Daily Food for Thought Trace and name the parts of the monogastric digestive system.

Daily Food for Thought

Trace and name the parts of the monogastric digestive system.

Monogastric Digestive SystemMouth

Esophagus

Stomach

Duodenum

Jejunum

Ileum

Cecum

Colon

Rectum

Anus

Ruminant Digestive Systems

Learning Target:I can trace identify the parts of the ruminant

digestive system and describe the functions of each.

The Ruminant Digestive System


Functions of the digestive system of animals include: ingestion (eating) chewing (mastication) swallowing (deglutition) absorption of nutrients elimination of solid wastes (defecation)


The digestive system changes food nutrients into compounds that are easily absorbed into the bloodstream.

Ruminants 2.8 billion domesticated ruminants

Cattle, sheep, deer, elk, bison Pregastric fermentation

Ability to chew cud at frequent intervals distinguishes true ruminant from other foregut fermenters

Kangaroo, colobine monkey are not true ruminants

Four compartment stomach Reticulum Rumen Omasum Abomasum

Ruminants vary in size and habitat


Different species of animals have digestive systems adapted to the most efficient use of the food they consume.

The anatomy and physiology of the digestive systems of herbivores, carnivores, and omnivores all differ.


Ruminants are those animals that contain a multi-chambered digestive system (polygastric) that allows the animal to gain the majority of their nutritional needs from forages and other roughages.

Forage refers to grasses, roughages refers to other high-fiber food sources.

Classification of Ruminants by Feeding Preference

Classes of ruminants Concentrate selectors Intermediate feeders Roughage grazers

Concentrate Selecting Species Properties

Evolved early Small rumens Poorly developed omasums Large livers Limited ability to digest fiber

Classes Fruit and forage selectors

Very selective feeders Duikers, sunis

Tree and shrub browsers Eat highly lignified plant tissues to extract cell solubles Deer, giraffes, kudus

Intermediate Feeding Species Properties

Seasonally adaptive Feeding preference

Prefer browsing Moose, goats, elands

Prefer grazing Sheep, impalas

Roughage Grazing Species Properties

Most recently evolved Larger rumens and longer retention times Less selective Digests fermentable cell wall carbohydrates

Classes Fresh grass grazers

Buffalo, cattle, gnus Roughage grazers

Hartebeests, topis Dry region grazers

Camels, antelope, oryxes


The length and complexity of the digestive system depends on the species.

In herbivores, it is very long and complex.


Picture of digestive system of cow

Rectum

Anus

Colon

Cecum

Small IntestineRumen

Kidney

Pancreas

Liver EsophagusPharynx

Teeth

Tongue

Salivary Gland

Reticulum

Omasum

Abomasum

Ruminant Digestive Systems The digestive system of ruminant animals

includes the : Mouth - grasps the food Teeth - grind the food

Ruminants have only one set of teeth in the front of the mouth (incisors), and two sets in the back (molars).


Tongue - covered with finger-like projections (papillae) that contain taste buds.

Salivary glands - secrete saliva, that moistens food and is mixed with the food material to aid in swallowing.


Pharynx - funnels food into the esophagus, preventing food material from entering the lungs.

Esophagus - food tube that leads from the mouth to the stomach.

Ruminant Stomach

Anatomy: Reticulum

Rumen

Omasum

Abomasum


At this point, ruminant animals have a multi-chambered “stomach” Reticulum - honeycomb-like interior surface,

this part helps to remove foreign matter from the food material.

Reticulo-rumen

Although structurally they appear as a single continuous compartment, functionally they are distinctly different

Reticulum - full

Reticulum - cleaned

Reticulum

Honeycomb lining No secretions

Formation of food bolus

Regurgitation initiated here

Collects hardware (nails, wire)


Ruminant animals grasp mouthfuls of food and swallow it before it is chewed. They wrap their tongue around a mouthful of

grass, clamp down their teeth, and pull to break the grass at its weakest point, and swallow.


Ruminants will“chew their cud” (regurgitate) their food material and then grind it with their molars at a time when the animal is resting.

This is done until the food particles are small enough to pass through the reticulum into the rumen.


Since ruminant animals do not “chew” their food when it is taken in, at times foreign material like rocks, nails, small pieces of wire, can be swallowed.


