Mesothelioma: Urinary Outline

Urinary Outline

I. Anatomy - Four urinary tract organs

II. Physiology

A. Glomerular filtration is a passive, nonselective process in which hydrostatic pressure forces fluid

& solutes through a membrane

1. the amount of fluid filtered from the blood into capsule per min. - "glomerular filtration rate"

GFR is = 125 ml/min (GFR also called ultrafiltration rate)

2. three factors influence this:

a. body surface area

b. permeability of filtration membrane (glomerulus more efficient than other capillaries)

c. net filtration rate determined by hydrostatic pressure (push) & osmotic pressure (pull)

3. The osmotic pressure is coming from the glomerulus primarily the plasma proteins in the

glomerular blood & hydrostatic pressure is excreted by the fluids within Bowman's capsule

4. The difference between these two forces determines net filtration pressure which is directly

proportional to GFR.

5. Normal glomerular filtration rate in both kidneys is 120-125 mL/min

a. This rate is held constant under normal conditions by intrinsic controls called renal

autoregulation

1. when ↓BP, renal blood vessels dilate

2. when ↑BP, renal blood vessels constrict

b. These changes adjust the glomerular hydrostatic pressure & indirectly maintain GFR

B. The kidneys maintain a stable internal environment by balancing fluid / solute composition of

blood within narrow ranges three intricate processes are used:

1. Filtration refers to the movement of fluid across a semi-permeable membrane. This occurs

when plasma flows through glomerular capillary into Bowman's capsule as a result of

osmotic capillary pressures & capillary permeability

2. Resorption the movement of water & dissolved substances from tubular fluid (filtrate) back

into blood (occurs in tubules & collecting ducts)

3. Secretion the movement of fluid and substances from blood into tubular fluid (occurs in

tubules & collecting ducts)

Mesothelioma