14 - Intestines

Question 1

What are the divisions of the small intestine

Answer 1

duodenum
jejunum
ileum

Question 2

What are the divisions of the large intestine

Answer 2

caecum
colon
rectum
anal canal

Question 3

What structures does the celiac trunk supply

Answer 3

stomach
pancreas
duodenum
liver

Question 4

What does the superior mesenteric artery supply

Answer 4

SI and 1/3 large intestine

Question 5

What does the inferior mesenteric artery supply

Answer 5

distal 2/3 of the large intestine

Question 6

Which structures drain through the hepatic portal vein

Answer 6

stomach, spleen, intestines (everything)

Question 7

What structures of the SI pass through the mesentery

Answer 7

Nerves, BV, lymphatics

Question 8

What are the layers of the SI

Answer 8

muscularis
submucosa
mucosa –> plicae circularis –> villi –> microvilli

Question 9

What are the features of the duodenum

Answer 9

densest plicae circularis
major site for calcium and iron absorption
contains duodenal glands –> at the first 10cm of the duodenum and secrete bicarb rich mucus

contains hepatopancreatic ampulla
- accepts digestive juices from pancreas and bile from the liver to aid with digestion

Question 10

What are the features of the jejunum

Answer 10

long vasa recta –> straight rods that come off anastamoses
glucose, aa, water absorption

Question 11

What are the features of the ileum

Answer 11

contain lymphatic nodules and prominent lacteals
only site for B12 absorption
plicae circularis taper out

ileum ends at the ileocacecal valve

Question 12

What is the gastroileal reflex

Answer 12

clears residual matter from the SI and serves ot limit the excessive growth of bacteriA

Question 13

What does pancreatic juice do

Answer 13

contains digestive enzymes for digestion

Question 14

What does CCK induce

Answer 14

secretion of enzyme rich juice

Question 15

What does secretin induce

Answer 15

secretion of bicarb rich juice

Question 16

What are the two patterns of intestinal contractions

Answer 16

fed pattern
- during feeding, irregular contractions to mix contents with digestive juices
fasting pattern
- migrating motility complex (perstalisis) begins at the duodenum and propels residual materiaal into the proximal colon (prevents vacterial overgrowth)

Question 17

Which strctures release enzymes to digest carbs

Answer 17

salivary amylase
pancreatic juice
microvili at brush border of intestinal absorptive cells

Question 18

What structures release enzymes to digest lipids

Answer 18

liver –> bile salts
sublingual gland of oral cavity
pancreas
stomach

Question 19

What structures release enzymes to digest proteins

Answer 19

stomach
pancrease
brush border enzymes

Question 20

What structures release enzymes to digest nucleic acids

Answer 20

pancreas
absorptive cells in brush border

Question 21

What prevents the digestion of the pancreas

Answer 21

pancreatic enzymes are secreted in an inactive form

enteropeptidase (brush border enzyme) begins the process by converting inactive trypsinogen into trypsin

Question 22

How is glucose transported into the intestine and then to blood

Answer 22

SAT to the brush border –> with sodium

facilitated diffusion into the capillaries

Question 23

How are amino acids transported into the intestine and then to blood

Answer 23

SAT to the brush border –> with sodium

simple diffusion into blood stream

Question 24

How are fats transported into the intestine and then to blood

Answer 24

short chain FA –> diffuse directly into blood

long chain FA –> transported as micelles and seperated into FA and monoglyceride
@ apical brush border, put back as triglyceride and delivered as a chylomicron to the blood

Question 25

How much is ingested and secreted How much is absorbed How much is excreted

Answer 25

9.3 9.2 0.1

Question 26

What are the layers of the large intestine

Answer 26

serosa muscularis submucosa mucosa

Question 27

What are the functions of the large intestine

Answer 27

producing vit B and vit K absorbing some water and vitamins forming feces emptying the rectum

Question 28

What is the gastrocolic reflex

Answer 28

encourages matter in the large intestine to migrate toward the rectum

Question 29

What do intesintal glands do

Answer 29

secrete mucus that helps to aid the passage of feces

Question 30

What cells are found in the intestine

Answer 30

absorptive cell --> absorb water goblet cell --> secretes mucus

Question 31

What are alterations in the LI

Answer 31

smoother mucosa teniae coli thinner circular muscle pouches (haustra) --> haustral contractions help to mix geces and facilitate water reabsorption

Question 32

Describe the defecation reflex

Answer 32

1. Stretched rectal wall --> mass movement of reflex (gastrocolic reflex) - sends afferent signals to the spinal cord 2. afferent signals --> parasympathetic relfex - contraction of the rectal wall and relaxation of the internal anal sphincter 3. external anal sphincter is under volutnary control --> if appropriate, may defecate conscioucly relaxing the external anal sphincter