Biopsychology Flashcards
divisions of the nervous systemxxx
the nervous system = CNS and peripheral nervous system
CNS = spinal cord and brain
PNS = somatic and autonomic
autonomic = sympathetic and parasympathetic
function of spinal cord and brain
spinal cord: receives and transmits some info, some simple reflex processing without brains involvement.
allows brain to regulate bodily processes.
brain: split into cerebrum, cerebellum, brainstem and diencephalon.
regulates automatic functions essential for life.
function of somatic and autonomic nervous system
somatic: controls skeletal muscles.
it is a voluntary system so there is conscious control.
autonomic: controls actions of internal organs and glands.
involuntary system.
function of sympathetic and parasympathetic nervous system
sympathetic: increases body activity, releases noradrenaline, activates in stress.
- increased heart rate, sweat, increased breath rate, dilates pupils.
parasympathetic: decreases body activity, acetylcholine released and rest activates it.
- decreased heart rate, decreased breath rate, constricted pupils.
the structure of neurons
neurons carry neural info throughout the body.
contain cell body, dendrites and an axon.
myelin sheath allows nerve impulses to travel rapidly along axon.
the function of sensory neurons
carry impulses from sensory receptors to spinal cord and brain.
translated into sensations such as heat and pain.
neurons terminate in spinal cord for quick reflex.
the function of relay neurons
allow sensory and motor neurons to communicate.
lie within brain and spinal cord.
the function of motor neurons
conduct signals from CNS to organs.
control muscle contractions.
release neurotransmitters which bind to receptors, triggering muscle movement.
the process of synaptic transmission
an action potential, once at the end of an axon, crosses the gap between the presynaptic neuron and the postsynaptic neuron (synaptic cleft).
synaptic vesicles at the end of an axon release chemical messengers (neurotransmitters), as the action potential reaches it, through exocytosis, which aids in the transfer of impulses.
once neurotransmitters cross, they bind to specialised receptors which recognise it and are activated by it.
this process takes a fraction of a second.
the effects are terminated by reuptake. the neurotransmitter is taken back by presynaptic neuron where it is stored for later use.
excitatory neurotransmitters (EN)
excitatory neurotransmitters such as noradrenaline are the nervous systems on switches. these increase the likelihood of excitatory signal being sent to postsynaptic cell, which is then more likely to fire.
EN binding with a postsynaptic receptor causes an electrical change in the membrane of that cell, resulting in EPSP. the postsynaptic cell then fires.
inhibitory neurotransmitters (IN)
such as serotonin are the nervous systems off switches.
decrease likelihood of neuron firing.
calm mind and body, induce sleep and filter out unnecessary excitatory signals.
IN binding with postsynaptic receptor results in IPSP making it less likely to fire.
what is EPSP/IPSP
excitatory/inhibitory postsynaptic potential
what is summation
nerve cells can receive EPSPs and IPSPs at the same time so the likelihood of the cell firing is determined by the summation.
the strength of EPSP is determined by spatial and temporal summation.
if excitatory synapses are more active, the cell fires at a high rate.
if inhibitory synapses are active, the cell fires at a low rate or not at all.
what is spatial summation
a large number of EPSPs generated at many different synapses on the same postsynaptic neuron at the same time.
what is temporal summation
a large number of EPSPs generated at the same synapse by a series of high-frequency action potentials on presynaptic neuron.
