CHAPTER 15 Flashcards
somatic nervous system
consciously perceived or controlled processes
somatic sensory portion
detects signals from special senses
special senses
vision, hearing, equilibrium, smell taste
somatic motor portion
sends signals from CNS to skeletal muscles
Voluntary movement involves the ____, and reflexive movement involves the _______
cerebrum, brainstem/spinal cord
ANS (autonomic nervous system)
controls processes regulated below a conscious level
transmits signals from CNS to heart, smooth muscle, glands
ANS
True or false? the SNS regulates homestasis
no, it is the ANS
Are neurons involved in sensory input from the heart technically part of the ANS?
no
True or false? the ANS is regulated by parts of the brain, and the spinal cord
true
nuclei mediate visceral reflexes are controlled by the
brainstem
integration and command center for autonomic functions, involved in emotions
hypothalamus
Contains ANS reflex centers for defecations and urination
spinal cord
parasympathetic vs sympathetic nervous system
sympathetic is fight or flight, parasympathetic is calm tf down
in what region of the spinal cord does the parasympathetic nervous system live?
craniosacral
Where are the preganglionic neurons of the parasympathetic nervous system?
S2-S4 of spinal cord, or in the brainstem
in the parasympathetic division, preganglionic axons are _____, postganglionic axons are _______
long, short
division of ANS in which ganglia are close to or within the effector organ
parasympathetic nervous system
Where in the spina lcord does the sympathetic nervous system live?
thoracolumbar division
Where do the preganglionic neurons of the sympathetic nervous sytem live?
lateral horns of t1-l2
in the sympathetic nervous system, preganglionic axons are _____, postganglionic axons are ______
short, long
division of ANS in which ganglia are closer to the spinal cord (lateral or anterior to it)
sympathetic
Do preganglionic axons of the sympathetic nervous system have a lot of branches?
yes
parasympathetic activity is fairly localized, true or false?
true
Long preganglionic axons with limited branches influence only one or ________
a few effectors at the same time
sympathetic nervous system activity often facilitates ____ activation
mass
short _______ with many _____ simultaneously influence several effectors
preganglionic axons, branches
Can a single effector of the sympathetic nervous system ever be engaged? if so, what would be an example.
it can. like when the pupil dilates in low light
mass activation is facilitated by the release of hormones from the ________
adrenal medullary glands
which division of the ANS maintains homeostasis at rest?
parasympathetic nervous system
terminal ganglia of parasympathetic divison
located close to the effector
intramural ganglia
in parasympathetic nervous system, located within wall of effector
Which cranial nerves convey parasympathetic signals?
oculomotor, facial, glossopharyngeal, vagus
parasympathetic - CN3
preganglionic axons from cell bodies in midbrain nuclei extend to ciliary ganglion within the orbit. postganglionc axons control lens and iris sphincter
CN7 parasympathetic nervous system
preganglionic axons with cell bodies in pons extend to pterygopalatine and submandibular ganglia. pterygopalatine= lacrimal, nose, mouth submandibular=salivation
CN 9 parasympathetic nervous system
preganglionic axons from cell bodies in medulla exend to otic ganglion near ear. postganglionic axons control parotid salivary gland
CN 10 parasympathetic nervous system
preganglionic axons form cell bodies in medulla project to a variety of ganglia in thorax and abdomen. postganglionic = swallowing, slowing heart rate, bronchiole constriction, increasing digestive secretions, storing carb
pelvic sphlanchnic nerves
preganglionic axons from cell bodies in lateral gray regions of s2-s4 project to ganglionic neurons in terminal or intramural ganglia. contributes to a HYPOGASTRIC PLEXUS. postganglionic = pelvic effectors
What is autonimic dysreflexia?
sympathetic spinal reflex with no counterbalancing parasympathetic response occurs
What causes autonomic dysreflexia?
hyperactivity of ANS after a spinal cord injury at or superior to T6 vertebra
micturition reflex
urination
micturition reflex what happens
stretch receptors signal when bladder fills with urine. signals sent to sacral spinal cord.
gastrointestinal reflex what happens
sensory neurons in rectum respond to stretch by fecal matter, singals sent to spinal cord, signals sent throgh motor neurons stimulate rectum to contract and internal anal spinchter to relax
cardiovascular reflex (blood pressure)
stretch receptors in vessel walls respond to pressure elvation, signals send to cardiac center in medullar oblongata. inhibits sympathetic and activates parasympathetic output to heart
autonomic reflexes are also sometimes called
visceral reflexes
Raynaud syndrome
sudden constriction of small arteries of digits. more common in women
effectors innervated by only the sympathetic division
sweat glands in the trunk, arrector pili muscles of skin, adrenal medulla neurosecretory cells
Can opposing effects be acheived without dural innervation?
yes
dual innervation
organ receives input from both the sympathetic and parasympathetic divisions
most effectors are innervated by both divisions of ANS. both continuously release neurotransmitter. this generates
autonomic tone
Blood vessels are usually in a partially constricted state due to
sympathetic tone
how epinephrine treats asthma
asthma attacks narrow the bronchioles. bronchioles contain b2 receptors. epinephrine binds to the receptors more effectively than norepinephrine. it dilates the bronchioles
Beta receptors
B1, B2, B3
B1 receptors
primarily stimulatory. located in heart and kidney (renin secretion)
B2 receptors
primarily inhibitory. smooth muscles of vessels to heart, liver, skeletal muscle, uterine and GI tract, detrusor muscle (relaxation)
B3 receptors
may be stimulatory (or inhibitory). located in adipose, urinary bladder,
Alpha receptors
A1 A2
A1 receptors
stimulatory receptors foundon most smooth muscle cells.
