Digestion 2

Question 1

What is chyme?

Answer 1

Fine particles of undigested material

Question 2

Is chyme acidic or alkaline?

Answer 2

Acidic

Question 3

What is in chyme?

Answer 3

Protein and polysaccharide fragments and fat

Question 4

Role of exocrine pancreas

Answer 4

Provides main digestive fluid of the small intestine

Question 5

What is the structure of the exocrine pancreas?

Answer 5

Similar to salivary gland

Question 6

What is secreted by the pancreas?

Answer 6

Water, HCO3- and enzymes

Question 7

What do parasympathetic nerves control for the pancreas?

Answer 7

ACh and VIP (vasoactive intestinal peptide)

Question 8

What do gut hormones control in the pancreas?

Answer 8

HCO3- and enzyme rich secretion

Question 9

Role of enterokinase

Answer 9

Catalyses trypsinogen to trypsin

Question 10

Role of trypsin

Answer 10

Catalyses conversion of all enzymes to active forms

Question 11

What does the liver receive?

Answer 11

All blood leaving the gastrointestinal tract

Question 12

What does the liver produce?

Answer 12

Bile and important plasma proteins

Question 13

What does the metabolic control centre store?

Answer 13

Carbohydrates, amino acids and fats

Question 14

What can the metabolic control centre convert amino acids to?

Answer 14

Other amino acids or sugars

Question 15

What does the metabolic control centre monitor?

Answer 15

Blood levels

Question 16

What does the liver do with old red blood cells?

Answer 16

Destroys them and breaks down the haemoglobin

Question 17

How does the liver improve blood quality?

Answer 17

Removes toxins and foreign components

Question 18

Role of bile salts

Answer 18

Aid absorption of fats

Question 19

Examples of bile salts

Answer 19

Cholic and chenodeoxycholic acid

Question 20

Role of bile pigments

Answer 20

Breakdown products of haemoglobin

Question 21

Examples of bile pigments

Answer 21

Biliverdin and bilirubin

Question 22

How do bile salts cause fats to be absorbed?

Answer 22

Form a hydrophilic shell around the fat to diffuse through villus tip

Question 23

What causes contractions of the gall bladder?

Answer 23

Cholecystokinin

Question 24

Role of gall bladder

Answer 24

Release stored bile into duodenum

Question 25

What is the final site of chemical breakdown and absorption of food?

Answer 25

Small intestine

Question 26

Role of enterocytes

Answer 26

Absorption across walls of villi

Question 27

How long to enterocytes live for?

Answer 27

2-3 days

Question 28

What happens when enterocytes differentiate?

Answer 28

They develop brush borders, digestive enzymes and transporter proteins

Question 29

What are propulsive movements?

Answer 29

Shifts material along the gut

Question 30

Role of mixing movements

Answer 30

Mixes digesta with secretions and ensures material is close to villi

Question 31

What is peristalsis?

Answer 31

Propulsive movement coordinated by enteric nerves

Question 32

How is peristalsis initiated?

Answer 32

Stretching of intestinal walls

Question 33

What occurs to muscles during peristalsis?

Answer 33

Muscle behind digesta contracts and muscle in front relaxes

Question 34

What causes segmentation of the digesta?

Answer 34

Stretching of the intestine

Question 35

How does segmentation occur?

Answer 35

Contractions of muscle at regular intervals of the digesta

Question 36

Role of segmentation

Answer 36

Easier absorption

Question 37

Parts of the large intestine

Answer 37

Colon Cecum Appendix Rectum

Question 38

Role of colon

Answer 38

Stores material and absorbs water and salt

Question 39

What are bowel movements?

Answer 39

Slow contractions that mix materials

Question 40

What are mass movements?

Answer 40

Large contractions that push faeces down the colon

Question 41

What is the gastrocolic reflex?

Answer 41

Mass movements that occur when food enters the stomach

Question 42

What is the defecation reflex?

Answer 42

Faeces entering rectum causes internal anal sphincter to relax

Question 43

What must occur before defecation?

Answer 43

Relaxation of external anal sphincter

Question 44

What causes disruption of the digestive system?

Answer 44

Emotional problems Vomiting Diarrhoea Constipation

Question 45

How do emotions effect gastric motility?

Answer 45

Autonomic nerves alter gastric smooth muscle excitability

Question 46

How does vomiting occur?

Answer 46

Action of the diaphragm and abdominal muscles

Question 47

What causes diarrhoea?

Answer 47

Excessive intestinal motility and osmotically active particles in digestive tract