Kidney Physiology Flashcards
What are the homeostatic kidney functions?
Regulation of blood ionic composition (Na+, K+, Cl-)
Regulation of blood pH
(H+, HCO3-)
Regulation of blood volume
(H2O)
Regulation of blood pressure
Maintenance of blood osmolarity
Production of hormones
(Calcitrol or Erythropoietin)
Excretion of metabolic wastes and foreign substances
(Drugs or Toxins)
Regulation of blood glucose levels
How much blood do the kidneys receive?
20 to 25% of cardiac output
Nerve supply of kidneys
Renal nerves: carry sympathetic outflow
What do the renal nerves do?
Regulate blood flow through the kidneys
What does the renal corpuscle consist of?
The glomerulus and the Bowman’s capsule
What is the glomerulus?
A mass of capillaries that is fed by the afferent arterioles and drains into the efferent arteriole.
What is the Bowman’s corpuscle?
It has a visceral layer of podocytes, which wrap around the capillaries.
(afferent article –> filtered in glomerulus –> efferent atriole)
What cannot pass through the fenestrations?
Blood cells and proteins
Where are the fenestrations located and what are they?
They are large leaky pores in the glomerular endothelial cells
What lies between the endothelium and the podocytes?
Basal lamina
What do podocytes form?
Pedicels
What are the two kinds of nephrons?
Cortical and Juxtamedullary
What is the function of the cortical nephrons?
To create urine with osmolarity similar to the blood.
Where do the juxtamedullary nephrons receive blood from?
Peritubular capillaries and vasa recta
What is the function of juxtamedullary nephrons?
To enable the kidney to secrete very concentrated urine.
Where do the ascending loops contact the afferent arteriole?
Macula densa
What kind of cells does the wall of the afferent arteriole contain?
Smooth muscle cells which are known as juxtaglomerular cells
What happens if the afferent dilates?
More blood is filtered
What happens if the efferent constricts?
Substances do not leave as quickly
What happens if the afferent dilates and the efferent constricts simultaneously?
The pressure increases and the substances are pushed out
Excretion of a solute equation
Glomerular filtration + secretion - reabsorption
What facilitates glomerular filtration?
Blood pressure (glomerular blood hypostatic pressure)