Digestion and Intestinal Absorption (part 2)

Question 1

state what it is meant by the key term - Fundus

Answer 1

the upper part of the stomach, next to the cardia

Question 2

state 2 facts about the Fundus

Answer 2

1. stores gas produced during digestion

2. doesn’t typically store food, but can do if the stomach is particularly full

Question 3

state what it is meant by the key term - Lower oesophageal sphincter

Answer 3

a bundle of muscles at the lower end of the oesophagus, where it meets the stomach

Question 4

state 1 additional fact about the lower oesophageal sphincter

Answer 4

prevents acids and stomach contents travelling back into the oesophagus

Question 5

state what it is meant by the key term - body (of stomach)

Answer 5

lies between the fundus and the pyloric antrum

Question 6

state an additional fact about the secretion in the body (of the stomach)

Answer 6

secretes mucus, pepsinogen and HCL

Question 7

state what it is meant by the key term - antrum

Answer 7

the lower portion (near the small intestine) where the food mixes with the gastric juice

Question 8

state an additional fact about the antrum

Answer 8

secretes mucus, pepsinogen and gastrin

Question 9

state what it is meant by the key term - pyloric sphincter

Answer 9

a band of smooth muscle that controls the movement of partially digested food and juices from the pylorus into the duodenum

Question 10

state 2 additional facts about the pyloric sphincter

Answer 10

1. allows the stomach contents to enter the small intestine

2. prevents contents re-entering the stomach

Question 11

state what it is meant by the key term - pylorus

Answer 11

the part of the stomach that connects to the duodenum (first part of the small intestine). a valve which opens and closes during digestion

Question 12

state what it is meant by the key term - cardia

Answer 12

the part of the stomach closest to the oesophagus. foods and liquids pass through the cardia to enter the stomach from the oesophagus

Question 13

how is it possible to live without the stomach ?

Answer 13

it is possible to live without the stomach with Vitamin B12 injections

Question 14

what are the three main structures in the small intestine ? (in order)

Answer 14

1. duodenum
2. jejunum
3. ilium

Question 15

state what it is meant by the key term - duodenum

Answer 15

the first part of the small intestine immediately beyond the stomach, leading to the jejunum

Question 16

state 2 additional facts about the duodenum

Answer 16

1. produces hormones

2. receives liver secretions (bile) and pancreas secretions (pancreatic juices containing digestive enzymes)

Question 17

state what it is meant by the key term - jejunum

Answer 17

the part of the small intestine between the duodenum and the ilium

Question 18

state an additional fact about the jejunum

Answer 18

absorbs sugars, amino acids and fatty acids

Question 19

state what it is meant by the key term - ilium

Answer 19

the third portion of the small intestine, between the jejunum and the caecum

Question 20

state an additional fact about the ilium

Answer 20

absorbs final nutrients (bile acids + Vitamin B12 especially)

Question 21

state what it is meant by the key term - villi

Answer 21

tiny hair like projections that line the inside of the small intestine with certain blood vessels to help absorb nutrients

Question 22

state what it is meant by the key term - micro-villi

Answer 22

protrusions from the apical surface of the epithelial cells which function to increase cell SA and the efficiency of absorption

Question 23

state what it is meant by the key term - brush border

Answer 23

the intestinal lining and is the site of terminal carbohydrate digestion

Question 24

state what it is meant by the key term - krept of Lieberkuhn

Answer 24

the pit between villi in the small intestine

Question 25

state an additional fact about the ‘krept of lieberkuhn’

Answer 25

contain numerous cells, such as stem cells to produce new cells, to replenish those lost due to abrasion as well as enteroendocrine cells to synthesise and secrete hormones

Question 26

state what it is meant by the key term - enteroendocrine

Answer 26

Enteroendocrine cells are specialized cells found within the gastrointestinal tract, stomach and pancreas. They produce and release hormones in response to a number of stimuli

Question 27

state the 3 roles of the pancreas in the digestion and absorption process

Answer 27

1. secretion of pancreatic juices (bicarbonate)
2. secretion of proteases
3. secretion of pancreatic lipase

Question 28

state the function of the gall bladder in the digestion and absorption process

Answer 28

the storage and concentration of bile

Question 29

state the function of - amylase (salivary)

Answer 29

initial digestion of starch

Question 30

state 4 functions of HCl in the digestion and absorption process

Answer 30

1. denaturation of proteins
2. acidification of pepsin action
3. antibacterial
4. activation of pepsinogen

