GI System
Session 5
Supplemental Instruction
IowaStateUniversity / Leader: / Ivy
Course: / AnS 214
Instructor: / Selsby
Date: / 1/27/11

INTESTINAL MOTILITY

1)What are the three purposes of intestinal motility?

2)Intestinal motility has two primary motive forces. The first, responsible for churning contents, consists of random ring-like constrictions, is called ______. The second consists of ______waves that push chyme towards the large intestine. These waves begin in the ______and move progressively downward, can be inhibited by ______.

3)What is the frequency of segmentation?

How long does it take to move chyme down the SI?

4)What is the gastroileal reflex?

CARBOHYDRATE DIGESTION:

1) What is the working pH range of salivary amylase?

What portion of ingested dietary starch is digested in the mouth? Absorbed in the mouth?

2) Below, trace the digestion of starch through the small intestine. Above the arrows, write the names of the enzyme(s) responsible for each step of the breakdown.

Starch ______

3) What channel is responsible for transport of glucose and galactose into the cell?

What ion is required to facilitate this transport?

What category of transports does this sort of channel fall into?

4) How does fructose enter the cell? What is the fate of some of the entering fructose molecules?

5) How do digested carbohydrates exit the cell into portal circulation?

PROTEIN/LIPID/NUCLEIC ACID DIGESTION:

1) Fill in the table below with the steps involved in protein digestion:

COMPARTMENT / .... DIGESTED TO ..... / ENZYMES INVOLVED / CLEAVAGE SITE FOR ENZYMES
Mouth
Stomach
SI
LI

2) What is the active pH range of pepsin?

3) Large fat globules are ______by bile salts in the duodenum. Digestion of fat by the pancreatic enzyme ______yields free fatty acids and monoglycerides. These then associate with bile salts to form ______which “ferry” them to the intestinal mucosa. Fatty acids and monoglycerides leave micelles and ______into epithelial cells. There they are recombined with proteins to form ______. These are extruded from the epithelial cells by ______. The chylomicrons enter ______and are carried away from the intestine by lymph.

4) What two main enzymes are involved with the digestion of nucleic acids?

What kind of transport is required to transport them into enterocytes?

LARGE INTESTINE:

1)What are the three components of the large intestine?

2)What structural differences exist between the small and large intestine?

4) What main movement type characterizes intestinal motility?

5)Define the gastro-colic reflex.

6)______in one area leads to ______in another.