Urinary System Flashcards
Kidney Functions
Maintaining water balance • Maintaining proper osmolarity • Maintaining proper ion concentrations • Maintaining proper plasma volume • Helping to regulate plasma pH • Excreting nitrogenous wastes • Excreting foreign compounds • Producing erythropoietin • Producing renin • Converting Vitamin D to it’s active form
The Nephron
ascular Components • Tubular Components • Combined Components • Location – Juxtamedullary – Cortical
Overview of
Kidney Function
Glomerular Filtration • Tubular Reabsorption • Tubular Secretion
Forces Driving Glomerular
Filtration
Hydrostatic, Osmotic Pressure,
Hydrostatic
Glomerular capillary and Bowman’s Capsule
Osmotic Pressure
Bowman’s to Glomerulus
Autoregulation
Myogenic mechanism
• Tubuloglomerular Feedback
Myogenic Mechanism
Vasoconstriction and dilation driven by vascular smooth muscle, Stretch causes smooth muscle contraction
Tubular Reabsorption
is specific, GFR is NOT. recovers what you
filter, but do not want to get rid of.
Transepithelial Transport
Tight Junctions Prevent passage of material
between the tubular epithelium
Steps to Transepithelial Transport
• Cross Luminal Membrane • Pass through Cytosol • Cross Basolateral Membrane • Diffuse across interstitial space • Enter capillary • Some molecules move passively – others require active transport
Sodium Reabsorption drives
In the Proximal Convoluted Tubule • Glucose • Amino Acid • Water • Chloride Ion • Urea
Sodium Reabsorption
Aldosterone Stimulates reabsorption
• Reabsorption in the DCT largely controlled
by renin-angiotensin system
Control of Renin-Angiotensin
Activation – Granular Cells are baroreceptors • Low Pressure more renin Macula Densa is sensitive to NaCl • Less NaCl, more renin – Sympathetic Innervation • More renin
Concept of the Tubular Max
Reabsorption requires carrier molecules
• If there are enough carriers, reabsorption
will be complete
