Midterm 1 - Autonomic Nervous System Flashcards
what does autonomic mean
controls body functions without conscious thought
what is the ANS key in maintaining
homeostasis
how is the ANS accomplished
reflexes
what does the ANS control
smooth muscle, cardiac muscle, glands
what does the ANS not control
skeletal muscle
what does the ANS control at length
respiration
heart rate
blood pressure
digestion
rumination
sleep
arousal
body temp
what is involved in a reflex
sensory cells
sensory nerve fiber
integration centre
motor nerve fiber
effectors
how is the ANS mainly controlled
negative feedback
what does the type of sensory cell depend on
the system considered
examples of sensory cells
baroreceptors
cold and warm receptors
are there any differences in sensory nerve fibers between somatic arc reflexes and ANS
nothing major
what are the control centres of the ANS
hypothalamus
brain stem
spinal cord
what is the master command of ANS
hypothalamus
what does the brain stem control in ANS
special control function: respiratory and cardiovascular centre
what does the spinal cord do in ANS
local integration in thoracic and sacral segments
what does the spinal cord receive
continuous info from sensory nerves - frequency of impulses
how does the spinal cord set a reference
compares information and if different, alters frequency on motor fiber
what is the main difference between autonomic and somatic system
the motor nerve fibers
what is the difference in motor fibers between autonomic and somatic system
target organs
number of neurons in its peripheral circuit
how many peripheral nerves does the ANS have in its peripheral circuit
2 (somatic arc reflex has 1)
what is the preganglionic neuron
cell body in the CNS with non that innervates a second neuron, the postganglionic neuron
what is a ganglion
cell body of the postganglionic neuron
are there any sensors specific to ANS
no
where is the sympathetic nervous system
thoracic-lumbar
how does the sympathetic nervous system work
preganglionic neurons originate in thoracic or lumbar spinal area and send axons to sympathetic ganglia which form a chain parallel to the spinal cord
what gets activated my a stressor
all systems i.e sweating, heartbeat… due to ganglion chain
where is the parasympathetic nervous system
cranio-sacral
how does the parasympathetic nervous system work
preganglionic neurons originate in brain or sacral part of spinal cord and send axons to ganglia near or within effector organs
what is the enteric nervous system associated with
the parasympathetic
are postganglionic fibers long or short in sympathetic
very long - some extend to adrenal medulla
where do postganglionic fibers innervate
hollow organs, blood vessels etc
what do postganglionic fibers do in adrenal glands
stimulate epinephrine/adrenaline and norepeinephrine secretion into blood circulation
important point about the sympathetic system
info is shared between ganglia along the chain
what cranial nerves supply parasympathetic fibers to body’s glands and organs
III, VII, IX
which cranial nerve is the major supplier to the body
X - vagus nerve
where are ganglia located
in the wall or adjacent to target organs
what kind of regulation in ganglia in parasympathetic
1 on 1 regualtion
is there any interconnection between ganglia in the parasympathetic nervous system
no - no chain
are postganglionic fibers long or short in parasympathetic
short
what fibers are very long in the parasympathetic system
preganglionic
selective action in postganglionic fibers
direct connection with specific organs with no enhancement by hormones
what are 2 receptors to acetylcholine
nicotinic
muscarinic
what does nicotinic help with
preganglionic synpases
what does it mean that nicotinic is inotropic
part of an ion channel - with Na+
where is muscarinic found
in target organs of parasympathetic
is muscarinic an ion channel
no - requires intracellular second messengers to activate target cell
the effect of muscarinic can be …
stimulatory or inhibitory - depends on messenger
what is the difference of muscarinic compared to nicotinic
it is slower and more prolonged effect
what is the pharmacological significance of ANS
use of agonist and antagonists to selectively activate or block receptors
what is pharmacological can be used during hypertension
B-adrenergic blocker (propranolol) - decreases heart rate (B1)
what does propranolol act on
the heart
what pharmacological can be used for asthma
B2 - adrenergic agonist (salbutamol) - bronchodilation
what is atropine
muscarinic receptor blocker
what does atropine do
drop in eye - dilate pupil
what does atropine inhibit
contraction of lower GI tract
reciprocal effects of eyes
sympathetic - pupil dilation
parasympathetic - pupil constriction
reciprocal effects of salivary gland
sympathetic - stimulation
parasympathetic - inhibition
reciprocal effects of heart rate
sympathetic - increased
parasympathetic - decreased
reciprocal effects of blood vessels
sympathetic - constriction (most)
parasympathetic - dilation (few)
reciprocal effects of lungs (bronchiole)
sympathetic - dilation
parasympathetic - constriction
reciprocal effects of intestinal mobility
sympathetic - inhibition
parasympathetic - stimulation
reciprocal effects of sphincters
sympathetic - stimulate closing
parasympathetic - inhibit closing
reciprocal effects of urinary bladder
sympathetic - muscle tone relaxed
parasympathetic - contraction
reciprocal effects of penis
sympathetic - ejaculation
parasympathetic - erection
