Animal Digestion and Nutrition

Essential Nutrients

Nutrients necessary for health, not synthesized by animals.

Vitamins

13 identified organic compounds essential for health.

Amino Acids

9 essential amino acids required from diet.

Long Unsaturated Fatty Acids

Essential fats not produced by the body.

Minerals

Inorganic elements like Na+, K+, Ca++, Cl-, PO4-, Mg+.

Autotrophs

Organisms that produce their own food.

Heterotrophs

Organisms that consume other organisms for food.

Gastrovascular Cavity

Digestive cavity with one opening in cnidarians.

Specialized Digestive Systems

Digestive tracts with separate mouth and anus.

Nematodes

Primitive organisms with simple digestive systems.

Cellulose Digestion

Bacteria in digestive tracts help break down cellulose.

Herbivores

Animals with longer digestive tracts for cellulose digestion.

Birds' Digestion

Lack teeth and possess a gizzard for grinding.

Esophagus

Tube delivering food from mouth to stomach.

Small Intestine

Primary site for digestion and nutrient absorption.

Stomach

Contains gastric juice for protein breakdown.

Gastric Juice

Contains HCl and pepsin for digestion.

Duodenum

Receives chyme and digestive enzymes from pancreas.

Villi

Finger-like projections increasing surface area in intestines.

Microvilli

Tiny projections aiding in digestion and absorption.

Large Intestine

Absorbs water and electrolytes; no digestion occurs.

Vitamin K

Essential vitamin reabsorbed in the large intestine.

Accessory Organs

Includes liver, gallbladder, and pancreas aiding digestion.