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Flashcards in digestive Deck (26):
1

mechanical digestion

physical breakdown of large food particles into smaller food particles
doesn't involve breaking chemical bonds
chewing to break apart food

2

chemical digestion

enzymatic cleavage of chemical bonds
peptide bonds of proteins or glycosidic bonds of starches

3

pathway of the digestive tract

oral cavity--> pharynx--> esophagus--> stomach--> small intestine--> large intestine--> waste enters the rectum (where it is stored until release

4

additional organs of digestive tract

salivary glands, pancreas, liver, and gallbladder

5

enteric nervous system

collection of millions of neurons that govern function of the gastrointestinal system
trigger peristalsis--> rhythmic contractions of the gut tube to move material through system
division of the parasympathetic NS

6

products secreted by stomach

1. HCl (kills microbes, denatures proteins, and converts pepsinogen into pepsin)
2. Pepsinogen (cleaved to pepsin in stomach, enzyme that partially digests proteins)
3. Mucus (protects mucosa)
4. Bicarbonate (protects mucosa)
5. Water (dissolves and dilutes ingested material)
6. Intrinsic factor (required for normal absorption of vitamin B12)

7

mucous cells

produce bicarbonate-rich mucus that protects muscular walls from acidic and proteolytic environment in the stomach

8

chief cells

secrete pepsinogen that is cleaved to pepsin in the stomach

9

parietal cells

secrete hydrogen ions as hydrochloric acid that cleaves pepsinogen

10

gastrin

induces parietal cells in the stomach to secrete more HCl and signals stomach to contract, mixing the contents
secreted by the G-cells in the pyloric gland

11

enteropeptidase

enzyme used for the activation of trypsinogen to trypsin

12

secretin

peptide hormone
causes pancreatic enzymes to be released into duodenum
regulates pH of digestive tract by reducing HCl secretion from parietal cells
slows motility through the digestive tract

13

cholecystokinin (CCK)

secreted in response to chyme into duodenum
stimulates release of bile and pancreatic juices
acts in the brain to promote satiety

14

pancreatic juices

complex mixture of enzymes in bicarbonate-rich alkaline solution
helps neutralize acidic chyme
contains enzymes to digest all 3 types of nutrients: carbs, fats, and proteins

15

bile

fluid composed of bile salts, pigments, and cholesterol

16

accessory organs of digestion

pancreas
liver
gallbladder

17

pancreas

endocrine function of release of insulin, glucagon, and somatostatin, to maintain blood sugar levels
exocrine function of acinar cells that produce pancreatic juices
secretes pancreatic amylase (sugar breakdown), pancreatic peptidases (protein breakdown), and pancreatic lipase (fat breakdown)

18

liver

processing of nutrients (glycogenesis, glycogenolysis, storage and mobilization of fats, gluconeogenesis)
production of urea
detoxification of chemicals
production of bile
synthesis of albumin and clotting factors

19

gallbladder

stores and concentrates bile
bile is released when CCK is released, gallbladder contracts, bile pushed into biliary tree
bile duct merges with pancreatic duct and then empties into duodenum

20

stone formation

cholesterol or bilirubin stones are common in the gallbladder
causes inflammation of the gallbladder
occurs due to precipitation of solid once concentration reaches Ksp of compound
may travel and get stuck in biliary tree, or may get stuck before duodenum causing block of pancreatic duct leading to pancreatitis

21

segments of small intestine

Duodenum (digestion)
Jejunum
Ileum
*absorption of nutients occurs here especially in jejunum and ileum

22

absorption

simple sugars, amino acids, and small fats are absorbed by secondary active transport and facilitated diffusion into the epithelial cells
then pass to the capillaries traveling down their concentration gradient
absorbed molecules go to the liver via the hepatic portal circulation

23

large intestine

3 sections: the cecum, the colon, and the rectum
primarily involved in water absorption

24

cecum

accepts fluid exiting the small intestine through the ileocecal valve
site of attachment of the appendix

25

colon

divided into ascending, transverse, descending, and sigmoid
absorb water and salts from the undigested material from the small intestine
primarily concentrates the remaining material into feces

26

rectum

storage site for feces
feces travels from rectum to anus where it is eliminated from the body