Nephrology Lecture Notes

Flashcards covering the structure and function of the nephron, urine formation, and hormonal regulation within the kidney.

Nephron

Functional unit of the kidney responsible for filtering blood and forming urine.

Glomerulus

Tuft of fenestrated capillaries that filters blood plasma in the renal corpuscle.

Capsular Space

Collects the filtrate pushed out of the glomerular capillaries.

Parietal Layer

Simple squamous epithelium providing structural support to Bowman's capsule.

Visceral Layer

Made of podocytes with foot processes that form filtration slits in Bowman's capsule.

Proximal Convoluted Tubule (PCT)

Cuboidal cells with microvilli that reabsorb ~65% of water and solutes (glucose, amino acids, Na⁺, Cl⁻, HCO₃⁻).

Descending Limb of Loop of Henle

Permeable to water but not solutes, leading to water reabsorption into the salty medulla.

Ascending Limb of Loop of Henle

Impermeable to water, actively transports out Na⁺, K⁺, Cl⁻ to help form salt gradient.

Juxtamedullary Nephrons

Nephrons with a more pronounced Loop of Henle for concentrated urine.

Distal Convoluted Tubule (DCT)

Fewer microvilli, mainly involved in regulated reabsorption and secretion of ions (K⁺, H⁺), sensitive to aldosterone and parathyroid hormone.

Collecting Duct

Collects filtrate from many nephrons, regulated by ADH to increase water reabsorption, drains urine into papillary ducts.

Glomerular Filtration

Occurs in the renal corpuscle, driven by glomerular blood hydrostatic pressure (GBHP).

Glomerular Filtration Rate (GFR)

Indicates kidney function; Normal GFR = 90–120 mL/min.

Capsular Hydrostatic Pressure (CHP)

Resistance from filtrate already in capsule.

Blood Osmotic Pressure (BOP)

Solutes in blood pulling water back.

Tubular Reabsorption

Returns water, ions, and nutrients to the blood via peritubular capillaries and vasa recta, mainly in PCT.

Tubular Secretion

Adds waste and excess substances into the tubule from the blood, key in controlling pH and removing drugs, toxins, creatinine, and excess K⁺.

ADH (Antidiuretic Hormone)

Increases water reabsorption in the collecting duct.

Aldosterone

Increases Na⁺ reabsorption in the DCT.

PTH (Parathyroid Hormone)

Increases Ca²⁺ reabsorption in the DCT.

Efferent Arteriole

Leads to peritubular capillaries in cortical nephrons.

Efferent Arteriole

Leads to vasa recta in juxtamedullary nephrons.