Intro to the Alimentary System

Question 1

Name all of the main parts of the GIT

Answer 1

Headgut = mouth, pharynx, oesophagus
Foregut = stomach
Midgut = duodenum, jejunum, ileum
Hindgut = Caecum, ascending colon, transverse colon, descending colon, rectum

Question 2

What are the associated glandular organs of the alimentary system?

Answer 2

Salivary glands (headgut)
Liver, gall bladder, pancreas (foregut)

Question 3

What are the 4 major functions of the alimentary system?

Answer 3

1) Motility
2) Digestion
3) Secretion
4) Absorption
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Question 4

Define motility in relation to the GI tract

Answer 4

Motility = the movements of the alimentary system that mix and circulate its contents and propels it along its length.

Question 5

What are the 4 main layers of the GI tract components?

Answer 5

Mucosa.
Submucosa (with glands)
Muscularis externa
Serosa / Adventitia

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Question 6

What is the function of the circular and longitudinal muscle in the GI tract?

Answer 6

Circular muscle contractions control the size of the lumen
Longitudinal muscle contractions control the length of the GI tract

Question 7

Where can the submucosal plexus and the myenteric plexus be found?

Answer 7

Myenteric found within the longitudinal muscle
Submucosal found within the submucosa

Question 8

Where do prehension and mastication occur?

Answer 8

In the headgut

Question 9

What type of epithelia can be found in the oesophagus?

Answer 9

Stratified squamous epithelia

Question 10

What are the 4 key salivary glands?

Answer 10

Parotid
Mandibular
Sublingual
Zygomatic

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Question 11

What type of stomach do dogs and cats have?

Answer 11

Simple

Question 12

What are the 4 regions of a simple stomach?

Answer 12

Cardiac region
Fundus
Body
Pyloric region

Question 13

What type of stomach do horses and pigs have?

Answer 13

Composite simple stomach

Question 14

What type of stomach is found in ruminants?

Answer 14

Complex composite stomach

Question 15

What are the 4 chambers of the ruminant stomach?

Answer 15

Reticulum
Rumen
Omasum
Abomasum

(Only the abomasum has glandular mucosa)

Question 16

What is the name of the sphincter at the top and the bottom of the stomach?

Answer 16

Cardiac sphincter
Pyloric sphincter

Question 17

What is the basic function of each of the 4 chambers of the ruminant stomach?

Answer 17

Reticulum: Filters food from the rumen, collects smaller digested particles
Rumen: Stores food prior to chewing. Cellulose broken down by microorganisms
Omasum: Water and salts absorbed.
Abomasum: Digestive enzymes and acid are added

Question 18

What are rugae?

Answer 18

Gastric folds in the lining of the stomach

Question 19

What is the importance of cardiac and pyloric glands in the stomach?

Answer 19

Cardiac and pyloric glands produce mucous which acts as a protective barrier against gastric juices

Question 20

What do parietal cells and chief cells produce and where are they found?

Answer 20

Parietal cells produce hydrochloric acid
Chief cells produce pepsinogen
They are both found in the fundic region of the stomach.

Question 21

What is special about the internal lining of the reticulum?

Answer 21

Honeycomb texture to increase SA

Question 22

What is the purpose of the oesophageal groove in calves?

Answer 22

Oesophageal groove closes during suckling to ensure milk goes straight into the abomasum and not into the rumen (it will otherwise sit in the rumen and ferment/ sour)

Question 23

What is the exocrine function of the liver?

Answer 23

Exocrine product = bile

Question 24

What is the role of the endocrine substances produced by the liver?

Answer 24

To aid in metabolism of fats, carbohydrates and proteins

Question 25

What is stored in the liver?

Answer 25

Glycogen

Question 26

What is the difference between exocrine and endocrine glands?

Answer 26

Exocrine glands secrete products through ducts and not directly into the bloodstream Endocrine glands secrete hormones directly into the blood.

Question 27

Biotransformation also occurs in the liver - what does this mean?

Answer 27

The transformation of a potentially harmful product, such as a drug, into a non-harmful product.

Question 28

What is the function of the gall bladder?

Answer 28

To store bile (which emulsifies fats)

Question 29

Why do horses and small rodents not ave a gall bladder?

Answer 29

Because they continuously make and use bile, so don't need to store it.

Question 30

What are the exocrine and endocrine functions of the pancreas?

Answer 30

Exocrine = produces pancreatic juices Endocrine = produces insulin, glucagon and somatostatin

Question 31

Where do pancreas ducts open into?

Answer 31

The small intestine

Question 32

How is the mucosal surface area increased in the small intestine?

Answer 32

By plicae circulares and villi

Question 33

What is the brush border in the small intestine?

Answer 33

A border formed by the microvilli of the columnar epithelial cells that make up the villi

Question 34

What are crypts and what do they contain?

Answer 34

Crypts are the invaginations of epithelium at the base of the villi crypts. They contain glands that secrete intestinal juices (mucus, peptides, proteins)

Question 35

What are Peyer's patches and what do they do?

Answer 35

Lymph node aggregations which prevent infection entering the small intestine

Question 36

What is the difference in fermenting location between horses and small mammals VS ruminants?

Answer 36

Horses and small mammals are hindgut fermenters, whereas ruminants are foregut fermenters

Question 37

What is not present in the colon?

Answer 37

Villi

Question 38

What is the longest part of the small intestine?

Answer 38

The jejunum

Question 39

What is the ileocolic orfice?

Answer 39

The joint between the lumen of the ileum and the ascending colon