While the animal is “chewing its cud” foreign particles that are heavy are allowed to “sink” in the reticulum, preventing many foreign particles from entering the rest of the digestive system.

Once foreign material enters the reticulum, it stays there for the life of the animal.


If enough of this foreign material remains in the reticulum, it may cause damage and infection of the reticulum (hardware disease).

Telephone Cord

Wire

Sponge taken from digestive system of an animal


Rumen - the organ that allows for bacterial and chemical breakdown of fiber.

The rumen has a very thick, muscular wall. It fills most of the left-side of the abdomen


The walls of the rumen contain papillae (that can be up to 1 cm. in length), where the bacteria that are used to breakdown fiber live.

In some ruminants (dairy cattle) the rumen can have a capacity of 55-65 gallons!

Rumen Digestion and fermentation

vat 40-50 gallons No secretions

Contains anaerobic microbes (25-50 billion bacteria/mL fluid) Also protozoa, fungi Produce VFA, protein

Papillae lining Increase surface area

Absorption of VFA Passive diffusion

Papillae in Rumen

Papillae in Rumen


Omasum - section that is round and muscular.

“Grinds” the food material and prepares the food material for chemical breakdown.

Omasum

Laminae/manyply lining Muscular folds No secretions

Reduces particle size Absorption of water

~60% removed Absorption of VFAs

~2/3 of VFAs entering or 10% of total produced

Prevents buffering of the abomasum

Omasum - full


Abomasum - very similar to the stomach of non-ruminants.

this is where the majority of chemical breakdown of food material occurs.

mixes in digestive enzymes (pepsin, rennin, bile, etc.).

Abomasum – inside view

Ruminant Digestive Systems Small Intestine - where most of the food

material is absorbed into the bloodstream Contains three sections:

duodenumjejunumileum

Ruminant Digestive Systems The food material is continually

squeezed as it is moved through the small intestine, becoming more solid.

The majority of the food material absorption occurs in the duodenum and the jejunum.

Ruminant Digestive Systems Large Intestine - begins to prepare unused

food material for removal from the body a portion of the large intestine in some

animals contain pouches that may contain enzymes for further species-specific digestion (horses and rabbits (cecum)).

Large Intestine

Fermentative digestion Bacteria similar to rumen, but no protozoa Digestion in colon may account for as much as:

27% of cellulose digestion 40% of hemicellulose digestion 10% of starch digestion

Only important in conditions that increase the amount of fermentative carbohydrate entering the large intestine

Increased rate of passage of forages High grain diets

May account for as much as 17% of total VFA absorption VFAs are efficiently absorbed, but primarily used as energy

source for large intestinal mucosa cells

Absorption of ammonia-N May account for as much as 30 to 40% of the net

transport of N into body fluid Absorbed N may be used for:

Synthesis of nonessential amino acids Recycling of N to the rumen

Important on low protein diets Regulated by:

Increased by increasing N concentration of diet Decreased by increasing the amount of carbohydrate

fermented in the large intestine

Mineral absorption Water absorption

90% of water entering the LI is absorbed

Large Intestine

Ruminant Digestive Systems Colon - collects the unused food material that

is to be removed from the body Rectum - “poop chute” Anus - opening through which the waste is

removed. Controlled by sphincter muscles, that also

help protect the opening.

Ruminant Digestive Systems In conclusion, the rumen allows for

bacteria to breakdown fiber, enabling ruminants to gain the proteins and energy from plant sources.

Non-ruminant animals cannot obtain the nutritional value from most plant sources unless the food has been modified (ground, mashed, etc.)

index


Ruminants are those animals that contain a multi-chambered digestive system (_________) that allows the animal to gain the majority of their nutritional needs from _______ and other _____________.


At this point, ruminant animals have a multi-chambered “__________” _________ - honeycomb-like interior surface,

this part helps to remove foreign matter from the food material.


______ - the organ that allows for bacterial and chemical breakdown of fiber.

The _____ has a very thick, muscular wall. It fills most of the _______ of the abdomen


_______ - section that is round and muscular. “______” the food material and prepares

the food material for chemical breakdown.


__________ - very similar to the stomach of non-ruminants.

this is where the majority of chemical breakdown of food material occurs.

mixes in digestive __________ (pepsin, rennin, bile, etc.).

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Daily Food for Thought Trace and name the parts of the monogastric digestive system.

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