Digestion

Question 1

What are the four layers of the digestive tract from superficial to deep?

Answer 1

Mucosa

Submucosa

Muscularis externa

Serosa

Question 2

What are the four layers of the mucosa of the digestive tract?

Answer 2

Epithelium

Lamina propria

Muscularis mucosae

Modifications

Question 3

What nerve supplies the submucosa?

Answer 3

Submucosal plexus

Question 4

What nerve supplies the muscularis externa?

Answer 4

Myenteric plexus

Question 5

What kind of contractions do sphincters normally perform?

Answer 5

Tonic (sustained) contractions

Question 6

What kind of phasic contraction patterns are there?

Answer 6

Peristaltic (propulsive)

Segmental (mixing, non propulsive)

Migrating motor complex (sweeps food remnants out of Upper GI tract)

Question 7

In what state (fasted/fed) does the migrating motor complex appear?

Answer 7

Fasted

Question 8

What are the long reflexes in the digestive system controlled by?

Answer 8

CNS

Question 9

Where are the short reflexes integrated?

Answer 9

ENS

Question 10

The upper GIT consists of?

Answer 10

Mouth, Pharynx, Esophagus

Stomach

Question 11

What part of the brain signals to the preganglionic parasympathetic neuron in the vagus nerve?

Answer 11

Medulla oblongata

Question 12

What enzymes are contained in saliva?

Answer 12

Amylase

Some lipase

Lysozyme (breaks down bacteria)

Question 13

During the swallowing reflex, what structure does the epiglottis close over?

Answer 13

Pharynx

Question 14

What sphincter relaxes to allow food into the stomach?

Answer 14

Gastro-esophageal sphincter

Question 15

Which part of the stomach performs digestion?

Answer 15

Antrum

Question 16

Peristaltic contractions digest food in the antrum by pushing up against what?

Answer 16

Pyloric sphincter

Question 17

What factors from within the duodenum decrease gastric emptying/motility?

Answer 17

Increased fat presence

Increased acid presence

Increased volume of chyme

Question 18

What factors from within the stomach increase motility/empyting rate?

Answer 18

Increased volume of chyme

Question 19

The mucous neck cells of the gastric gland secretes what substances?

Answer 19

Mucus

Bicarbonate (buffers gastric acid)

Question 20

What do chief cells release that are activated by gastric acid and what is the active form called?

Answer 20

Pepsinogen (inactive)

Pepsin (active state digests proteins)

Question 21

What cell releases acid and what are its stimuli?

Answer 21

Parietal/oxyntic cell

Acetylcholine, gastrin and histamine

Question 22

What cell releases histamine to stimulate parietal cells to release acid?

Answer 22

ECL cells

Question 23

What do G cells release that stimulates ECL cells and parietal cells?

Answer 23

Gastrin

Question 24

What cells are stimulated by acid in the stomach to release somatostatin?

Answer 24

D cells

Question 25

What does somatostatin regulate?

Answer 25

Acid secretion

Question 26

In a parietal cell, H⁺ is exchanged by an ATP pump into the lumen of the stomach for what ion?

Answer 26

K⁺

Question 27

What ion follows the H⁺ from the interstitial fluid by an exchange with HCO₃^-, through the parietal cell and into the lumen of the stomach via a leak channel to make acid??

Answer 27

Cl^-

Question 28

What is the first cell in the gastric phase to initiate the cascade of events to produce acid?

Answer 28

G cells

Question 29

What cells does the vagus nerve stimulate in the gastric phase?

Answer 29

G cells ECL cells Parietal cells

Question 30

What hormones are released by the small intestine in response to carbohydrate presence?

Answer 30

GIP GLP-1 (Both stimulate insulin release from pancreas)

Question 31

What stimulates the release of CCK from the small intestine to activate pancreatic enzyme secretion and gall bladder contraction?

Answer 31

Fats Proteins

Question 32

What hormone is involved in the negative feedback loop to regulate acid by release of pancreatic bicarbonate?

Answer 32

Secretin

Question 33

The liver first encounters the blood which has absorbed nutrients from the digestive tract through what vessel?

Answer 33

Hepatic portal vein

Question 34

What endocrines does the pancreas release?

Answer 34

Insulin - fed state Glucagon - fasted state

Question 35

What exocrines does the pancreas release?

Answer 35

Inactive proteases Active amylase Active lipase

Question 36

After being broken down into disaccharides by amylase from the saliva and pancreas, where are disaccharides broken down and by what?

Answer 36

Intestinal brush border Maltase, sucrase, lactase

Question 37

What two monosaccharides are cotransported with Na⁺ in order to be absorbed?

Answer 37

Glucose Galactose

Question 38

What monosaccharide has its own transporter in order for it to be absorbed?

Answer 38

Fructose

Question 39

Di/tripeptides cotransport with what to be absorbed into the blood on the basolateral side of the intestinal brush border?

Answer 39

H⁺

Question 40

What do amino acids cotransport with to be absorbed into the bloodstream?

Answer 40

Na⁺

Question 41

What process allows small peptides to be carried across the enterocytes to the bloodstream?

Answer 41

Transcytosis

Question 42

What transport occurs at the apical side of the brush border in protein absorption?

Answer 42

Cotransportation

Question 43

What transport occurs at the basolateral side of the brush border in protein absorption?

Answer 43

Antiporting

Question 44

What kind of digestion do bile salts perform in emulsification?

Answer 44

Mechanical

Question 45

Colipase opens up bile salt coated fat droplets to allow what to move into the centre of the fat droplet to digest it?

Answer 45

Lipase

Question 46

Where are fat globules absorbed into first before entering the bloodstream?

Answer 46

Lymphatic system

Question 47

When water is held in the lumen of the small intestine and reabsorption of solutes does not occur, what kind of diarrhoea occurs?

Answer 47

Osmotic diarrhoea

Question 48

Secretory diarrhoea relies on secretion of what ion to draw water into the lumen of the small intestine to flush out toxins?

Answer 48

Cl^-