Anatomy and Physiology of the GIT Flashcards
Elements of the digestive system?
- mouth
- pharynx
- esophagus
- stomach
- small intestine
- large intestine
- rectum
- accessory glands (salivary, liver, pancreas)
What is the role of the pharynx?
defines whether going from larynx –> trachea or esophagus
What animal is similar to horse?
rabbit
What is the anatomical location of the GIT?
caudal to diaphragm
What is the upper lip useful for?
food selection (separating particles) and grazing
Tongue anatomy
apex, body, root
What is the structure of the tongue?
keratinized stratified squamous epithelium
- papillae to help sense food
Why do animals perform flehmen response?
- to detect smells (that humans cannot)
- could be nutritive
What is the purpose of saliva?
~20L per day
- more than other non-ruminant counterparts - ket higher dry matter food
- secrete more in the winter (dryer food)
- dehydration limits saliva secretion
What are the functions of the mouth?
- grasp feed
- moistening feed with saliva
- chew food –> reduce particle size
Mouth anatomy
- Diastema
- gaps between teeth (very large between incisors and molars) - diphyodont
- deciduous (baby teeth)
- permanent - Hypsodont
- pattern of dentition - ever growing/high crowned teeth (enamel extends past gum line) - Heterodonts
- incisors
- canine
- premolars
- molars –> grinding
Anatomy of the tooth
- crown
- root
- alveolus = socket where the tooth sits
- peridontium = connective tissue that holds tooth in place in jaw
- cementum = thin bone layer that covers entire tooth
- dentin = mineral deposition; vast majority of tooth
- enamel = superficial part of tooth; hardest part
- dental pulp/infundibulum = middle part that has all the innervation and nutrition for tooth
What gland secretes 90% of equine saliva?
Parotid gland
- also the sublingual and submaxillary glands
What is in saliva to buffer and lubricate feed?
bicarbonate = H,C, O
- makes sure its the right pH for amylase to start carb digestion
What is the pharynx a junction between?
- nasal cavity
- mouth
- trachea
- esophagus
Can horses breath through their mouths?
no
What are tonsils
aggregations of lymphatic nodules associated with mucous membranes
- lingual –> base of tongue, pharyngeal
What is the guttural pouch?
more dorsal and bigger in horses
- food can get caught here
What is the esophagus?
Muscular tube extending from the pharynx to the stomach
What aids in swallowing?
Tunica muscularis
What is the mesentery?
Anchors small intestine to back of intestinal wall
- attached to pelvis
- SI not attache to each other –> more flexibility
- LI is attached to each other but not back of intestinal wall
The walls of the digestive tract consist of?
- tunica mucosa
- stratified squamous epithelium - secretes enzymes, buffers, absorbs and secretes nutrients - tunica submucosa
- loose connective tissue - tunica muscularis
- striated vs. smooth - tunica serosa
- visceral peritoneum and connective tissue
What is the role of the cardiac sphincter?
Very strong –> forces food from esophagus into stomach and prevents stuff from coming back up
- prevents vomiting
What does fast emptying mean in terms of managing their feeding programs?
more frequent, smaller meals to match stomach size and gastric emptying rate
What regulates the pyloric region
Pylorus
- sphincter which controls gastric emptying into small intestine
How much acid is secreted per day? And what kind?
10-30 L per day
HCl - breaks down quaternary structures
Pepsin - converts tertiary to secondary
- partially controlled by the amount of protein a horse eats and how much water it consumes
Functional anatomy of the stomach
Non-glandular
- squamous
Glandular
- secretion of HCl and pepsinogen –> lower pH –> activates pepsin –> degradation of protein
Functions of the stomach
- small amount of fermentation
- digestion facilitated by HCl
- gastric lipase is also present –> emulsification of fat for digestion