Chapter 13 Part 6

Question 1

Serosa

Answer 1

connective tissue, continuous with mesentery layer

Outer most layer

Question 2

Muscularis externa

Answer 2

▪ Made up of longitudinal muscle and circular muscle
▪ two layers of muscles, longitudinal and circular; to push food into gut, they alternate contraction times
▪ Middle layer

Question 3

Submucosa

Answer 3

▪ contains nerves and blood vessels
▪ middle layer

Question 4

mucosa

Answer 4

▪ layer where absorption takes place
▪ Smooth muscle: muscularis mucosae, thin
▪ Inner most layer

Question 5

Describe the digestive system of cyclostomes

Answer 5

• Alimentary canal is a straight tube leading from mouth to anus without coils, folds, or major bends
• The ciliated esophagus runs directly from the pharynx to the intestine
• No distinct stomach is present

Question 6

Spiral valve

Answer 6

• part of digestive system
• found in the intestines of elasmobranchs and many primitive bony fishes, but it is absent in teleosts

Question 7

Describe esophagus in cartilaginous fish/bony fish

Answer 7

• Espohagus short and not well defined
• Esophagus in sharks continuous with stomach(also spiral valve present)

Question 8

Crop

Answer 8

• found in birds
• Esophageal pouch that stores and moistens food

Question 9

Hoatzin

Answer 9

• bird that uses crop for digestion of thick leaves
  ▪ Retains food in its foregut where it is digested by microbes
  ▪ Microbial digestion enhances the detoxification of plant defenses, production of amino acids, and extraction of nutrients

Question 10

Stomach in cartilaginous fish

Answer 10

stomach realtively undifferentiated

Question 11

Stomach in chimeras

Answer 11

not defined/developed with specialities, not much of a stomach anyways lol

Question 12

Stomach of sarcopterygians and actinopterygians

Answer 12

• Well developed stomach
• Duodenum: for digestion and absorption of food (not fermentation chambers)

Question 13

Tetrapod vertebrate stomach

Answer 13

• Gastric pits lead to fundic glands: chief cells (pepsinogen), parietal cells (HCL)
• Gastric pits: lead to glands called fundic glands; cells within it
• Pepsin breaks down proteins, formed from chief and parietal cells combination

Question 14

What is the function of the pyloric ceca?

Answer 14

• Found in actinopterygians
• Pyloric ceca: open into the duodenum form at the junction between the stomach and the intestine. These number from several to nearly 200 in some teleosts

Question 15

Gastric pits

Answer 15

lead to glands called fundic glands, full of chief and parietal cells

Question 16

Chief cells

Answer 16

pepsinogen

Question 17

Pairetal cells

Answer 17

have HCL

Question 18

Pepsin

Answer 18

combo of chief and parietal cells, break down cells

Question 19

Name the two major areas of the stomach

Answer 19

glandular and nonglandular region

Question 20

glandular region

Answer 20

includes gastric glands and often exhibits three divisions: cardia, fundus, pylorus; three regions that secrete things

Question 21

nonglandular region

Answer 21

lined with an epithelium devoid of gastric glands that in some species also may be keratinized