4. The Kidneys Flashcards
Main function of kidneys?
Filter waste products out of blood and reabsorb useful solutes.
Regulate water content
Ultrafiltration?
Filtering of blood that takes place under pressure, as blood passes from glomerulus into bowmans capsule.
Selective reabsorption?
Reabsorbtion of useful substances along the kidney nephron back into blood
What is a nephron ?
One of the filtering units of kidney.
Responsible for removing waste products from blood and involved in regulating water potential of blood.
Where does ultrafiltration occur?
In the glomerulus and bowmans capsule:
Where does blood from renal artery go ?
Into smaller arterioles in the cortex of kidney.
What does each arteriole split into ?
Glomerulus which is a bundle of capillaries looped inside hollow ball called bowmans capsule.
What is the arteriole that takes blood into glomerulus ?
Afferent arteriole.
What is the arteriole that takes filtered blood away from glomerulus?
Efferent arteriole.
Different between efferent and afferent?
Efferent smaller in diameter than afferent.
So blood under high pressure at efferent.
What does the high pressure do at the efferent arteriole ?
Forces liquid and small molecules in blood out of capillary into bowmans capsule.
Where do the liquid and small molecules go ?
Through 3 layers to get to bowmans capsule
capillary endothelium.
Basement membrane.
Epithelium of bowmans capsule.
What are the cells called that make up epithelium of bowmans capsule?
Podocytes.
What are the substances called that enter bowmans capsule ?
glomerular filtrate.
It Passes through rest of nephron and useful substances are reabsorbed along the way.
Where does the glomerular filtrate eventually go ?
Through collective duct and passes out of kidney along ureter.
What can the glomerular filtrate also be called?
Tubular fluid.
Where does selective reabsoprtion occur?
Along the proximal convoluted tubule
Loop of Henle
Distal convoluted tube.
as the glomerular filtrate passes by
Where do useful substances end up going ?
To capillary network wrapped around them from the tubules.
Which 2 things are found in medulla?
Loop of Henle.
Ureter.
What 5 things found in cortex?
Renal artery. Bowmans capsule. PCT DCT Collecting duct
What is present on the epithelium of the wall on the PCT?
Microvili
What do the microvilli do ?
Increase surface area for reabsorbtion of useful substances from glomerular filtrate.
Name some useful substances which are reabsorbed ?
Glucose.
Along pct by facilitated diffusion
How does water enter blood ?
Osmosis.
As water potential of blood is lower than that of the filtrate.
Where is water reabsorbed from ?
Pct
Loop of Henle
DCT
Collecting duct
What is urine made up of ?
Water Dissolved salts Urea Hormones Excess vitamins
What does urine NOT contain?
Proteins
Blood cells as they’re too big to be filtered out of blood.
Glucose - actively reabsorbed into blood.
What is urea?
Product produced from breakdown of amino acids in liver.
