1. Renal System: Functional unit is the Nephron. Kidneys (2) Ureter (2)
Bladder (1)
Urethra (1)

2. Functions of the Renal System
1) Regulates ECF volume:
a) Regulates Osmolarity:
b) Regulates ion balance:
2) Regulates pH of body fluids:
3) Eliminates metabolic waste:
4) Removes foreign substances:
5) 2o Endocrine gland:

5. Outer renal cortex Inner renal medulla ~ 1.25 million nephrons in
each kidney
~ 180 Liters of
Filtrate made
each day
~ 1.5 Liters of
urine excreted
each day

6. The Nephron 1. Renal Corpuscle 2. Renal Tubule a) Glomerulus
b) Bowman’s Capsule
c) Bowman’s Space
2. Renal Tubule
a) Proximal CT
b) Loop of Henle
c) Distal CT

7. In Human Renal System ~85% are Cortical nephrons
Renal corpuscle higher in cortex.
Shorter loop of Henle.
~15% are Juxtamedullary nephrons
Renal corpuscle closer to medulla.
Loop of Henle extends deep into medulla.

9. 1. Renal Corpuscle (3 parts)
Glomerulus  
Bowman’s Capsule
Bowman’s Space

10. 2. Renal Tubule a) Proximal Convoluted Tubule (PCT) b) Loop of Henle
c) Distal
Convoluted Tubule (DCT)

11. Filtration:
Reabsorption:
Secretion:
Excretion:

12. Overview of the Renal Process in Nephron

13. Barriers to Filtration
1. Endothelium
Restricts cells
2. Basement Membrane
Restricts proteins
3. Podocytes
Changes Glomerular Filtration Rate (GFR)

14. Filtration is favored by
Hydrostatic Pressure
(HP) of Glomerulus.
Opposed by Colloid
Osmotic Pressure
(COP) of blood.
Opposed by
Hydrostatic Pressure
of Bowman’s capsule.

16. Glomerular Filtration Rate (GFR)
e.g., normally GFR is 180L/day (or 125ml/min)
Things that can influence GFR:
Changes in blood pressure can change
GFR but this is autoregulated.

17. Autoregulation of Renal System

18. Autoregulation 1. Myogenic Stretch 2. Tubuloglomerular Feedback
If ↑ blood pressure in afferent arteriole, this
stretches smooth muscle and it contracts in
response, thus vasoconstricts.
This decreases blood flow (↓ pressure and GFR)

19. Arteriole Resistance Changes Blood flow and GFR

20. Autoregulation 2. Tubuloglomerular Feedback Macula Densa JG Cells
Juxtaglomerular
Apparatus
JG Cells

22. ANS-Sympathetic Modulation
Both Afferent and Efferent Arterioles are
innervated by SYM neurons.
NE binds to  receptors on smooth muscle,
causing vasoconstriciton.
e.g., if hemorrhage or dehydration,
↑ Sym, vasoconstriction,
↓GFR, conserves fluid volume.
Hormones
Angiotensin II – vasoconstrictor.
Prostaglandins – vasodilator.