Question 31

state the function of - pepsin (secreted as pepsinogen)

Answer 31

initial digestion of proteins

Question 32

state the function of - gastric lipase

Answer 32

lipid hydrolysis in the stomach

Question 33

state the function of - bile

Answer 33

neutralisation of chyme

Question 34

state the function of - bile salts

Answer 34

emulsification of fats

Question 35

state the function of - saccus entericus (intestinal juice)

Answer 35

lubrication

Question 36

state the function of - pancreatic juice

Answer 36

neutralisation of chyme

Question 37

state the function of - proteases

Answer 37

digestion of proteins to oligopeptides and free amino acids

Question 38

state the function of - pancreatic lipase

Answer 38

triacylglycerol hydrolysis

Question 39

state the function of - diahaccharidase

Answer 39

disaccharide hydrolysis

Question 40

state the function of - peptidases

Answer 40

hydrolysis of peptides to dipeptides and tripeptides

Question 41

state 2 functions of the liver in the digestion and absorption process

Answer 41

1. secretion of bile (bile and bile salts)

2. processing of absorbed nutrients

Question 42

state 3 functions of bile in the digestion process

Answer 42

1. bile salts
2. phospholipids
3. bicarbonate (HCO3-)

Question 43

state the 3 functions of bile in the ‘substance removal from the blood’ function

Answer 43

1. cholesterol
2. bile pigments
3. trace metals

Question 44

state the names of the 2 incretin hormones you need to know

Answer 44

1. Glucose dependent insulinotropic polypeptide (GIP)

2. Glucagon-like peptide 1 (GLP-1)

Question 45

state 3 facts about glucose-dependent insulinotropic polypeptide (GIP)

Answer 45

1. stimulated by nutrients in the small intestine
2. secreted by K cells in the duodenum and jejunum
3. stimulates insulin secretion

Question 46

state 3/6 facts about glucagon-like peptide 1 (GLP-1)

Answer 46

1. stimulated by nutrients in the small intestine
2. secreted by L cells in the ilium
3. promotes insulin release
4. inhibits glucagon release
5. delays gastric emptying
6. surpasses appetite + energy intake

Question 47

state 3 introductory facts about lipid emulsification

Answer 47

1. lipids are insoluble in water
2. lipase can only act on the surface of fat droplets
3. emulsification increases surface area (SA)

Question 48

explain the 6 step fat emulsification process

Answer 48

1. emulsified
2. hydrolysed by lipase
3. temporarily stored as micelles
4. transported into epithelial cells
5. re-synthesised to triaglycerides (TAG)
6. packaged as Chylomicrons

Question 49

state 4 facts about small intestine motility

Answer 49

1. more segmentation than peristalsis
2. rhythmic contraction and relaxation by longitudinal muscles
3. greater mixing of material
4. contributes to the net flow through the small intestine

Question 50

explain what it is meant by the key term - gastroileal reflex (2 points)

Answer 50

1. segmentation increased in ilium with gastric emptying

2. once the majority of a meal is absorbed, segmentation is replaced with peristalsis

Question 51

explain what it is meant by the key term - migrating myoelectric complex (MMC) - (2 points)

Answer 51

1. moves undigested materials to the large intestine

2. prevents bacteria from remaining in the small intestine too long

Question 52

state the 3 main functions of the colon/large intestine in the digestion and absorption process

Answer 52

1. primary storage of material prior to defecation
2. some digestion of undigested material (via bacteria)
3. fluid absorption helps to concentrate fecal matter

Question 53

state 2 facts about the iliocecal sphincter

Answer 53

1. opens to allow chyme into colon from ilium when ilium contracts
2. closes when large intestine distends

Question 54

explain segmentation in the large intestine

Answer 54

slower in large intestine, approx 18-24 hour duration

Question 55

state what it is meant by the key term - endopeptidases

Answer 55

Endopeptidase, or endoproteinase, are proteolytic peptidases that break peptide bonds of non-terminal amino acids

Question 56

state what it is meant by the key term - exopeptidases

Answer 56

An exopeptidase is any peptidase that catalyzes the cleavage of the terminal peptide bond; the process releases a single amino acid or dipeptide from the peptide chain

Question 57

state what it is meant by the key term - membrane bound dipeptidases

Answer 57

enzymes secreted by enterocytes are secreted onto the brush border of the villi in the small intestine and into the small intestine where they hydrolyse dipeptides into their two component amino acids prior to absorption