Phsiologic Anatomy of the GI wall - Enteric NS

Question 1

measurement of individual muscle fibers in the GI tract

Answer 1

200-500 micrometers long and 2-10 micrometers in dm

Question 2

Longitudinal muscle layer

Answer 2

extends longitudinally down the intestinal tract

Question 3

circular muscle layer

Answer 3

bundle extends around the gut

Question 4

gap junctions

Answer 4

found within each bundle

Question 5

where can electric signals travel faster

Answer 5

along the length of the bundle

Question 6

what separates each bundle of smooth muscle but not on its entirety?

Answer 6

loose connective tissue

Question 7

How is branching lattice work of smooth muscle formed?

Answer 7

When muscle fibers fuse with one another at any joints

Question 8

syncytium

Answer 8

when an action potential is elicited anywhere within the bundle masa, it generally travels in all directions in the muscle

Question 9

How is the electrical activity of the GI smooth muscle?

Answer 9

Continuous but slow

Question 10

2 basic type of electrical activity

Answer 10

Slow waves and spikes

Question 11

Intensity in slow waves

Answer 11

between 5 and 15 mv

Question 12

Frequency in the stomach, duodenum and ileum during slow waves

Answer 12

stomach (3/min)
duodenum (12/min)
ileum (8-9/min)

Question 13

interstitial cells of cajal

Answer 13

electrical impulse in the slow waves

Question 14

Normal resting membrane potential in the smooth muscle fibers of the gut

Answer 14

-50 to -60 mv

Question 15

spike potentials frequency

Answer 15

1-10 spikes/s

Question 16

the normal resting membrane potential

Answer 16

-56 mv

Question 17

depolarization

Answer 17

potential is less negative, muscle fibers more excitable

Question 18

hperpolarization

Answer 18

potential is more negative, fibers less excitable

Question 19

When do spike potential occur?

Answer 19

When resting membrane potential of the gi smooth muscle becomes more positive than -40 mv

Question 20

Calmodulin control mechanism

Answer 20

causes muscle contraction by activating the myosin filaments in the fiber

Question 21

Enteric nevrous system

Answer 21

-lies in the wall of the gut from esophagus to anus and controls gi movement and secretion

Question 22

2 plexus of the enteric nervous system

Answer 22

Myenteric plexus (Auebach’s) and submucosal plexus (meisner’s)

Question 23

Auerbach’s plexus

Answer 23

controls gi movements

Question 24

Meissners plexus

Answer 24

gi secretion and local blood flow