Colonic Motility Flashcards Preview

Physio U4 > Colonic Motility > Flashcards

Flashcards in Colonic Motility Deck (53)
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1
Q

Phasic contractions of the colon are optimized for

A

Water and electrolyte absorption and storage and evacuation of feces

2
Q

Tenia Coli

A

3 bands of longitudinal muscle from cecum to rectum

3
Q

Haustra

A

bulges of colon wall where longitudinal muscle is thin, increases SA of colon

4
Q

IAS

A

circular smooth muscle

5
Q

EAS

A

striated muscle

6
Q

Parasympathetic innervation to colon - VAGUS

A

cecum, ascending colon, and transverse colon

7
Q

Parasympathetic innervation to colon - PELVIC

A

descending colon, sigmoid colon, rectum

8
Q

PUDENDAL n

A

somatic motor innervation to EAS

9
Q

Sympathetic innervation to colon

A

innervate ENTIRE colon

10
Q

Innervation of the IAS

A

Pelvic n indirectly via enteric neurons

11
Q

5 types of phasic contractions in the colon

A

Haustral shuttling, haustral propulsion, multihaustral propulsion, haustral retropulsion, mass movement

12
Q

Haustral shuttling

A

Mixing of contents for absorption of water and electrolytes, (NON-PROPULSIVE), tenia coli and circular muscle contractions cause random appearance and disappearance of haustra

13
Q

Haustral propulsion

A

few adjacent hausfrau contract sequentially for aboral displacement of contents (5-10cm movement)

14
Q

Multihaustral propulsion

A

Contraction of many hausfrau, aboral movement of 18-20cm

15
Q

Haustral retropulsion

A

adjacent haustra contract in an oral direction, and contents move backward 5-20cm

16
Q

Mass movement

A

gastrocolonic reflex; strong contraction of MANY circular muscle and tenia coli, aboral movement >30cm; after ingestion of meal

17
Q

Common motility pattern of proximal colon

A

haustral propulsion, multihaustral propulsion, haustral retropulsion

18
Q

Common motility pattern of distal colon

A

Haustral shuttling, haustral retropulsion

19
Q

Purpose of common motility patterns

A

slow transmit in distal colon to increase absorption and minimize incontinence

20
Q

Mass movements effect on normal motility patterns

A

cause strong aboral contractions, initiated by TRANSVERSE, descending or sigmoid colon

21
Q

MMC in colon

A

DOES NOT EXIST :( :(

22
Q

Rectum motility

A

fecal material enters during a mass movement, can be stored and sent back to sigmoid via retropulsion

23
Q

Rectoanal inhibitory reflex

A

distention of the rectal smooth muscle causes IAS relaxation (long and short neural pathways)

24
Q

EAS

A

HIGH basal tone (pudendal n) - voluntary

25
Q

Gastrocolonic Reflex

A

food enters stomach and causes increased colonic motility

26
Q

Fast component of Gastrocolonic Reflex

A

gastric distention - long neural reflex - PNS (vagal and pelvic) activity

27
Q

Slow component of Gastrocolonic Reflex

A

gastric distention - increased gastrin release - short neural reflex - increased colonic motility

28
Q

The urge to defecate often occurs

A

30 min after a meal due to gastrocolonic reflex and MASS movements

29
Q

rectum is generally empty because

A

mass movement and filling leads to defecation (lax IAS), or retropulsion

30
Q

Rectum as temporary storage

A

if defecation is not appropriate, the rectum can store the feces -> rectal SM relaxes –> rectal pressure decreases –> IAS constricts –> haustral retropulsion into sigmoid colon

31
Q

What causes IAS to relax

A

PNS to myenteric inhibitory neurons –> increased NO

32
Q

Hirschsprung’s Disease

A

ENS absent in distal colon/rectum, failure of phasic contractions or relaxation of IAS

33
Q

Pressures during defecation

A

rectum: HIGH, IAS: medium, EAS: low

34
Q

Defecation involves ______________ neural reflex

A

long and short

35
Q

Short neural reflex functions to

A

Increase haustral propulsion, increase intra-luminal pressure, and relax the IAS

36
Q

Short neural reflex for defecation is activated by

A

IPAN activation by rectal distention

37
Q

Long neural reflex functions to

A

Increase haustral propulsion, increase intra-luminal pressure, and relax IAS

38
Q

Muscles active to defer defecation

A

puborectalis, EAS contract = narrow anorectal angle and increase pressure

39
Q

Defecation

A

puborectalis and EAS relaxed via pudendal n, widen the anorectal angle and relieve pressure

40
Q

Somatic and PNS act on various structures during defecation

A

Valsalva maneuver and relaxation of pelvic muscles

41
Q

Constipation definition

A

> 2 stools/week, straining, hard stools, feeling of incomplete evacuation

42
Q

Slow-Transit Constipation (STC)

A

increased transit time from proximal to distal colon

43
Q

Cause for Slow-Transit Constipation

A

weak mass movement contractions, uncoordinated activity in distal colon resisting aboral movement

44
Q

Pelvic Floor Dysfunction

A

prolonged storage of feces in rectum

45
Q

Casuses of Pelvic Floor Dysfunction

A

Muscular hypertonicity of EAS (paradoxical contraction or incomplete relaxation), or hypotonicity of rectum

46
Q

transit time in the colon

A

1.5-4 days

47
Q

Fiber decreases transit time to

A

<30 hrs

48
Q

How fiber works

A

draws water into stool, increases stool weight, stretching of colon = motility, absorbs organic materials

49
Q

Fiber can absorb organic materials like

A

lipids, bile acids, and cholesterol

50
Q

ICC are more active in

A

a colon of a healthy patient than one who is constipated

51
Q

Hemorrhoids

A

acute lower GI bleed due to strained passage of hard stools or frequent diarrhea

52
Q

Colonic lesions

A

acute lower GI bleed due to ulcerative colitis, colon cancer or polyps, or infections

53
Q

Diverticulosis

A

acute lower GI bleed due to outpouchings of the colon wall