Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology > Lecture 30 Digestive > Flashcards

Lecture 30 Digestive Flashcards

1
Q

GI Tract

A 
mouth -stratified squamous epithelium 
pharynx 
esophagus 
stomach -simple columnar epithelium 
small intestine
large intestine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Accessory Organs

A

salivary glands
liver
pancreas
gallbladder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Functions of the Digestive System

A

digestion
absorption
secretion
motility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

digestion

A

chemical breakdown of food molecules by hydrolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

absorption

A

of nutrients, electrolytes and H2O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

secretion

A

mucus, digestive enzymes, acid, bicarbonate, electrolytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

motility

A

muscular movements of GI tract to mix and propel food
peristalsis - moves material forward
segmental contractions - mix contents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

regional specialization (“assembly line”)

A

ingestion → mechanical breakdown → chemical digestion → absorption → waste processing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

GI tract structure: 4-layered tube

A

mucosa
submucosa
muscularis (externa)
serosa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

mucosa

A

mucosa - epithelium + lamina propria (areolar CT) + muscularis mucosae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

submucosa

A

submucosa - connective tissue, vascular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

muscularis (externa)

A

muscularis (externa) - smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

serosa

A
  • thin covering membrane (visceral peritoneum)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Mouth, Pharynx and Esophagus

functions:

A

ingestion, mastication (chewing), deglutition (swallowing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

salivary glands

A

secrete saliva: H2O, ions, mucus, enzymes: amylase, lipase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

amylase

A

begins chemical digestion of starch → disaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

esophagus

A

swallowing (upper portion), peristalsis (lower portion)

lower esophageal sphincter controls entry into the stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Stomach

functions

A

storage
mechanical breakdown of food → chyme
sterilization
chemical digestion: acid (HCl) and enzymes (pepsin)

19
Q

stomach structure

A

mucosa: simple columnar epithelium, gastric glands
- secrete acidic gastric juice (pH 1-2), 1-3 L/day
- mucous cells secrete alkaline mucus to protect stomach epithelium
muscularis: 3 layers thick
- pyloric sphincter controls passage of chyme from stomach to duodenum

20
Q

acid secretion

A

parietal cells secrete hydrochloric acid (HCl)
CO2 + H2O  H2CO3  H+ + HCO3-
H+ is active transported into the lumen, Cl- follows via diffusion through channels
HCO3- is transported back into ECF (countertransport with Cl-)

21
Q

chief cells

A

enzyme secretion
chief cells secrete pepsinogen (inactive), activated at low pH to form pepsin
pepsin digests proteins into smaller peptides

22
Q

Small Intestine, Liver and Pancreas Functions and SI regions

A

Small Intestine, Liver and Pancreas
functions: chemical digestion and absorption
SI regions: duodenum, jejunum, ileum

23
Q

Digestion

A

duodenum receives chyme from stomach, secretions from liver and pancreas

24
Q

Liver

A

processes absorbed nutrients (delivered via hepatic portal vein)
secretes bile, stored in gallbladder
bile salts

25
Q

bile salts

A

derived from cholesterol, function to emulsify fats → micelles

26
Q

bile pigments

A

(bilirubin, biliverdin) - waste products from hemoglobin breakdown

27
Q

Pancreas

A

acinar cells secrete digestive enzymes:
trypsin, chymotrypsin, carboxypeptidase, amylase, lipase
many enzymes are secreted in inactive form (zymogens), activated by trypsin in lumen

28
Q

duct cells

A

secrete bicarbonate (NaHCO3) to neutralize acid (pH → 8)

29
Q

SI (brush border)

A

enzymes complete digestion

complete digestion of starch

30
Q

exopeptidase

A

digests terminal peptide bonds to release amino acids

31
Q

endopeptidase

A

digests internal peptide bonds

32
Q

small intestine

A

has huge surface area, specialized for absorption

(1) length > 3 meters
(2) circular folds
(3) villi - epithelium (enterocytes and goblet cells) + lamina propria (capillaries and lacteals)
(4) microvilli - “brush border” membrane

33
Q

transport mechanisms of the small intestine

A
  • Na+, Cl
  • , K+ absorbed via active transport and diffusion through channels
  • glucose & amino acids - cotransport with Na+ (secondary active transport)
  • H2O - via osmosis, follows solute transport
34
Q

water soluble nutrients

A

are absorbed into intestinal capillaries → liver (via HPV)

35
Q

chylomicrons

A

lipids are formed into chylomicrons and absorbed into lymphatic vessels (lacteals)

36
Q

Large Intestine

functions

A

fluid absorption, waste packaging and elimination

  • LI absorbs most remaining water and ions from chyme
  • intestinal microflora - bacteria in colon, produce some vitamins (K, B12)
  • defecation reflex
37
Q

Neural and Hormonal Control

A 
enteric ns
ans
GI peptides
hormones 
phases of digestion
38
Q

. Enteric Nervous System

A
  • submucosal and myenteric plexuses

- local control within the GI tract (short reflex)

39
Q

Autonomic Nervous System

A

parasympathetic: vagus nerve - stimulates GI tract motility and secretion (long reflex)
sympathetic division mostly inhibits GI tract

40
Q

gastrin

A

secreted by G cells in the gastric glands
- stimulates gastric acid secretion; stimulates gastric motility and mucosal growth
(- acid secretion is also stimulated by histamine secreted by ECL cells in gastric glands)

41
Q

CCK

A

(cholecystokinin) - secreted by endocrine cells in intestinal crypts
- stimulates bile release from gallbladder and pancreatic enzyme secretion

42
Q

secretin

A
  • stimulates bicarbonate secretion by pancreas
43
Q

GIP

A

(gastric inhibitory peptide) - stimulates insulin secretion by pancreas;
- GIP, CCK and secretin all inhibit gastric acid secretion

44
Q

Phases

A
  1. Cephalic Phase - sensory stimuli and thoughts of food activate autonomic NS (vagus n.)
  2. Gastric Phase - vagus n., mechanical & chemical stimuli in stomach stimulate gastric secretion
  3. Intestinal Phase - arrival of chyme in duodenum triggers SI endocrine and exocrine secretion;
    hormonal feedback inhibits gastric acid secretion and slows stomach emptying

Physiology (33 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions