1. |
anatomical sphincter
|
smooth or skeletal muscle surrounding the lumen of a vessel or hollow organ that can restrict flow
when contracted |
2. |
angiotensin II
|
protein produced by the enzymatic action of ACE on inactive angiotensin I; actively causes vasoconstriction
and stimulates aldosterone release by the adrenal cortex |
3. |
angiotensin I
|
protein produced by the enzymatic action of renin on angiotensinogen; inactive precursor of angiotensin II |
4. |
angiotensin-converting enzyme
|
(ACE) enzyme produced by the lungs that catalyzes the reaction of inactive angiotensin I into active
angiotensin II |
5. |
angiotensinogen
|
inactive protein in the circulation produced by the liver; precursor of angiotensin I; must be modified
by the enzymes renin and ACE to be activated |
6. |
anuria
|
absence of urine produced; production of 50 mL or less per day |
7. |
aquaporin
|
protein-forming water channels through the lipid bilayer of the cell; allows water to cross; activation
in the collecting ducts is under the control of ADH |
8. |
Bowman's capsule
|
cup-shaped sack lined by a simple squamous epithelium (parietal surface) and specialized cells called
podocytes (visceral surface) that participate in the filtration process; receives the filtrate which
then passes on to the PCTs |
9. |
brush border
|
formed by microvilli on the surface of certain cuboidal cells; in the kidney it is found in the PCT;
increases surface area for absorption in the kidney |
10. |
calyces
|
cup-like structures receiving urine from the collecting ducts where it passes on to the renal pelvis
and ureter |
11. |
cortical nephrons
|
nephrons with loops of Henle that do not extend into the renal medulla |
12. |
countercurrent multiplier system
|
involves the descending and ascending loops of Henle directing forming urine in opposing directions
to create a concentration gradient when combined with variable permeability and sodium pumping |
13. |
detrusor muscle
|
smooth muscle in the bladder wall; fibers run in all directions to reduce the size of the organ when
emptying it of urine |
14. |
distal convoluted tubules
|
portions of the nephron distal to the loop of Henle that receive hyposmotic filtrate from the loop of
Henle and empty into collecting ducts |
15. |
diuretic
|
compound that increases urine output, leading to decreased water conservation |
16. |
efferent arteriole
|
arteriole carrying blood from the glomerulus to the capillary beds around the convoluted tubules and
loop of Henle; portion of the portal system |
17. |
endothelins
|
group of vasoconstrictive, 21-amino acid peptides; produced by endothelial cells of the renal blood
vessels, mesangial cells, and cells of the DCT |
18. |
external urinary sphincter
|
skeletal muscle; must be relaxed consciously to void urine |
19. |
fenestrations
|
small windows through a cell, allowing rapid filtration based on size; formed in such a way as to
allow substances to cross through a cell without mixing with cell contents |
20. |
filtration slits
|
formed by pedicels of podocytes; substances filter between the pedicels based on size |
21. |
forming urine
|
filtrate undergoing modifications through secretion and reabsorption before true urine is produced |
22. |
glomerular filtration rate
|
(GFR) rate of renal filtration |
23. |
glomerulus
|
tuft of capillaries surrounded by Bowman's capsule; filters the blood based on size |
24. |
glycosuria
|
presence of glucose in the urine; caused by high blood glucose levels that exceed the ability of the
kidneys to reabsorb the glucose; usually the result of untreated or poorly controlled diabetes mellitus |
25. |
incontinence
|
loss of ability to control micturition |
26. |
intercalated cell
|
specialized cell of the collecting ducts that secrete or absorb acid or bicarbonate; important in
acid-base balance |
27. |
internal urinary sphincter
|
smooth muscle at the juncture of the bladder and urethra; relaxes as the bladder fills to allow urine
into the urethra |
28. |
inulin
|
plant polysaccharide injected to determine GFR; is neither secreted nor absorbed by the kidney, so
its appearance in the urine is directly proportional to its filtration rate |
29. |
juxtaglomerular apparatus
|
(JGA) located at the juncture of the DCT and the afferent and efferent arterioles of the glomerulus;
plays a role in the regulation of renal blood flow and GFR |
30. |
juxtaglomerular cell
|
modified smooth muscle cells of the afferent arteriole; secretes renin in response to a drop in blood pressure |