Digestive System Flashcards Preview

Nicole mcat > Digestive System > Flashcards

Flashcards in Digestive System Deck (41):
1

Passage of food

Oral cavity, pharynx, esophagus, stomach, small intestine, large intesine, rectum

2

Enteric nervous system

peristalsis, rhythmic contractions of the cut, heavily regulated by autonomic nervous system

3

all glands of the body except for sweat glands are

parasympathetically innervated

4

Salivary amylase

breaks starch into smaller sugars

5

Lipase

Breaks down lipids

6

Stomach

Highly muscular, 2 L capacity, upper left quadrant, under diaphram

7

4 main anatomical divisions of stomach

fundus, body, antrum, pylorus

8

Gastric glands

fundus and body

9

Pyloric glands

Andrum and pylorus

10

Gastric glands respond to

signals from vagus nerve of parasym. activated by brain in response to light taste, smell of food.

11

Three types of gastric gland cells

Mucus cells (bicarb rich mucus that protects wall from acidic/ proteolytic environment) 2 Chief cells (secrete pepsinogen) 3 Parietal cells- secrete H ions as HCL that cleave pepsinogen to pepsin. They also secrete intrinsic factor which helps in proper absorbtion of B12. Pepsin= digests proteins by cleaving peptide bonds

12

Pyloric glands

G cells - secrete gastrin (a peptide hormone, it induces parietal cells to secrete more HCL) chyme- semifluid mixture of food and hcl that enters the small intestine

13

Small intestine parts

duodenum, ilieum, jejunum

14

Duodenum

Majority of chemical digestion and some absorption

15

The presence of chyme in duodenum stimulates

release of brush border enzymes on luminal surface of cells to break down dimer and trimers. also in duodenum there is secretion of enteropeptidase and hormones secretin and cholecystokinin (CCK)

16

Lack of a certain enzyme means that bacteria will breakdown and release

methane

17

Peptidases

Break down proteins. Aminopeptidase glands in the duodenum secrete this to remove n terminal from peptide. also there are dipeptidases which cleave bonds of dipeptides to release free amino acids.

18

enteropeptidase (enterokinase)

Activates trypsinogen (pancreatic protease) to trypsin. Can also activate procarboxypeptidases A and B into active forms

19

Secretin

Peptide hormone, causes pancreatic enzymes to be released into duodenum. Can reduce HCL secretion by parietal cells. and can increase bicarb from pancreas. It is considered an enterogastrone which is a hormone that slows motility through digestive tract to increase absorption

20

CCK cholecytokinin

Secreted in response to entry of chyme in the duodenum

21

Bile salts

made from cholesterol. not enzymes but play a mechanical role by emulsifying fat and cholesterol into michelles.

22

without bile what what happen

fats would seperate out of an aq mix and become inaccessible to pancreatic lipase which is water soluble. Improtant to note michelles increase surface area and increase abs rate

23

Pancreatic juices

several enzymes in bicarb rich alkaline solution. bicarb can reduce acidic chyme

24

Pancreas

Exo and endocrine functions. the endocrine side- release of insulin, glucagon and somatostatin. Hormona cells reside in islets of langerhans . The exocrine cells are called acinar cells and produce pancreatic juices

25

Pancreatic amylase

Break down large polysaccharides to small disaccharides. takeaway= CARBS

26

Pancreatic peptidases

Protein digestion. Trypsinogen, chymotripsinogen and carboxy peptidases A and B. all activated by enteropeptidases

27

Pancreatic Lipase

Fats broken into free fatty acids and glycerol.

28

Liver

Upper right quadrant. Bile ducts connect liver to the small intestine and the gallbladder. Bile stored in gallbladder.

29

Liver receives nutrient rich blood via the

hepatic portal vein.

30

glycogenesis and gluconeogenesis occurs in the

liver

31

Urea is produced from ammonia in the

liver

32

Bile

Made up of bile salts, pigments and cholesterol. the major pigment is bilirubin which is a byproduct of hemoglobin breakdown.

33

Bilirubin

travels to the liver where it is conjugated (attached to a protein) and secreted into bile for secretion. The inability to process or excrete bilirubin could be due to liver damage, rbc destruction, or bile duct blockage.

34

albumin is synthesized in the

liver. this protein maintains plasma oncotic pressure, serves as a carrier, clotting factor during blood coagulation

35

absorption and defacation

jejunum and ileum. lg intestine is for h20 absorption

36

Larger fats, glycerol and cholesterol

can move seperately into intestinal cells but then reform into triglycerides.

37

Chylomicrons

contain triglycerides and cholesterol and travel via lymphatic system via lacteals to thoracic duct to left subclav vein

38

The large intestine

It is larger in diameter but shorter in length. Consists of cecum, colon (ascending, transverse, descending, sigmoid) and retum.

39

Cecum

outpocketing that accepts fluid exiting small intestine through ileocecal valve. site of appendix.

40

fat soluble vitamins that are transported in chylomicrons

adek

41

water soluble

b complex and c