Digestive System

Question 1

What is the mesentery?

Answer 1

The fold of the peritoneum that attaches the digestive system to the abdominal wall.

Question 2

Going from the lumen of the gut moving onwards, name the layers.

Answer 2

Lumen
Epithelium
Lamina Propia
Muscularis Mucosae
Muscularis Externa
Submucosa
Serosa

Question 3

Name some functions of the digestive system.

Answer 3

Store food
Digest food
Kill pathogens
Remove waste material
Move food along

Question 4

What does saliva contain?

Answer 4

Lipase and amylase to start digestion, bacteriastatic (antibodies), alkaline, calcium to protect teeth

Question 5

What does the saliva turn into?

Answer 5

A bolus

Question 6

What does the stomach turn the bolus into?

Answer 6

Hypertonic Chyme

Question 7

What is the name of the folds in the stomach?

Answer 7

Rugae

‘Fold’ or ‘wrinke’ in Latin

Question 8

What do surface mucous cells in the stomach secrete?

Answer 8

HCO-3 ions which neutralise H+ ions and protect lining of stomach.

Question 9

Where does the chyme go after the stomach?

Answer 9

The duodenum

Question 10

What are the five layers on cells in a gastric gland and what do they do?

Answer 10

Gastric pit - mucus secreting cells
Isthmus - where stem cells divide
Parietal cells - secrete HC03-
Chief cells - secrete pepsinogens which hydrolyse proteins
Enteroendocrine cells - secrete gastric and causes wider gastric mucosa to secret acid.

Question 11

What glands does the duodenum contain and what do they secrete?

Answer 11

Brunner’s glands - secrete bicarbonate rich mucus to neutralise chyme.

Question 12

What other substances are realised into the duodenum and where from?

Answer 12

H20 from the extracellular fluid
Bile from the liver
Enzyme from the pancreas and liver

Question 13

What do the enzymes from the pancreas and liver break down?

Answer 13

Peptides into amino acids
Polysaccharides into monosaccharides
Lipids

Question 14

What are the folds in the jejunum called?

Answer 14

Plicae circularis

Question 15

Name the layers of the jejunum.

Answer 15

In centre of folds: Muscularis Mucosal
Jejunal mucosa
Submucosa and muscularis externa underneath
Villi on the folds

Question 16

What is a lacteal?

Answer 16

A lympathetic vessel of the small intestine, absorbs fats.

Question 17

What do the a) Duodenum b)Jejunum and c) Illeum absorb?

Answer 17

A) ions
B) Sugars, amino acids, fatty acid
C) all nutrients absorbed, still contains water

Question 18

Name the different parts of the colon.

Answer 18

Appendix, Caecum, Ascending colon, Transverse colon, Descending colon, Sigmoid colon, Rectum.

Question 19

What are crypts of lieberkuhn?

Answer 19

Intestinal glands that line epithelium and mucosa.

Question 20

What do we not excrete involuntarily?

Answer 20

Our higher control centre overrides any reflex, can reverse peristalsis (involuntary movement of GI tract).

Question 21

What three processes in the bacteria in the colon used in?

Answer 21

Synthesis of vitamins K, B12, thiamine
Breakdown of bile acids
Conversion of bilirubin to non-pigmented metabolites

Question 22

What two things can decreased fluid absorption result in?

Answer 22

Dehydration and electrolyte imbalance

Question 23

Name two neuronal plexus in the gut where they are found.

Answer 23

Submucosal plexus (plexus of Meisser) - found between the layers of the gut
Myenteric plexus - between submucosa and muscularis externa.

Question 24

How does paracrine control control our fluid retention?

Answer 24

Histamine - controls acid in stomach

Vasoactive substance - control blood flow in the gut

Question 25

What does the hormone secretin do?

Answer 25

Promotes HCO-3 secretion from pancreas
Promotes bile production
Inhibits acid secretion in stomach

Question 26

Where the hormone gastric releases and what does it do?

Answer 26

Released by G cells in stomach, pancreas, duodenum

Promotes gastric acid in the stomach.

Question 27

What does the hormone cholecystokinin (CCK) do?

Answer 27

Synthesised by enteroendocrine cells of duodenum
Promotes digestive enzymes in pancreas
Promotes bile in the gall bladder
is a hunger suppressant