PNS PT 1 Flashcards
what does the peripheral nervous system include
all neural structures outside of the brain and spinal cord, so sensory receptors, peripheral nerves + ganglia, efferent motor endings
what do the various components of the PNS do
link our CNS to other parts of our body and our surroundings
what are nerves
bundle of axons of various neurons
do nerves have artery + blood supply
yes
describe the two arms of the autonomic nervous system
sympathetic division, which is fight or flight
parasympathetic division, which is rest and digest
describe the parasympathetic division of the ANS
rest and digest; keeps body energy use as los as possible, even while carrying out maintenance activities, like digestion, diuresis, defecation; bp, heart rate and respiratory rates are low and GI tract activity is high
what innervates the PNS
vagus nerves
describe vagus nerves + other PNS nerves
account for ~90% of all preganglionic parasympathetic fibers in the body; serve all thoracic and abdominal viscera
where do PNS pregang fibers arise from
medulla and synapse in terminal ganglia in walls of target organs
describe the sympathetic division of the ANS
fight or flight; mobilizes body during activity; activated by exercise, excitement, emergency, embarrassment
what happens when SNS is on
increased heart rate, dry mouth; blood to skeletal muscles and heart; dilates bronchioles, causes liver to release glucose
does the SNS or PNS act on adrenal medulla
only the sympathetic nervous system
where do you find muscainic receptors
only on organs stimulated by the PNS
where does the somatic nervous system release Ach
at neuromuscular junctions
what neurotransmitter does the somatic nervous system release
ach
what neurotransmitter do pre and post ganglia release in pns
ach
describe the two pre/post gang SNS pathways
first one: lightly myelinated pre gang release Ach at nicotinic receptor and then nonmyelinated post release NE at muscinaric receptor
second one: lightly myelinated pre gang release Ach at adrenal medulla, which releases NE and E into blood vessel
describe parasympathetic nervous system pre and post gang pathways
light myelinated pre release Ach at niotonic receptors and nonmyelinated post release Ach at muscarnic receptors
what are the effector organs of the autonomic nervous system (so parasymp and sympathetic)?
smooth muscle, glands, cardiac muscle
how does the PNS act on heart and digestive tract?
speeds up heart, slows down digestion
describe effects of somatic nervous system vs autonomic (sympathetic and parasymp)
somatic nervous system is always stimulatory, but autonomic is sometimes stimulatory and sometimes inhibitory, depending on neurotransmitter and receptor on effector organs
what are sensory receptors
specialized to respond to changes (stimuli) in their environment
how are sensory receptors classified
type of stimulus they detect, body location, structural complexity
what are mechanoreceptors
sense touch, pressure, tension, movement
where are mechanoreceptors located
skin, ears, muscles
what are thermoreceptors
respond to changes in temperature
where are thermoreceptors located
skin, hypothalamus
what are photoreceptors + where are they located
sense changes in light and located in the eye
what are chemoreceptors and where are they located
sense chemical stimuli and located in the tongue and nose
what are nocicreceptors and where are they located
sense tissue damage/pain; located anywhere that can sense noxious stimuli
what are extereoreceptors
located outside body + near body surface; sense touch, pressure, pain on skin, special sense
what are interoreceptors
located in the body (internal viscera, blood vessels); tissue stretch, body temp, chemical changes
what are proprioreceptors
in body, advising brain of external body movement; located in skeletal muscles, tendons, joints, ligaments
