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Key Terms

Key Terms

afferent arteriole
arteriole that branches from the cortical radiate artery and enters the glomerulus
ammonia
compound made of one nitrogen atom and three hydrogen atoms
ammonotelic
describes an animal that excretes ammonia as the primary waste material
angiotensin converting enzyme (ACE)
enzyme that converts angiotensin I to angiotensin II
angiotensin I
product in the renin-angiotensin-aldosterone pathway
angiotensin II
molecule that affects different organs to increase blood pressure
anti-diuretic hormone (ADH)
hormone that prevents the loss of water
antioxidant
agent that prevents cell destruction by reactive oxygen species
arcuate artery
artery that branches from the interlobar artery and arches over the base of the renal pyramids
ascending limb
part of the loop of Henle that ascends from the renal medulla to the renal cortex
blood urea nitrogen (BUN)
estimate of urea in the blood and an indicator of kidney function
Bowman's capsule
structure that encloses the glomerulus
calyx
structure that connects the renal pelvis to the renal medulla
cortex (animal)
outer layer of an organ like the kidney or adrenal gland
cortical nephron
nephron that lies in the renal cortex
cortical radiate artery
artery that radiates from the arcuate arteries into the renal cortex
countercurrent exchanger
peritubular capillary network that allows exchange of solutes and water from the renal tubules
countercurrent multiplier
osmotic gradient in the renal medulla that is responsible for concentration of urine
descending limb
part of the loop of Henle that descends from the renal cortex into the renal medulla
distal convoluted tubule (DCT)
part of the renal tubule that is the most distant from the glomerulus
efferent arteriole
arteriole that exits from the glomerulus
electrolyte
solute that breaks down into ions when dissolved in water
flame cell
(also, protonephridia) excretory cell found in flatworms
glomerular filtration
filtration of blood in the glomerular capillary network into the glomerulus
glomerular filtration rate (GFR)
amount of filtrate formed by the glomerulus per minute
glomerulus (renal)
part of the renal corpuscle that contains the capillary network
hilum
region in the renal pelvis where blood vessels, nerves, and ureters bunch before entering or exiting the kidney
inferior vena cava
one of the main veins in the human body
interlobar artery
artery that branches from the segmental artery and travels in between the renal lobes
juxtaglomerular cell
cell in the afferent and efferent arterioles that responds to stimuli from the macula densa
juxtamedullary nephron
nephron that lies in the cortex but close to the renal medulla
kidney
organ that performs excretory and osmoregulatory functions
lobes of the kidney
renal pyramid along with the adjoining cortical region
loop of Henle
part of the renal tubule that loops into the renal medulla
macula densa
group of cells that senses changes in sodium ion concentration; present in parts of the renal tubule and collecting ducts
Malpighian tubule
excretory tubules found in arthropods
medulla
middle layer of an organ like the kidney or adrenal gland
microvilli
cellular processes that increase the surface area of cells
molality
number of moles of solute per kilogram of solvent
molarity
number of moles of solute per liter of solution
mole
gram equivalent of the molecular weight of a substance
nephridia
excretory structures found in annelids
nephridiopore
pore found at the end of nephridia
nephron
functional unit of the kidney
non-electrolyte
solute that does not break down into ions when dissolved in water
osmoconformer
organism that changes its tonicity based on its environment
osmoregulation
mechanism by which water and solute concentrations are maintained at desired levels
osmoregulator
organism that maintains its tonicity irrespective of its environment
osmotic balance
balance of the amount of water and salt input and output to and from a biological system without disturbing the desired osmotic pressure and solute concentration in every compartment
osmotic pressure
pressure exerted on a membrane to equalize solute concentration on either side
perirenal fat capsule
fat layer that suspends the kidneys
peritubular capillary network
capillary network that surrounds the renal tubule after the efferent artery exits the glomerulus
proximal convoluted tubule (PCT)
part of the renal tubule that lies close to the glomerulus
renal artery
branch of the artery that enters the kidney
renal capsule
layer that encapsulates the kidneys
renal column
area of the kidney through which the interlobar arteries travel in the process of supplying blood to the renal lobes
renal corpuscle
glomerulus and the Bowman's capsule together
renal fascia
connective tissue that supports the kidneys
renal pelvis
region in the kidney where the calyces join the ureters
renal pyramid
conical structure in the renal medulla
renal tubule
tubule of the nephron that arises from the glomerulus
renal vein
branch of a vein that exits the kidney and joins the inferior vena cava
renin-angiotensin-aldosterone
biochemical pathway that activates angiotensin II, which increases blood pressure
segmental artery
artery that branches from the renal artery
semi-permeable membrane
membrane that allows only certain solutes to pass through
transport maximum
maximum amount of solute that can be transported out of the renal tubules during reabsorption
tubular reabsorption
reclamation of water and solutes that got filtered out in the glomerulus
tubular secretion
process of secretion of wastes that do not get reabsorbed
urea cycle
pathway by which ammonia is converted to urea
ureotelic
describes animals that secrete urea as the primary nitrogenous waste material
ureter
urine-bearing tube coming out of the kidney; carries urine to the bladder
uric acid
byproduct of ammonia metabolism in birds, insects, and reptiles
urinary bladder
structure that the ureters empty the urine into; stores urine
urine
filtrate produced by kidneys that gets excreted out of the body
vasa recta
peritubular network that surrounds the loop of Henle of the juxtamedullary nephrons
vasodilator
compound that increases the diameter of blood vessels
vasopressin
another name for anti-diuretic hormone