Digestive Tract

Question 1

What 6 parts does the alimentary system consist of?

Answer 1

• oral cavity
• esophagus
• forestomachs
• stomachs/abomasum
• small & large intestines
• anus

Question 2

What are the 3 glands associated with the alimentary system?

Answer 2

• Salivary glands
• Liver
• Pancreas

Question 3

What are the 8 functions of the digestive tract?

Answer 3

• Ingestion
• motility
• release hormone
• secretion of mucus
• digestive enzymes/fluids/bile
• absorption of small molecules & water into the blood
• lymphatics (Peyer’s patches + appendix)
• elimination of indigestible, unabsorbed components of food.

Question 4

What is the epithelial lining of the oral cavity in domestic animals?

Answer 4

Keratinized stratified squamous epithelium.

Question 5

What is the skin transition at the external lip?

Answer 5

Mucocutaneous junction; to the mucosa on the oral side of the lip.

Question 6

What do ruminants have on the inside surface of their cheeks?

Answer 6

Buccal papilla; highly keratinized conical projections.

Question 7

What does the hard palate of the oral cavity separate?

Answer 7

The oral & nasal cavities.

Question 8

What tissues make up the hard palate of the oral cavity?

Answer 8

Has a core of bone covered by dense irregular connective tissue; the oral surface is lined by keratinized stratified squamous epithelium.

Question 9

What does the soft palate separate?

Answer 9

Oropharynx from nasopharynx.

Question 10

What tissues make up the soft palate?

Answer 10

Has a core of skeletal muscle; the oral surface is lined by non-keratinized stratified squamous epithelium.

Question 11

Where are branches mucus & seromucous palatine glands located?

Answer 11

Within the propria-submucosa.

Question 12

What is the function of the tongue?

Answer 12

Manipulates food during mastication/swallowing; has sensory awareness for taste & touch.

Tongue of a cat

Question 13

What type of muscle is the tongue?

Answer 13

Skeletal muscle with fibers running in all 3D planes.

Question 14

What type of epithelium is the tongue covered by?

Answer 14

Mucosa with stratified squamous epithelium.

Question 15

What does the mucosal surface of the tongue have?

Answer 15

Papillae; mushroom shaped, series of folds, threadlike, spiny.

Question 16

What are the 2 types of teeth in domestic mammals that differ in pattern of growth and morphology?

Answer 16

Brachydont teeth and Hypsodont teeth.

Question 17

What species have brachydont teeth?

Answer 17

Carnivores & swine.

Question 18

What are the characteristics of brachydont teeth?

Answer 18

The enamel covers the tooth above gumline; the teeth stop growing after fully erupted.

Question 19

What species have hypsodont teeth?

Answer 19

Herbivores.

Question 20

What are the characteristics of hypsodont teeth?

Answer 20

Enamel covers the body of tooth & extends under the gumline; some have 1-2 infundibula; teeth continue to grow for some years after they come into wear.

Question 21

What are the 5 components of the teeth?

Answer 21

• Enamel
• dentin
• dental pulp cavity
• cementum
• periodontium.

Question 22

What is the enamel produced by?

Answer 22

Highly mineralized, hard material produced by ameloblasts
**(brachydont teeth make enamel only before eruption, after which the ameloblasts die)

Question 23

What is dentin?

Answer 23

bone-like connective tissue that is secreted by
odontoblasts

Question 24

The dental pulp cavity lies within the ____ and contains
______ & ___________ .

Answer 24

dentin ; vessels & nerves

Question 25

What is cementum and what is it secreted by?

Answer 25

It is calcified connective tissue secreted by cementoblasts ; it covers the tooth root

Question 26

What is the periodontium composed of?

Answer 26

It is composed of: -cementum -periodontal ligament -alveolar bone (socket) -associated gingiva

Question 27

What does the periodontium do?

Answer 27

It attaches the tooth to the jaws

Question 28

The gingiva is composed of _______ mucosa firmly bound to the:

Answer 28

Keratinized oral mucosa; firmly bound to the periosteum of the alveolar bone

Question 29

What/where does the gingiva attach?

Answer 29

It attaches to the tooth at the dentogingival junction

Question 30

What is the dentogingival junction? What is its function?

Answer 30

The zone of attachment between the gingiva and enamel /cementum of the tooth and is a sealing point that prevents periodontal diseases.

Question 31

What is the gingival sulcus?

Answer 31

The area of potential space between a tooth and the surrounding gingival tissue

Question 32

Describe the tubular portion of the digestive tract on **gross** examination?

Answer 32

Normal mucosal & serosal surfaces should be **smooth and shiny**; except for the rumen, whose mucosal surface / papillae have a roughened, dull appearance

Question 33

Describe the tubular portion of the digestive tract on **microsopic** examination? | what are the different layes/ parts?

Answer 33

* Mucosa (mucus membrane)- the epithelial lining; * underlying lamina propria (loose connective tissue, lymphocytes, +/- glands) * often a muscularis mucosae (separating mucosa from the submucosa)

Question 34

# tubular portion Describe the submucosa layer microscopically:

Answer 34

* Denser connective tissue * larger blood & lymph vessels, * submucosal autonomic nerve plexus, * +/- glands & lymphoid tissue

Question 35

# tubular portion What does the muscularis externa consist of?

Answer 35

* smooth muscle (mostly 2 layers: an inner circular & an outer longitudinal layer) - blood / lymph vessels - myenteric autonomic nerve plexus