Ap Biology Chapter 44 Vocabulary

Front 1

afferent arteriole

Back 1

The blood vessel supplying a nephron.

Front 2

aldosterone

Back 2

An adrenal hormone that acts on the distal tubules of the kidney to stimulate the reabsorption of sodium (Na+) and the passive flow of water from the filtrate.

Front 3

ammonia

Back 3

A small, very toxic molecule made up of three hydrogen atoms and one nitrogen atom; produced by nitrogen fixation and as a metabolic waste product of protein and nucleic acid metabolism.

Front 4

angiotensin II

Back 4

A hormone that stimulates constriction of precapillary arterioles and increases reabsorption of NaCl and water by the proximal tubules of the kidney, increasing blood pressure and volume.

Front 5

anhydrobiosis

Back 5

The ability to survive in a dormant state when an organism’s habitat dries up.

Front 6

antidiuretic hormone (ADH)

Back 6

A hormone produced in the hypothalamus and released from the posterior pituitary. It promotes water retention by the kidneys as part of an elaborate feedback scheme that helps regulate the osmolarity of the blood.

Front 7

atrial natriuretic factor (ANF)

Back 7

A peptide hormone that opposes the renin-angiotensin-aldosterone system (RAAS).

Front 8

Bowman’s capsule 

Back 8

A cup-shaped receptacle in the vertebrate kidney that is the initial, expanded segment of the nephron where filtrate enters from the blood.

Front 9

collecting duct

Back 9

The location in the kidney where filtrate from renal tubules is collected; the filtrate is now called urine.

Front 10

cortical nephrons

Back 10

Nephrons located almost entirely in the renal cortex. These nephrons have a reduced loop of Henle.

Front 11

countercurrent multiplier system

Back 11

A countercurrent system in which energy is expended in active transport to facilitate exchange of materials and create concentration gradients. For example, the loop of Henle actively transports NaCl from the filtrate in the upper part of the ascending limb of the loop, making the urine-concentrating function of the kidney more effective.

Front 12

distal tubule

Back 12

In the vertebrate kidney, the portion of a nephron that helps refine filtrate and empties it into a collecting duct.

Front 13

efferent arteriole

Back 13

The blood vessel draining a nephron.

Front 14

euryhaline

Back 14

Referring to organisms that can tolerate substantial changes in external osmolarity.

Front 15

excretion

Back 15

The disposal of nitrogen-containing waste products of metabolism.

Front 16

filtrate

Back 16

Fluid extracted by the excretory system from the body fluid. The excretory system produces urine from the filtrate after extracting valuable solutes from it and concentrating it.

Front 17

filtration

Back 17

The extraction of water and small solutes, including metabolic wastes, from the body fluid into excretory system.

Front 18

glomerulus

Back 18

A ball of capillaries surrounded by Bowman’s capsule in the nephron and serving as the site of filtration in the vertebrate kidney.

Front 19

juxtaglomerular apparatus (JGA)

Back 19

A specialized tissue that releases the enzyme renin when blood pressure or blood volume drops in the afferent arteriole that supplies blood to the glomerulus.

Front 20

juxtamedullary nephrons

Back 20

Nephrons with well-developed loops of Henle that extend deeply into the renal medulla.

Front 21

loop of Henle

Back 21

The long hairpin turn, with a descending and ascending limb, of the renal tubule in the vertebrate kidney; functions in water and salt reabsorption.

Front 22

Malpighian tubule

Back 22

A unique excretory organ of insects that empties into the digestive tract, removes nitrogenous wastes from the hemolymph, and functions in osmoregulation.

Front 23

metanephridium

Back 23

(plural, metanephridia) In annelid worms, a type of excretory tubule with internal openings called nephrostomes that collect body fluids and external openings called nephridiopores.

Front 24

nephron

Back 24

The tubular excretory unit of the vertebrate kidney.

Front 25

osmoconformer

Back 25

An animal that does not actively adjust its internal osmolarity because it is isoosmotic with its environment.

Front 26

osmolarity

Back 26

Solute concentration expressed as molarity.

Front 27

osmoregulation

Back 27

How organisms regulate solute concentrations and balance the gain and loss of water.

Front 28

osmoregulator

Back 28

An animal whose body fluids have a different osmolarity than the environment and that must either discharge excess water if it lives in a hypoosmotic environment or take in water if it inhabits a hyperosmotic environment.

Front 29

peritubular capillaries

Back 29

The network of tiny blood vessels that surrounds the proximal and distal tubules in the kidney.

Front 30

protonephridium

Back 30

An excretory system, such as the flame bulb system of flatworms, consisting of a network of closed tubules having external openings called nephridiopores and lacking internal openings.

Front 31

proximal tubule

Back 31

In the vertebrate kidney, the portion of a nephron immediately downstream from Bowman’s capsule that conveys and helps refine filtrate.

Front 32

renal artery

Back 32

The blood vessel bringing blood to the kidney.

Front 33

renal cortex

Back 33

The outer portion of the vertebrate kidney.

Front 34

renal medulla

Back 34

The inner portion of the vertebrate kidney, beneath the renal cortex.

Front 35

renal pelvis

Back 35

Funnel-shaped chamber that receives processed filtrate from the vertebrate kidney’s collecting ducts and is drained by the ureter.

Front 36

renal vein

Back 36

The blood vessel draining the kidney.

Front 37

renin-angiotensin-aldosterone system (RAAS)

Back 37

A part of a complex feedback circuit that helps regulate blood pressure and blood volume.

Front 38

secretion

Back 38

1) The discharge of molecules synthesized by a cell. (2) The discharge of wastes from the body fluid into the filtrate.

Front 39

selective reabsorption

Back 39

The selective uptake of solutes from a filtrate of blood, coelomic fluid, or hemolymph in the excretory organs of animals.

Front 40

stenohaline

Back 40

Referring to organisms that cannot tolerate substantial changes in external osmolarity.

Front 41

transport epithelium

Back 41

One or more layers of specialized epithelial cells that regulate solute movements.

Front 42

urea

Back 42

A soluble nitrogenous waste excreted by mammals, most adult amphibians, sharks, and some marine bony fishes and turtles; produced in the liver by a metabolic cycle that combines ammonia with carbon dioxide.

Front 43

ureter

Back 43

A duct leading from the kidney to the urinary bladder.

Front 44

urethra

Back 44

A tube that releases urine from the body near the vagina in females and through the penis in males; also serves in males as the exit tube for the reproductive system.

Front 45

uric acid

Back 45

An insoluble precipitate of nitrogenous waste excreted by land snails, insects, and many reptiles, including birds.

Front 46

urinary bladder

Back 46

The pouch where urine is stored prior to elimination.

Front 47

vasa recta

Back 47

The capillary system that serves the loop of Henle.