Digestive System Slides

Question 1

Peritoneum:

Answer 1

lines coelom;

covers organs

Question 2

Mesentery:

Answer 2

peritoneal extension
provides support; vessels draw
nutrients from canal

Question 3

Extramural gland;

Answer 3

e.g.

salivary; pancreas

Question 4

Mucosa

Answer 4

Epithelia mostly simple columnar
or stratified squamous.
Lamina propria with lots of WBCs

Question 5

Mucosal pits

Answer 5

Some are glands e.g. gastric pits.

Also sanctuaries for mitosis.

Question 6

Muscularis

Answer 6

Inner circular layer; outer longitudinal
Causes “gut motility” e.g. Peristalsis:
wave of contraction drives digesta
analward as a bolus

Question 7

Oral Cavity

Answer 7

Tongue manipulates food
Salivary glands make saliva:
Lubrication
Digestive enzymes
Modified as reptile venom glands
Teeth typical

Question 8

Keratin Teeth or equivalent

Answer 8

Epithelial outgrowths; are composed of keratinocytes
Agnatha
Baleen in whales
Most vertebrates have bony teeth
Ectoderm derivatives develop in connective tissue

Question 9

Outer layer of human teeth

Answer 9

Pure hydroxyapatite.
Hardest substance in the body.
Made by cells called Ameloblasts.

Question 10

Inner layer of human teeth

Answer 10

Bonelike matrix.

Made by cells called Odontoblasts.

Question 11

Tooth held in place by

Answer 11

“Periodontal Ligament” of

dense connective tissue

Question 12

Pulp Cavity

Answer 12

Vascular and innervated.

Lined with Odontoblasts

Question 13

Odontoblasts

Answer 13

Monitor dentin condition;

make 2o dentin to accommodate wear

Question 14

Esophagus Parts and pieces

Answer 14

Peristalsis of swallowing
muscularis transition
skeletal muscle to smooth muscle
abundant mucus glands

Question 15

Esophagus adaptations

Answer 15

Crop in birds
dilated portion; stores food
Rumen in “Foregut Fermenters”
e.g. Cattle
houses microbes to digest cellulose

Question 16

Stomach parts and functions

Answer 16

Stores food; begins protein digestion
Rugae: inner folds permit stretch
3 layered muscularis for mixing motions
Gastric pits secrete “gastric juice”

Question 17

Gastric juice includes:

Answer 17

Hydrochloric acid
Digests; protects against parasites
Proteases: enzymes that break down proteins
Mucus: keeps stomach from digesting self

Question 18

Birds have two stomachs:

Answer 18

Glandular stomach: secretes juice
Gizzard: grinding stomach
Mucosa covered with hard 
keratin-like protein
Some birds swallow small rocks
to help grind food

Question 19

The vertebrate stomach produces an

acidic product called

Answer 19

Chyme
Chyme moves into the Duodenum, the
beginning of the small intestine

Question 20

Duodenum receives:

Answer 20

Chyme from the stomach
Digestive enzymes from the pancreas
Bile from the liver

Question 21

Duodenum wall has Brunner’s glands:

Answer 21

secrete alkaline mucus to neutralize chyme

Question 22

Small Intestine parts and functions

Answer 22

Lined with columnar Enterocytes
Enterocytes have apical “brush border” enzymes
   that finish digestion
Enterocytes perform all absorption
Enterocyte surface area is maximized

Question 23

How enterocyte surface is maximized

Answer 23

Great intestinal length
Spiral valve in some fishes e.g. sharks
~Circular internal folds
~Villi: finger-like mucosa projections
~Microvilli of enterocytes

These ~ increase SA by 600X`