Brainscape's Knowledge GenomeTM

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


See full index

Physiology > Digestive System > Flashcards

Digestive System Flashcards

1
Q

What are the four basic processes performed by the digestive system?

A

1.) motility
2.) secretion
3.) digestion
4.) absorption

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

What are the two types of motility movements? Which type of muscle produces them?

A

1.) mixing movements
2.) propulsive movements

accomplished by smooth muscle lining digestive tract

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

What is the difference between exocrine and endocrine secretions?

A

exocrine = secretions into digestive tract (mix of H20, electrolytes, enzymes)

endocrine = secretions of GI hormones and GI peptides that enter blood and have targets inside and outside of digestive system

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

Where does absorption mostly occur?

A

small intestine

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

What is hydolysis?

A

adding H2O to bond site to break bond

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

What are the three main categories of energy-rich food components?

A

Carbs, proteins, and fats

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

What are the absorbable units of carbohydrates?

A

monosaccharides, disaccharides, polusaccharides

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

What are the absorbable units of proteins?

A

small peptides, amino acids

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

What are the absorbable units of fats?

A

monoglycerides, fatty acids

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

What do starch and glycogen consist of? What are soluble and insoluble fibers?

A

starch: amylase and amylopectin
glycogen: storage form of glucose in muscle

dietary polysaccharides that either can or cannot be digested

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

What are the four layers of the digestive tract?

A

1.) serosa
2.) mucosa externa
3.) mucosa
4.) submucosa

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

In what layer(s) are cells that secrete found? Which layer mainly contains smooth
muscle?

A

mucous membrane: contains exocrine and endocrine gland cells as well as absorptive epithelial cells

muscularis externa: contains smooth muscle

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

Where are the two plexuses?

A

submucosal plexus and myenteric plexus

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

What is function of serous fluid?

A

prevents friction between digestive organs and surrounding viscera

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

What are the four means by which digestive activity can be regulated?

A

1.) autonomous smooth muscle function
2.) intrinsic nerve plexuses
3.) extrinsic nerves
4.) GI hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What do the interstitial cells of Cajal do? How does electrical activity pass between
smooth muscle cells in the digestive tract? Does the slow-wave potential always lead to
contraction?

A

pacemaker cells throughout muscularis externa, generate spontaneous, rhythmic, slow-wave membrane potentials

propagates to adjacent smooth muscle cells via gap junctions

if depolarization peak crosses threshold (not a given), multiple action potentials fire = contraction of smooth muscle

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

What is enteric nervous system comprised of?

A

submucosal plexus and myenteric plexus

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

How does sympathetic activity generally change digestive processes?

A

inhibits digestive motility and secretion

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

How does parasympathetic activity generally change digestive processes?

A

promotes digestive motility and secretion

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

Where are GI hormones secreted and what do they act on?

A

secreted in digestive tract and alte activity of smooth muscle and exocrine cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the functions of mastication?

A

1.) breaks down food into smaller peaches (increases surface area for salivary enzymes to act on)
2.) mixes food with saliva
3.) exposes food to taste buds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the functions of saliva? What secretes it?

A

1.) begins digestion of dietary starch through enzyme salivary amylase
2.) facilitates swallowing by lubricating with mucus
3.) inhibits bacteria via lysozyme (lyses bacteria) and lactoferrin (sequesters iron), antibodies, rinsing away leftover food material
4.) acts as solvent for tastants
5.) aids speech by allow surfaces of tongue, lips, and cheeks to glide over eachother
6.) neutralizes acids in food and bacteria via bicarbonate buffer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the two reflexes by which salivary secretion increases?

A

1.) simple salivary reflex (pressure receptors and chemoreceptors in brain)
2.) conditioned salivary reflex (thinking, seeing, smelling food
-> cerebral cortex)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What brain structure controls swallowing?

A

pharyngeal mechanoreceptors send signals to swallowing centers in medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the three functional sections of the stomach?

A

1.) fundus
2.) body
3.) antrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the main functions of the stomach?

A

1.) stores food until it can be emptied into small intestine
2.) secrete HCl and enzymes that begin protein absorption
3.) pulverizes ingested food and mixes with gastric secretions to produce this liquid called chyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is receptive relaxation of the stomach?

A

occurs when stomach is being filled, vagus nerve activity relaxes smooth muscle

allows stomach folds to unfold, volume expands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Which area of the stomach has thicker smooth muscle? What function does it provide?

A

antrum, greater force for propulsion and mixing (retropulsion)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Does chyme simply dump straight into the duodenum from the stomach?

