ans Flashcards
define autonomic nervous system
the division of the peripheral nervous system that controls involuntary motor functions
what does the ANS consist of
sympathetic and parasympathetic divisions
what does the ANS regulate
smooth muscle, cardiac muscle, glands
what does the somatic nervous system do
sends information between the brain and muscles
what is the visceral motor system
another name for the autonomic nervous system
describe the somatic pathway (skeletal muscles)
starts with efferent innervation, goes through the myelinated fibers, to the ACh into the target organ
(look up video)
autonomic pathways (cardiac and smooth muscle, and glands)
autonomic efferent innervation to the myelinated preganglionic fibers to the autonomic ganglion with ACh inside, to the unmyelinated postganglionic fibers, to the ACh or NE going into the target organs. (visceral effectors)
look up video
define ganglia
clusters of nerve cell bodies found throughout the body. they are a part of the peripheral NS and carry nerve signals to and from the CNS
define preganglionic
literally “before the ganglion”
referring to neurons in the autonomic nervous system that run from the central nervous system to the autonomic ganglia
postganglionic
literally “after the ganglion”
referring to neurons in the autonomic nervous system that run from the autonomic ganglia to various targets in the body
how many neurons are in the pathway to the effector organ
two neurons that transmit impulses from the central nervous system to the effector tissue
what neurotransmitters and receptors are use in the ANS
neurotransmitters: ACh, epi, and norepinephrine
receptors: alpha and beta
where do you find Ach and Ach receptors?
ACh is secreted by preganglionic neurons in the sympathetic and parasympathetic divisions, and in the postganglionic neurons of the parasympathetic division.
Any neuron that secretes ACh is a cholinergic neuron and any receptor that binds to it is a cholinergic receptor.
where would you find NE and NE receptors
NE is secreted by nearly all sympathetic postganglionic fibers. Neurons that secrete NE are called adrengic neurons and the receptors are called adrengic receptors
what are involved in regulating the ans
cerebral cortex, hypothalamus, the brain stem, and the spinal cord
what does afferent mean
moving towards a center
what does efferent mean
moving away from the center
what is the cerebral cortex
the outer layer of the brain (wrinkly), that controls consciousness, memory, and language.
what is the role of the cerebral cortex
to carry out emotional, sensory, and motor functions
what is the hypothalamus
it is in the floor of the brain, and it controls the pituitary gland
what is the role of the hypothalamus
contains centers for behavioral drives, temperature regulation, coordination of reproductive hormones, flight or fight response, and growth
what is the brainstem
it is made up of the midbrain, pons, and medulla oblongata
what is the role of the brainstem
mostly autonomic functions (breathing, sleeping, heart beating)
what is the spinal cord
the main communication link between the brain and the body
what is the role of the spinal cord
integrates autonomic reflexes like urination, defecation, erection, and ejaculation
what are the visceral arc components
receptor, sensory neuron, integration center, motor neuron, and effectors
what are visceral reflex arcs
a series of events where a sensory stimulus in an organ leads to a predictable visceral motor response mediated by the ANS
what stimuli trigger visceral reflex arcs
stretch, blood pressure, and body temp
what is the pattern of a visceral reflex arc
watch youtube video
what physiological processes are regulated by the ANS
heart rate, blood pressure, respiration, digestion, and sexual arousal
describe the regulation of blood pressure by the parasympathetic divisions as an example of autonomic reflex arcs
receptors: baroreceptors in the carotid sinus
afferent neurons: via glossopharyngeal nerve to medulla oblongata
integration takes place in the reticular formation of the medulla
what are the two divisions of the ANS
sympathetic and parasympathetic
what does the parasympathetic division do
supports state of inactivity
define rest and digest
physical state that occurs when the body is at rest
what does the sympathetic division do
prepares the body for activity
define fight or flight
reaction that helps the body confront or avoid a stressor
what is the anatomy of the parasympathetic division
origin of fibers: brain and sacral spinal cord
length of fibers: long preganglionic and postganglionic
location of ganglia: in the visceral effector organs
what is the anatomy of the sympathetic division
origin of fibers: thoracolumbar region of the spinal cord
length of fibers: short preganglionic and long postganglionic
location of ganglia: close to spinal cord
what does craniosacral mean
relating to the cranium and sacrum
what does thoracolumbar mean
pertaining to the chest and lower spine
define autonomic tone
the balance between sympathetic and parasympathetic activity
how does autonomic tone relate to the control of vasculature
the endothelium and ANS work together to regulate vessel tone. Vasodilation and vasoconstrictor substances from the endothelial cells can maintain the vascular tone properly via affecting the activity of ANS
what is vasculature
network of blood vessels in a particular organ
define vasomotor tone
the partial state of smooth muscle constriction in the arterial walls
how does the sympathetic division regulate vasodilation and vasoconstriction
the activation of sympathetic nerves results in vasoconstriction
increasing metabolic activity induces vasodilation
what is vasodilation
widening of blood vessels
what is vasoconstriction
narrowing of blood vessels
how do cardiac and skeletal vasculature have different NE receptors than skin and visceral vasculature?
