Digestion II

Question 1

what does the mucosa in the small intestine contain

Answer 1

Brunner’s glands which secrete mucous to neutralise gastric acid

Question 2

what are the deep crevices which form the walls of the small intestine lined with

Answer 2

glandular epithelium

Question 3

the glandular epithelium form intestinal glands called

Answer 3

crypts of Lieberkuhn which secrete intestinal juice. This together with pancreatic juice aids absorption of constituents of chyme

Question 4

the epithelial cells at this part of the small intestine begin what process

Answer 4

absorption

Question 5

what aids absorption

Answer 5

brush border enzymes

Question 6

what are the main 3 types of brush border enzymes

Answer 6

1) Dextinase, maltase, sucrase and lactate
2) peptidase
3) nucletide digesting enzymes

Question 7

dextrinase, maltase, sucrase and lactase all digest

Answer 7

carbohydrates

Question 8

what is peptidase

Answer 8

protein digesting enzyme

Question 9

what is the mucosa lining the inner walls covered with

Answer 9

villi

Question 10

what are villi and what does it do

Answer 10

finger like projections that increase the surface area for digestion

Question 11

what does the villi house and why

Answer 11

an arteriole/venule and lymphatic vessel because walls are so thin the passage of nutrients is possible

Question 12

what do the globlet cells secrete

Answer 12

mucous aiding digestion

Question 13

what do paneth cells do

Answer 13

regulate the number of microbes- keeping the environment optimum

Question 14

what is the function of micro-villi

Answer 14

smaller than villi- increase the surface area further to aid digestion

Question 15

how many micro-villi and estimated per square millimeter

Answer 15

200 million

Question 16

what are pilcae circulares

Answer 16

deep folds within intestine again serve to increase surface area for successful digestion

Question 17

what do the plicae circulares enable

Answer 17

the chyme to spiral rather than travel in a straight line

Question 18

what is segmentation

Answer 18

a movement of the intestine to bring the food contents in close contact with the mucosa

Question 19

how many times is the food sloshed back and forth per min in duodenum and in the ileum

Answer 19

12 times per min in duodenum and 8 times per min in the ileum

Question 20

what does intestinal distention trigger

Answer 20

nerve impulses to stimulate motility

Question 21

what is peristalis in the small intestine called

Answer 21

migrating motility complex (MMC)

Question 22

what does the MMC do

Answer 22

moves food through the GIT 1cm/1min controlled by nervous impulse

Question 23

how long does it take from the stomach to the end of the small intestine

Answer 23

120 minutes

Question 24

what do all carbohydrates become for absorption

Answer 24

monosaccharides

Question 25

fructose and glucose are monosaccarides and absorbed by

Answer 25

diffusion or active transport through the lumen of the villi

Question 26

what do proteins become and how are they absorbed through the lumen of the villi

Answer 26

become amino acids and are absorbed by active transport

Question 27

monosaccarides and amino acids enter blood stream and transported to

Answer 27

the liver

Question 28

what do triglycerides and diglycerides become

Answer 28

monoglycerides by the action of bile

Question 29

what are monoglycerides converted to and by what

Answer 29

glycerol and fatty acids by lipase

Question 30

glycerol and fatty acids recombine with proteins to become

Answer 30

phospholipids which are too large to pass into the bloodstream

Question 31

where do phospolipids enter

Answer 31

the lymphatic system and drain eventually into the bloodstream through the subclavian vein. They are transported to the liver for further breakdown

Question 32

how are electrolytes absorbed by

Answer 32

sodium/potassium pumps and diffusion and secondary transport

Question 33

how are vitamins absorbed

Answer 33

mostly by simple diffusion but vitamin B12 needs intrinsic factor and needs active transport for absorption

Question 34

how is water absorbed

Answer 34

via osmosis but fluctuates as it is dependent on the concentration of electrolyte balance within water. approx 8.3 litres water absorbed 90& absorption takes place in small intestine

Question 35

where does alcohol absorption begin

Answer 35

in stomach

Question 36

alcohol is absorbed more quickly in

Answer 36

the small intestine as larger surface area

Question 37

what does the presence of fat do

Answer 37

slows gastric emptying so blood alcohol level rises slower as remains in stomach longer

Question 38

gastric alcohol dehydrogenase enzyme found within the stomach do what

Answer 38

break down alcohol into non intoxicating elements

Question 39

the longer the alcohol remains in the stomach

Answer 39

the less enters the bloodstream

Question 40

what is the large intestine in length and diameter

Answer 40

1. 5 m in length | 6. 5cm in diameter

Question 41

where does the small intestine start and end

Answer 41

commences at ileo-caecal valve and finishes at anal orifice

Question 42

what 9 things does the large intestine consist of

Answer 42

1) caecum & appendix 2) ascending, transverse, descending & sigmoid colon 3) rectum & anal column

Question 43

where does the caecum hang

Answer 43

below ileo-caecal valve

Question 44

what is the appendix

Answer 44

small coiled tube (8cm)

Question 45

where is the ascending colon

Answer 45

ascends right side of abdomen and turns left under the liver at hepatic flexure

Question 46

where does the transverse colon go

Answer 46

travels across to left side of the abdomen

Question 47

where does the transverse colon turn to become the descending colon

Answer 47

splenic flexure

Question 48

where does the descending colon travel

Answer 48

down the left side of the abdomen

Question 49

at the level of iliac crest, what does the descending colon become

Answer 49

the sigmoid colon where it travels towards midline terminating at the 3rd sacral vertebra= rectum

Question 50

name 3 things about the rectum

Answer 50

1) 20cm long 2) has good blood supply 3) has internal and external muscular sphincter

Question 51

the mucosa in the large intestine

Answer 51

have no villi an no permanent folds, but do have goblet cells which secrete mucus to assist passage through intestine

Question 52

the muscularis in the large intestine

Answer 52

have external/longitudinal fibres and internal/circular fibres

Question 53

what is the Taeniae coli in the large intestine

Answer 53

bands of muscle fibre which run the length of the large intestine and gather it into haustral folds during contraction

Question 54

name 5 functions of the large intestine

Answer 54

1) haustral churning 2) peristalsis 3) mass paristalsis 4) chemical digestion 5) pressure receptors

Question 55

what is haustral churning in the large intestine

Answer 55

process movement of food contents from one haustra to the next

Question 56

how many contractions per min does the peristalsis do

Answer 56

12 contractions/min to move food along

Question 57

what is the function of the mass peristalsis

Answer 57

move food from mid transverse colon to rectum in strong peristaltic movement

Question 58

how is chemical digestion in the large intestine carried out

Answer 58

bacterial action breaks down any remaining carbohydrates and prepares waste products for elimination

Question 59

what do pressure receptors in the rectal walls do

Answer 59

recognise the need for expulsion although voluntary control of external sphincter controls rate of release

Question 60

prior to expulsion, what is the large intestine responsible for

Answer 60

absorption of remaining water- approx 100mls along with electrolytes such as sodium