Autonomic Nervous System

What major features distinguish the ANS from the somatic motor component of the peripheral nervous system?

- Autonomic fibers that leave the CNS do not terminate on an end organ as do voluntary motor fibers, they terminate in the autonomic ganglia -The ANS supplies smooth muscle, cardiac muscle, and certain glands -The visceral motor system, 2 neurons are required to transmit a nerve impulse from the CNS to the end organ -Somatic motor system, only one neuron is required to transmit a nerve impulse from the CNS to Skeletal muscle.

Where does the axon of a sympathetic pre-ganglion neuron go after it leaves the spinal cord? Name all of the options.

- Leaves the spinal cord (T1-L2), Synapse in sympathetic chain ganglia -Joins the sympathetic trunk -Some fibers end in the trunk at the same level entered - Some fibers run up or down the trunk before ending - Some fibers traverse the trunk to form splanchinic nerves

Describe the anatomy and function of the adrenal medulla.

-Cells in the adrenal medulla are derivatives of nerve tissue and constitute a modified sympathetic gland -Composed of chromaffin cells

Where does the autonomic nervous system fit in the overview of the nervous system?

-Fits in the visceral motor of Efferent System of the Peripheral Nervous System from the Spinal Cord -No Voluntary control

What are the differences between the Sympathetic and Parasympathetic divisions?

-Location of the cell bodies of their preganglionic and postganglionic neurons. -Length of preganglionic fibers (preganglionic parasympathetic fibers are longer than the postganglionic sympathetic fibers due to location in the body) -Length of postganglionic fibers (postganglionic parasympathetic fibers are longer than the postganglionic sympathetic fibers due to location in the body)

What are splanchnic nerves?

-Visceral- Preganglionic axons - Nerves that did not synapse in chain ganglia, they synapse in collateral ganglia

Why is the adrenal medulla considered to be a modified sympathetic ganglion?

Composed of an outer cortex and inner medulla????? ASK DEBBI

Is the autonomic nervous system a motor or sensory system?

Motor System

Do the sympathetic and parasympathetic both always innervate an organ? Example?

Not all organs are innervated both by both of the subdivisions

Describe the specific effects the ANS has on the Sexual Response.

Parasympathetic Fibers and Sympathetic fibers work together in this response. - In the male: Parasympathetic Fibers: Stimulates the erection of the penis Sympathetic Fibers: Induce ejaculation -In the Female: Parasympathetic Fibers: Cause erection of the clitoris Sympathetic Fibers: Constrict the vagina

Describe the specific effects the ANS has on the eye.

Parasympathetic Fibers: -Act on the constrictor pupillae and ciliary muscles -Cause pupillary constriction and thickening of the lens for accommodation -Contraction of the ciliary muscles relaxes the suspensory ligaments of the lens causing the lens to thicken Sympathetic Fibers: - Act on the dilator pupillae muscle causing pupillary dilation

Describe the specific effects the ANS has on the Lungs.

Parasympathetic Fibers: -Innervates the smooth muscle and mucosal glands of the trachea and bronchial tree -Causes Bronchoconstriction and stimulation of secretion Sympathetic Fibers: -Innervate the smooth muscle and the mucosal glands of the trachea and bronchial tree - Cause bronchodilation and inhibition of secretion

Describe the specific effects the ANS has on the Heart.

Parasympathetic Fibers: -Vagus Nerve terminates on the nodes, muscle fibers of the atria, and the ventricles on the coronary arteries -Causes cardiac inhabitation Sympathetic Fibers: -Innervate the nodes, cardiac muscle, and the coronary arteries -Cardiac acceleration and dilation of the coronary arteries

Describe the specific effects the ANS has on the peripheral blood vessels.

Parasympathetic Fibers:(Lacking in the cutaneous areas) -Supply blood vessels only in some visceral structures Sympathetic Fibers: -Causes vasoconstriction of cutaneous vessels and vasodilation of the blood vessels in skeletal muscle

Describe the specific effects the ANS has on the Stomach and Intestines.

Parasympathetic Fibers:(Via Vagus Nerve) -Increase the peristaltic rate, relax sphincters, and stimulate secretion - Promotes digestion Sympathetic Fibers: -Inhibit peristalsis and secretion, contract sphincters, and causes vasoconstriction -Inhibits digestion

Which system is described as having a localized response? Explain.

Parasympathetic Nervous System; -No divergence of stimuli -Each preganglionic neuron synapses with a limited number of postganglionic neurons and each of the latter ends on numerous effector cells

What systems do the pelvic splanchnic nerves belong to?

Parasympathetic System

What neurotransmitters do the preganglionic neuron use for the sympathetic and parasympathetic nervous system?

Parasympathetic: -Acetylcholine Sympathetic: -Acetylcholine

What neurotransmitters do the postganglionic neuron use for the sympathetic and parasympathetic nervous system?

Parasympathetic: -Acetylcholine Sympathetic: - Norepinephrine

Where are the postganglionic neurons found for the parasympathetic and sympathetic systems?

Postganglionic Neurons: Found in the Autonomic Ganglia Parasympathetic: -Terminal and Intramural Ganglia (located near or in the wall being innervated) Sympathetic: -Paravertebral Ganglia -Prevertebral Ganglia (Celiac, Superior mesenteric, Inferior mesenteric ganglia)

Where are the preganglionic neurons found for the parasympathetic and sympathetic systems?

Preganglionic Neurons : Are found in the CNS (Brain or spinal cord) Parasympathetic: -Cranial Outflow (CNs 3,7,9,10) -Sacral Outflow (S2-4) Sympathetic: -Throacolumbar Outflow (T1-L2)

What three general structures/tissues does the autonomic nervous system innervate?

Smooth Muscle, Cardiac Muscle, and the Glands of the body

Describe the specific effects the ANS has on the Skin.

Sympathetic Fibers: Contraction of the arrector pili muscles and stimulate perspiration. Parasympathetic system does not go to the peripheral areas

Which system is described as having a mass response? Explain.

Sympathetic Nervous System; -A sympathetic neuron synapse with as many as 20 or more postganglionic neurons and each of the latter ends on numerous effector cells

Describe some of the differences between the sympathetic and parasympathetic divisions.

Sympathetic System: -Primarily an emergency one, preparing the body so that the individual can FLEE OR FIGHT - Accelerates the heart rate -Rise in arterial pressure -Increases blood flow to the skeletal muscles Parasympathetic System: -Primarily a HOMEOSTATIC one tending to promote quiet and orderly processes of the body. -Decreases heart rate -Lowers blood pressure -Augment to digestive activity

What are the two main subdivison of the Autonomic Nervous System?

Sympathetic and Parasympathetic Divisons

Do the sympathetic and parasympathetic always oppose each other? Example?

The division can have opposing functions; Inhibiting effects versus stimulating effects. Ex. Parasympathetic fibers to the stomach increase peristalsis and relax the sphincters, while sympathetic fibers have the opposing effect.

Do the sympathetic and parasympathetic ever work together? Example?

They work together in sexual response. Ex. In the male: Parasympathetic Fibers: Stimulates the erection of the penis Sympathetic Fibers: Induce ejaculation In the Female: Parasympathetic Fibers: Cause erection of the clitoris Sympathetic Fibers: Constrict the vagina

Do sensory fibers sometimes travel with autonomic fibers?

Yes, visceral sensory fibers may travel with autonomic fibers but they are not technically part of the ANS