A

no, rate of gastric emptying depends on strength of antral contractions

28
Q

If given a list, could you identify the factors the influence gastric emptying?

A

Increase
1.) volume of chyme
2.) degree of fluidity of chyme

Decrease
3.) enterogastric reflex (neural response regulated thru intrinsic plexuses and autonomic nerves)
4.) release of enterogastrones (GI hormones that act on the smooth muscle in the stomach
5.) fat, acid, hypertonicity
6.) intense pain

7.) emotion (through autonomic nerves, can promote or inhibit motility)

29
Q

What factors in the duodenum affect gastric emptying? What mechanisms do they
elicit? Which hormones are secreted by the duodenum by these factors?

A

enterogastric reflex (neural response regulated thru intrinsic plexuses and autonomic nerves)
release of enterogastrones (GI hormones that act on the smooth muscle in the stomach)

release secretin and CCK

30
Q

Where are the oxyntic mucosa and pyloric gland area? What component of these areas secretes gastric juices?

A

located in the fundus and body

1.) mucous cells (lubricant)
2.) chief cells (pepsinogen)
3.) parietal (oxyntic) cells (secrete HCl and intrinsic factor)

31
Q

What do mucous cells secrete? How about chief cells? How about parietal cells?

A

1.) mucous cells = mucus (lubricant)
2.) chief cells = pepsinogen
3.) parietal = HCl and intrinsic factor (Vitamin B absorption)

32
Q

Why does the stomach secrete HCl? Why does it secrete pepsinogen?

A

HCl = activates pepsin, aids in breakdown of connective tissue and muscle fibers, kills microorganisms, denatures proteins (unwinds it so pepsin can break it down)

Pepsinogen = inactive form of pepsin (breakdowns proteins)

33
Q

If a stomach epithelial cell dies, is it replaced?

A

yes, by stem cells

:inside gastric pits continually divide and replace worn-out cells -> entire gastric mucosa replaced every 3 days.

34
Q

What do G cells secrete? How about ECL cells? How about D cells?

A

1.) G cells = gastrin
2.) ECL cells = histamine
3.) D cells = somatostatin

35
Q

What does gastrin do?

A
  • stimulates secretion of gastric juice (HCL, pepsinogen)
  • stimulate ECL cells
36
Q

What are the three phases of gastric secretion? In which phases is secretion increased
and which reduced?

A

1.) cephalic (increases secretion) (vagus nerve stimulate intrinsic plexuses and G cells)

2.) gastric (increases secretion) (protein stimulates intrinsic plexuses and G cells)

3.) intestinal (decreases secretion) (absence of protein to turn on G cells, high acidity triggers D cells)

37
Q

How is the stomach lining protected from HCl?

A

1.) luminal membrane of gastric mucosal cells impermeable to H+
2.) tight junctions between gastric mucosal cells
3.) thick mucus acting as a physical barrier
4.) alkalinity of mucus neutralized acid

38
Q

In the pancreas, what do acinar cells secrete? How about duct cells?

A

1.) acinar cells = pancreatic enzymes
2.) duct cells = alkaline solution

39
Q

What are the three main types of pancreatic enzymes, and what do they do?

A

1.) proteolytic enzymes = digest proteins
2.) pancreatic amylase = digest carbs
3.) pancreatic lipase = digest fats

40
Q

What causes the pancreas to secrete its juices? Where does it secrete them into?

A

pancreatic secretion regulated by enterogastrones secreted by duodenal mucosa– secretin and CCK

secreted into duodenal lumen

41
Q

How is blood flow to the liver unique? What is the name of the circulation from the digestive tract to liver?

A

liver receives oxygenated blood from the hepatic artery and deoxygenated blood from hepatic portal vein

hepatic portal system: (digestive tract->liver) carries products absorbed in digestive system thru liver before entering general circulation

42
Q

What are the functional units that make up the liver?

A

lobules

43
Q

What is the function of Kupffer cells?

A

line sinusoids- resident macrophages that engulf old red blood cells and bacteria

44
Q

How are hepatocytes organized in the lobules?

A

organized into plates with bile canaliculi running in between

45
Q

What does bile contain? Where is it stored? Is it all excreted into the large intestine?

A

bile contains: bile salts (derivatice of cholesterol), lecithin (phospholipid), bilirubin (waste product from red blood cell breakdown)

46
Q

What causes the secretion of bile into the duodenum?

