Test 1 (Renal Histology, Dr. Cole) Flashcards
Functions of the Urinary System
1) Elimination:
- Urine and toxic metabolites from the blood
2) Conservation:
- Salts, Glucose, Proteins, and H2O
3) Regulation:
- Blood Pressure, Hemodynamics, and Acid-base Balance
4) Endocrine:
- Produces Vitamin D, Renin, Erythropoietin, and Prostaglandins (Hormonal Control of other tissues/ Organs)
Kidney: Blood Supply
- As a blood filtering organ, the kidney’s Blood Supply is critical to its function
- Supplied by RENAL ARTERIES, branch directly from the AORTA
Blood Supply of the Kidney
1) Segmental (LOBAR) Artery —->
2) INTERLOBAR Artery —->
3) ARCUATE Artery —–>
4) INTERLOBULAR Artery
Map of Blood Supply
1) Renal Artery
2) Segmental Artery
3) Interlobar Artery
4) Arcuate Artery
5) Interlobular Artery
6) Afferent Arteriole
7) Glomerulus
8) Efferent Arteriole
9) Peritubular Capillaries
10) Vasa Recta
11) Interlobular Vein
12) Arcuate Vein
13) Interlobar Vein
14) Renal Vein
Kidney Blood Supply Cont.
- Efferent arterioles drain the Glomeruli and form capillary networks
- Drain cortical Nephrons and form PERITUBULAR CAPILLARY ENTWEK (take up substances resorbed by Tubular Epithelium)
The Nephron: Functional Unit of the Kidney
Parts are modified for specific physiological functions
- RENAL CORPUSCLE filter fluid from Blood
- TUBULAR Portions modifies filtrate into Urine
Nephron
- Two (Three) types depending on location of their Henle Loop
1) CORTICAL (short):
- Can be superficial or Midcortical
2) JUXTAMEDULLARY (long)
Renal Corpuscle
1) Tuft of fenestrated Capillaries- The GLOMERULUS
2) Surrounded by URINARY (Bowman’s) Capsule
- Capillaries INVAGINATE into Bowman’s Capsule**
- Capillaries are in contact with the Visceral Layer (Podocytes)
- Parietal Layer is SIMPLE SQUAMOUS EPITHELIUM
- Separated by Urinary Space
Mesangial Cells
- Supporting Cells
- Modified SMOOTH MUSCLE
- Extraglomerular (Vascular Pole)
- Intraglomelular
Functions of Mesengial Cells
1) Contractile:
- Reduce/ Increase blood flow through capillaries
2) Supportive:
- In area where the Visceral layer of the Renal Corpuscle is absent
3) Phagocytic:
- Resorption and maintenance of the Basal Lamina
4) Secretory:
- Secrete Prostaglandins and Endothelia’s (Induce Constriction of Afferent/ Efferent arterioles)
Glomerular Filtration Barrier
- Fluid from capillaries leaks into the Urinary space through a complex filtration barrier
- FENESTRATED CAPILLARY Endothelium
- BASAL LAMINA (Basement Membrane)
- Podocytes of the Visceral Layers of Bowman’s Capsule
- High POLYANIONIC Charge on some components of both Basal Lamina and surface of Podocyte processes
Glomerular Capillaries
- Fenestrated
- Large pores not covered by a Diaphragm
- Permeable to Water, Urea, Glucose, and Small Proteins
- Barrier only to FORMED ELEMENTS in Blood and Large Macromolecules
Basal Lamina
Lamina Rarae Contains:
1) Type IV Collagen
2) Laminin
3) Fibronectin
4) Negatively-charged Proteoglycans
- Lamina Densa (IV)
- Lamina Rarae
Podocytes
- Have P1 (Big) and P2 (Small) processes
Pedicels and Filtration Slits
- Each pedicel has a GLYCOCALYX of Negatively-charged PODOCALYXIN
- Separated by Clefts- FILTRATION SLITS
- Covered by a porous SLIT DIAPHRAGM