Brainscape's Knowledge GenomeTM

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


See full index

Physiology II > GI: Small & Large Intestines > Flashcards

GI: Small & Large Intestines Flashcards

1
Q

What three features of the small intestines increase surface area by 600x?

A

mucosal folds, villi, microvilli

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

What structure has the following characteristics?

  • site of new enterocyte production via stem cells
  • sit between individual villi
  • produce mucus and other secretions
A

crypts of lieberkuhn

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

Enterocyte microvilli are also called the…

A

brush border

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

What is the basal electrical rhythm from the duodenum to the ileum?

A

12 to 9/min

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

What are the two types of movement in the small intestine?

A

segmentation and peristalsis

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

This method of motility mixes chyme with juices and exposes it to mucosa…

A

segmentation

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

This method of intestinal motility is reflex initiated and moves chyme towards the colon…

A

peristalsis

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

The peristaltic reflex is initiated by ________ and mediated by_______

A

initiated by intestinal lumen distension

mediated by myenteric plexus

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

Rhythmic segmentation occurs via simultaneous contractions of …

A

segments of circular muscle

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

progressive contraction of successive sections of _______ is responsible for peristalsis in the small intestines

A

circular smooth muscle

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

In orthograde wave of relaxation/contraction, circular muscle ________ is relaxed while _______ is contracted

A

relaxed in front of bolus

contracted behind bolus

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

What mediates circular muscle relaxation in front of the bolus in orthograde wave?

A

VIP and NO

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

What mediates circular muscle contraction behind the bolus in orthograde wave?

A

ACh

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

This “housekeeping” process occurs with bursts of contractile activity separated by longer periods of quiescence q 75-90 min

A

Migrating motility complex

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

where does the migrating motility complex run in the GI?

A

stomach to ileum

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

The migrating motility complex is assoc. with increases in plasma _____

A

motilin

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

PNS preganglionic fibers synapse with ______ neurons

A

enteric nervous system neurons

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

SNS postganglionic fibers synapse with neurons of the _______

A

myenteric plexus

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

SNS stimulation of the myenteric plexus has what effect?

A

inhibit contraction

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

PNS/Vagal stimulation has what effect on the intestines?

A

stimulates contractions

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

The enterogastric intestinal reflex has what mechanism and effect?

A

increased H+ in duodenal chyme inhibits gastric emptying

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

The gastroileal intestinal reflex has what mechanism and effect?

A

Gastric secretion/motility increases ileal motility

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

What 2 effectors stimulate the gastroileal intestinal reflex?

A

gastrin and PNS

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

The ileocecal intestinal reflex has what mechanism and effect?

A

distension of ileum relaxes ileocecal sphincter

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

The gastrocolic intestinal reflex has what mechanism and effect?

A

stomach distension increases colonic motility

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

4 substances that increase intestinal motility…

A

ACh, Gastrin, CCK, Motilin

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

5 substances that decrease intestinal motility…

A

NE, Somatostatin, Secretin, VIP, GIP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

The duodenal brush border secretes ______ which has what effect on pancreatic secretions?

A

enterokinase, activate pancreatic zymogens

29
Q

What two structures secret mucus to protect and lubricate the small intestine?

A

glands of lieberkuhn and goblet cells

30
Q

What three substances stimulate small intestinal secretion, along with local neural reflexes after chyme entry…

A

secretin, CCK, ACh

31
Q

How long is the human colon?

A

about 1.3m

32
Q

3 separated bands of longitudinal muscle makes up the…

A

taeniae coli

33
Q

What forms the internal anal sphincter?

A

circular muscle

34
Q

The external anal sphincter is made up of…

A

striated muscle

35
Q

these structures of the wall of the colon form pockets…

A

haustra

36
Q

T/F:

colonic mucosa do not contain villi

A

T

37
Q

Is mucosa thicker in the colon or small intestine?

A

colon

38
Q

The colon has deeper crypts with increased presence of what cell type?

A

more goblet cells

39
Q

What are two functions of the ileocecal valve?

A

prevent backflow and contamination

40
Q

Gastric activity mediated by gastrin increases ileal motility. This is called the _____ reflex

A

gastroileal

41
Q

What causes relaxation of the ileocecal sphincter?

A

ileocecal reflex

42
Q

What two substances are not transported in the colon?

A

glucose and AAs

43
Q

Most sodium in the GI tract is absorbed where?

A

colon

44
Q

What volume of chyme does the colon receive every day?

A

500 ml/day

45
Q

Of the 500 ml entering the colon per day, _____mL is absorbed and ______ is voided

A

350 ml absorbed

150 ml voided

46
Q

of the 150 ml of chyme voided every day, what volume is water?

A

100

47
Q

The intestines are an (aerobic/anaerobic) environment…

A

anaerobic

48
Q

What are the products of intestinal bacterial metabolism?

A

gases: H2, N2, CO2, methane, hydrogen sulfide

49
Q

intestinal bacteria aid in synthesizing what two substances?

A

b complex vitamins and vitamin K

50
Q

extrinsic regulation of colonic motility is controlled by the____

A

PNS (Excitatory) and SNS (Inhibitory)

51
Q

This PNS nerve innervates the cecum, ascending and transverse colon…

A

vagus

52
Q

This PNS nerve innervates the descending colon, sigmoid colon, and rectum

A

pelvic nerve

53
Q

What two SNS structures innervate the colon?

A

superior mesenteric ganglion (distal 1/2)

inferior mesenteric ganglion (proximal 1/2)

54
Q

Intrinsic innervation of colonic motility is obtained by…

A

enteric plexuses

55
Q

What are the 2 principal functions of the colon?

A

absorb water and lytes

store/expel fecal matter

56
Q

Are strong contractions necessary to accomplish the chief functions of the colon?

A

no

57
Q

Characterize colonic motility…

A

sluggish

58
Q

What two types of motility are present in the colon?

A

mixing/haustration

propulsion

59
Q

what process is described below?

  • very slow movement
  • aids in absorption of water and lytes
  • no propulsion, mixing action
A

haustration

60
Q

Slow movement of haustration allows growth of what?

A

bacteria

61
Q

how many mass movements in the colon are there per day?

A

1-3

62
Q

What stimulates colonic mass movement?

A

gastrocolic reflex (gastrin)

63
Q

Gastrocolic reflex is most evident when, causing a strong urge to do what?

A

evident after 1st meal

urge to defecate

64
Q

In mass movement, what two parts of the colon contract simultaneously?

A

ascending and transverse colon

65
Q

Contraction of the colon during mass movement drives feces how far in just a few seconds?

A

1/3 to 3/4 length of colon

66
Q

What factor initiates defecation?

A

rectal filling by mass movement

67
Q

What three things occur when intraluminal rectal pressure increases with colon distension?

A

active rectal contraction

reflex relaxation of internal sphincter

constriction of external sphincter

68
Q

When defecation is to occur, the external sphincter is relaxed how?

A

voluntarily

69
Q

What increases intra-abdominal pressure to assist with defectaion?

A

valsalva

Physiology II (28 decks)

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