Ch 28 Nutrition and Digestive/Urinary Systems

Vocabulary flashcards covering nutrients, digestion, and urinary system topics from the lecture notes.

Nutrient

A chemical that an organism needs to live and grow or a substance used in metabolism, which must be taken in from the environment.

Water

The most important nutrient and the most abundant substance in the body; about three quarters of body mass and a major component of cells.

Carbohydrates

Sugars and starches; digested to simple sugars; cellulose is not digested by humans and provides dietary fiber.

Lipids

A broad group of molecules including fats, waxes, and sterols; sources include phospholipids, cholesterol, and triglycerides; used for energy and cellular structures.

Proteins

Macromolecules that must be broken down into amino acids for absorption; amino acids can be rearranged by the liver.

Vitamins

Organic compounds required in small amounts; can be fat-soluble or water-soluble and cannot be synthesized in sufficient quantities by the body.

Minerals

Inorganic elements required in small amounts; macrominerals (major minerals) vs microminerals (trace elements) with varying dietary needs.

Glucose

The form of sugar most cells use for respiration; liver converts sugars to glucose and stores it as glycogen under insulin.

Insulin

Hormone that promotes uptake of glucose into cells and its storage as glycogen.

Glycogen

Storage form of glucose in liver and muscle cells.

Glucagon

Hormone that stimulates release of glucose from glycogen when blood glucose is low.

Cellulose

A complex carbohydrate not digestible by humans; provides dietary fiber and digestive bulk.

Linoleic acid

An essential fatty acid that cannot be synthesized by the liver and must be obtained from the diet.

Triglycerides

The most common form of dietary lipids; a major energy source.

Cholesterol

Not used for energy; essential for cell membranes, organelles, and steroid hormone synthesis.

LDL (low-density lipoprotein)

“Bad” cholesterol carrier associated with cholesterol deposition in arteries.

HDL (high-density lipoprotein)

“Good” cholesterol carrier that helps remove cholesterol from the blood.

Amino acid

Building blocks of proteins; contain an amino group, a carboxyl group, and a side chain (R).

Essential amino acids

Eight amino acids that cannot be synthesized by the liver and must be obtained from the diet.

Nonessential amino acids

Amino acids that can be synthesized by the liver and do not need to be obtained from the diet.

Digestion

The process by which nutrients in food are broken down and delivered to the bloodstream.

Small intestine

Long tube where most enzymatic digestion and nutrient absorption occur.

Pancreas

Gland that secretes pancreatic juice containing enzymes (trypsin, chymotrypsin, amylase, lipase) and bicarbonate into the small intestine.

Bile

Digestive fluid produced by the liver and stored in the gallbladder that emulsifies fats.

Emulsification

Process by which bile breaks fats into small droplets to mix with water for enzyme action.

Trypsin

Pancreatic enzyme that digests proteins.

Chymotrypsin

Pancreatic enzyme that digests proteins.

Amylase

Enzyme that digests starch into sugars.

Lipase

Enzyme that digests fats.

Bicarbonate

Alkaline ions from pancreatic juice that neutralize stomach acid in the small intestine.

Liver

Organ that produces bile and participates in lipid metabolism and many other metabolic processes.

Gallbladder

Organ that stores and releases bile into the small intestine.

Salivary glands

Glands that secrete saliva containing enzymes to begin carbohydrate digestion.

Mouth

Site where digestion begins with mechanical chewing and chemical digestion by saliva.

Ammonia

Nitrogenous waste excreted by many aquatic animals; produced from protein metabolism.

Urea

Nitrogenous waste common in mammals and many amphibians; produced in the liver from ammonia.

Uric acid

Nitrogenous waste typical of birds, many reptiles, insects, and land snails.

Kidneys

Major excretory organs that filter blood, remove wastes, and regulate water/electrolyte balance.

Nephron

Functional unit of the kidney; millions per kidney responsible for filtration and cleansing of blood.

ADH (antidiuretic hormone)

Hormone that promotes water reabsorption in the kidneys, reducing urine volume.

Aldosterone

Hormone from the adrenal cortex that promotes Na+ reabsorption (water follows by osmosis) in the kidneys.

Dialysis

Substitute filtration system that removes wastes and excess water when kidneys fail; uses a semipermeable membrane.

Hypervitaminosis

Overdose of fat-soluble vitamins that can accumulate in the body.

Macrominerals

Major minerals required in relatively large amounts (e.g., potassium, sodium, calcium, phosphorus).

Trace elements

Microminerals required in small amounts (e.g., iron, copper, iodine, zinc, selenium).

Mouth

Oral cavity where initial mechanical and chemical digestion occurs.

Ureter

Tube that transports urine from the kidneys to the urinary bladder.

Urinary bladder

Organ that stores urine before its elimination through the urethra.

Urethra

Anatomical channel through which urine exits the body.