3. PNS and ANS Flashcards
afferent
sensory
IN
efferent
motor
OUT
somatic afferents
IN from
skin
muscle
joints
visceral afferents
IN from
organs
nociceptors
respond to chemicals
aka chemoreceptors
sensory receptors
free nerve endings (pain/temp)
pacinian corpuscel (pressure)
meissners corpuscle (touch)
muscle spindle (stretch)
Explain myocardial infarction
- blocked coronary artery = no blood supply
- increase pH -> acidosis
- increase proinflammatory cytokines
- Action potential in medulla
- increase Ach = decrease HR
(motor vagus) - decrease Nor = decrease HR
(sympathetic)
- increase Ach = decrease HR
inflammatory reflex (MI)
inhibits cytokine synthesis through cholinergic anti-inflammatory pathway
negative feedback loop
3 types of neurons
sensory
interneuron
motor neuron
sensory neuron
somatic
visceral
motor neuron
organs
Location of AP generation in motor neuron
axon hillock
Location of AP generation in sensory neuron
1st node of Ranvier
mechanoreceptors
pressure/stretch
pulmonary stretch receptor location
trachea
central airways
pleurae
inflation reflex
lung inflates
stimulates stretch receptors in pleurae
receptors send inhibitory signals to medullary respiratory centers
inhibits further inhalation
expiration occurs
**protective response to not over-inflate lungs
proprioceptors
changes in muscle length or tension
proprioception
self-movement
body postion
proprioceptor locations
muscle spindles
golgi tendon organ
golgi tendon organ (GTO)
muscle scensors
sensory fibers (Ib type) relay info about force production
GTO detect
muscle tension/force
Muscle spindles
muscle receptors
sensory neuron = stretch
Type Ia and II sensory afferents
muscle spindles detect
muscle length/change
fine movement =
more muscle spindles
extrafusal fibers
alpha motor neurons
contraction
intrafusal fibers
gamma motor neurons
form (taut) spindles
motor unit
motor neuron and skeletal muscle fibers that it innervates
or
motor end plate synapsing w/muscle fibers
motor neurons form
2-neuron circuit
upper motor neuron
originates in cerebral cortex
travels to brain stem/sc
lower motor neuron
originates in spinal cord
innervate muscle and glands
Neuromuscular junciton (NMJ)
a synaptic connection between the terminal end of a motor nerve and a muscle (skeletal/ smooth/ cardiac). It is the site for the transmission of action potential from nerve to the muscle.
all motor neurons release _____ at synapse
Ach
Ach causes a
EPP
always excitatory
what is the receptor on the postsynaptic membrane of somatic motor neurons
n1AchR
Myasthenia Gravis (MG)
chronic autoimmune neuromuscular disease
causes weakness in skeletal muscles
MG mechanism
antibodies bind to nAChR
MG treatment
use AChE inhibitors
(neostigmine/pyridostigmine)
block Ach breakdown
neostigmine MG mechansim
blocks AchE from breaking down ACh
Increases ACh in synaptic cleft
downregulates ACh receptors
somatic efferents
innervate skeletal muscle, skin
autonomic efferents
involuntary
innervate smooth muscle, cardiac muscle, gland, etc
sympathetic
fight or flight
usually through spinal cord
parasympathetic
rest and digest
usually through vagus/cranial nerves
autonomic nervous system (ANS)
part of the PNS that acts as a control system
functions below level of consciousness
controls visceral functions
Sympa heart
increase HR
increase contractility
sympa blood vessels
constriction
increase BP
sympa lungs
bronchodilation
increase O2 levels
sympa GIT
decrease motility
schincter contraction
decrease secretions
para heart
decrease HR
decrease contractility
para blood vesses
no effect
para lungs
bronchoconstriction
less O2
para GIT
increase motility
relax sphincter
increase secretions
efferent autonomic nerves originate in
medulla
brainsstem controls
cardiovascular system
respiratory system
autonomic control of respiratory drive and cardiovascular function originates in
medulla
efferent autonomic pathways
sympathetic
parasympathetic
sympathetic preganglionic neurons release
ACh which stimulates the adrenal medulla to release epinephrine to blood stream
ratio of epinephrine and norepinephrine released
Epi:NE
4:1
somatic nervous system neurons originate
spinal cord
somatic nervous system target organ
skeletal muscle
somatic nervous system NT
ACh
somatic nervous system NT receptor
N1 AChR
somatic nervous system ganglion locations
no ganglion
parasympathetic autonomic nervous system ganglion location
close to organs
parasympathetic autonomic nervous system preganglionic fiber length
long
parasympathetic autonomic nervous system target organ
smooth muscle
cardiac muscle
gland
parasympathetic autonomic nervous system NT
ACh
parasympathetic autonomic nervous system ganglion receptor
N2ACh
parasympathetic autonomic nervous system NT receptor
MACh
sympa auto nervous system preganglion length
short
sympa auto nervous system ganglion NT
ACh