Anatomy Lab - Digestive System

Oral cavity (mouth)

most cranial part of digestive system; mastication, vocalization, thermoregulation

Lips

prehension and manipulation of feed

Teeth

mechanical breakdown of feed

Types of teeth:

Incisors

Canine

Premolars

Molars

Surfaces of teeth:

Lingual

Palatal

Labial

Buccal

Occlusal

What is the lingual surface of the teeth?

towards the tongue

What is the palatal surface of the teeth?

faces the hard palate

What is the labial surface of the teeth?

towards the lips

What is the buccal surface of the teeth?

towards the cheeks

What is the occlusal surface of the teeth?

where teeth come together

Tongue

three fibers of muscles

assists with moving food and mechanical digestion

feed moistening mixing feed with salivary secretions

grooming

taste receptors

Salivary Glands

secretion of saliva (digestive and lubrication functions)

contains salivary amylase (breaks down carbohydrates)

What are the 4 salivary glands?

Sublingual

Mandibular

Parotid

Zygomatic

Pharynx

muscular propulsion of materials into esophagus

What are the 3 portions of the pharynx?

oropharynx

nasopharynx

laryngopharynx

Esophagus

muscular tube which transports ingesta from the oral cavity to the stomach

left of trachea

What is special about the esophagus of horses and rabbits?

closure is strong to prevent reflux or vomiting

Stomach

mechanical - breaks down food by mixing and grinding

chemically - breaks down food with HCl and enzymes

has mucosal folds = rugal folds

Cardiac sphincter of stomach

muscular ring between stomach and esophagus - controls what enters the stomach

Cardia of stomach

entrence area - nearest to esophagus - NO GLANDS

Greater Curvature of stomach

attaches the greater omentum - convex - left margin

Lesser Curvature of stomach

attaches the lesser omentum - concave - right margin

Cardiac Region of stomach

below cardiac sphincter - location of ulcers in horses

Fundus of stomach

large, inflated region before body of stomach

located between cardiac and body region

dome-shaped

What is the fundus rich with?

glands - holds more food

Body of stomach

large middle portion - rich with glands

Pylorus of stomach

constricted part that joins with duodenum

what is the wider part of the pylorus (towards the stomach body)

Pylorus antrum

Pylorus sphincter of stomach

muscular ring between stomach and duodenum

controls what exits the stomach

Rumen of the ruminant stomach

located on the left side and largest compartment

high fermentation with favored microorganism environment

papillae that increases surface area + VFA production

absorption!

Reticulum of ruminant stomach

pouch like structure (honeycomb) and close to heart

selects heavy dense feed that will be ruminated

Omasum of ruminant stomach

tissue leaves that look like a book (butchers bible)

Abomasum of the ruminant stomach

only compartment with glands - release HCl and digestive enzymes

Small Intestine

enzymatic digestion and absorption of water, organic substrates, vitamins, and ions

What are the 3 portions of the small intestine?

Duodenum

Jejunum

Ileum

Duodenum of small intestine

right after pyloric sphincter - associated with pancreas

Jejunum of small intestine

middle and longest portion

Ileum of small intestine

last section BEFORE cecum

Ileocecal sphincter

separates ileum and large intestine

regulates flow unto colon or cecum

Mesentary

membranes in abdominal cavity that support intestines

Large Intestine

dehydration and compaction of indigestible materials in preparation for elimination

What are the 6 sections of the large intestine?

cecum

ascending colon

transverse colon

descending colon

rectum

a-nus

Cecum of the large intestine

small in carnivores - larger in horses

Why is the cecum in horses larger that in carnivores?

due to forage based diet

Ascending colon of the large intestine

small portion up from abdominal cavity

Transverse colon of the small intestine

across abdominal cavity

Descending colon of the small intestine

straight portion foes down in abdominal cavity

Rectum of the small intestine

goes through pelvic inlet

A-nus of the small intestine

muscular ring at the end of the rectum - excretion of indigestible matter

Accessory organs of digestive system

Pancreas

Liver

Gallbladder

Pancreas

Exocrine Cells

Secretes pancreatic juice

Endocrine Cells

What are the exocrine cells of the pancreas

acinar and duct cells

What are the compondent of pancreatic juice?

bicarbonate buffer and digestive enzymes

What are the digestive enzymes within pancreatic juice

proteases, lipases, amylases

What are the endocrine cells of the pancreas and what hormones does it secrete?

Islet cells - insulin and glucagon

Liver

secretion of bile, metabolism (protein + fat), storage of nutrients

What is the importance of bile salts from the secretion of bile in the liver?

lipid digestion

How many lobes does the liver have?

6

What are the 6 lobes of the liver from left to right

Left lateral lobe

Left middle lobe

Quadrate lobe

Right medial lobe

Right lateral lobe

Caudate lobe

Gallbladder

storage and concentration of bile - 3 main ducts for passage of bile

What are the 3 main ducts for passage of bile in the gallbladder?

hepatic ducts

cystic duct

common bile duct

Hepatic ducts of the gallbladder

drains bile into cystic duct

Cystic duct of the gallbladder

comes directly from gallbladder to the common bile duct

Common bile duct of the gallbladder

Releases bile into duodenum

Spleen

left side of abdomen

blood storage and removes old RBC’s