nervous system Flashcards
divisions of the peripheral
somatic
autonomic
into
sympathetic
parasympathetic
divisions of the central
brain
hindbrain, forebrain and midbrain
spinal cord
autonomic nervous system
regulates automatic behaviours of the body
eg heart rate, blood pressure
divides in sympathetic
stimulates fight or flight
and parasympathetic
inhibits
somatic nervous system
voluntary movements
efferent - transmitting signals from CNS to body
afferent - deliver sensory information from body to CNS
role of the spinal cord
spinal reflexes
simple pathways in the nervous system that rapidly generate muscle contractions
hindbrain
medulla
pons
cerebellum
midbrain
tectum
tegmentum
forebrain
subcortical structures:
thalamus
hypothalamus
pituitary
limbic system
basal ganglia
cerebral cortex
thalamus
relays and filters information from the senses
transmits information to cerebral cortex
receives inputs from all major senses (except smell)
hypothalamus
regulates body temperature, hunger, thirst and sexual behaviour
ensures kept in optimal range for human functioning
pituitary gland
master gland of bodies hormone system
releases hormones that control other glands
limbic system
group of forebrain structures
includes amygdala and hippocampus
involved in motivation, learning and memory
amygdala
part of limbic system
central role in emotional processes
hippocampus
part of limbic system
creating new memories and integrating them into knowledge
stored in cerebral cortex
basal ganglia
set of subcortical structures
relieve input from cerebral cortex and send output to motor centres in brainstem
voluntary movement
cerebral cortex
highest level
involved in most complex aspects of perception
contains gyri and sulca
divided into left and right hemispheres
contralateral control
connected by corpus callosum
divided into 4 lobes
frontal lobe
movement
executive functions
memory
central sulcus
temporal lobe
hearing
language and visual processing
memory
occipital lobe
visual processing
parietal lobe
somatosensory processing
attention
structure of a neuron
cell body (soma) - contains nucleus
dendrite - branch structures from cell body, receive electrical signals from others
axon - carries electrical impulse away from cell body to terminal buttons
terminal button - bud at end of branch of an axon, forms synapses with other neurons
synapse - junction between terminal button and membrane of next neuron
neurotransmitters
myelin sheath - extension of a glial cell that wraps around the neuronal axon
provide insulation and facilitate electrical transmission
nodes of ranvier - naked portion of myelinated axon between adjacent glial cells, help speed up conduction
glial cells - make up myelin sheath, providing insulation to facilitate transmission
action potentials move by saltatory conduction
conduction jumps from node to node
resting potential
difference in electric charge between inside and outside of membrane
higher concentration of K+ inside and higher Na+ outside
Na+ channels closed
action potential
electrical signal conducting along the length of an axon
occurs when threshold met
‘all or nothing’ principle
depolarisation
electrical signal from receptor causes Na+ channels to open
if threshold met, all Na+ channels open
Na+ flow into axon
becomes depolarised
depolarisation
at peak depolarisation Na+ channels close
K+ channels open
K+ diffuse out of cell
membrane potential becomes more negative
hyperpolarisation
K+ continues to flow out of axon causing membrane potential to drop below resting
refractory period
neurotransmitters
small molecules
released by presynaptic neuron
facilitate change in membrane potential of post synaptic neuron
can be inhibitory or excitatory
inhibitory = decrease chance of action potential in post
excitatory = increase chance
how does neurotransmission stop?
reuptake - neurotransmitter transported back to presynaptic cell to be recycled
autoreception - autoreceptors in presynaptic cell inhibit further neurotransmitter release or synthesis
enzyme degradation - neurotransmitter is broken down by enzymes in synapse
how is firing rate determined?
shared inputs from both inhibitory and excitatory
determined by strength of inputs
more excitatory = high firing rate
more inhibitory = reduced firing rate
how do drugs work?
increase, interfere or mimic neurotransmitters
may have similar structures
can bind to receptor and activate (agonist = increase action) or block (antagonist = inhibit action) neurotransmitters
