glands to produce cortisol)
Posterior pituitary gland- releases oxytocin (stimulates bonding between
mother & infant)
The adrenal glands:
Adrenal cortex (outer layer- necessary for life)- cortisol (cardiovascular & anti-
inflammatory functions, also inc in response to stress)high cortisol= poor
immune function & inability to deal with stress)
, Adrenal medulla (inner layer- not necessary for life)- adrenaline &
noradrenaline (prepare body for fight or flight- inc heart rate, breathing rate,
etc)
Neurons & Synaptic transmission:
Sensory neuron- carry nerve impulses from sensory receptors to spinal
cord & brain. Convert info from receptors to neural impulses. In brain, they’re
translated into sensations. Some info only reaches spinal cord for quick reflex
reactions.
Relay neuron (interneurons) – allow sensory & motor neurons to
communicate. Found in brain & spinal cord.
Motor neuron- Send messages from brain to muscles. Form synapses
(junctions) on the muscle to control contraction. When stimulated, motor neurons
release neurotransmitters which bind to receptors on the muscle (triggering a
response).
Synaptic transmission:
Signals within neurons transmitted electrically, signals between neurons
transmitted chemically.
1. When the action potential reaches end of neuron (axon terminal) it
triggers neurotransmitters to release from vesicles.
2. Neurotransmitters diffuse across the synapse & bind to receptors on post-
synaptic neuron (dendrites of next neuron)
3. This triggers the next action potential (electrical impulse). The likelihood of
cell firing determined by excitatory/inhibitory neurotransmitter input. Eg-
high levels of dopamine (excitatory) triggers nerve impuses (action
potentials).
4. Enzymes released to break down neurotransmitters. There then taken in
by presynaptic neuron’s reuptake pumps.
5. Vesicles replenished with new & reused neurotransmitters.
Types of neurotransmitter:
Excitatory- trigger nerve impulses in the receiving neuron & stimulate brain into
action. Inc positive charge of post synaptic neuron. Make it more likely to fire.
(eg- dopamine, adrenaline)
Inhibitory- inhibit nerve impulses to calm brain/balance mood. Neuron becomes
negatively charged & less likely to fire. (eg- serotonin)
Likelihood of cell firing = synaptic imput (excitatory + inhibitoty)
