large intestine

Question 1

name the 4 regions of the large intestine

Answer 1

Cecum
Colon
Rectum
Anal Canal

Question 2

explain the cecum region of the large intestine

Answer 2

Small intestine meets at cecum (blind sac)

Appendicitis = inflammation of v.appendix, due to obstruction. Secretions accumulate –> enlarge, pain, bacteria cause infection —>appendectomy

Peritonitis = if appendix bursts, life-threatening

• Vermiform appendix (worm-shaped); many lymph nodules in walls

Question 3

explain the colon region of the large intestine

Answer 3

1.5-1.8m long

consists of 4 parts:
- Ascending colon
- Transverse colon
- Descending colon
- Sigmoid colon = (S-shape) ends at rectum

Colon has:
- larger diameter &
- thinner wall
than small intestine

Question 4

name the 3 distinctive features to the colon

Answer 4

Taenia coli
Haustra
Epiploic appendages

Question 5

describe the colons distinctive feature: Taenia coli

Answer 5

(corresponds to outer layer of muscularis externa of other GI) 3 bands of longitudinal smooth muscle that run entire length of colon

Question 6

describe the colons distinctive feature: haustra

Answer 6

pouches, permit expansion & elongation

Question 7

describe the colons distinctive feature: epiploic appendages

Answer 7

small, teardrop-shaped, fat-filled sacs, attached to outer surface

Question 8

what are the major structural characteristics of the colon

Answer 8

Lack of villi

Distinctive intestinal glands (deeper) = crypts

Abundance of goblet cells
- (also have absorptive
cells).

Question 9

explain the rectum region of the large intestine

Answer 9

Straight, muscular tube, last 15cm of digestive tract

Expandable organ for temporary storage of faecal material

Movement into it triggers urge to defecate.

Question 10

explain the anal canal region of the large intestine

Answer 10

Last portion of rectum, contains rectal columns

• small longitudinal folds), joined by transverse folds that mark boundary between columnar & stratified squamous epithelium

Ends at anus with internal (SMC) & external (skeletal muscle) sphincters

haemorrhoids can occur in this region of the large intestine

Question 11

explain haemorrhoids

Answer 11

enlargement/inflammation of veins supplying anal canal; pain, itching, bleeding.

Question 12

does the mucosa of the large intestine produce enzymes

Answer 12

no

Question 13

whats an important function of the large intestine

Answer 13

Reabsorption of water

Question 14

explain the overall summary of the journey of carbohydrates

Answer 14

salivary glands secrete saliva which starts the breakdown of starches

food begins as complex carbs

carbs are broken down into simple sugars

glucose goes to the liver

insulin tells the liver to store glucose as glycogen

the liver stores some glucose as glycogen

glucagon tells the liver to change glycogen into glucose

when blood sugar is low the pancreas sends the hormone glucagon to the liver

when blood sugar is high, the pancreas sends the hormone insulin to the liver

some type of enzyme is secreted by the pancreas into the beginning portion of the small intestine

in the beginning part of the small intestine, this enzyme cuts down carbs into simple sugars