lecture 29 - the nephron Flashcards
(50 cards)
How many nephrons are found in each kidney?
1 million
What are the 2 types of nephron?
Cortical and juxtamedullary nephrons
What is the major type of nephron, making up 85% of all nephrons?
Cortical nephrons
Where do cortical nephrons mainly lie?
The cortex of the kidneys
Where do juxtameduallry nephrons sit?
Glomerular capsule and tubules in the cortex, but the nephron loop extends deep into the medulla
What are juxtamedullary nephrons important for?
The formation of concentrated urine
What are the 3 key components of a nephron?
A glomerular capsule, renal tubules and a collecting duct
What blood vessels are each nephron associated with?
A glomerulus and peritubular capillaries
What are glomerular capillaries specialised for?
Filtration
What is the structure of glomerular capillary walls?
Single layer of fenestrated endothelial cells
What regulates glomerular capillary blood pressure?
Input and output via the afferent and efferent arteriolar sphincters
What are the peritubular capillaries specialised for?
Absorption - are fenestrated
Where are the peritubular capillaries located?
Wrapped around the renal tubules
What blood do the peritubular capillaries receive?
Filtered blood from the glomerulus via efferent arterioles
How do peritubular capillaries remove unwanted solutes?
Some solutes that were unfiltered in the glomerulus and need to be excreted can pass into the nephron via secretion
What are the vasa recta?
Extensions of the peritubular capillaries that follow juxtamedullary nephron loops deep into the medulla
What type of nephrons have vasa recta?
Only juxtamedullary nephrons - not cortical nephrons
What is the renal corpuscle?
The first part of a nephron, where the glomerulus sits, enclosed by the glomerular capsule. Where the capillary and nephron meet, and where filtration occurs
What is the site of the filtration barrier in the kidneys?
The renal corpuscle of nephrons
What are the 2 layers of the glomerular capsule?
Outer parietal layer of simple squamous cells, and an inner visceral layer of podocytes
What sits between the 2 layers of the glomerular capsule?
The capsular space/urinary space
What is the function of the capsular space in the glomerular capsule?
Receives filtrate from the filtration of blood in the glomerular capillaries
Where are podocytees located?
Make up the inner layer of the glomerular capsule in the renal corpuscles of the kidneys
What is the structure of a podocyte?
Highly branched, specialised epithelial cell that has branches that form intertwining foot processes called pedicels with filtration slits between them.
