ANS Flashcards
The autonomic nervous system is a system of ____ neurons
motor
The ANS innervates the:
Smooth muscle
Cardiac muscle
Glands
Function of the ANS
To maintain homeostasis. The ANS regulates: Heart rate Blood pressure Body temperature Sweating Digestion
Autonomic output originates in
CNS
Input from ____, ______, _____, and _____ regulate ANS
cerebral cortex, hypothalamus, medulla oblongata, and somatic nervous system
______contains nuclei for autonomic functions including: hunger, thirst, thermoregulation, and sexual response
Hypothalamus
The “boss”: Overall integration of ANS
Hypothalamus
Regulates pupil size, heart, blood pressure, airflow,
salivation, etc.
Brain stem (reticular formation, etc.)
Reflexes for urination, defecation, erection and ejaculation
Spinal cord
Visceral sensory neuron cell bodies are located in
Dorsal root ganglion
ANS afferet input
Stretch Tissue damage Blood chemistry Body temperature Other internal stimuli
ANS efferent output
Contraction/relaxation of blood vessels
Smooth muscle of organs
Increase/decrease in HR, breath rate, etc.
Unconscious, automatic, stereotyped responses of visceral effectors to stimuli
Visceral Reflexes
contain only unmyelinated postganglionic fibers traveling to peripheral structures
Gray rami
contain myelinated preganglionic fibers traveling to sympathetic trunk ganglia
White rami
“Fight-or-flight” responses for increased physical activity
Concerned with preparing the body for emergencies and executing the necessary changes so that the body can survive and emergency
Increases heart rate and blood glucose
Reduces blood flow to skin and GI tract
Sympathetic division
“Rest and digest” responses with calming effects Decreases heart rate Stimulates digestion and waste elimination maintaining the body’s steady state “house keeping”
Parasympathetic division
Balance between activity of sympathetic and parasympathetic NS
Both systems are working more-or-less all the time
Sympathetic and Parasympathetic divisions may act antagonistically or cooperatively
Autonomic Tone
The Parasympathetic operates ____, one function is concentrated one at a time
locally and discretely
The Sympathetic division often works by _____everything goes at the same time
“mass action”
Preganglionic somas are housed in different regions of the CNS
Parasympathetic: 1
Sympathetic: 2
- brainstem or sacral spinal cord
2. lateral horns of the thoracic and upper lumbar spinal cord
Location of Ganglia
Parasympathetic ganglia are______
Sympathetic are close to ______
- close to the effector organ
2. the spinal cord (sympathetic trunk)
Post-ganglionic branches (how many)
Parasympathetic =
Sympathetic =
- few (4 or less), localized
2. many (more than 20), widespread effects across many organs
Parasympathetic preganglionic fibers arise from the ____ or ____-of the spinal cord
cranial nerves or sacral regions
Preganglionic fibers are very ___and ____
long and branching
Terminal ganglia are located in ______
the wall of the effector
Postganglionic fibers are very ____ and ____
short and specific for one effector
Sympathetic preganglionic fibers arise through the ______of the spinal cord
Preganglionic somas are in lateral horns
thoracic and lumbar regions
Most ganglia are located in a chain just outside the ____
spinal cord
Postganglionic fibers are _____, innervating multiple organs
highly branched
Sympathetic Trunk Ganglia:
Located on what side of the vertebral column?
Linked by short nerves into ______
Joined to ventral rami by_______
Both sides
Sympathetic trunks
white and gray rami communicantes
Collateral Ganglia differ from sympathetic trunk ganglia in three ways
Unpaired, not segmentally arranged
Occur only in abdomen and pelvis
Lie anterior to the vertebral column
Celiac, superior mesenteric, inferior mesenteric, and inferior hypogastric ganglia
Main ganglia
The Adrenal Medulla is a major organ of the ____
sympathetic nervous system
What constitutes the largest sympathetic ganglia
Adrenal Medulla
The adrenal medulla secretes great quantities of _____ and _____
norepinephrine and epinephrine (adrenaline)
The adrenal medulla is stimulated to secrete by _____
preganglionic sympathetic fibers
Outer part
Secretes steroid hormones
Adrenal cortex
The Adrenal Glands are located
Superior to kidneys
Inner part
Secretes epinephrine, norepinephrine
Resembles a sympathetic ganglion
Somas lack processes
Adrenal medulla
Nervous system of the digestive tract
Enteric Nervous System
Enteric Nervous System:
Innervates ____ and ____
Has its own reflexes to control___ and ___
smooth muscle and glands
motility and emptying of GI organs
Regulates Enteric Nervous System
Motility of the esophagus, stomach, and intestines
Secretion of digestive enzymes and acid
Most organs receive input from both parasympathetic and sympathetic neurons
May have antagonistic or cooperative effects on the same organ
Parasympathetic and sympathetic neurons at effectors may utilize different neurotransmitters
Duel Innervation
Hair follicle muscles, sweat glands and most blood vessels are under sympathetic or parasympathetic control only?
Sympathetic
What dictates the magnitude of the response for hair follicle muscles, sweat glands and most blood vessels
In these cases, more or less frequent signals from the neuron dictates magnitude of response
