Large Intestine Flashcards

1
Q

what are the functions of the large intestine?

A
  • to convert undigested material into feces by removing water and adding mucus
  • store and transport feces
  • largest microbial presence
  • slower motility to allow for water and solute absorption
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2
Q

what is the widest part of the colon and most prone to perforation

A

cecum

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3
Q

what transitions to the transverse colon at the hepatic flexure

A

ascending colon

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4
Q

what marks the transition from transverse colon to descending colon

A

splenic flexure

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5
Q

what is the narrowest part of LI and most mobile

A

sigmoid colon

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6
Q

what runs anterior to rectum and separates it from prostate and seminal vesicles or vagina

A

Denonvilliers’ fascia/rectovaginal fascia

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7
Q

what supports the lower portion of the rectum and provide scaffold for blood vessels and nerves

A

lateral ligament

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8
Q

the rectum is innervated by ?

A

parasympathetic NS;pelvic splanchnic nerves

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9
Q

the anal canal connects ? to ?

A

rectum to anal opening

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10
Q

the internal anal sphincter is ?

A

involuntary; circular layer of smooth muscle

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11
Q

the external anal sphincter is ?

A

voluntary; skeletal muscle

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12
Q

Does the large intestines mucosa have any folds or villi?

A

no folds or villi

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13
Q

the muscularis externa of the large intestine has ?

A

teniae coli

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14
Q

what is teniae coli?

A

3 thick longitudinal bands of smooth muscle in the outer layer with thin layer of smooth muscles between the bands

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15
Q

what is the teardrop-shaped adipose-filled outpockets within the serosa throughout the colon

A

Appendices epiploicae

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16
Q

what are the 3 types of movement in the large intestine?

A

segmentation
peristalsis
mass action contraction

17
Q

what is Hirschsprung Disease

A

a congenital disorder where ganglions are absent in myenteric and submucosal plexuses in distal colon resulting in lack of peristalsis and defecation rate of 1 every 3 weeks

18
Q

what is the gastroileal reflex

A

Food leaving the stomach allows the cecum to relax which allows the ileocecal valve to relax and chyme to pass from SI to LI

19
Q

what is the gastrocolic reflex

A

Large waves of peristalsis are stimulated by presence of food in the stomach after a meal

20
Q

what causes distention of the rectum which initiates a reflex contraction of the rectal muscles and communicates to the CNS a desire to defecate

A

the presence of feces

21
Q

what is involuntarily relaxed in response to inhibitory signals from sacral parasympathetic NS and distention

A

internal anal sphincter

22
Q

what can voluntarily relax and expulsion of feces may occur unaided if enough pressure has been reached or supported by contraction of abdominal muscles

A

external anal sphincter

23
Q

what innervates the external anal sphincter

A

pudendal nerve

24
Q

what are the 3 components of inhibition of defecation

A

○ Both sphincters are tonically active
○ Puborectalis muscle maintains contraction
- Angle between rectum an anus is 90 degrees

25
Q

what is the most common functional gastrointestinal disorder

A

Irritable Bowel Syndrome

26
Q

what is visceral hypersensitivity?

A

increased pain sensation in the bowel; normal amount of distention causes atypical amount of pain

27
Q

what is low-grade mucosal inflammation

A

Greater amount of immune cells infiltrating the colonic mucosa compared to healthy controls
- increased release of inflammatory cytokines

28
Q

Crohn’s Disease includes ? which are ?

A

Discontinuous pattern - areas of healthy tissue between spots of ulceration

29
Q

ulcerative colitis typically involves ?

A

rectum

30
Q

what are small bulges or pockets within the lining of the large intestine

A

diverticula

31
Q

what is inflammation or infection of the diverticula called

A

diverticulitis

32
Q

what is the theory of sliding anal canal lining

A

Disintegration of supporting connective tissues surrounding the hemorrhoid allows for downward displacement of anal cushions and subsequent venous dilation

33
Q

what is the clinical presentation of hemorrhoids

A

bright red blood on toilet tissue or surface of stool

34
Q

will there be pain on defecation for hemorrhoids

A

yes for external hemorrhoids and no for internal hemorrhoids