Chapter 60 - Guyton Flashcards Preview

Physiology > Chapter 60 - Guyton > Flashcards

Flashcards in Chapter 60 - Guyton Deck (20):
1

Portion of the nervous system that controls most visceral functions of the body.

autonomic nervous system (control arterial pressure, gastrointestinal motility, gastrointestinal secretion, urinary bladder emptying, sweating, body temperature, etc.)

2

Organization of the Autonomic Nervous System

cell body of preganglionic axon located in the brain stem or spinal cord, axon of the visceral motor neuron is thinly myelinated and projects to an autonomic ganglia, cell body of postganglionic neuron in the autonomic ganglia projects to visceral effector cell

3

Location of sympathetic ganglia vs. parasympathetic ganglia.

sympathetic - close to the spinal cord (short preganglionic, long postganglionic); parasympathetic - close to the visceral effector tissues (long preganglionic, short postganglionic)

4

Sympathetic System - Axon Paths (3)

1) enter the sympathetic chain via the white ramus and terminate there; 2) enter the sympathetic chain via the white ramus and ascend or descend a few segments before terminating there; 3) enter via the white ramus and exit via a splanchnic nerve and terminate in prevertebral ganglia

5

Where do parasympathetic nerves originate?

CN III (pupillary sphincter and ciliary muscle), CN VII (nasal, lacrimal, and submandibular glands), CN IX (parotid gland), CN X (motor to visceral organs), sacral segments (descending colon, rectum, bladder, and genitalia)`

6

Sympathetic nerves release ____________ and we call these nerves ___________.

norepinephrine, adrenergic

7

Parasympathetic nerves release ____________ and we call these nerves ___________.

acetylcholine, cholinergic

8

Norepinephrine and epinephrine are synthesized from the amino acid ________.

tyrosine (tyrosine --> DOPA --> dopamine --> NE/EPI)

9

What occurs after sympathetic nerves release norepinephrine?

stimulates alpha and beta adrenergic receptors, alpha receptors on blood vessels cause vasoconstriction, beta1 increases heart rate and contractility, beta2 causes bronchial dilation, dilation of blood vessels in skeletal muscles, calorigenesis, glycogenolysis

10

What occurs after parasympathetic nerves release acetylcholine?

Ach activates nicotinic (between pre- and post-ganglionic receptors) and muscarinic (found on all effector cells and stimulated by post-ganglionic parasympathetic fibers) receptors

11

Effect of Autonomic Nervous System on the Eye

sympathetic - pupillary dilation; parasympathetic - pupillary restriction and accommodation of the lens (focusing)

12

Effect of Autonomic Nervous System on the Glands

sympathetic - sweat glands; parasympathetic - nasal, lacrimal, salivary, GI glands

13

Effect of Autonomic Nervous System on the GI Tract

sympathetic - very little effect; parasympathetic - overall activity including GI smooth muscle

14

Effect of Autonomic Nervous System on the Heart

sympathetic - increase HR and contractility; parasympathetic - decrease HR

15

Effect of Autonomic Nervous System on the Blood Vessels

sympathetic - vasoconstriction; parasympathetic - some vasodilation

16

Function of the Adrenal Medulla

large sympathetic ganglion, releases EPI (80%) and NE (20%) when stimulated, stimulates cardiovascular function and metabolism, helps body deal with stress

17

What is meant by sympathetic and parasympathetic tone?

sympathetic - normally accounts for 50% vasoconstriction; parasympathetic - provides background GI activity

18

What occurs during a stress response?

mass sympathetic discharge, increase in arterial pressure, HR and contractility, blood flow to muscles, blood glucose, metabolic rate, muscle strength, mental activity, blood coagulation (preparing the body for vigorous activity aka "fight or flight")

19

How do drugs affecting the sympathetic nervous system work?

adrenergic or sympathomimetic drugs act like EPI or NE, much more prolonged effect than real thing, drugs can increase release (albuterol, phenylephrine, ephedrine, amphetamine) or block the effect (beta blockers)

20

How do drugs affecting the parasympathetic nervous system work?

parasympathomimetic drugs activate nicotinic (nicotine) or muscarinic receptors, potentiate effect of Ach (cholinesterase inhibitors) or block Ach (atropine)