Physiology 1

Question 1

Name the layers of the muscoas from in to out

Answer 1

1. epithelium 2. lamina propria 3. muscularis mucosa

Question 2

made of connective tissue, contains gut associated lymphoid tissue

Answer 2

lamina propria (2nd layers of the muscosa)

Question 3

Thick layer of connective tissue provides digestive tract distensibility and elasticity
It consist of large blood vessels, lymphatics, glands and submucosal plexuses that supports the mucosa.

Answer 3

submucosa

Question 4

the largest barrier in the body, and its characteristics

Answer 4

Lumen- Blood Barrier“ between the body and a lumenal environment.
Physical, biochemical and Immunological barrier

Question 5

name the pre-epithelial defenses (6)

Answer 5

Bicarbonate secretion • Duodenal pH
• Mucus
• Surface hydrophobicity • Prostaglandins
• Surface active phospholipids

Question 6

name the epithelial defenses (4)

Answer 6

• Apical barrier
• Mucoid cap
• Extrusion of back diffused H+
• Oxidant stress and antioxidant
mechanisms

Question 7

name the subepithelial defence (1)

Answer 7

mucosal blood flow

Question 8

Heat shock proteins are which line of defense

Answer 8

pre-epitheilial

Question 9

whats the composition of the muscosal gel

Answer 9

95% water, 5% cross linked mucin (glycoprotein)

Question 10

whats the first line of mucosal defense

Answer 10

musosal buffer barrier - bicarb bitch

Question 11

prevent back diffusion of luminal hydrogen ion.

Answer 11

surface hydrophobicity

Question 12

• It provides the cellular protection against stressor (NSAIDs, ethanol) induced damage by refolding or degrading denatured proteins, produced by these stressors.
• It protects the gastric mucosa through inhibition of apoptosis and pro- inflammatory cytokines.

Answer 12

heat shock proteins

Question 13

Provides resistance to back diffusion of acid from gastric lumen to blood plasma

Answer 13

intercellular junction

Question 14

It is composed of mucous, cell debris, fibrin and other plasma proteins
Provides impermeable barrier to back flow of acid and simultaneously block the flow of ECF into gastric lumen.

Answer 14

mucoid cap

Question 15

It is an important regulator of mucous and bicarbonate production.
• Increase mucosal blood flow.
• It inhibits the acid secretion

Answer 15

prostaglandins

Question 16

how do prostaglandins inhibit acid secretion

Answer 16

G protein coupled EP3 receptor.

Question 17

antagonize the

effects of inhibitors of cyclo-oxygenase and lipo- oxygenase pathways.

Answer 17

prostaglandin E2, lipoxin A4

Question 18

scavenges the reactive oxygen species and induces antioxidant enzymes

Answer 18

melatonin

Question 19

the trefoil factor family protein is a part of which line of defense

Answer 19

epithelial

Question 20

TFF are secreted by _________act as a _______

Answer 20

mucous cells, barrier

Question 21

protect mucous epithelia from a range of insults and contribute to mucosal repair, increased blood flow and migration of cells.

Answer 21

TFFs

Question 22

pancreatic bicarb secretion is a part of which line of defense?

Answer 22

epitheilial

Question 23

Duodenal acidification stimulates pancreatic secretion mainly through the release of

Answer 23

cholescysotkinin and secretin

Question 24

inhibits the acid secretion from the gastric mucosa and stimulates secretion of bicarbonate from the pancreas.

Answer 24

secretin

Question 25

Protective Peptides and Enzymes are a part of which line of defense

Answer 25

epitheilial

Question 26

are specialized secretory cells which are the main source of antimicrobial peptides.

Answer 26

paneth cells

Question 27

where are paneth cells located

Answer 27

located primarily in the small intestine,

Question 28

role in host defense, the alpha- defensin and other antimicrobials peptides that are produced by______________have a key homeostatic role in establishing and maintaining the intestinal microbiota

Answer 28

paneth cells

Question 29

also secrete Protective Enzymes such as Lysozyme & Phospho lipase A.

Answer 29

paneth cells

Question 30

also function as vital trophic factors for the stem cells of the small intestine.

Answer 30

paneth cells

Question 31

sensory afferent neurons and growth factors are a part of which line of defense

Answer 31

subepitheilial

Question 32

Themainsensoryneuroninstomachare

Answer 32

small diameter c fibers containing CGRP (this is a calcitonin peptide)

Question 33

how does CGRP protect against ulceration and help restitution

Answer 33

1. stimulation of blood flow 2. inhibition of acid secretion 3. release of somatostatin 2. inhibition of motility

Question 34

T or F, blood flow decreases during gastric secretion

Answer 34

false, it increases

Question 35

stimulates the production of Nitric Oxide (NO), which leads to the dilation of blood vessels and hence blood flow.

Answer 35

CGRP

Question 36

gastro protective against ethanol, acetic acid and aspirin induced injury and involved in wound healing.

Answer 36

TGF alpha

Question 37

name the two growth factors invovled in cell renewal/repair

Answer 37

TGF alpha nad IGF-1

Question 38

Rapid re-epithelialization (restitution) to flat cells takes _______to occur

Answer 38

an hour

Question 39

What are the three phases of damage repair of the GIT

Answer 39

1. Rapid re-epithelialization (restitution) to flat cells 2. Transition of flat to columnar cells 3. Reformation of pits

Question 40

how long does it take to repair the IGT

Answer 40

2 days

Question 41

why do epitheilial cells rapidly migrate into the denuded area

Answer 41

restore barrier integrity

Question 42

it starts within minutes to hours of injury and is INDEPENDENT of proliferation

Answer 42

epitheilal restitution

Question 43

Proliferation of the mucosal epithelium to increase the pool of enterocytes available to resurface the defect generally begins __________after injurt

Answer 43

hours or days after injury

Question 44

The wall of the alimentary canal has four basic tissue layers:

Answer 44

1. Mucosa, 2. Submucosa, 3. Muscularis, and 4. Serosa