Zoology

• Food is any substance which contains nutrients and essential requirements of an organism like proteins, carbohydrates and fats to supply energy, sustain growth and vital processes.
• Digestion is the process of preparing food for absorption and assimilation.
• Digestion is the process of breaking down food into small water-soluble food molecules so that it can be absorbed into the body of organisms.
• Herbivorous animals feed mainly on plants, examples include cats, deer, goats, sheep, horses, and others.
• Carnivorous animals eat every other animal, examples include cats, lions, tigers, sharks, and others.
• Omnivorous animals eat various plants and animals, they are known as general feeders, examples include humans, bears, rats, and others.
• Proteins, which are composed of the amino acids of which they are composed, are necessary for the synthesis of specific proteins and other nitrogen-containing compounds.
• Water-soluble vitamins are found in water-soluble fluids such as urine and lipid-soluble vitamins are found in lipid-soluble fluids such as feces.
• Vitamins are accessory factors from food that are often built into the structure of many enzymes.
• Water is required as the solvent for body chemistry and as a major component of all fluids of the body.
• Organic salts are required as the anions and cations of body fluids and issues and for the formation of important structural and physiological components throughout the body.
• Microphagous feeders feed on small particles, either living or dead, examples include paramecium, certain protazoans, some sea anemone, certain fish, and others.
• Macrophagous feeders use larger particles as food, examples include humans, mammals, and other higher forms of animals.
• Liver functions in the breakdown and disposal of waste nitrogenous products, converts ammonia to urea, and helps to dispose of the toxic substances.
• Liver produces heparin which is a blood anticoagulant.
• Amylase breaks down starches into sugars.
• Bile greens up the color of urine.
• Liver is involved in hormone metabolism.
• Liver stores and releases vitamins.
• Trypsin and chymotrypsin break down proteins and peptides into amino acids.
• Gallbladder stores and releases bile when stimulated by the presence of fatty food in the duodenum.
• Lipase breaks down fats into fatty acids and glycerol.
• Other functions of liver include storing and providing glucose (glycogen) to the body as needed, and regulating the concentration of amino acids in the blood.
• Bile is secreted from the liver.
• Liver is the largest gland of the body.
• Salivary glands secrete saliva to lubricate the food and start digestion.
• Reception region of the animal’s digestive tract is composed of organs which are responsible for the entry of food particles into the animal’s body.
• Digestive tract of earthworm is composed of mouth with lips, esophagus to carry food, crop for the storage of food, gizzard where food is ground and early digestion occurs, and terminal digestion and absorption and excretion occur at the opposite end of the system.
• Entronic digestive tract is essentially a tube within the body.
• Vermiform appendix is a part of the human digestive tract.
• Incomplete versus complete digestive tract.
• The animal’s alimentary canal can be divided into five major regions: reception, condition and storage, grinding and early digestion, terminal digestion and absorption and excretion, and water absorption and concentration of solids.
• Mouth, tongue, and teeth may help in capturing or manipulating the food.
• The food enters the mouth and passes through various organs for storage, digestion, or absorption and any residue passes out of the body at the opposite end of the system.
• Anus is the postero-ventral opening for the passage of undigested residue.
• In many vertebrates (annelids, insects, and octopods), the esophagus is expanded into a crop.
• The condition and storage region serves as a passageway of food particles from the upper region to the lower region where the digestive process occurs.
• Pha ry n x has no directed digestive function and contains gills, slits, and some aquatic amphibians.
• Esophagus (gullet) is a flexible tube that carries food down to the lower part of the digestive tract.
• Among vertebrates, only birds have a crop.