Large Intestine

Question 1

what are the functions of the large intestine?

Answer 1

• 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

Question 2

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

Answer 2

cecum

Question 3

what transitions to the transverse colon at the hepatic flexure

Answer 3

ascending colon

Question 4

what marks the transition from transverse colon to descending colon

Answer 4

splenic flexure

Question 5

what is the narrowest part of LI and most mobile

Answer 5

sigmoid colon

Question 6

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

Answer 6

Denonvilliers’ fascia/rectovaginal fascia

Question 7

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

Answer 7

lateral ligament

Question 8

the rectum is innervated by ?

Answer 8

parasympathetic NS;pelvic splanchnic nerves

Question 9

the anal canal connects ? to ?

Answer 9

rectum to anal opening

Question 10

the internal anal sphincter is ?

Answer 10

involuntary; circular layer of smooth muscle

Question 11

the external anal sphincter is ?

Answer 11

voluntary; skeletal muscle

Question 12

Does the large intestines mucosa have any folds or villi?

Answer 12

no folds or villi

Question 13

the muscularis externa of the large intestine has ?

Answer 13

teniae coli

Question 14

what is teniae coli?

Answer 14

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

Question 15

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

Answer 15

Appendices epiploicae

Question 16

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

Answer 16

segmentation
peristalsis
mass action contraction

Question 17

what is Hirschsprung Disease

Answer 17

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

Question 18

what is the gastroileal reflex

Answer 18

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

Question 19

what is the gastrocolic reflex

Answer 19

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

Question 20

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

Answer 20

the presence of feces

Question 21

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

Answer 21

internal anal sphincter

Question 22

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

Answer 22

external anal sphincter

Question 23

what innervates the external anal sphincter

Answer 23

pudendal nerve

Question 24

what are the 3 components of inhibition of defecation

Answer 24

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

Question 25

what is the most common functional gastrointestinal disorder

Answer 25

Irritable Bowel Syndrome

Question 26

what is visceral hypersensitivity?

Answer 26

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

Question 27

what is low-grade mucosal inflammation

Answer 27

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

Question 28

Crohn's Disease includes ? which are ?

Answer 28

Discontinuous pattern - areas of healthy tissue between spots of ulceration

Question 29

ulcerative colitis typically involves ?

Answer 29

rectum

Question 30

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

Answer 30

diverticula

Question 31

what is inflammation or infection of the diverticula called

Answer 31

diverticulitis

Question 32

what is the theory of sliding anal canal lining

Answer 32

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

Question 33

what is the clinical presentation of hemorrhoids

Answer 33

bright red blood on toilet tissue or surface of stool

Question 34

will there be pain on defecation for hemorrhoids

Answer 34

yes for external hemorrhoids and no for internal hemorrhoids