Digestive System - Class Notes

Front 1

Three sections of small intestine

Back 1

duodenum
jejunum
illeium

Front 2

4 layers of intestine

Back 2

Serosa (outside, thin layer)
Tunica muscularis (smooth muscle)
Submucosa
Mucosa (Houses specialized epithelial cells)

Front 3

Monosacrides (carbohydrates) that can be absorbed by the gut.

Back 3

Glucose
Fructose
Galactose

Front 4

What is leptin and what does it do?

Back 4

Hormone secreted by fat cells.

More leptin:
Decrease food intake
Increase energy expenditure:
Increase temp.
Increase O2 consumption

Front 5

What two sugars comprise Lactose?

Back 5

Glucose and galactose

Front 6

Propulsion through the digestive system is also called ____

Back 6

peristalsis

Front 7

Effect of distention in

Lower stomach

Upper stomach

Back 7

Lower: Vigorous contraction

Upper: relaxation of resevoir

Front 8

What activates pepsinogen? What does it become after activation?

Back 8

HCL.
Pepsin itself (autocatalytic)

Pepsin

Front 9

What are the three activator receptors on a parietal cell?

Back 9

acetycholine (Nervous system)
Gastrin
Histamine

Front 10

3 phases of gastric function

Back 10

cephalic phase
gastric phase
intestinal phase

Front 11

What hormone is secreted by the gut when acidic chyme is detected? What is the effect of this hormone on the stomach?

Back 11

Secretin
Slows down the digestion in the stomach.

Front 12

What enzymes are secreted by the pancreas which digest protein?

Back 12

chymotrypsinogen => chymotrypsin when activated

trypsinogin => trypsin when activated

Front 13

What enzyme is secreted by the pancreas to convert starch to maltose?

Back 13

amylase

Front 14

What class of enzymes is released by the pancreas to digest protein. What are two members of this class?

Back 14

proteases

trypsinogen
chymotrypsinogen

Front 15

What activates the pancreas to secret HCO3-?

To secret enyzmes?

Back 15

secretin

CCK

Front 16

What activates trypsinogen?

Back 16

The brush boarder enzyme enterokinease

Front 17

Give the steps for digesting lactose

Back 17

Brush boarder enzyme lactaid breaks lactose into free glucose and galactose molecules. Na+ and then Glucose binds to Na+ dependent hextose transporter. Glucose transported into cell. Transporter flips back and galactose is transported into cell in the same manner.

Front 18

Four Pregastric "processes"

Back 18

Prehension - Food intake

Mastication - Chewing. Fracture into
smaller pieces so enzymes can attack.

Salivation - Lubrication, Solubilize
-> taste

Swallowing

Front 19

What are two ways to reduce the production of stomach acid? They involve a___ of h____ and elimination of P___ P____.

Back 19

Antagonists for Histamine.
Elimation of proton pump.

Front 20

If the gut looses its lactaid brush boarder enzyme, what will be the result when lactose is ingested?

Back 20

The lactose will result in a high os molarity in the gut and water will diffuse into the gut => diarrhea.

Front 21

The folds in the gut consist of the v___ and the c___

Back 21

villus, crypt

Front 22

Method for removing Na+ from an epithelial cell of the gut

Back 22

Na+/K+ ATPases (pumps) in the basolateral surface. Na+ is pumped into the region between two cells. It then moves to a nearby blood vessel.

Front 23

Hepatocytes secrete B___ into the B____

Back 23

Bile
Bilecannaliculus

Front 24

Bile consists of

Back 24

H2O, Na+Cl-, HCO3-,
cholesterol, bile salts,
bilribubin (bile pigment)

Front 25

Show the two chief components of bile acids and indicate which part is hydrophobic, lipohillic, etc.

Back 25

~~~~~~~~~~~~~~O
cholesterol amino acid
hydrphobic hydrophillic
lipohillic lipophobic

Front 26

Two types of motion in the gut

Back 26

peristalsis - propulsive
segmentation contractions - mixing

Front 27

What enzyme digests triglcerides? What are the resultant molecules?

Back 27

Lipase

monoclyceride + 2 fatty acids

Front 28

What hormone is secreted by the gut when fat and proteins are detected? What is the effect on the stomach? On the pancreas? On the gallbladder?

Back 28

CCK (cholecystokinin)
Slows down the action in the stomach.
Stimulates pancreas to secrete enzymes into the gut.
Stimulates the gall bladder to contract and release bile to the gut.

Front 29

___ from the ____ breaks a glob of trigylceride into small droplets. ___ from ____ digests these droplets into monoglyceride plus two free fatty acids.

Back 29

Bile Salts, Liver
Lipase, pancreas

Front 30

Give the steps for digesting and absorbing starch

Back 30

1) Amylase from pancreas breaks starch into maltose.
2) Maltase (brush boader enzyme) breaks maltase into glucose and glucose
3) Na+ binds to Na+ dependent hexose transporter...opens glucose receptor
4) Glucose binds
5) molecule flips (Na+, G inside cell)
6) Na+ falls off
7) Glucose falls off
8) Molecule flips back to face lumen of gut.

Front 31

Four main types of cells in the gastric pit of the stomach and what they secrete. Also give the order in which they are found in the pit - top to bottom.

Back 31

Mucus cell - mucus
Parietal cell - HCL (and intrinsic factor)
Chief cell - Pepsinogen
G cell - Gastrin (stimulates parietal cell)

Front 32

Where are mature absorptive cells found in the gut? How often do epithelial cells slough off and get replaced?

Where are stem cells found?

Back 32

Top portion of the villa.

Every few days

Bottom of the crypt.

Front 33

Effect of distention of gut - due to entrance of chyme - on the stomach. What mechanism is used to deliver the message to the stomach?

Back 33

Slow down signal sent to gut by the enteric nervous system when distention is sensed in the gut.