Download URINARY SYSTEM 2 - Kidneys 2 - Ureters 1 - Bladder 1

URINARY SYSTEM
2 - Kidneys
2 - Ureters
1 - Bladder
1 - Urethra
KIDNEYS
Location
Anatomy of
Renal Capsule
Cortex
Medulla
Pyramids
Columns
Papillae
Pelvis
Calyces
Nephron Units
NEPHRON UNIT
Bowman's Capsule
Proximal Convoluted Tubule
Loop of Henle
Descending limb
Ascending limb
Distal Convoluted Tubule
Collecting Tubule
BLOOD SUPPLY TO THE NEPHRON
Renal Artery
Afferent Arteriole
Glomerulus
Efferent Arteriole
Reabsorption Capillaries
Renal Venules
Renal Vein
RENAL FUNCTION
1. Excretion of wastes and excess
materials: Urea, Uric Acid,
Salts, H+ ions.
2. Maintenance of osmotic pressure
and fluid volume.
3. Conservation of useful substances.
PROCESS OF RENAL FUNCTION
Glomerular Filtration
Pressure
Tubular Reabsorption and Secretion
Diffusion
Active Transport
GLOMERULAR FILTRATION
Afferent Artery
Glomerulus
Efferent Artery
GLOMERULUS
Increased Surface Area
Thin Walls
Increased Pressure
PRESSURE
Blood pressure
COP of Blood
50 mmHg
30 mmHg
20 mmHg
Pressure of Filtrate
in nephron
10 mmHg
Total Outward Force - 10 mmHg
GLOMERULAR FILTRATION RATE (GFR)
Marker - (Inulin)
GFR = U
X
V (vol. of urine
P (conc. of marker in urine)
GFR = 120 ml/min
(180 l/day)
Renal Blood Flow (Fick method) 1,200 ml/min
(1,800 l/day)
Renal Plasma Flow
RPF =
RBF
1 - Hematocrit
RPF = 660 ml/min.
Filtration Fraction
GFR = 120 = .18
RPF
660
use of >< .2
Regulation of RBF and GFR
Vasoconstriction and Dilation of
Afferent Artery
Efferent Artery
Control of constriction - dilation
Neural
Humoral
Extrinsic
Intrinsic
Renin (kidney)
Blood
Angiotensin
Autoregulation
Smooth Muscle
REABSORBED MATERIALS
Low - High Threshold
Low Threshold
Diffusion
Urea (100 gm. filtered,
50 gm. reabsorbed)
Uric Acid
Creatinine
Water ??
High Threshold
Active Reabsorption
Glucose, Amino Acids, Vitamins
ions of Sodium, Potassium,
Calcium, Phosphates, etc.
Transport maximum - Tm
Ex. Glucose: TmG = 325 mg/min
Normal Transport
100 mg glucose/100 ml blood
if GFR = 120 ml/min
then about 120 mg of glucose
filtered and reabsorbed
per minute
if tubular load reaches
about 220 mg of glucose,
significant quantities of
glucose in urine
Sodium Reabsorption - H+ secretion
BLOOD
PROXIMAL TUBULE FILTRATE
CO2
________
H2O
_________
> CO2
> H2O _____> H2CO3
Carbonic
Anhydrase
H+ __________> H+
HCO3- <_________ HCO3Na+
<_________ Na+
<_______________
Na+
Water Reabsorption
Counter Current Multiplier
Action of Proximal Tubule
and Descending Limb
Action of Ascending Limb
and Distal Tubule
Role of ADH (antidiuretic
hormone)
Ascending Limb
Distal Tubule
Collecting Tubule