SHPEP A&P - autonomic system (lecture 7)

Autonomic nervous system

the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.

Efferent fibers typically lead to…

…ganglia outside of the cell

Ganglia

clusters of cell bodies in the PNS

How is the autonomic nervous system divided?

sympathetic and parasympathetic

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations (STRESS/fight or flight)

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy (rest & digest)

All of the autonomic nerve fibers are…

…motor (efferent)

preganglioic fibers

Axons of preganglionic neurons. Neuron cell bodies in CNS

Postganglianic fibers

Axons of postganglionic neurons. Neuron cell bodies in ganglia

Adrenal medulla

secretes epinephrine and norepinephrine

What stimulates the adrenal medulla?

sympathetic nervous system

Where are ganglia of the sympathetic division located?

Thoracolumbar region (close to spinal cord)

Adrenal cortex

outer section of each adrenal gland; secretes cortisol, aldosterone, and sex hormones

What is the adrenal cortex stimulated by

ACTH from anterior pituitary (sympathetic nervous system)

preganglionic fibers leave spinal nerves through _ rami & enter __ ganglia

White, pravertebral

paravetebral ganglia and fibers that connect them make up what?

The sympathetic trunk

Postganglionic fibers extend from sympathetic ganglia to…

…visceral organs

Postganglionic fibers usually pass through rami and return to a spinal nerve before proceeding to an ____

Gray, effector

What kind of preganglionic fibers DO NOT synapse with postganglionic neurons?

Preganglionic fibers to the adrenal medulla

Craniosacral division

Another name for the parasympathetic division.

Where are preganglionic neurons located?

Craniosacral division

Cholonergic fibers release what?

They release acetylcholine

Adrenergic fibers release what?

They release norepinephrine

Cholergenic fibers are…

…preganglionic sympathetic and parasympathetic fibers

Adrenergic fibers are…

…postganglionic and sympathetic fibers

• think aggravation think STRESS so sympathetic

Cholinergic receptors bind to what?

They bind to acetylcholine (Ach)

Muscaranic Receptors

receptor cites for acetylcholine in the parasympathetic nervous system, where they mediate various functions by interacting with the neurotransmitter acetylcholine

adrenergic receptors

receptor sites for the sympathetic neurotransmitters norepinephrine and epinephrine on effector cells

excitatory neurotransmitters

Cause depolarization of postsynaptic membranes. Promote action potentials

Slow neurotransmitters

regulate release of neurotransmitters from synapse over a period of time

nicotinic receptors

cholinergic receptors that also respond to stimulation by nicotine

T/F: nicotinic receptors are found in both sympathetic and parasympathetic pathways

True, nicotinic receptors are found in the ganglia of the post ganglionic neuron

antagonistic effects of dual innervation

the two divisions exerting opposing effects on a target organ. in an emergency, the sympathetic division inhibits many processes of the parasympathetic division. when the emergency is over, the parasympathetic division takes over once again

dual innervation

organs that receive instructions from both sympathetic and parasympathetic divisions

beta-adrenergic receptors

Portions of the nervous system that, when stimulated, can cause an increase in the force of contraction of the heart, an increased heart rate, and bronchial dilation.

alpha-adrenergic receptors

Portions of the nervous system that, when stimulated, can cause constriction of blood vessels.

What organs are ONLY innervated by the sympathetic nervous system?

Adrenal medulla, arector pilli muscles in skin, sweat glands in skin, most blood vessels

Beta blockers block what

Sympathetic function (they block beta-Adrenergic receptors)

What controls the autonomic nervous system?

hypothalamus and medulla oblongata (CNS)

medulla oblongata

regulates cardiac, vasomotor andrespiratory activities

hypothalamus

regulates visceral functions, such as body temperature, hunger, thirst, and water and electrolyte balance

Limbic system and cerebral cortex

control emotional responses