L49 ANS - Just a Review, NEURO GOLD is better!

Question 1

The ANS contributes to ______; maintaining the internal environment WITHOUT voluntary control.

Answer 1

homeostasis

Question 2

what is the control center for most basic life processes?

Answer 2

hypothalamus

Question 3

what major systems does the hypothalamus receive info from?

Answer 3

• neuronal input

- humoral input

Question 4

describe neuronal input.

Answer 4

• visceral afferent sensory info enters CNS via spinal nerves to hypothalamus
• may also enter via cranial nerves but it will stop in the solitary nucleus of the brainstem before hypothalamus

Question 5

describe humoral input.

Answer 5

• received thru circumventricular organs int he walls of the ventricles which contain fenestrated capillaries
• lack of BBB –> detect chemical changes in blood and relay the info to the internal regulatory system

Question 6

what two divisions make up the ANS.

Answer 6

PNS and SNS

Question 7

most organs receive motor innervation from what division of ANS?

Answer 7

both

Question 8

describe the enteric division.

Answer 8

-formed by 2 layers of ganglia/plexus in GIT
each pleas receives sensory info from the gut wall (via afferents) and modulate their respective task

*note that the enteric division does NOT work completely independently and may be modified by efferent fibers of the sympathetic and parasympathetic divisions

Question 9

where is the myenteric (Auerbach) plexus found and what is its function?

Answer 9

• between the longitudinal and circular smooth m.

- gut motility

Question 10

where is the submucosal (Meissner’s) plexus and what is its function?

Answer 10

• adjacent to the mucosal epithelium

- water/ion txp and digestive juice secretion

Question 11

what are the pathways in the ANS?

Answer 11

sympathetic and parasympathetic pathways

Question 12

describe the sympathetic pathway.

Answer 12

-preganglionic fibers leave the intermediolateral column of the spinal grey matter via ventral roots
fibers enter either the paravertebral chain ganglia or pre vertebral ganglia
-post ganglionic fibers leave their respective ganglia to reach their target tissue

Question 13

what is the exception of the sympathetic pathway?

Answer 13

-when preganglionics leave the cord and synapse directly on the adrenal medulla

-the adrenal medulla acts like a second order neurons releasing adrenaline directly into blood
in this fashion, any adrenergic receptor in the entire body can react to sympathetic stimulation

Question 14

describe the parasympathetic pathway.

Answer 14

-preganglionic fibers originate in the brainstem (as CN’s) or in the spinal cord (as spinal nerves)
there are distinct parasympathetic ganglia (clearly, pterygopalatine, otic, submandibular ganglia)

-apart from these four distinct ganglia, post ganglionic fibers originate in their “terminal ganglia” found in the wall of the target organ

Question 15

what are the pharmacological influence of autonomic function?

Answer 15

-directed toward the receptors on the target organ

side effects are avoided by ensuring specificity for the specific type/subtype of adrenergic receptor

Question 16

Describe Hirschsprug’s disease - Megacolon.

Answer 16

• congenital absence of motility and peristalsis of the distal colon
• cause by the absence of Parasympathetic terminal ganglia in the distal colon
• feces is trapped and causes abnormal dilation, hence megacolon

Question 17

Describe complex regional pain syndrome.

Answer 17

-chronic neuropathic pain syndrome follows injury to bone, soft tissue or nerves tissue
-pain persists after apparent healing is complete
caused by an increase of sympathetic activity or increased sensitivity of nociceptors to NE
-increased sympathetic activity may also cause excessive sweating