Lower GI Tract

Question 1

The stomach and intestine have a complex network of neurons called?

Answer 1

The Enteric nervous system

Question 2

what is particular about the digestive neural circuits that have to do with the CNS?

Answer 2

there is no CNS involvement- no interneurons

Question 3

What are the three major stages of gastric function?

Answer 3

cephalic, gastric, intestinal

Question 4

Explain the three phages of gastric function?

Answer 4

Cephalic- smell, sight, thought of food- causes secretion of gastric juices in prep for arrival of food
Gastric- entry of food in stomach- even more gastric secretions and muscle contractions
Intestinal phase- sphincter allows small amounts of chyme to enter stomach

Question 5

Mechanoreceptors (afferent neurons of a reflex) are embedded in the muscular walls of the stomach. As food enters the stomach, the mechanoreceptors will ___________ the rate of action potentials to efferent neurons (hint – think of baroreceptors!).

Answer 5

increase

Question 6

Result of increased action potentials of mechanoreceptors causes the release of even more gastric secretions initiated in the cephalic stage AND muscle contractions. This is an example of what type of feedback?

Answer 6

Positive

Question 7

Where do absorbed nutrients go?

Answer 7

absorbed by villi
enter bloodstream at capillary, collected in vein
goes to liver via hepatic portal system
liver helps remove and metabolize nutrients

Question 8

Blood in the hepatic portal vein is nutrient _____ and oxygen _____?

Answer 8

rich; poor

Question 9

Hepatic triads are made up of what?

Answer 9

arterioles: O2 rich blood supply to liver
bile ducts: collect bile
Hepatic venues: O2 poor, nutrient rich from GI

Question 10

Liver cells form _____ surrounded by ______ ______.

Answer 10

Lobules
hepatic triads

Question 11

What is the purpose of the central vein in Liver Lobules?

Answer 11

carries deoxygenated blood out of liver lobule

Question 12

What is the exocrine and endocrine function in the pancreas?

Answer 12

exocrine function- pancreatic enzymes (Acinar cells)
Endocrine function- hormones (Langerhands)

Question 13

What is the roll of Langerhans cells?

Answer 13

synthesize insulin or glucagon INTO capillaries

Question 14

What is the role of insulin and glucagon?

Answer 14

Insulin: responds to high blood glucose - gets liver to store glucose
Glucagon: responds to low blood glucose- gets liver to release glucose

Question 15

Type 1 and Type 2 Diabetes

Answer 15

Type 1: total lack of insulin production
Type 2: insulin resistance

Question 16

A person has an auto-immune disease where their immune cells produce antibodies that match their own Islet cells. This results in which type of diabetes?

Answer 16

Type 1

Question 17

One result of diabetes is an increase of glucose in the initial filtrate of the nephron. Subsequently, the PCT is unable to reabsorb all the glucose. This causes a(n) ________ in filtrate osmolarity.

Answer 17

increase

Question 18

If filtrate osmolarity increases, how does this affect water reabsorption (think of osmosis in the nephron loop)?

Answer 18

increase urination

Question 19

the large intestine functions reabsorption of water and salts resulting in _____.

Answer 19

feces

Question 20

What are the four regions of the large intestine?

Answer 20

ascending, transverse, descending, sigmoid

Question 21

Longitudinal muscular is modified to form ____ ____ that result in pocked called _______.

Answer 21

tenia coli
haustrum

Question 22

Cholera bacteria produce a toxin that causes uncontrollable movement of ions into the lumen of the large intestine. What would be the result of this?

Answer 22

diarrhea

Question 23

the microorganisms in our gut are called the ___ ________.

Answer 23

gut microbiome

Question 24

the anal canal is controlled by what two sphincters?

Answer 24

internal- involuntary
external- voluntary

Question 25

mucosa layer in the rectum is stratified and produces extra _____ during deification.

Answer 25

mucus