TEKS: 130.6 (c)(11)(a)

Define what a digestive system does;

List the five functions of the digestive

system;

Explain the difference between a Ruminant

and Non-Ruminant;

List the 6 major parts of the digestive

system;

Explain what each part of the digestive

system does;

List the compartments of a ruminant

stomach;

Label the parts of a ruminant stomach;

Write where the absorption sites are for

water and nutrients;

Label the parts of a small intestine;

Label the parts of a large intestine;

Label the digestive system of a chicken;

List the accessory digestive organs;

List the three digestive process actions;

List the mechanical actions of digestion;

Collect pictures of the parts of real

polygastric and monogastric digestive tracts;

Distinguish the parts of the digestive tracts

for each picture their classmates brought;

and

Rearrange an incorrect digestive tract to

make it correct.

Break food into smaller

particles so the body can

absorb and utilize the

nutrients

Ingesting Food

Grinding Food

Digesting Food

Absorbing Nutrients

Eliminating Body Waste

Ruminant animals have a 4-

chamber stomach (polygastric)

that includes a large rumen.

Has large digestive system for

utilizing bulky, forage-type feeds

Non-ruminant animals have a

single compartment stomach

(monogastric).

Cattle

Sheep

Goat

Deer

Swine

Chicken

Human

Mouth

Pharynx

Esophagus

Stomach

Small Intestine

Large Intestine

Digestive tract extends from the lips to the

anus.

Grasp food, grind food, and mix the food

with saliva

Accomplishes these tasks with the use of the

lips, tongue, teeth, cheeks, jaw, and salivary

glands

Horse lips are used to grasp food

Sheep & Cattle’s lips are to simply close the

mouth

Used by most animals to grasp food

Helps in the chewing process & formation of

boluses (cud)

In ruminants, large quantities of ingested food

are regurgitated as boluses (cud) so that it can

be re-chewed.

Papillae cover the top of the surface and

contain the taste buds

Papillae – finger-like projections

Responsible for cutting (incisors) and grinding

(premolars & molars) food.

New born animal develops milk teeth or baby

teeth

Milk teeth are replaced with permanent

teeth as the animal ages

Consist mostly of muscle that is lined with a

mucous membrane

Cheeks line up food with teeth

Common pathway for food & air

Food passes from mouth to pharynx

Pharyngeal muscles force food to the

esophagus

A muscular tube that connects the pharynx

to the stomach

The esophagus passes through the chest cavity

& connects with the stomach just after

passing through the diaphragm

Serves to digest food

Monogastric – 1 true stomach

Polygastric – 4 compartments

Single stomach compartment

“true” stomach

Location: just beyond the diaphragm on the

left side of the body

Has folds in the lining that creates gastric

pits

Glands secrete digestive fluids into the pits:

Hydrochloric acid

Pepsin

Rennin

AKA: Ruminants

4 compartments:

Rumen

Reticulum

Omasum

Abomasum

Contain no glands

Soak food

Allow microbial digestion to take place

1st compartment

Fills most of the left side of abdomen

Thick muscular wall

2 sacs that contain many papillae

Dorsal sac

Ventral sac

Food passes into rumen, where it can be

regurgitated as cud.

Site of 60%-90% of digestion in ruminants

Becomes functional at 6-8wks of age in a calf

Makes up 80% of total stomach capacity when

animal reaches maturity

Forward most portion of the stomach

Inner surface has inward folds

Resembles a honeycomb shape

Capable of closing off the rumen and

reticulum

Food passes straight to the omasum

Seen in calves before the rumen is functional

3rd compartment

Contain muscular projections

Covered by mucous membrane

Contain many small papillae

Papillae in omasum is responsible for grinding

roughage

“True” stomach

Only glandular stomach of ruminants

Located under omasum

Lining and glands are the same as those in

the stomach of a non-ruminant

3 part tube

Duodenum

Jejunum

Ileum

Site of some digestion & absorption of

nutrients

Lined with mini villi, which absorb nutrients

Villi – tiny finger-like projections that protrude

from the lining of the intestinal wall

Larger tube of digestive tract

Consists of:

Cecum (a blind pouch)

Colon

Colon – site of water absorption

Excretes waste from the body

Little nutrients other than water are

absorbed here

Cecum is larger in horses and rabbits

Action of microorganims allows for digestion

of fiber (roughage)

Differs from other animals

Do not have teeth

Prehensile structure is the beak

Prehensile – body part adapted for grasping or

holding

Food passes from mouth to esophagus to the

crop

Crop – enlargement of the gullet

Crop temporarily stores food & softens it

Food passes to the glandular stomach

Food passes to the gizzard

Mouth Esophagus Crop Glandular stomach Gizzard

Crushes & grinds coarse feed

Aided by grit & gravel that has accumulated in

the gizzard during the bird’s life

Food then goes to the small intestine

Salivary glands

Pancreas

Liver

Gall bladder

Secretes saliva that softens food, which aids

in swallowing

Contains mostly water

Contains some enzymes that begins the

chemical breakdown

In pairs

Located under the ears

Ducts pass over the rear of the mandible to

near the middle of the cheek

Penetrate mucous membrane of the mouth &

secrete saliva

Mandibular – pertaining to the jaw of an

animal

Location: under & to the rear of the parotid

glands

Ducts pass in the middle of the mandibles &

open into the mouth under the tongue

Located: under mucous membrane around

the outer sides of the tongue

Empty into the floor of the mouth

Serous

Secretes clear, watery fluid

Parotid & Mandibular glands

Mucous

Secretes a thick, cloudy substance

Serves as a protective coating to the mucous

membranes

Mixed

Secretes both serous & mucous

Sublingual glands

An elongated, lobe-shaped organ

Location: beginning of small intestine,

behind the liver

Exocrine functions:

Largest function

Produces digestive juices

Pass through pancreatic duct & empty into the

beginning of the duodenum

Endocrine functions:

Produce insulin, which lowers blood sugar

Insulin goes directly into the bloodstream

A lobe-shaped organ

Location: behind the diaphragm on the right

side of the body

Receives blood from the hepatic artery

Purifies blood it receives from:

Stomach

Spleen

Pancreas

Intestines

Produces bile (waste)

Small, sac-like organ attached to the liver

Collects bile produced by liver

Secretes it into the duodenum

Horses are the ONLY domestic animal that

does not have a gall bladder

Mechanical actions

Mastication (chewing)

Deglutition (swallowing)

Regurgitation

Gastric & Intestinal motility

Defecation

Chemical actions

Actions of enzymes & glandular secretions

Microbial actions

Activities of bacteria & protozoa

Glucose level

Amount of feed in the stomach

Environmental temperature (hot or cold)

Appetite is controlled in the hypothalamus

gland

Digested nutrients pass through the walls of

the digestive tract into the blood

Small intestine – site for nutrient absorption

Villi are responsible for collecting & absorbing

nutrients

Very little nutrients are absorbed in the mouth,

esophagus, or stomach

Colon of large intestine – site for water

absorption