A2 receptors
located throughout CNS , in pancreas, GI tract sphincters
catecholamines are a chemical subtype of ______ _____
biogenic amines
2 types of adrenergic receptors
alpha and beta
receptors found in all target organs of parasympathetic division and a few of sympathetic division
muscarinic receptors
catecholamines are a chemical subtype of
biogenic amines
ligands that bind to membrane receptors
amines
norepinephrine and epinephrine are both catecholamines that bind to _________
adrenergic receptors
cells with alpha receptors are typically ______ by NE
stimulated
cells with beta receptors are typically ____ or ______ by NE
stimulated or inhibited
somatic motor neuron
transmits nerve signals to skeletal muscle
the sympathetic trunk resembles a
pearl necklace
in the “pearl necklace”, what are the strings and pearls made of?
pearls = sympathetic trunk ganglia housing cell bodies
string= axons
The cervical porton of the sympathetic trunk only has 3 ganglia
superior, middle, inferior,
target of superior cervical ganglion cells (sympathetic)
sweat glands, blood vessels, dilator pupillae musle of eye, superior tarsal muscle of eyelid
What causes horner syndrome?
injury of cervical sympathetic trunk or T1 trunk ganglion
horner syndrome symptoms
ptosis, miosis, anhydrosis, facial flushing
ptosis
drooping of superior eyelid due to paralysis of superior tarsal muscle
miosis
constricted pupil due to paralysis of pupil dilator muscle
anydrosis
lack of sweating because sweat glands not receiving sympathetic innervation
facial flushing
due to lack of sympathetic innervation, vasodilation resutls
sympathetic effector stimulation - HEART
increase heart rate and force of contraction
sympathetic effector stimulation SALIVARY GLANDS
more viscous saliva is produced
sympathetic effector stimulation - PANCREAS
inhibit insulin release, stimulate glucagon release
sympathetic effector stimulation- LIVER
glycogenolysis
sympathetic effector stimulation - RESPIRATORY SYSTEM
bronchi/bronchiole dilation
sympathetic effector stimulation- URINARY
retention of urine, release of renin (which helps increase blood pressure)
sympathetic effector stimulation - REPRODUCTIVE
stimulate release of secretions in male during ejaculation, contraction of uterine and vaginal walls in female orgasm
sympathetic effector stimulation - INTEGUMENTARY
arrector pili contraction, release of sweat, vasoconstriction preventing blood flow to skin
sympathetic effector stimulation - IRIS
dilation
Which releases epinephrine/ norepinephrine? sympathetic or parasympathetic?
sympathetic
networks of nerves within thoracic and abdominopelvic cavities
autonomic plexuses
What does an autonomic plexus consist of?
sympathetic postganglionic axons, parasympathetic preganglionic axons, and some visceral sensory axons.
includes sympathetic axons from cervical and thoracic trunk (quicken heart rate) and parasympathetic axons from vagus nerve (slow the heart)
cardiac plexus
includes sympathetic axons from cervical and throacic trunk (bronchodilation) and parasympathetic axons from vagus nerve (bronchoconstriction)
pulmonary plexus
consists of celiac (solar) plexus, superior mesenteric plexus, and inferior mesenteric plexus
abdominal aortic plexus
What plexus innervates all abdominal and some pelvic organs?
abdominal aortic
What plexus innervates viscera within the pelvic region?
hypogastric
What does the hypogastric plexus consist of?
sympathetic axons from aortic plexus and sympathetic trunk, parasympathetic axons from pelvic splanchnic nerves
peristalsis involves two large plexuses
submucosal, myenteric
What neurotransmitters does the ANS use?
acetylcholine, norepineprhine
cells that release NE are ____ neurons
adrenergenic
What are the 2 main types of cholinergic receptors?
nicotinic and muscarinic
Where are nicotinic receptors found?
on all ganglionic neurons and adrenal medulla cells. also, skeletal muscle cells at the neuromuscular junction
When ACh binds a nicotinic receptor, it opens a
cation channel
When ACh binds to muscarinic receptors of smooth muscle in GI tract, it is _________
stimulated to contract more
When ACh binds to muscarinic receptors on cardiac muscle what happens?
the heart rate decreases
connecting spinal nerves to each sympathetic trunk are
rami communicantes
white rami communicantes
composed of preganglionic sympathetic axons from t1-l2.
gray rami communicante
postganglionic sympahtetic
