Herbivore - eats plants (cow, rabbit)

Carnivore - eats meat (cat)

Omnivore - eats both (dog)

Monogastric - one stomach (dog)

Ruminants - multiple stomachs/chambers (cow)

Hind gut fermenters - herbivores with one stomach (horse, rabbit)

Prehension - grasping of food by tounge and lips 

Mastication - chewing with teeth and jaw; increase surface area of food

Chemical digestion - enzymes breakdown; starts in stomach  (rats/pigs start in oral cavity)

Absorption of nutrients, water, and medications

Elimination of waste

Mucosa - epithelial layer

- mucucs membrane

- goblit cells

Submucosa - blood vessels

Muscle layer - smooth and skeletal

Serosa - fluid

Epithelial lining

Stratified squamous in mouth, pharynx, esophagus, and anus

Simple columnar in stomach, intestines, colon, and rectum

Skeletal muscle

- voluntary control

- first part of esophagus

Smooth muscle

- involuntary 

- mid esophagus to the anus

- purpalsion of food

Circular - narrows 

Longatude - shortens

Conective tissue that holds up the GI tract

Blood vessels, nerves, lymphatic ducts and nodes

Omentum

Circular muscle contractions that move along in waves 

Movement of the ingesta

Segmental Contractions

Periodic, circular muscle contractions 

Helps food get to surface area

Slows for more digestion and absorption `

Oral cavity - salivary glands - pharynx - esophagus

Stomach - liver - duodenum - pancreas

Jejunum - ileum - cecum - colon 

Rectum - anus 

Lips

Tongue

Teeth

Hard palate

Salivary glands

Prehension in herbivores

Sense organ function (cow)

Taste

Grooming

Function - lubrication and increase PH in cattle

Location - parotid, under eye

- mandibular, under parotid

- sublingual, under tongue

zygomatic, under eye (not in all spieces)

Function - mastication

Upper arcade - inccissive and maxilla

Lower arcade - mandible 

Incisors - grasping

Canines - tarring

Premolars - cutters

Molars - grinding 

Lingual surface - inner surface of lower arcade

Palatal surface - inner surface or upper arcade

Labial suface - front of incisors 

Buccal surface - toward the cheek 

Typical number of each type of tooth found in the upper and lower arcade on one half of the mouth

Double the formula to include total number of teeth on both sides 

Lower case - baby

Upper case - adult 

i3/3, c1/1, m2/3 = 6+2+5 = 13x2 = 26

Pulp - blood vessels and nerves

 Dentin - surrounds and protects pulp

 Cementum - cements tooth into bone

Crown - head/part you see

Apex - bottom tip pf tooth

Root

Neck

Enamel - hardest thing in body

Gingiva - gum tissue 

Brachyodont - long roots and short crowns

Hypsodont - long crown and continue to grow (horse)

Prehansion

Mechanical digestion

Chemical digestion

Soft palate - caudal of hard palate

- Prevents food from getting into the nasal cavity 

Epiglottis - cartilaginous

- Protects larynx when food passes the parynx 

Between pharynx and stomach 

Mucosa - stratified squamous

Submucosa - blood vessels and nerves

Transportation of ingesta to the stomach 

Horses and rabbits have thick and tight cardia sphincters so they can not throw up 

Cardia - where esophagus enters stomach

Fundus - expands when stomach gets full (blind pouch)

Body - middle, gland rich part; most digestion done here

Pyloric antrum - digestion occurs here; churnning occurs

Pylorus - exit of stomach 

Fundus and Body

- parietal cells - production of hydrochloric acid 

- cheif cells - produce pepsin

- mucous cells - mucus

Pyloric antrum 

- G cells - gastrin

- slows things down and tells parietal cells to produce more hydrochloric acid 

Shape - C shapped

Location - behind liver; closely assocciated with the spleen (left side)

Mucosa

Submucosa - blood vessels

Muscular - smooth

Serosa

Peristalsis

Inervation - parasympathetic; vegus nerve

Gastrin - G cells - slows things down and causes release of hydrochloric acid 

Enterogastric reflex - slows down stomach to stop flow of food into the intestine 

Cholecystokinin (CCK) - Small intestine; slows down stomach; a lot of fat and protein 

Pepsin - cheif cells - causes pepsin to be released

Mucins - goblet cells; mucus; lining of stomach

Bicarbonate - buffer/balance things out; increase ph

ph less then 3 stops hydrocholic acid production 

Imflammation

Released by most tissues

Can be good and bad

NSAIDs block prostagloadins, thus contributing to gastric erosion. 

Four stomachs/compartments

Rumen - fore stomach

Reticulum - fore stomach

Omasum - fore stomach 

Abomasum - true stomach 

Regurgitation - chewing cud

Most cranial

Smallest

Honeycomb - increase surface area

Muscular wall - churnning 

Hardware disease 

Magnents 

After reticulum

Largest

Muscular pilars/papillaries

Reguritation - digestion

Eructation - burping 

Bacteria and protozoa in ruminant produce enzymes for digestion

Microbes are eventually flushed to the omasum, abomasum and intestines to be digested and used as protein source 

Right side of the abdomen 

Continues to breakdown food and pushes food into the abomasum

Has folds that increase surface area 

Simple columnar

True stomach 

Milk vs grain

Reticular groove 

Absorption and digestion

Three segments

- Duodenum - short

- Jejunum - long

- Ileum - before colon

Inervation 

Parasympathetic 

Ileocecocolic junction - end of GI tract 

Layers

- mucosa - simple columnar

- submucosa - blood vessels and nerves

- muscle - circular; longitudinal

-serosa -  outside surface 

Folds/Villi (brush border) - increase surface area and absorption 

Crypts - where new epithellium cells are formed

Goblet cells - produce mucus; protection