nervous system Flashcards
nervous system integration function
information gathering, processing info, sending a response to alter/control body functions/actions
nervous system motor functions
initiate and regulate movement of body parts, regulate secretions from glands, maintain appropriate state of conscoiusness
brain and spinal cord function
receive, analyze, store, integrate information. brain sends a signal or response that leads to some action in the body or by the body
what is required from the nervous system?
rapid transmission of info from one site to another in the body, via electrical impulses.
neuroglia/glial cells
supports NS structurally + functionally. forms myelin which forms a sheath around the axon anchors neurons destroys pathogens removes dead pathogens.
neurons
second type of cell.
are excitable, develops action potentials.
involved in info transmission through CNS
need neutron for muscle contraction
central neuron cell body
soma or perikaryon
- receives info from dendrites, processes it and decides what to do.
dendrites
receive stimuli - part of neuron
short and multi branched. dendro = branch
transmits info to soma
axons
conduct nerve pulses away from the cell
can be v long (>1m) or small.
conducts nervous impulse from soma to another neuron/cell
1 axon/neuron
myelinated axon
conduct impulses faster
myelin sheath
made of glial cells that are wrapped tightly around the axon. its white
oligodendrites
myelin functions as the cell membrane for these functional glial cells inside the brain and spinal cord in CNS
Schwann cells
myelin outside fo the brain and spinal cord, in peripheral nervous system
nodes of ranvier
gaps between adjacent glial cells, works together w myelin sheaths to speed up transfer of the nerve inpulse
central nervous system
includes brain and spinal cord, deals w central/cranial-caudal axis of the body
peripheral nervous system
nerves that radiate from CNS to all other parts of the body, extends from central axis to periphery
cranial nerves
PNS nerves that originate from the brain
spinal nerves
PNS nerves that originate from the spinal cord
afferent nerves
going to, carries nerves impulses towards CNS
- inc sensory nerves that carry sensations from sensory receipts in the skin and other parts of the body
efferent nerves
going away
carries nerve impulses away from the CNS to muscles and other organs,
aka motor nerves, cause skeletal muscle contractions
involuntary nerve functions controlled by the ANS
contract intestines
increase heart rate in response to threat
stim secretion of digestive juices
self-regulating system w automatic functions
doesnt go to skeletal, goes to smooth, cardiac, endocrine glands
somatic NS function
voluntary part of the PNS
conscious/voluntary control of skeletal muscles
sodium potassium pump
pumps Na+ to outside, K+ inside.
specialized to help maintain resting state of the cell
resting membrane potential
diff in electron charge across neurons membrane
net negative charge
excitability of resting/unstimulated neuron
presence of Na/K pump which pumps Na inside to outside against gradient, polarizes cell membrane
- diff of electrical charge across membrane
resting state nerve cell
neuron not being stimulated
- na has been pumped out of cell
- k pumped into cell
- net negative charge
depolarization
external stimuli causes the gates to open
- Na channels open, only briefly
happens bc of concentration gradient
refractory period
no depolarization under any circumstances
how does info travel down axon to send a signal
generation of action potential which results from adjoining neuron sending an impulse or presence of external stimuli to stem a neuron
salatory conduction
its more efficient to skip parts of the neuron to speed up the process.
what is multiple sclerosis (MS)
myelin sheath is damaged in nerves. loss of normal muscle control, unable to make coordinated movements.
synaptic transmission
depolarization face or ap crosses entire axon - neuron must release a chemical that will cause subsequent synaptic transmission
synapse?
junction between 2 neurons
nuron and target cell
synaptic cleft
physical gap between neuron and celll located across the gap
neurone that receives neurotransmitter from the synapse:
post synaptic neuron, doesnt have to be a neuron that receives a neuro transmitter, could be a muscle fibre, organ, or other tissue
neurotransmitter
replaces
ap to stim depolarization of the embrace across synaptic cleft
Ca2+ defficiency?
no Ca influx into knob membrane, no release of neurotransmitter into synaptic cleft. no stim of postsynaptic membrane across the synaptic cleft.
excitatory neurotransmitters
causes Na influx through post synaptic membrane, membrane becomes depolarized a +’ve membrane potential
inhibitory neurotransmittes
hyperpolarizes postsynaptic membrane, cell becomes more negative, RMP becomes more negative
acetyl choline
excitatory at junction between somatic neutrons (voluntary) and muscles that stim muscle contraction.
somehow related to bradycardia
catecholamines
produced by adrenal medulla. inc epinephrine and norepinephrine (fight or flight)
autonomic nervous system
motor and sensory nerves which transmit impulses to smooth and cardiac muscle.
does not go to skeletal muscles
includes sensory nerves
self regulating
includes sympathetic and parasympathetic NS
what slide did u end at?
85
function of nervous system
regulate body function and maintains homeostasis
rxn to stimuli
fast
duration of effects
short
chemical messenger
neurotransmitters
messenger producing cells
neurons
distance from site of production
short