A

presence of fat in duodenum causes release of CCK, sphincter of Oddi relaxes and gallbladder contracts, secretion of bile into duodenum

47
Q

How do bile salts end up breaking big fat droplets into a lipid emulsion? Why is this important?

A

detergent action: increases surface area for attack by pancreatic lipase)

48
Q

What are micelles? What are they made of? What role do they play in absorption?

A

micelles: lecithin and bile salts aggregate to form these..

lecithin and bile salts each have hydrophobic and hydrophilic ends, monoglycerides and free fatty acids hide inside hydrophobic core, micelles are water soluble and are able to diffuse to the luminal membrane

49
Q

What is bilirubin and how is it produced?

A

bilirubin: waste product in the breakdown of heme from hemoglobin in worn out red blood cells

produced by kupffer cells (macrophages) and removed from blood by liver (major constituent of bile)

50
Q

What is jaundice due to?

A

due do accumulation of bilirubin in body
could occur with excessive breakdown of red blood cells, diseased liver, or obstruction of bile duct

51
Q

What are the three segments of the small intestine?

A

1.) duodenum
2.) jejunum
3.) ileum

52
Q

What is segmentation motion and what does it do?

A

alternating ring like contraction of small intestines…
1.) mix chyme together with digestive juices
2.) expose chyme to absorptive surfaces of interstitial lining

(established by pacemaker cells in smooth muscle)

53
Q

What mechanisms prevent the contents of the large intestine from leaking back into the
small intestine?

A

ileocecal valve and sphincter prevent small intestine from being contaminated by bacteria in large intestine

54
Q

What is succus entericus and what does it do?

A

succus entericus: salt and mucus solution that provides H2O and lubrication of contents (secreted by exocrine glands in mucosa of small intestine)

55
Q

What structural features increase the surface area of the small intestine mucosa? Why
is this important?

A

1.) circular folds
2.) villi (microscopic finger like projections lined with epithelial cells and interspersed mucous cells)
3.) microvilli (brush border): extending from each epithelial cell; visible only with electron microscope

56
Q

Where are the Crypts of Lieberkühn located? What important cells do they contain?

A

located between villi; contain stem cells that constantly produce new epithelial cells

contain paneth cells: produce lysozyme and defensins that thwart intestinal bacteria

57
Q

What enzymes are embedded in the brush border? What do they do?

A

1.) enteropeptidase: activate trypsinogen (pancreatic proteolytic enzyme)
2.) disaccharidases: hydrolyzes disaccharides into monosaccharides
3.) aminopeptidases: hydrolyzes small peptide fragments into amino acids

58
Q

Does the body regulate absorption of carbohydrates, proteins and fats?

A

No (usually only calcium and iron absorption is regulated)

59
Q

Where does the energy come from to power transport of carbohydrates and proteins?

A

ultimately depend on energy expended by the Na+/K+ pump

60
Q

Do we excrete digestive enzymes, or proteins from sloughed off intestinal epithelial
cells?

A

proteins within epithelial cells that are sloughed off of villi become digested and absorbed

61
Q

What is a chylomicron?

A

lipid droplets coated with a lipoprotein that makes them water-soluble (exit cell via exocytosis and enter central lacteal, can’t enter capillaries due to structural reasons)

62
Q

Do absorbed carbohydrates, proteins and fats all enter the blood capillaries?

A

absorbed carbs and proteins are immediately passed thru the liver before entering general blood circulation

absorbed fats pass directly into general circulation- processed by liver later in diluted form

63
Q

What are the main functions of the large intestine? What does it receive from the small
intestine?

A

primary function is a drying and storage organ

cecum receives chyme consisting of: indigestible food residues (ex: cellulose), bilirubin, H2O

64
Q

Where are the cecum, colon, and rectum?

A

the large intestine

65
Q

Does the colon contain a little or a lot of bacteria? What do the bacteria do that is beneficial?

A

contains 4 lbs of beneficial bacteria… bacteria digest additional plant fiber primarily into fatty acids (some diffuse thru wall of colon)

66
Q

What do feces contain?

A

mostly water, plus undigested cellulose, bilirubin, bacteria and small amounts of salt

67
Q

What do haustral contractions do?

A

mixing contraction (about every 3o minutes) that shuffle contents to maximize absorption - not a propulsive movement

68
Q

What are the contractions that propel feces thru the
colon?

A

mass movement (massive contraction of colon that drive colon contents forward quickly)

69
Q

What is the gastrocolic reflex?

A

food enters the stomach -> stomach release of gastrin -> gastrocolic reflex (triggering of propulsive movements (mass movements))

Physiology (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions