Structure and function of the kidney Flashcards
Where are the kidneys located?
Posteriorly on the right lower part of the body.
Where is the blood supply for the kidney from?
The renal arteries from the aorta.
What is the protective tissue that surrounds the kidney?
The renal capsule.
What is the hilum?
The opening for attachment of the renal artery and vein, nerves and ureter.
What is the central cavity called of the kidney?
The renal sinus.
What direction is the afferent arteriole to?
Towards the nephron.
What direction is the efferent arteriole to?
Leaves the nephron.
What is the name of the network of capillaries that surrounds the kidney?
Peritubular capillaries.
What is the functional unit of the kidney?
The nephrons.
What is the Bowman’s capsule?
It is where filtration occurs.
What are the different types of nephron?
Cortical nephrons (close to the the cortex) and ones closer to the medulla - juxtamedullary.
How many nephrons are there per kidney?
1.3 x 10^6.
What percentage of the blood is filtered?
20%.
Why is the glomerulus tangled?
It creates a large surface area for filtration.
What is the renal corpuscle?
It contains the functional units of the kidneys such as the glomerulus and Bowman’s capsule.
What is the brush border.
A microvilli-covered surface that provides a large surface area for processes to occur.
What is the limb of Henle made up of?
Flattened squamous epithelial cells with few organelles.
What are the two layers of the Bowman’s capsule?
The visceral layer and the parietal layer. The visceral layer is in contact with the organs and the parietal is the outer layer.
What is the visceral surface made up of?
It is covered with podocytes.
Where is the juxta glomerular?
It is next to the glomerulus. It secretes hormones into the glomerulus. They are important for regulation.
What are fenestrations in the capillaries?
Large gaps between endothelial cells.
What is the basal lamina?
The thin layer of extracellular matrix that separates the endothelial cells from the podocytes.
What are podocytes?
Narrow filtration slits that are the finest level of filtration.
What are the three filtration barriers?
Fenestrations of the glomerular endothelial cells, the basal lamina of glomerulus and the slit membrane between pedicels
What drives filtration?
The hydrostatic pressure of the glomerular capillaries.
How does the relaxation of the arterioles drive filtration?
The afferent arteriole is more relaxed than the efferent arteriole leaving which forces filtration to occur.
What is oncotic pressure?
Pressure due to osmotic forces.
What is glomerular filtration rate?
The volume of filtrate produced by the kidneys per minute.
What is the average healthy GFR for adults?
125ml/minute.
Despite a relatively low filtration pressure, why is the volume of filtrate large?
The surface area of the glomerular capillaries is large, the glomerular capillary endothelium is fenestrated and the glomerular capillary blood pressure is high.
What are some of the ways that GFR can be altered?
Changes in diameter of the afferent and efferent arterioles, The efferent arteriole usually has a smaller diameter than the afferent arteriole to help drive the GFR.
What does the urinary excretion of a substance depend on?
FIltration, reabsorption and secretion.
Where are most of the fluid and solutes reabsorbed?
In the proximal convoluted tubule.
Where is most of the water reabsorbed in the loop of Henle?
At the end.
What primarily controls the regulation of the loop of Henle and glomerulus?
Autoregulation - tubuloglomerular feedback.
What primarily controls the regulation of collecting duct and DCT?
Hormones.
