Bio 449 Lecture 26 – Renal Physiology II Nov. 10, 2010

Nephrons (cont’d)Urine formationGlomerular filtration Proximal tubuleLoop of Henle & initial distal tubuleEnd distal tubule & collecting ductMechanisms of reabsorption and secretionCounter-current multipliersSummary of nephron function

Terms to KnowBowman's capsule Proximal tubuleLoop of HenleDescending limbThin ascending limbThick ascending limbDistal tubuleCollecting duct Glomerular filtrationGlomerular filtration rate (GFR) Tubular lumenApical or luminal membraneBasolateral membrane Counter-current multiplier

ReadingsLectures 25-27: Chapters 19 & 20

Nephrons

Secretion and reabsorption

Urine Formation

Overview of nephron function

Fig. 19-1

Collectingduct

Distal tubule

Afferentarteriole

Loopof

Henle

Efferentarteriole

Glomerulus

Peritubular capillaries

ProximaltubuleBowman’s

capsule

To renalvein

To bladder andexternal environment

KEY = Filtration: blood to lumen

= Reabsorption: lumen to blood

= Secretion: blood to lumen

= Excretion: lumen to externalenvironment

Glomerular filtration

Renal corpuscle

Fig. 19-5

Bowman’scapsule

Podocyte

GlomerularcapillaryLumen ofBowman’scapsule

Proximaltubule

Efferentarteriole

Afferentarteriole

Thickascending

limb ofloop ofHenle

Podocytes

Fig. 19-5

Renal corpuscle

Fig. 19-5

Lumen ofBowman’s

capsule

Podocytefoot

processes

Glomerularcapillary

Podocyte

Mesangialcell

Capillaryendothelium

Renal corpuscle

Fig. 19-5

Filtration slit

Basal lamina

Filteredmaterial

Foot processof podocyte

Lumen ofBowman’scapsule

Capillarylumen

Pores inendothelium

Proximal tubule

Loop of Henle & initial distal tubule

End distal tubule & collecting duct

Mechanisms of reabsorption and secretion

Counter-current multipliers

Summary of nephron function

Fig. 19-1

Collectingduct

Distal tubule

Afferentarteriole

Loopof

Henle

Efferentarteriole

Glomerulus

Peritubular capillaries

ProximaltubuleBowman’s

capsule

To renalvein

To bladder andexternal environment

KEY = Filtration: blood to lumen

= Reabsorption: lumen to blood

= Secretion: blood to lumen

= Excretion: lumen to externalenvironment

Summary of nephron function