Anti-diuretic hormone; AVP; Arginine vasopressin. Hormone, released from the posterior pituitary gland, which regulates water reabsorption in the distal tubule and collecting duct.
ANP -
Atrial natriuretic peptide.
Aquaporin -
A water channel, inserted in the apical membrane of collecting duct principal cells, upon stimulation by ADH.
Autoregulation -
Vasodilation or constriction in response to a change in local blood pressure, in order to maintain local blood flow. This response is intrinsic to the vessel's smooth muscle. In the kidney, autoregulation of the afferent and efferent arterioles maintains normal RPF and GFR in the face of changing pressure in the renal artery.
C
Chart Reader -
LabChart Reader for Mac or Windows is a free application program that allows the students to view and conduct limited analysis of LabChart data files.
CHF -
Congestive heart failure. A condition where the myocardium (heart muscle) weakens to the point that it can't produce the cardiac output needed to maintain tissue perfusion and blood pressure. Though CHF may occur in the right ventricle, the more common and more serious form involves a weakened left ventricle. Among the many results are elevated plasma volume and pre-renal failure.
Clearance -
The rate at which blood is "cleared" of a given solute X by renal excretion. Clearance is given by the equation:
where C = clearance of X, P = plasma concentration of X, U = concentration of X in urine, and V = rate of urine production (usually measured by 24-hour urine collection). Clearance is most useful clinically for measuring GFR. More.
Creatinine -
A metabolite of muscle creatine, a molecule which provides a quick, short supply of ATP to muscles. Creatinine is released into the blood at a relatively constant rate, and is used as an indicator of GFR and renal function.
G
GFR -
Glomerular Filtration Rate. The volume of plasma which is filtered through the glomerulus per second.
I
Inulin -
A polysaccaride built from fructose, which is not naturally-occurring in the body. Inulin is freely filtered at the glomerulus but is not handled in any way in the tubules (reabsorbed, secreted, metabolized). It is used as the best measure of GFR.
J
Juxtaglomerular Apparatus -
A specialized group of cells at the point where the afferent arteriole meets the distal tubule. It is made up of the macula densa of the distal tubule, and the juxtaglomerular cells of the afferent arteriole. The apparatus is involved in controlling GFR, circulating volume, and blood pressure, primarily through the release of renin.
K
Kali_ -
Relating to potassium (K).
M
Macula densa -
A specialized group of cells of the distal tubule, which form part of the juxtaglomerular apparatus.
N
Natri_ -
Relating to sodium (Na).
P
PAH -
Para-amino hippurate, a molecule which is completely secreted into the tubules, so that blood leaving the kidney has no PAH in it. PAH is used to measure renal plasma flow (RPF).
Pre-renal failure -
A condition where perfusion of the kidney is reduced by a problem before the blood reaches the kidney (hence pre-renal). This may be caused by reduced perfusion pressure (ex. congestive heart failure), decreased blood volume (ex. haemorrhage, severe diarrhoea), or obstruction of blood flow (ex. renal artery stenosis). As less blood arrives to be filtered at the glomeruli, GFR is reduced, even as the kidney attempts to maintain it through autoregulation. In the short term, pre-renal failure is reversible with correction of the underlying condition (ex. treat CHF, give blood transfusion), but irreversible tissue necrosis may occur if the tissue is nutrient-deprived for too long.
R
RAA system -
Renin-Angiotensin-Aldosterone system. Also called RAS (Renin-Angiotensin system). Endocrine system involved in regulation of blood pressure and sodium reabsorption.
Reabsorption -
The process by which solutes, filtered from blood at the glomerulus, are transported back from the tubular fluid into capillary blood.
RPF -
Renal Plasma Flow. The volume of plasma flowing through the renal artery per second.
S
Secretion -
The process by which solutes are transported from capillary blood into the tubular fluid.
T
TAL -
Thick ascending limb
TBA -
To Be Announced
Tubuloglomerular feedback -
Afferent arteriole dilation or constriction induced by a change in fluid flow through the distal tubule, in order to adjust GFR. Thought to be mediated through the macula densa. The feedback prevents distal flow from exceeding the distal tubule's reabsorbtive capacity, and avoids heavy fluid losses in urine.
_
_emia -
In the blood. E.g. hypercalcemia = high calcium levels in the blood
_uria -
In the urine. E.g. glucosuria = glucose in the urine
MEDSCI 205 Glossary
