GI Tract Flashcards
What are the 6 parts of the GI system?
- Mouth
- Esophagus
- Stomach
- Small intestine
- Large intesine
- Anus
What is another name for the gastrointestinal tract?
Digestive tract or alimentary canal
What is another name for the mouth? What is its function
AKA: oral cavity
Function: Where food is take into the body
Define: Soft palete
Tissue that separates the oropharynx and nasopharynx, prevents food from going into the nasal passageways when swallowing
Define: Hard palate
Bony partition between the mouth and nose
Define: Oropharynx
The part of the pharynx between the tongue and the soft palate
What is the function of the salivary glands
To secrete saliva (mandibular, submandibular, parotid)
What is the fucntion of the teeth
Used for biting/mastication
Define: Mastication
Chewing
How does the mouth contirbute to the GI tract?
- Starts mechanical digestion of food by increasing the surface area of the food by chewing
- Chemical digestion of food is accomplishe by secretion of enzymes that help to break down sugar, fat, and protein
- Bolus is created, then passed through the esophagus
- Plays a KEY role in coolin off dogs via the evaporation of salvia, thereby cooling blood in mucus membranes
Define: Bolus
Ball of food
Define: Esophagus
Tubular organ that connects the mouth to the stomach
Anatomy of the Esophagus
- 2 layer of lining: mucos and submucosa
- 2 layers of mucsle: longitudinal and circular
What are the functions of the Esophagus
- Moves food through peristalsis:
- The bolus is moved through the esophagus in this manner until it reaches the stomach
What are the 4 compartments in the ruminant stomach in order? Examples of ruminant species
- Reticulum
- Rumen
- Omasum
- Abomasum
Ruminants: Cow, sheep, goats
What are the 3 parts in the ruminant stomach in order? Examples of Monogastric species
- Fundus
- Body
- Antrum
Monogastic (single stomach): Dog, cat, horse
What are the 4 functions (physiology) of the stomach
- Further digest food by peristalsis
- Produce hydrochloric acid (via parietal cells) which aids in the breakdown of food.
- The pH of the stomach is tightly controlled by active transport
- Enzymes, most notably pepsin, break down proteins into amino acids.
- The stomach itself is not digested by its own secretions because it produces a layer of mucus
containing mucin and bicarbonate to protect itself from acidity.
Define: Peristalsis
alternating contraction and relaxation of the the muscles to push contents forward
What is the function of the small intestine
- Peristalsis occurs
- Segmental contractions also take place here, moving contents more slowly through the system allowing for more contact time with the intestine and greater nutrient uptake.
What are the 3 parts of the Small intestine in order?
- Duodenum - upper small intestine which is connected to the stomach and on which the
pancreas is attached - Jejunum – makes up the majority of the small intestine (middle segment)
- Ileum - connects to the cecum
What are the 2 functions (physiology) of the small intestine?
- Absorb nutrients, water, vitamins, and electrolytes
- Due to the large surface area created by the folds in the intestinal wall and the millions of villi along its surface
- The villi themselves contain microvilli, which secrete digestive enzymes and absorb nutrients (the brush border)
- Alter Fats, carbohydrates and proteins before absorption
- Must be altered prior to absorption, through enzymes associated with the lumen or microvilli
How are fats, carbohydrates, & proteins digested?
Fats: Emulsification and micelle formation
Carbohydrates:
- Ruminates: Via the fermentation process
- Monogastric animals: amylase, lactose, sucrase, maltase, isomaltase, and lactase convert carbohydrates into monosaccharides that are then absorbed across the brush border
Proteins: Enzymes made by the small intestine & pancreas known as proteases
- Help woth chemical digestion
- Break down proteins into amino acid chains that are then absorbed across the brush border
What is the large intestine responsible for?
- Recovery of fluid and electrolytes
- store feces prior to elimination
What are the 2 components of the large intestine? What are their functions in each species
- Cecum: Blind sac, where the small and large intesine meet
- Monogastric: Less developed
- Ruminant: More advanced than monogastric animals, some ferentation
- Hindgut: More developed than the small intestine in the horse and has a much greater capacity for absorbing nutrients - Colon
- Monogastric: Tubulor organ that uses peristalsis and segmental contractions
- Main functions:
- Absorb nutrients and water not already absorbed by the small intestine
- Store feces (rectum)
