PLTW-HBS Unit 3

Homeostasis
The maintenance of relatively stable internal physiological conditions (as body temperature or the pH of blood) in higher animals under fluctuating environmental conditions.
Macromolecule
A very large molecule (as of a protein, nucleic acid, or carbohydrate) built up from smaller chemical structures.
Resource
A natural feature or phenomenon that enhances the quality of human life.
Adenosine Triphosphate (ATP)
An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in the cell.
Anabolism
Synthetic, energy-requiring reactions whereby small molecules are built up into larger ones.
Basal Metabolic Rate (BMR)
The rate at which heat is fiven off by an organism at complete rest.
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Body Mass Index (BMI)
A measure of body fat that is the ratio of the weight of the body in kilograms to the square of its height in meters.
Bolus
A soft mass of chewed food.
Calorie
The amount of heat energy required to raise the temperature of 1 g of water by 1 degree Celsius. The Calorie (with a capital C), usually used to indicate the energy content of food, is a kilocalorie.
Catabolism
Chemical reactions that break down complex organic coumpounds into simple ones, with the net release of energy.
Digestion
The process of making food absorbable by mechanically and enzymatically breaking it down into simpler chemical compounds in the alimentary canal.
Digestive System
The bodily system concerned with the ingestion, digestion, and absorption of food.
Enzyme
A protein serving as a catalyst, a chemical agent that changes the rate of reaction without being consumed by the reaction.
Esophagus
A muscular tube that in adult humans is about nine inches (23 centimeters) long and passes from the pharynx down the neck between the trachea and the spinal column and behind the left bronchus where it pierces the diaphragm slightly to the left of the middle line and joins the cardiac end of the stomach.
Gallbladder
A membranous muscular sac in which bile from the liver is stored.
Gastrointestinal Tract
The stomach and intestines as a functional unit.
Large Intestine
The more terminal division of the vertebrate intestine that is wider and shorter than the small intestine, typically divided into cecum, colon, and rectum, and concerned especially with the reabsorption of water and the formation of feces.
Liver
The largest organ in the vertebrate body; performs diverse funcitons such as producing bile, preparing nitrogenous wastes for disposal, and detoxifying poisonous chemcials in the blood.
Metabolism
The totality of an organism’s chemical reactions, consisting of catabolic and anabolic pathways.
Monomer
A molecule that can combine with others to form a polymer.
Oral Cavity
The part of the mouth behind the gums and teeth that is bound above by the hard and soft palates and below by the tongue and by the mucous memberane connecting it with the inner part of the mandible.
Pancreas
A gland with dual functions: the nonendocrine portion secretes digestive enzymes and an alkaline soulution into the small intestine via a duct; the endocrine portion secretes the hormones insulin and glucagon into the blood.
Peristalsis
Successive muscular contractions along the wall of a hollow muscular structure.
Pharynx
An area in the vertebrate throat where air and food passages cross.
Polymer
A large molecule composed of repeating structural units or monomers.
Salivary Amylase
A salivary gland enzyme that hydrolyzes starch.
Salivary Glands
Exocrine glands associated with the oral cavity. The secretions of salivary glands contain substances to lubricate food, adhere together chewed pieces into a bolus, and begin te process of chemical digestion.
Small Intestine
The part of the intestine that lies between the stomach and colon, consists of duodenum, jejunum, and ileum, secretes digestive enzymes, and is the chief site of the absorption of digested nutrients.
Stomach
A saclike expansion of the alimentary canal of a vertebrate communicating anteriorly with the esophagus and posteriorly with the duodenum and being typically a simple often curved sac with an outer serous coat, a strong complex muscular wall that contracts rhythmically and a mucuous lining membrane that contains gastric glands.
Abdominal Cavity
The body cavity in mammals that primarily houses parts of the digestive, excretory, and reproductive systems. It is separated from the thoracic cavity by the diaphragm.
Alveoli
Terminal air sacs that constitute the gas exchange surface of the lungs.
Bronchi
Pair of breathing tubes that branch from the trachea into the lungs.
Diaphragm
A sheet of muscle that forms the bottom wall of the thoracic cavity in mammals; active in ventilating the lungs.
Intercostal Muscle
Muscle located between the ribs.
Minute Volume
The Volume of air breathed in one minute without concious effort. Minute volume = Tidal Volume x (breaths/minute)
Residual Volume
The volume of air remaining in lungs after maximum exhalation.
Resume
a brief written account of personal, educational, and professional qualifications and experience, as that prepared by an applicant for a job.
Spirometer
An instrument for measuring the air entering and leaving the lungs.
Thoracic Cavity
The body cavity in mammals that houses the lungs and heart. It is surrounded in part by ribs and separated from the lower abdominal cavity by the diaphragm.
Tidal Volume
The volume of air that can be exhaled after maximal inhalation.
Adrenal Glands
Hormone-producing glands located superior to the kidneys; each consists of a medulla and a cortex.
Aldosterone
A mineral cortocoid produced by the adrenal cortex that promotes sodium and water reabsorption by the kidneys and potassium excretion in urine.
Antidiuretic Hormone (ADH)
Hormone produced by the neurosecretory cells in the hypothalamus that stimulates water reabsorption from kidney tubule cells into the blood and vasoconstriction of arterioles.
Exrection
The disposal of nitrogen-containing waste products of metabolism.
Filtration
In the vertebrate kidney, the extraction of water and small solutes, including metabolic wastes, from the blood by the nephrons.
Glomerular Filtration
The first step in urine formation in which substances in blood pass through the filtration membrane and the filtrate enters the proximal convoluted tubule of the nephron.
Glomerulus
A ball of capillaries surrounded by Bowman’s capsule in the nephron and serving as the site of filtration in the vertebrate kidney.
Kidney
One of a pair of vertebrate organs situated in the body cavity near the spinal column that excrete waste products of metabolism, in humans are bean-shaped organs about 4 1/2 inches (11 1/2 centimeters) long lying behind the peritoneum in a mass of fatty tissue, and consist chiefly of nephrons by which urine is secreted, collected, and discharged into the pelvis of the kidney whence it is conveyed by the ureter to the bladder.
Nephron
The tubular exretory unit of the vertebrate kidney.
Ureter
A duct leading from the kidney to the urinary bladder.
Urethra
A tube that releases urine from the body near the vagina in females or through the penis in males; also serves in males as the exit tube for the reproductive system.
Urinalysis
Chemical analysis of urine.
Urinary Bladder
The pouch where urine is stored prior to elimination.
Urinary System
The organs of the urinary tract comprising the kidneys, ureters, urinary bladder, and urethra.
Urine
Waste material that is secreted by the kidney, is rich in end products (as urea, uric acid, and creatinine) of protein metabolism together with salts and pigments, and forms a clear amber and usually slightly acid fluid.