Ch 45 Nutrition and Digestive Systems Flashcards
(24 cards)
The act of taking food into the body via a structure such as a mouth.
Ingestion
If the nutrients in food are in a form that cannot be directly used by cells, they must be broken down into smaller molecules.
Digestion
Ion, water, and small molecules diffuse or are transported from the digestive cavity into an animal’s circulatory system or body fluids.
Absorption
(Defecation) the process by which animals pass undigested material out of the body.
Egestion
Any organic or inorganic substance that is taken in by an organism and is required for survival, growth, development, tissue repair, or reproduction.
Nutrient
Nutrients that must be obtained in the diet in their complete form because the organism does not produce this vitamin
Essential nutrient
Only in sponges and single-celled organisms. Organisms use phagocytosis to bring food particles directly into a cell, where the food is segregated from the rest of the cytoplasm in food vacuoles.
Intracellular digestion
In an organism’s cavity. Food enters the digestive cavity, where it is stored, slowly digested, and absorbed gradually over long periods of time, ranging from hours to weeks.
Extracellular digestion
The digestive cavity of animals in extracellular digestion, because not only does digestion occur within it, but fluid movements in the cavity also serve as a circulatory—or vascular—system to distribute digested nutrients throughout the animal’s body.
Gastrovascular cavity
Rhythmic, spontaneous waves of muscle contraction that begin near the mouth and end at the stomach.
Peristalsis
To initiate digestion of polysaccharides through the action of a secreted enzyme
Amylase
Glands within the stomach wall secrete HCl acid and an inactive molecule called pepsinogen into the stomach lumen. One function of the acid is to convert pepsinogen into an active enzyme which is a protease and begins the digestion of protein.
Pepsin
The glandular portion of the stomach, and it secretes acid and pepsinogen.
Proventriculus
Partially digested and acidified food move from the stomach to a muscular structure with a rough inner lining that grinds food into smaller fragments.
Gizzard
Certain Herbivores (sheep, goats, llamas, and cows) lack the enzymes, the digest cellulose (fiber), but they digest cellulose with the help of microorganisms living within their digestive tract.
Ruminant
In the small intestines, Finger-like projection that extend into the lumen of the vertebrate small intestine.
Villi
The surface of each villus is covered with a layer of epithelial cells whose plasma membranes form small projection that are known collectively as the brush border.
Microvilli
A special type of vessel in the body, which is part of the lymphatic system. Absorbed fat enters these and is eventually dumped into the circulatory system.
Lacteal
Contains HCO3-, cholesterol, phospholipids, organic waste, and bile salts. Made in the liver.
Bile
A protease is secreted by the pancreas inactively, it is activated in the small intestine by an active molecule enzyme enteropeptidase, This enzyme then activates the inactive forms of chymotrypsin.
Trypsin
A protease involved in the breakdown of proteins in the small intestive. Secreted by the pancreas, and activated in the small intestine by the active enzyme Trypsin.
Chymotrypsin
The enzyme that digests lipids (triglycerides). Secreted by the pancreas into the small intestine. It is an emulsifier.
Lipase
Large lipid droplets are disrupted into many tiny droplets, increasing their total surface area and exposure to lipase.
Emulsification
Bile salts, phospholipids, fatty acids, and monoglycerides clustered together.
Micelles
