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Systems Physiology Exam 3

Terms in this set (31)

The Urinary Sytem and Renal Physiology
- Filters your blood to make pee
- regulate water, ion, acid-base balance
- excretes metabolic wastes, foreign chemicals
The Nephron is the
functional unit of the kidney
Each Nephron contains
renal corpuscle and renal tubule
Fenestrated capillaries are more
porous than usual
Things passed through the filter
- water
- electrolytes
- glucose
- amino acids
- fatty acids
- vitamins
-urea
- uric acid
- creatine
Things turned back ( don't go through filter)
- blood cells
- plasma proteins
- large anions
- protein bound minerals and hormones
- most molecules > 8 nm in diamater
The two types of nephrons differ in their
loop length
Two types of Nephrons
juxtamedullary and cortical
Characteristics of Juxtamedullary
(~15%)
long deep loop of Henle, dive deep into medulla and help generate osmotic gradient
Characteristics of Cortical
(85%)
short or even no loop of Henle, not involved in generating osmotic gradient
Vasta recta are
capillaries that follow the juxtamedullary nephron
Mesengial cells
modifid smooth muscle cells
Juxtaglomerular cells
wrapped around afferent arterioles and secrete renin
Macula densa
can detect Na+ concentration
If a substance is reabsorbed, that means it is traveling
back into the blood
Glomerular filtration
blood( glomerular capillaries) -> Bowman's space
Glomerular filtrate is cell
free and it looks like plasma minus large proteins
Tubular reabsoprtion
renal tubule -> peritubular capillaries ( back to blood)
Tubular secretion
peritubular capillaries -> renal tubule
Amount excreted=
amount filtered+ amount secreted- amount reabsorbed
Main Forces involed in Filtration
- blood pressure in glomerular capillaries
- hydrostatic pressure in Bowman's space
- Osmotic force due to the protiens in plasma
Blood pressure in glomerular capillaries
pretty high ~ 60 mmHg ( Favors movement from GC-> Bowman's space)
Hydrostatic Pressure in Bowman's space
~15mmHg
Osmotic force due to proteins in plasma
~29 mmHg
Net Filtration pressure
60-15-29=16mmHg
Glomerular FIltration Rate: volume of fluid filtered from glomeruli into Bowman's space per unit time is determined by:
1. Net filtration pressure
2. permeability of corpuscle membrane/surface area available for filtration
Factors that increase GFR
- constrict efferent arteriole
- Dilate afferent arteriole
Factors that decrease GFR
- dilate efferent artiole
- constrict afferent arteriole
Using GFR to calculate Filtered Load for a non-protein or non-protein bound substance
(180L/day)(1g/1L)
If the amount filterd= amount excreted then
no reabsorption occurred
Glucose is not excreted in healthy individuals because
it is a vital energy source
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