12.2 - Avian Digestive System

Question 1

the mouth and pharynx of birds constitute a combined cavity that is surrounded dorsally and ventrally by the?

Answer 1

beak

Question 2

► the mouth and pharynx of birds constitute a combined cavity that is surrounded dorsally and ventrally by the beak
► This macroscopically and functionally common space is referred to as the?

Answer 2

oropharynx

Question 3

While the beak is a particular avian adaptation for feeding, it also makes a significant contribution during flight as an?

Answer 3

aerodynamic feature

Question 4

► The maxilla and mandibles form the bony foundation of the beak
► These bones are covered in a horny sheath, the?

Answer 4

rhamphotheca

Question 5

dorsal median ridge of the upper beak

Answer 5

Culmen

Question 6

ventral midline structure of beak equivalent to culmen

Answer 6

Gonys

Question 7

a hard horny plate at the tip of the upper and lower beak in many waterbird species.

Answer 7

Nail

Question 8

the cutting edge of the upper and lower beak, where the inner and outer layers of horn come together

Answer 8

Tomium

Question 9

in several species, a sharp calcified projection found on the culmen of full term chicks; used by young birds during hatching to break the egg membrane and sometimes also to penetrate the shell; lost shortly after hatching.

Answer 9

‘egg tooth’

Question 10

the beak is pointed and hooked appearance

Answer 10

Galliformes (e.g., chickens, turkeys, quail)

Question 11

The beak is flattened into a spoon-like shape appearance

Answer 11

Anseriformes

Question 12

In most avian species, the tip of the beak contains multiple aggregations of sensory receptors that form part of a complex sensory structure known as the?

Answer 12

bill tip organ

Question 13

The sensory receptors are housed within so-called?

Answer 13

‘touch papillae’

Question 14

The sensory receptors within the papilla include what corpuscles ?, which are thought to correspond functionally with the sensory Merkel’s discs and Meissner’s corpuscles of mammals

Answer 14

Herbst corpuscles and Grandry corpuscles

Question 15

What forms the dorsal boundary of the combined cavities, or oropharynx?

Answer 15

Palate

Question 16

An elongated, sometimes oval called ? in the palate connects the oropharynx with the left and right nasal cavities

Answer 16

median cleft (choana)

Question 17

What cleft lies caudal to the choana which connects with the middle ear?

Answer 17

infundibular cleft

Question 18

body of the tongue is supported by a bone, the?

Answer 18

paraglossum

Question 19

What avian apparatus differs markedly from the hyoid apparatus of mammals?

Answer 19

hyobranchial apparatus

Question 20

What surrounds the slit-like glottis, the entrance to the laryngeal cavity?

Answer 20

laryngeal mound

Question 21

► What is formed by the dilation of the esophagus immediately before its entry into the body cavity?

► Permits temporary storage of ingesta as well as softening and predigestion of poorly digestible foodstuffs

Answer 21

crop

Question 22

columbiform crop also produces a substance known as ?, which is regurgitated and fed to nestlings

Answer 22

‘crop milk’

Question 23

What type of avian stomach is highly expandable?

Answer 23

Carnivorous

Question 24

What type of avian stomach in which the stomach prepares the ingesta physically and chemically;
► in these species there is typically a clear distinction between the glandular and muscular stomachs.

Answer 24

Herbivorous

Question 25

What type of avian stomach is reduced to a rudimentary diverticulum?

Answer 25

intermediate (e.g., fruit- and nectar-eaters)

Question 26

► glandular stomach

Answer 26

Proventriculus

Question 27

► Muscular stomach

Answer 27

ventriculus, gizzard

Question 28

Gizzard are sometimes referred to as a ? as it replaces the function of the teeth

Answer 28

‘masticatory organ’

Question 29

Among avian species, the intestine is longer in ? than in carnivores.

Answer 29

grain- and grass-feeders

Question 30

Chemical digestion and absorption of nutrients takes place in the?

Answer 30

small intestine

Question 31

What is responsible for breakdown of cellulose?

Answer 31

caecum

Question 32

Reabsorption of water occurs in the?

Answer 32

rectum and cloaca

Question 33

Ileum; jejunum and the ileum are sometimes referred to collectively as the?

Answer 33

‘jejunoileum’

Question 34

Particularly in chickens, aggregated lymph nodules known as ? are most conspicuous near the Meckel’s diverticulum, in the distal jejunoileum and at the entrance to the caecum

Answer 34

Peyer’s patches

Question 35

► an embryonic remnant of the yolk stalk, located on the ansa axialis (an intestinal loop in the middle of the jejunoileum), opposite the longest middle branch of the cranial mesenteric artery ► rudimentary structure often considered to represent the boundary between the jejunum and ileum

Answer 35

Meckel’s diverticulum

Question 36

Meckel’s diverticulum located on the?

Answer 36

ansa axialis

Question 37

At its base, each caecum is richly endowed with lymphatic tissue, sometimes referred to as the?

Answer 37

cecal tonsils

Question 38

the site of digestion of plant polysaccharides such as cellulose

Answer 38

Ceca

Question 39

► the common excretory passage for the digestive and urogenital systems

Answer 39

Cloaca

Question 40

► part of cloaca which is the continous with rectum?

Answer 40

Coprodeum

Question 41

reters and genital duct (male: deferent ducts; female: left oviduct) open in this part of cloaca

Answer 41

Urodeum

Question 42

► Terminal section; cloacal bursa (bursa of fabricius) opens in the dorsal wall; in males, houses the copulatory organ (phallus) on its floor

Answer 42

Proctodeum

Question 43

external opening of the cloaca

Answer 43

Vent

Question 44

What allow the cloaca to expand for copulation, egg laying and defaecation?

Answer 44

Cloacal muscles (mm. cloacales)

Question 45

What sphincter surrounds the vent of cloaca

Answer 45

muscular sphincter (m. sphincter cloacae)