Lect 1: GI overview

Question 1

what is found at the bottom opening of the stomach?

Answer 1

pyloric sphincter

Question 2

Absorptive cells line the upper part of the villi and contain _________ which are necessary for the final digestion of proteins and carbohydrates, forming products that can be absorbed.

Answer 2

brush border enzymes

Question 3

what is the product of the stomach called?

Answer 3

chyme

Question 4

where is the common bile duct located?

Answer 4

the beginning of the duodenum

Question 5

the majority of the contents of the chyme are absorbed by ____

Answer 5

mid jejunum

Question 6

the small intenstine can histologically be distinguished from the large intestine and colon by:

Answer 6

the villus lining

Question 7

the one-cell thick lining of the small intestines:

Answer 7

enterocytes

Question 8

what are the two nerve plexuses that line the gi tract? what do they do?

Answer 8

myenteric (movement-mostly local), submucosal (secretion)

Question 9

where is the submucosal plexus?

Answer 9

between the circular muscle and the submucosa

Question 10

where is the myenteric plexus?

Answer 10

between the longitudinal and circular muscle

Question 11

skeletal muscle in the GI tract is found at:

Answer 11

the mouth, upper esophagus and external anal sphincter

Question 12

the internal area of a villus cells is known as a ____

Answer 12

crypt of Lieberkuhn

Question 13

what is the first pass effect?

Answer 13

absorbed nutrients go into the portal veins which go directly through the liver.

Question 14

most fats go into the ____, are dumped into the ____ and go through the _____ back to the ____

Answer 14

lymphatics, large vessels of the thoracic cavity, systemic circulation, liver to be processed

Question 15

what are the functions of the GI tract?

Answer 15

DEEPMASS digestion, endocrine, elimination, protection, motility, absorption, secretion, storage

Question 16

fluid intake is about ____

Answer 16

2 Liters/day

Question 17

saliva secretion is about ____

Answer 17

1.5 liters/day

Question 18

gastric secretions are about _____

Answer 18

2 liters/day

Question 19

bile secretion is about ___

Answer 19

.5 liters/day

Question 20

pancreatic juices secretion is about _____

Answer 20

1.5 liters/day

Question 21

intestinal buffers and secretions are about ____

Answer 21

1.5 liters/day

Question 22

on any given day, there are about ____ liters of fluid trunning through your tract

Answer 22

9-10

Question 23

the movement of fluids and gases in and out of the intestines can be heard as sounds called ____

Answer 23

borborygmi

Question 24

the small intestine absorbs about ______ of fluid a day

Answer 24

8.5 liters

Question 25

the colon absorbs about ____ of fluid a day

Answer 25

400 mL

Question 26

we excrete about ____ of water a day

Answer 26

100 mL

Question 27

parasympathetics in the GI tract are mainly from the ____

Answer 27

vagal to transverse colon, then pelvic nerves to anus

Question 28

sympathetics to the GI tract are from the:

Answer 28

post-ganglionic adrenergic fibers from celiac, superior and inferior mesenteric and hypogastric plexes

Question 29

cells that line the Crypts of Lieberkuhn include..

Answer 29

1. Goblet cells - secrete thick mucus
2. Stem cells
3. Endocrine cells - produce and secrete hormones into the blood, including gastrin, secretin, cholecystokinin, gastric inhibitory peptide (aka glucose insulinotropic peptide) and motilin.

Question 30

The enteric nerves are crucial to the efficient actions of the GI tract from ____ through the______.

Answer 30

esophagus to colon

Question 31

Blood flow to the intestines increases for _____ after eating, to facilitate absorption.

Answer 31

3-6 hours

Question 32

epithelial secretions serve to _____

Answer 32

lubricate, protect and digest material

Question 33

Liver functions:

Answer 33

• Secretion of bile (lipid digestion)
• storage of nutrients
• production of cellular fuels
• plasma proteins, clotting factors
• detoxification
• phagocytosis

Question 34

Pancreas secreates:

Answer 34

• buffers and digestive enzymes – by exocrine cells
• hormones – by endocrine cells to regulate digestion

Question 35

Gallbladder functions:

Answer 35

Storage and concentration of bile

Question 36

Large intestine functions

Answer 36

1. Dehydration and compaction of indigestible materials for elimination
2. resorption of water and electrolytes
3. host defense

Question 37

Small intestine functions:

Answer 37

1. Enzymatic digestion
2. absorption of water, organic substrates, vitamins, and ions
3. host defense

Question 38

Stomach functions:

Answer 38

1. Chemical breakdown of food by acid and enzymes
2. mechanical breakdown via muscular contractions

Question 39

Salivary gland function:

Answer 39

Secretion of lubricating fluid containing enzymes that initiate digestion

Question 40

Enteric nervous system (ENS), acts locally with input from ____ and _____

Answer 40

autonomics and local receptors

Question 41

T/F: Central nervous system (CNS) does not take part in regulation of GIT

Answer 41

False - helps with anticipatory sensory responses and reflexes

Question 42

Lumenal receptors, including chemo-, mechano- and osmoreceptors respond to ____ and signal to ______.

Answer 42

• acidity and chemical composition of the chyme, its osmolarity, and stretch, respectively. \
• These receptors signal the ENS and endocrine cells.

Question 43

T/F: Hormones in GIT affect other organs only in an endocrine fashion.

Answer 43

False - Hormones in the GI tract act in endocrine and paracrine manners to affect other parts of the GI tract and related organs.