Transcript The Digestive System

The Digestive System
Introduction to Veterinary Science
Chapter 7
Structures of a Tooth
Enamel
Dentin
Pulp
Crown
Neck
Root
Cementum
Vein, Artery,
and Nerve
Canine Dentition
Molars (2)
Premolars (4)
Canine (1)
Incisors (3)
Molars (3)
Incisors (3)
Canine (1)
Premolars (4)
Match the description with the tooth type
2
___Used
for tearing food
1,2
___Absent in upper jaw of cattle (2)
3,4
___”Cheek teeth” (2)
___Root
is twice as long as exposed crown
2
3,4
___Used for crushing and grinding food (2)
4
___Most
caudally located
1
___Used
to bite into food
___Tusks
in pigs
2
3,4
___Flatter and tightly packed in herbivores (2)
1
___Used
for age estimation
1.
2.
3.
4.
Incisors
Canines
Premolars
Molars
Intestinal Tract of a Dog
Duodenum
Anus
Esophagus
Rectum
Cecum
Ileum
Colon
Jejunum
Stomach
Intestinal Tract of a Horse
Colon
Anus
Dorsal Colon
Left Ventral Colon
Rectum
Duodenum
Esophagus
Stomach
Ileum Cecum
Right Ventral Colon
Jejunum
Intestinal Tract of a Ruminant
Rumen
Duodenum
Colon
Esophagus
Rectum
Anus
Reticulum
Ileum
Omasum
Cecum
Abomasum
Jejunum
Spiral Loops
Functions of the Liver and Pancreas
Liver:
•Produces bile for storage in
gallbladder. Bile salts emulsify
fat for faster digestion.
•Stores vitamins and iron in
reserve.
•Controls blood sugar levels and
removes excess amino acids
from blood.
Pancreas:
•Produces sodium bicarbonate to
neutralize stomach acid.
•Secretes digestive enzymes and
hormones (glucagon and insulin).
•Secretions from the liver and pancreas empty into the duodenum through ducts.
Intestinal Lining
Large circular folds, villi, and microvilli increase surface area for absorption.
Match the description with the digestive structure
__Absorbs
nutrients
4
__An
8
exocrine gland
4
__Divided
into duodenum, jejunum, and ileum
__Has
folds called rugae
3
1
__Where
bolus of food is formed
__Contains
ascending, transverse, and
5
descending sections
1
__Where
digestion begins
__Associated
4
with the mesentery
5
__Absorbs
water
__Divided
into cardia, body, and pylorus
3
2
__Where
paristalsis first occurs
__Drains
through the hepatic duct
6
__Secretes
3
hydrochloric acid
7
__Stores
bile
1.
2.
3.
4.
5.
6.
7.
8.
Mouth
Esophagus
Stomach
Small intestines
Colon
Liver
Gallbladder
Pancreas
The Ruminant Stomach
Bacteria in the reticulorumen
digest plant fiber and release
nutrients for the host animal
to absorb and use. This is a
symbiotic relationship in
which both the animal and the
bacteria benefit.
Chamber
Function
Rumen
Fermentation vat, plant fiber digested by bacteria
Reticulum
Traps heavy objects, secondary site of fermentation
Omasum
Grinds food and extracts fluid
Abomasum Secretes digestive enzymes, acts as “true stomach”
Rumination
Rumination: The process of bringing up food material from
the stomach to the mouth for further chewing
• Phase 1 – Regurgitation:
– Animal inhales, difference in pressure causes rumen contents to
enter esophagus, reverse paristalsis moves food bolus into
mouth
• Phases 2 and 3 – Remastication and Resalivation:
– Food bolus (cud) is chewed repeatedly, liquid is squeezed out
and swallowed
• Phase 4 – Redeglutition:
– Cud is reswallowed, next rumination cycle begins