The Intestines

Question 1

What is the role of the intestines?

Answer 1

Absob water and electyres and absorb nutirents

Question 2

What are the parts of the small intestine proximal to distal?

Answer 2

The duodenuem proximally, the jejunum and ileum in the distal parts,

Question 3

What is the blood supply of the small intestine?

Answer 3

Supplied by the gastrodudenal atery which is a branch of the celiac drunk and then the aterial supply is from the SMA

Question 4

What are the the different parts of the large intestine from proximal to distal?

Answer 4

The cecum, the ascending colon, the right colic felexure, the tranverse colon, the left colic felxure and the desceding colon and then the sigmoid colon

Question 5

What are some of the antomical fetures of the rectum and the anla canl?

Answer 5

Is retropertioneal and immeadty anterior to the sacrum, and the distal protion is expanded

Question 6

What are the basic features needed for absorption?

Answer 6

Needs a large surface area, proved by mucosa folded into vili and then mircovilli that help to form a brush border,

Question 7

What are some of the features of the intestinal eptiehlia>

Answer 7

The epthiela cells are known as enterocytes are there are also mucus sereting foblet cells, the mucosa is shed every 3 to 6 days and there are intestinal glands or cyrpts that have stem cells at the base, and that migrate to the surface maturing as they migrate n

Question 8

What are the key points regarding carbohydrate digestion?

Answer 8

Glucose can only enter with Na+, and the final breakdown of polysacchrides occurs within the brush border.

Question 9

What are the bonds found in amylase?

Answer 9

A1-4

Question 10

What are the bonds found in amylopectin?

Answer 10

A1,4 ad A1,6

Question 11

What is the ezyme used on A1,4 bonds?

Answer 11

Amylase

Question 12

What is the enzyme that is used in amylopectin>

Answer 12

A 1,6

Question 13

What are the transporters for glucose in the apical membranes of intestinal cells?

Answer 13

SGLUT-1 transports glucose(co transport wiht Na+) and galactase and GLUT-5 is used for fructose

Question 14

What are the transporters for glucose in the basolateral membrane of cells?

Answer 14

GLUT-2- faciliated diffusion

Question 15

What is the princple of oral rehydration fluid>

Answer 15

Glucose uptake stimulates the uptake of Na+and the mixture of water and salt will therefore faciliate maximal glucose uptake

Question 16

How are proteins digested within the stomach?

Answer 16

Pepsinogen is realeased from the cell, and gets convereted to pepsin by HCL, and pepsin acts on protein, and therefore digests the amino acids and then moves to the small intestine

Question 17

What is a exopeptidase and give an example?

Answer 17

An enzyme that breaks bonds at the end of a polypeptides to produce dipeptides or indivdual amino acids, an example is carboxypeptidases A and B

Question 18

What is an endopeptidase and give examples?

Answer 18

Breaks bonds in the middle of a polypeptide in order to produce smaller peptides, including trypsin, chymotrypsin,

Question 19

How are proteins absorbed wihtin the small intestine?

Answer 19

Na+ amino acid co transporters there are different ones that can be neutral, acidic and basic, and most protein products that are ingested as dipeptides or tripeptides, that are moved in by H+ co transporters

Question 20

What are the differences between electroylte reabsorption in the small and large intestines?

Answer 20

large intestine there are Na+ channles that are induced by aldosterone, and in the small intestine Na+ is co transported

Question 21

What are some of the different features of the uptake of calicum?

Answer 21

When calcium is low there is active transcellular reabsoprtion in a proccess that requires vitamin D, and where calcium is normal or high there is passive paracellular absorption

Question 22

What are some of the features of iron absoprtion?

Answer 22

When iron levels are high the iron is contained within ferrin complexes that are lost when eneterocytes are replace, and where ion in low iron binds to transferrin

Question 23

What are some of the features of the motility of the small intestine?

Answer 23

In the small intestine there is a intestinal gradient between meals controlled by an intestinal pacemaker to keep the movement of the differen prodcuts flow, and there is segmentaiton following a meal where the contents are moved back and forht and then mixed

Question 24

What are some of the features of motility within the large intesitn?

Answer 24

There is segmentation that is also known as hastural shuttling, and this agitates and mixes the contents, and there is also mass movement that occurs 1-3 times a day, and can move contents rapidly from the tranverse colon to the rectum, and is triggere by eating 1-3 times a day

Question 25

What are some of the features of the proccess of defecation?

Answer 25

The rectum is normally empty, when it is 25% full the urge to defectat ocurs, the internal spinther relaxes under parasymptathia contorl whereas the external spincther relaxes under voluntary control and then a rise in intrabdominal pressure pushes the contents out