Transcript Nephron PPT

Kidney
Objective:
Nephron
Anatomy and
Function
Nephron
Anatomy
consists of
Renal corpuscle
Renal tubule
Bowman’s
capsule
Renal corpuscle
1. Glomerulus
2. Bowman’s
capsule
Glomerulus
Renal tubule
1. Proximal
convoluted
tubule
(PCT)
Proximal
Convoluted
(twisted)
tubule
Renal tubule
2. Loop of Henle
Loop of
Henle
Renal tubule
3. Distal
convoluted
tubule
(DCT)
Distal
Convoluted
tubule
Collecting
tubule
Collecting
tubule
Nephron Function
Three Processes 1. Filtration
(blood to capsule)
2. Reabsorption
(return to blood)
3. Secretion
(added to urine)
1. Filtration
In Renal corpuscle
 Glomerulus → Bowman’s
capsule
 Filters from blood
180 liters/day
(45 gallons)
[barrel is 55 gallons]
Filtration (cont)
 To Bowman’s capsule:







Water
Amino acids
Glucose
Urea
Na, K, Cl
Hormones
Vitamins
Filtration (cont)
 What doesn’t cross
 Blood cells
 Medium to Large
proteins
2. Reabsorption
Peritubular capillaries →
PCT, DCT, &
Loop of Henle
PCT
•
•
•
•
•
Most of water
Glucose
Na K Cl
Amino acids
Vit &
Hormones
Loop of
Henle
3. Secretion
Peritubular capillaries →
PCT and DCT
• Urea
• H+ (pH)
• Toxins
–
–
Drugs
Antibiotics
Secretion (cont)
Peritubular capillaries →
Collecting tubules
Collecting
tubules
Daily Totals
 Filtration ~ 180 liters
filtered out/day
 Reabsorption ~ 179
liters returned to the
blood/day
 ~ 1 liter excreted as
urine/day
(0.78 mL/min)
Ureter
 Connects kidney to
bladder
 10-12 inches long
 Made of smooth muscle
 Uses peristalsis
 Rhythmic contractions of
muscle
Bladder
 hollow, muscular
 Capacity:
 700-800 mL (average)
 Made of:
 Transitional epithelium

Stretchy!
 Smooth muscle
Sphincters
 Internal
 Smooth muscle
 Autonomic
(Automatic)
 Controlled by spinal
cord
Sphincters
 External
 Skeletal muscle
 Cerebral control
 Micturition
 Expel urine from
bladder