Intro to the Alimentary System Flashcards
Name all of the main parts of the GIT
Headgut = mouth, pharynx, oesophagus
Foregut = stomach
Midgut = duodenum, jejunum, ileum
Hindgut = Caecum, ascending colon, transverse colon, descending colon, rectum
What are the associated glandular organs of the alimentary system?
Salivary glands (headgut)
Liver, gall bladder, pancreas (foregut)
What are the 4 major functions of the alimentary system?
1) Motility
2) Digestion
3) Secretion
4) Absorption
MDSA = My Dog Shits A-lot
Define motility in relation to the GI tract
Motility = the movements of the alimentary system that mix and circulate its contents and propels it along its length.
What are the 4 main layers of the GI tract components?
Mucosa.
Submucosa (with glands)
Muscularis externa
Serosa / Adventitia
MSMS = Mondays Sabotage My Soul
What is the function of the circular and longitudinal muscle in the GI tract?
Circular muscle contractions control the size of the lumen
Longitudinal muscle contractions control the length of the GI tract
Where can the submucosal plexus and the myenteric plexus be found?
Myenteric found within the longitudinal muscle
Submucosal found within the submucosa
Where do prehension and mastication occur?
In the headgut
What type of epithelia can be found in the oesophagus?
Stratified squamous epithelia
What are the 4 key salivary glands?
Parotid
Mandibular
Sublingual
Zygomatic
Please Make Singing Zapzoomers
What type of stomach do dogs and cats have?
Simple
What are the 4 regions of a simple stomach?
Cardiac region
Fundus
Body
Pyloric region
What type of stomach do horses and pigs have?
Composite simple stomach
What type of stomach is found in ruminants?
Complex composite stomach
What are the 4 chambers of the ruminant stomach?
Reticulum
Rumen
Omasum
Abomasum
(Only the abomasum has glandular mucosa)
What is the name of the sphincter at the top and the bottom of the stomach?
Cardiac sphincter
Pyloric sphincter
What is the basic function of each of the 4 chambers of the ruminant stomach?
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
What are rugae?
Gastric folds in the lining of the stomach
What is the importance of cardiac and pyloric glands in the stomach?
Cardiac and pyloric glands produce mucous which acts as a protective barrier against gastric juices
What do parietal cells and chief cells produce and where are they found?
Parietal cells produce hydrochloric acid
Chief cells produce pepsinogen
They are both found in the fundic region of the stomach.
What is special about the internal lining of the reticulum?
Honeycomb texture to increase SA
What is the purpose of the oesophageal groove in calves?
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)
What is the exocrine function of the liver?
Exocrine product = bile
What is the role of the endocrine substances produced by the liver?
To aid in metabolism of fats, carbohydrates and proteins
What is stored in the liver?
Glycogen
What is the difference between exocrine and endocrine glands?
Exocrine glands secrete products through ducts and not directly into the bloodstream
Endocrine glands secrete hormones directly into the blood.
Biotransformation also occurs in the liver - what does this mean?
The transformation of a potentially harmful product, such as a drug, into a non-harmful product.
What is the function of the gall bladder?
To store bile (which emulsifies fats)
Why do horses and small rodents not ave a gall bladder?
Because they continuously make and use bile, so don’t need to store it.
What are the exocrine and endocrine functions of the pancreas?
Exocrine = produces pancreatic juices
Endocrine = produces insulin, glucagon and somatostatin
Where do pancreas ducts open into?
The small intestine
How is the mucosal surface area increased in the small intestine?
By plicae circulares and villi
What is the brush border in the small intestine?
A border formed by the microvilli of the columnar epithelial cells that make up the villi
What are crypts and what do they contain?
Crypts are the invaginations of epithelium at the base of the villi crypts. They contain glands that secrete intestinal juices (mucus, peptides, proteins)
What are Peyer’s patches and what do they do?
Lymph node aggregations which prevent infection entering the small intestine
What is the difference in fermenting location between horses and small mammals VS ruminants?
Horses and small mammals are hindgut fermenters, whereas ruminants are foregut fermenters
What is not present in the colon?
Villi
What is the longest part of the small intestine?
The jejunum
What is the ileocolic orfice?
The joint between the lumen of the ileum and the ascending colon
