Test 2 (Autonomic Nervous System) Flashcards
Voluntary
Innervates skeletal muscle
Somatic nervous system
Involuntary
Innervates cardiac muscle, smooth muscle, exocrine/endocrine glands, and adipose tissue
Autonomic nervous system
dominates in emergency or stressful situations and promotes responses that prepare body for strenuous physical activity
Sympathetic NS
Dominates in quiet, relaxed situations and promotes body-maintenance activities such as digestion
Parasympathetic NS
What is the anatomy of ANS
2 neuron chain with a preganlionic fiber and post ganglion fiber
Synapses with cell body of second neuron
preganglionic fiber
Innervates effector organ
postganglionic fiber
Fibers exit the ventral root of spinal cord from T1-L2 and paired bundle of nerve fibers run from the skull superiorly to the coccyx inferiorly
Sympatheric/Thoracolumbar division
Ganglia run along the lateral aspects of the vertebral bodies, linking together to form the sympathetic chain
SYmpathetic/Thoracolumbar divison
Preganglionic axons enter the sympathetic chain of ganglia just lateral to the spinal cord
Sympathetic chain
Axons typically terminate in several visceral effectors and are more widespread than the effects of parasympathetic stimulation
Postganglionic axons
Fibers originate in the brain stem and S1-S4 levels of spinal column
Parasympathetic/craniosacral division
Fibers synapse in ganglia located next to or within the target structure
Parasympathetic/craniosacral division
How are neurons classified?
Based on the neurotransmitters released
What releases acetylcholine?
Cholinergic
What releases norepinephrine?
Adrenergic
Released by all preganglionic fibers
Released by most parasympathetic postganglionic fibers
Cholinergic
Released by most sympathetic postganglionic fibers
Has both excitatory and inhibitory effects
Adrenergic
Major organ of the sympathetic nervous system that secretes large quantities of epinephrine (adrenaline) and secretes smaller quantities of norepinephrine
Adrenal Medulla
Stimulated to secrete by preganglionic sympathetic fibers
Adrenal Medulla
Has short cholinergic pre ganglion fibers and long adrenergic postganglionic fibers
Sympathetic
Has long cholinergic preganglionic fibers and short cholinergic postganglionic fibers
Parasympathetic
Found on postganglionic cell bodies of all autonomic ganglia
Nicotinic receptors (Cholinergic receptor)
Found on effector cell membranes
Muscarinic receptors (Cholinergic receptor)
receptors that receive norepinephrine and epinephrine
Alpha (NE)
Beta (E)
SNS due to epinephrine in the blood or norepinephrine from sympathetic nerves
Adrenergic stimulation
How can the adrenergic stimulation stimulate receptors?
Stimulates heart, dilatory muscles of the iris, smooth muscles of many blood vessels
How can Adrenergic stimulation inhibit receptors?
Bronchioles in lungs, other blood vessels; inhibits contraction and causes dilation of these structures
Why are most visceral organs innervated by both sympathetic and parasympathetic fibers?
They help maintain homeostasis
Effects counter one another
Antagonistic effectors
Effects of parasympathetic and sympathetic stimulation produce similar effects
Complementary effects
Systems work together toward common goal
Cooperative effects
What organs are innervated by the sympathetic division only?
Adrenal medulla
Arrector pili muscles in skin?
Sweat glands in skin
Most blood vessels
