Ch 19 The Kidneys Flashcards
Urinary Functions of the Kidneys
Regulate body water vol
- Regulated concentrations of inorganic ions
- Remove metabolic wastes (mainly urea, uric acid, creatinin) from blood
Homeostatic Functions of the Kidneys
- Help regulate blood vol and bp
- Assist in controlling body salt balance
- Help regulated acid-base balance and blood pH
- Control production of RBCs
- Activate Vit D.
Function of Ureters
Transport urine to bladder
Function of Urethra
Transport urine to body surface
The Nephron
Tubule with Glomerular Capsule (Bowman’s), proximal tubes, Loop of Henle, Distal Tubule
-Functional unit of kidney
Sequence that filtrate travels through the nephron
- Afferent arteriole
- Glomerulus
- Proximal tubule
- Loop of Henle
- Distal tubule
- Collecting duct
- Renal pelvis
- Ureter
Afferent Arteriole
Initial blood supply
-Blood comes in here
Glomerulus
Capillaries inside glomerular capsule
- Deposits plasma into capsule
- Takes most stuff out of blood so good stuff can be put back in
Efferent Arteriole
Carries filtered blood away from glomerular capsule
-Blood is still O2 rich
Efferent Glomerular Arterioles
- From Cortical Nephrons: form peritubular capillary network for entire cortical labyrinth
- From Juxtamedullary nephrons: form hairpin capillary network that extends into medulla
- Arteriolae rectae and venae rectae
Arteriolae Rectae
Descending limb of Efferent Glomerular Arterioles
-Reabsorbs H2O
Venae Rectae
Ascending limb of Efferent Glomerular Arterioles
-Reabsorbs Na, K, etc
Peritubular Capillaries
Absorb most H2O and solutes from tubules
Vasa Recta
Supplies loop of Henle and collecting duct
Bowman’s Capsule Visceral Layer
Covers glomerulus as podocytes
Urinary Pole
Continuation of Bowman’s capsule as the proximal tubule
Bowman’s Capsule and the Glomerulus
Bowman’s capsule becomes invaginated by a glomerulus at the urinary pole
3 Layers of basal lamina of the glomerulus
- Lamina Rara Interna
- Lamina Densa
- Lamina Rara Externa
- Laminin and fibronectin attach the endothelial cells and podocytes to lamina densa
- To prevent clogging of basil lamina, intraglomerular mesongial cells remove the basal lamina and podocytes and endothelial cells constantly produce more
Lamina Rara Interna
- Innermost layer of basal lamina in glomerulus
- Layer rich in laminin, fibronectin, and heparin
- Heparin filters pos charged particles
Lamina Densa
- Middle layer of basal lamina in glomerulus
- 100 nm thick, consisting of Type IV collagen
- Traps molecules >69kD
Lamina Rara Externa
- Outermost layer of basal lamina in glomerulus
- Adjacent to the visceral layer of Bowman’s capsule (podocytes)
Principles of Renal Function:
1. Glomerular Filtration
Exit of water into Bowman’s capsule
-Creates filtrate
Principles of Renal Function:
2. Tubular Reabsorption
Recovery of water and solutes from filtrate
-Puts things back into blood
Principles of Renal Function:
3. Tubular Secretion
Selective transport of solutes INTO tubular fluid
-remaining fluid and solutes in tubule becomes = urine
