UARK Physiology Term Quiz 6

countercurrent multiplier system

The interaction that occurs between the descending limb and the ascending limb of the loop of Henle in the kidney. This interaction results in the multiplication of the solute concentration in the interstitial fluid of the renal medulla

Urea

The chief nitrogenous waste product of protein catabolism in the urine, formed in the liver from amino acids

Aquaporin

The protein channels in a plasma (cell) membrane that permit osmosis to occur across the membrane. In certain tissues, particularly the collecting ducts of the kidney, aquaporins are inserted into the plasma membrane in response to stimulation by antidiuretic hormone

Secretion

The transport of a substance from the blood through the wall of the nephron tubule into the urine

Vasopressin

Another name for antidiuretic hormone (ADH), released from the posterior pituitary. The name vasopressin is derived from the fact that this hormone can stimulate constriction of blood vessels

Aldosterone

The principal corticosteroid hormone involved in the regulation of electrolyte balance (mineralocorticoid)

Reabsorption

The transport of a substance from the flltrate fluid in the lumen of the renal nephron into the peritubular capillaries, where it can be returned to the general circulation.

Glomeruli

Glomeruli are the spherically-shaped tufts of capillaries in the kidneys that filter fluid into the kidney tubules. Spherically-shaped arrangements of neurons in the olfactory bulb are also referred to as glomeruli

Pertibular capillaries

tiny blood vessels, supplied by the efferent arteriole, that travel alongside nephrons allowing reabsorption and secretion between blood and the inner lumen of the nephron

Afferent arteriole

The small artery that carries blood toward the capillaries of the glomerulus.

Efferent Arteriole

The small artery that carries blood away from the capillaries of the glomerulus.

Absorption

The transport of molecules across epithelial membranes into the body fluids

Digestion

The process of converting food into molecules that can be absorbed through the intestine into the blood

Motility

The property of movement. In the gastrointestinal (GI) tract, motility refers to the ability to mix its contents and move them from the oral to the anal end of the GI tract by muscularcontractions

Peristalsis

Waves of smooth muscle contraction in smooth muscles of the tubular digestive tract. It involves circular and longitudinal muscle fibers at successive locations along the tract and serves to propel the contents of the tract in one direction.

Chyme

A mixture of partially digested food and digestive juices that passes from the pylorus of the stomach into the duodenum

H/K ATPase pump

Pumps H+ from cytoplasm into stomach lumen in exchange for K+; Cl- is secreted by Cl-/HCO3- exchange to yield HCl

Segmentation (Digestion)

alternating contractions and relaxations of non-adjacent segments of the intestine that move food forward and backward, breaking it apart and mixing it with digestive juices

Hepatocytes

liver cells; produce bile, absorb and secrete nutrients like glucose, and secrete plasma proteins

Bile salt

Salts of derivatives of cholesterol in bile that are polar on one end and nonpolar on the other end of the molecule. Bile salts have detergent or surfactant effects and act to emulsify fat in the lumen of the small intestine

Micelles

tiny spherical complexes of emulsified fat that arise during digestion; most contain bile salts and the products of lipid digestion, including fatty acids, monoglycerides, and cholesterol

Amylase

A digestive enzyme that hydrolyzes the bonds between glucose subunits in starch and glycogen. Salivary amylase is found in saliva and pancreatic amylase is found in pancreatic juice

Trypsin

A protein-digesting enzyme in pancreatic juice that is released into the small intestine

Pancreatic lipase

breaks down fats

Emulsification

The process of producing an emulsion or fine suspension. In the small intestine, fat globules are emulsified by the detergent action of bile

Enterehepatic circulation

The recirculation of a compound between the liver and small intestine. The compound is present in the bile secreted by the liver into the small intestine. It is then reabsorbed and returned to the liver via the hepatic portal vein

Bilirubin

Bile pigment derived from the breakdown of the heme portion of hemoglobin.