Glomerular Function Flashcards
Describe the renal blood flow
- Renal artery
- Segmental arteries
- Interlobar arteries
- Arcuate arteries
- Interlobular arteries
- Afferent arterioles
- Glomerular capillaries
- Efferent arterioles
- Peritubular capillaries
- Interlobular veins
- Arcuate veins
- Interlobar veins
- Renal vein
What are the factors determining GFR?
- Balance of hydrostatic and colloid osmotic forces acting across the capillary membrane
- The capillary filtration coefficient (Kf)
What is Kf?
- GFR/NFP
- Determined by the product of permeability and surface area of the capillaries for filtration
What are the membrane layers of the glomerular capillary?
- endothelium of the capillary
- basement membrane
- layer of podocytes
What are the layers of Bowman’s capsule?
- Inner visceral layer
- Outer parietal layer
Define nephron
Structural and functional unit of kidney
What is juxtaglomerular apparatus?
A specialized organ situated near the glomerulus of each nephron
What is the normal urinary output?
1 to 1.5L/day
What is the role of renin in the body?
- Converts inactive angiotensinogen into Angiotensin I
- Angiotensin I is converted to Angiotensin II by the converting enzyme
What are the factors which stimulate secretion of renin?
- Decreased arterial blood pressure
- Reduction in ECF volume
- Increased sympathetic activity
- Decreased load of sodium and chloride in macula densa
What are the normal values of GFR?
125 mL/minute or 180 L/day
Define glomerular filtration rate
The total amount of filtrate formed in the nephrons of both the kidneys per unit time
What is the normal filtration fraction?
15 - 20%
Name the pressures, which determine the GFR
- Glomerular capillary pressure (60 mmHg)
- Colloidal osmotic pressure in the glomeruli (25 mmHg)
- Hydrostatic pressure in the Bowman’s capsule (15 mmHg)
Name the processes involved in urine formation
- Glomerular filtration
- Tubular reabsorption
- Tubular secretion of excretion