define dual control by sympathetic and parasympathetic divisions
it means that they receive competing inputs from both divisions
compare the heart, salivary glands, and pupil diameter during dual control
look in book
compare the neural pathways of both divisions
look in book
all outflow from the CNS is from the
spinal nerves
what does paravertebral mean
near the vertebrae or spinal column
what is chain ganglia
a sequence of ganglia running parallel to spinal column on either side o
what are prevertebral ganglia (aka collateral ganglia)
autonomic ganglia that are anterior to the vertebral column and functionally related to the sympathetic chain ganglia
what is the cardiac plexus
complex network of nerve fibers near the base of the heart that receive sympathetic and parasympathetic stimulations to regulate heart rate
what is the pulmonary plexus
network of autonomic nervous system fibers found near the hilum of the lung
what is the abdominal aortic plexus
consists of the celiac plexus, the superior mesenteric plexus, and the inferior mesenteric plexus
what is the anatomy of the abdominal aortic plexus
it is on the sides and front of the aorta, between the origins of the superior and inferior mesenteric arteries
what is the anatomy of the paravertebral (aka chain ganglia)
wedged shape compartment adjacent to the vertebral bodies
paravertebral ganglia run on either side of the vertebral bodies
what is the anatomy of the prevertebral (aka collateral ganglia)
situated anterior to the vertebral column and receive input from splanchic nerves as well as central sympathetic neurons.
they are associated with controlling organs in the abdominal canvity
what is the anatomy of the cardiac plexuas
lies beneath the aortic arch and anterior to the right of the pulmonary artery
what is the anatomy of the pulmonary plexus
network of autonomic nerves and ganglia situated at the pulmonary hila of each lung. it regulates smooth muscle tone and blood flow
what is the role of spinal nerves
to communicate with the CNS via incoming sensory information from the body to the spinal cord, and outgoing information from the spinal cord to the rest of the body via spinal nerves
what is the role of sympathetic nerves
fight of flight response
what is the role of splanchnic nerves
they connect the prevertebral ganglia to the sympathetic chain
what effectors do splanchnic nerves service
effectors in the abdominal cavity and reproductive organs
what effectors do the spinal nerves service
effectors in the skin and skeletal muscle
what effectors do sympathetic nerves service
viscera of the head and thoracic cavity
know this: the sympathetic division has
high divergence and widespread actions due to the short preganglionic and long postganglionic fibers
what are adrenal glands
a pair of endocrine glands that sit above the kidneys and secrete hormones that help arouse the body in times of stress
what is the adrenal medulla
modified sympathetic ganglion that released cateocholamines into the blood
what are cateocholamines
another word for epinephrine and norepinephrine
what is the adrenal cortex
outer section of each adrenal gland: secretes cortisol and sex hormones
how is blood vessel diameter regulated without dual innervation
by the sympathetic nervous system
what cranial nerves are involved in the ANS
third (III), seventh (VII), ninth (IX), and the tenth (X)
where are ganglia of the sympathetic NS
near the vertebral column and aorta, distant from the target organs
where are the synapses of the parasympathetic nervous system
near or within the target organs, resulting in less divergences
what does divergence mean
the act of splitting into different directions
describe the cranial nerve pathways
these are responsible for transmitting information between he brain and rest of the body. they consist of different fibers carrying information from the brain to different afferent fibers, which then carry info to the body
what are the cranial nerves
olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, accessory, and hypoglossal.
what is the cranial nerve pneumonic
OH (olfactory) OH (optic) OH (oculomotor) TO (trochlear) TOUCH (trigeminal) AND (abducens) FEEL (facial) VERY (vestibulocochlear) GOOD (glossopharyngeal) VAGINA (vagus) AH (accessory) HEAVEN (hypoglossal)
what are oculomotor nerves
cranial nerves that control smooth muscle of eye, cause pupils to constrict and lenses to bulge for focusing
what are optic nerves
cranial nerves that carry visual messages to the brain
what are olfactory nerves
cranial nerves that are used for sense of smell
what are facial nerves
cranial nerves that help with facial expression and salivary glands
what are abducens nerve
one of the cranial nerves responsible for eye movement
what are glossopharyngeal nerves
cranial nerves that stimulates salivary glands, help transmit information to mouth and throat
what are vagus nerves
cranial nerves for the pharynx, larynx, and viscera
vagus nerves targets
majority of abdominal organs
facial nerve targets
glands of oral cavity, sensory info to face and tongue
oculumotor nerve targets
movement of eye muscles, constriction of pupils, focusing the eyes and eyelid position
glossopharyngeal nerve targets
pharynx, middle ear cavity, eustachian tube, sinuses
describe the cardiac plexus and its targets
mesh work of neurons that innervate the heart and cardiac tissue
target: influences heart rate, cardiac output, and heart contractions
describe the pulmonary plexus and its targets
innervates the lungs and carries visceral afferents back into the CNS
consists of efferent and afferent nerve fibers and branches around the pulmonary vasculature
describe the abdominal aortic plexus
neurons and ganglia that are situated on the anterior and lateral surface of the abdominal aorta and supply hindgut and pelvis viscera
KNOW THIS: THE PARASYMPATHETIC DIVISION DOES NOT HAVE
an equivalent to the adrenal medulla to release signals into the blood
where are muscarinic receptors used
all glands, smooth muscle, cardiac muscles
where are nicotinic receptors used
adrenal medulla, preganglionic fibers, skeletal muscle
where are alpha receptors used
on arterioles of skin, abdominal viscera
where are beta receptors used
on vasculature, cardiac muscle, airways
what is a beta blocker
used to manage abnormal heart rhythms and to protect from second heart attack
- meds that block NE and EPI receptors
what are the types of cholinergic receptors
nicotinic and muscarinic
what are the types of adrengic receptor classes
alpha and beta
