Veterinary Technology

Chapter 7

•Describe the basic function of the primary components of the digestive system.

• Compare the function and location of the digestive organs to those in the monogastric, modified monogastric and ruminant digestive systems.

• Explain the difference between and identify diagrams of the different types of digestive systems of various animals.

The process by which food is taken into the body and broken down into smaller molecules.

Digestion must happen before absorption

The remnants on non-nutritional portions are eliminated.

Digestive System StructuresTeeth are used to gather, cut and grind the

food. Page #92 Differences between:

CarnivoreHerbivore Omnivore

Parts of the tooth: - Crown vs. Root - Enamel: hardest substance in body! - Dentin: majority

Digestive System Structures“Baby” teeth = AKA: deciduous teeth Teeth are classified by function:

Incisor: foremost – used to bite the foodCanine: longest teeth – used for tearing foodPremolars: used for crushing and grinding

foodMolar: used for crushing and grinding food

Equine Teeth Floating/Aging System

Digestive System StructuresIn all types of digestive systems, digestion begins

in the mouth.Saliva is produced by 4 salivary glands (page 94)The tongue (skeletal muscle) Esophagus = food pipe, 4 layers

1. Epithelial lining AKA mucosa2. & 3. two layers of smooth muscle 4. Connective tissue covering AKA serosa

Pharynx = posterior portion of throatLarynx = voice box Trachea = wind pipeEpiglottis = flap that protects

larynx/trachea/esophagus

Digestive System StructuresPeristalsis = process that moves food bolus

through the esophagus.

All of these are common to all types of digestive systems. The four main types are1. Monogastric2. Ruminant 3. Avian 4. Pesudo-Ruminant

Humans, swine, dogs and cats all have a simple stomach, which is also known as a

monogastric digestive system.

Theses animals are designed to consume concentrates.

The simple, one chambered stomach is divided into 3 regions.

Parts and functions of the monogastric mammal digestive

system•Mouth

-gather and chew feed using tongue and teeth -salivary glands moisten feed to aid in swallowing -saliva begins the carbohydrate breakdown with salivary

amylase

• Esophagus -tube from mouth to stomach that is open at the mouth end -separated from stomach by the esophageal sphincter

• Stomach -muscular gland lined sac that receives ingesta from the

esophagus and conducts both physical and chemical digestion

-primary secretions:pepsin - enzyme that digests protein; hydrochlorides - acids that aid in protein digestion

Parts and functions of the monogastric mammal digestive

system continued…•Small Intestine

-enzymatic digestion and absorption -Functions of the small intestine: digestion of proteins, carbohydrates, and fats; absorption

of the end products of digestion 1. duodenum - most digestion occurs

here 2. jejunum - some digestion and some

absorption occur 3. ileum - mostly absorption

-Bile - made in liver, stored in gall bladder, active in the small intestine, emulsifies fat to aid in digestion

Parts and functions of the monogastric mammal digestive

system continued…•Enzymes in the small intestine

Parts and functions of the monogastric mammal digestive

system continued…

•Cecum - essentially non functioning in many monogastrics. Rabbits and horses have an enlarged

cecum that acts like a rumen and is involved with microbial digestion (fermentation)

• Large Intestine -bacterial activity -water absorption -waste storage

Known as a modified monogastric system

•Mouth/Beak - gather and break down feed

• Esophagus - tube from mouth to stomach that is open at the mouth end

• Crop - feed storage and moistening

• Proventriculus - glandular stomach (HCI and gastric juices); enzymatic

• Gizzard - muscular stomach; mechanical breakdown

Parts and functions of the avian digestive system

Parts and functions of the avian digestive system continued…

•Small Intestine - enzymatic digestion and absorption -Functions of the small intestine: digestion of proteins, carbohydrates, and fats; absorption of the end products of digestion -Enzymes in the small intestine

• Large Intestine -bacterial activity -water absorption -waste storage

• Cloaca - common chamber for GI and urinary tracts

• Vent - common exit for GI and urinary tracts

Sheep, cows, and goats are examples of animals with complex stomachs, which are also known as ruminant digestive systems

Parts and functions of the ruminant digestive system

Rumination - the regurgitation, rechewing and reswallowing of ingested food

Cud - mass of regurgitated ingesta; bolus

Process of rumination 1. regurgitate bolus from rumen 2. rechew and reinsalivate 3. reswallow 4. repeat with another bolus

1. Anus 7. Reticulum

2. Rectum 8. Esophagus

3. Cecum 9. Abomasum

4. Colon 10. Omasum

5. Duodenum 11. Small Intestine

6. Rumen

Ruminants are characterized by having a stomach with four compartments

Parts and functions of the ruminant digestive system

continued…• Mouth

-contains dental pad, teeth, tongue and saliva -saliva contains no salivary amylase

• Esophagus -tube from mouth to stomach -tube from stomach to mouth

• Rumen - large fermentation vat; also called the "paunch"

-anaerobic -Temperature = 39oC (103oF) -saturated with gasses -constant motion

Parts and functions of the ruminant digestive system continued…

Lining of the rumen

Parts and functions of the ruminant digestive system continued…

• Functions of Microorganisms -digest roughages to make Volatile Fatty Acids -make protein -make vitamins K and B complex

(Very similar to cecum of rabbit and horse)

The function of the rumen is to house microorganisms.

Parts and functions of the ruminant digestive system continued…

• Reticulum - "honeycomb" -houses microorganisms -catches hardware (ingested by animal) -houses the opening to the omasum

• Omasum - "manyplies“ or “book” -full of folded tissue -water absorption

• Abomasum - true stomach -pepsin-HCl

Parts and functions of the ruminant digestive system continued…

•Small Intestine -enzymatic digestion and absorption -Functions of the small intestine: digestion of proteins, carbohydrates, and fats;

absorption of the end products of digestion 1.duodenum 2.jejunum 3.ileum

•Cecum - some microbial fermentation

•Large Intestine -water absorption -waste storage

Pigs, Rabbits, Horses, Chickens, and Humans have a simple stomach or a monogastric digestive system

Cows, Sheep and Goats have a complex stomach or a ruminant digestive system

What type of digestive system is this?

Ruminant

What type of digestive system is this?

Avian Monogastric System

(modified monogastric)

What type of system is this?

Monogastric