Formation Of Urine Flashcards
The three processes involved in formation of urine:
- filtration
- selective reabsorption
- secretion
Where does filtration take place?
Glomerulus and the glomerulus capillaries
What passes through the walls of the glomerulus capillaries?
Water and other small molecules
What does auto regulation regulate?
Renal blood flow
Where does reabsorption take place?
Proximal convoluted tubule
What substances are absorbed in the PCT
- water
- nutrients
- glucose
- amino acids
What is reabsorbed in the medullary loop?
- water
- sodium
- chloride
Where does active reabsorption take place?
Carrier sites in the epithelial membrane
( active transport)
What is the transport maximum?
Kindneys maximum capacity of reabsorption
Parathyroid hormone
- secreted by the parathyroid glands
- regulates reabsorption of calcium and phosphate to maintain normal blood levels
Anti diuretic hormone function
- secreted by the posterior pituitary gland
- increases water permeability of DCT and CD
- osmoreceptors (in the hypothalamus) measure the water levels in the blood
Aldosterone
- secreted by adrenal cortex
- increases reabsorption of sodium and water
- increases excretion of potassium in the urine
ANP
- secreted by atria
- in response to stretching of atrial wall when blood volume is increased
- increase urinary volume -> decrease in blood volume
What happens to the Glomerular filtration rate during pregnancy?
Increases by 40-50%
Progesterone and relaxin cause vasodilation so blood flow to glomerulus is increased
How does an increase in relaxin and hCG affect levels of ADH?
increases levels of ADH due to vasodilation
