Lecture 19 & 20 - Avian GI anatomy, physiology & disease Flashcards Preview

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Flashcards in Lecture 19 & 20 - Avian GI anatomy, physiology & disease Deck (43):
0

Name 1 airborne ruminant (there arent many)

hoatzin

1

what structures in the oral cavity normally found in mammals are absent in birds?

lips
teeth
soft palate
no distinct separation between oral cavity and pharynx = oropharynx
no true intrinsic muscles in avian tongue

2

what is the choana?

median fissure in palate connecting oropharynx and nasal cavity

3

what is tongue supported by?

the hyobranchial (hyoid) apparatus

4

where are salivary glands most prominant?

around the choanal slit, glottis and base of tongue

5

describe the action of swallowing

1. pellet of food is seized by beak and moved by tongue to palate
2. choanal opening reflexlively closed by muscular action - stops food entering nasal cavity
3. rapid rostro-caudal movements of tongue move bolus into caudal part of oropharynx aided by caudally directed papillae
4. infundibular cleft and glottis are reflexively closed
5. propulsive action continued by laryngeal mound, etc.

6

describe the action of drinking

1. fluid enters mouth by rapid rostro-caudal movements of tongue and accumulates in floor of oropharynx, caudal to tongue
2. simultaneously larynx moves rostrally to lie close to choana
3. head is raised and fluid flows around larynx and into esophagus mainly by gravity

7

common problems seen in oral cavity

hypovitaminosis A
bacterial microabsceses
candidiasis
trichomoniasis
capillariasis
coccidosis

8

describe the internal surface of the esophagus

is longitudinally folded to increase distensibility of tube

abundant subepithelial mucus glands to lubricate food passage

9

describe location of esophagus

most of cervical esophagus is on the RIGHT side of the neck

10

what is another name for the crop?

ingluvies

11

where is the crop located?

dilatation of the esophagus

12

is the crop present in all species?

no!

13

are there mucus glands in the crop?

no!

14

describe the internal surface of the crop

its aglandular with a thin muscularis

15

innervation to the crop and esophagus is mediated by what nerve?

the vagus!

16

the esophagus and crop of granivores/omnivores have primarily what type of bacteria?

Gram (+) bacteria

17

transport of food down esophagus is aided by lubrication from what 2 things?

1. esophageal glands
2. peristalsis

18

retroperistalsis

regurgitation of food stored in esophagus or crop

19

where is food stored if ventriculus is full?

crop and/or esophagus!

20

what does entry of food into crop do to contractions?

initially decreases them

21

when the ventriculus is empty, where does food go?

directly to the stomach - entrance to the crop is blocked by contraction of longitudinal muscle layer of esophagus

22

what is crop milk?

fed by pigeons and doves (columbiformes) to their young

23

how is crop milk produced?

produced by desquamation of fat-laden cells of the proliferated stratified squamous epithelium lining the very well-developed crop of both sexes

24

which pituitary hormone controls production of crop milk?

prolactin

25

describe the nutritional content of crop milk

rich in fat and protein

LACKS Ca and carbs!

26

common problems of esophagus and crop

paralysis
impaction
perforation
infection
burn injuries (in infant or debilitated birds that are gavage fed)

27

what is the demarcation between the esophagus and proventriculus?

there is none!

28

what is the primary function of the proventriculus?

production and release of gastric secretions: pepsin, HCl and mucus

29

proventricular folds are usually absent except in what two types of birds?

piscivores and carnivores

30

describe the distribution of glands within the proventriculus for:
domestic fowl
owls
ostrich
anhinga (a type of water bird)

domestic fowl = distributed throughout proventriculus
owls = present along longitudinal tracts
ostrich = present along circular patches
anhinga = separate diverticular

31

where do gastric glands open into?

proventricularis - visible to naked eye

32

what type of cell is seen within gastric glands and what do they secrete?

gastric glands contain only CHIEF CELLS.

chief cells secrete PEPSIN & ACID

33

what type of granules do chief cells contain? when are they increased?

chief cells contain zymogen or pepsinogen granules

they are increased during fasting or immediately after feeding

34

what type of flora is usually seen within the proventriculus?

Lactobacillus (Streptobacillus)-like flora

35

what are common problems seen with the proventriculus?

can be colonized with Candida sp. or bacteria

megabacteriosis

36

what is the main function of the ventriculus?

main functions are mechanical digestion and preliminary proteolysis

37

is grit essential for grinding action in the ventriculus?

no!

38

what is another name for ventriculus?

gizzard

39

what is the cuticle or koilin layer?

its present on the surface of the epithelium in the highly muscular ventriculus.

40

what produces cuticle (koilin layer)?

condensed or polymerized secretions of simple tubular glands and by entrapment of sloughed cells and cellular debris

41

how is cuticle (koilin layer) of ventriculus removed?

its constantly being worn away by grinding movements of ventriculus

it can also be eroded from perforating foreign bodies, heavy metal intoxication, or hyper-acidity

42

describe the appearance of the cuticle (koilin layer)

it has many longitudinal parallel folds and is usually brown, green or yellow as a result of regurgitation of bile pigments from duodenum

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