F214:02:04 The Kidney Flashcards Preview

F214:02 Excretion > F214:02:04 The Kidney > Flashcards

Flashcards in F214:02:04 The Kidney Deck (34):

Where are the kidneys positioned?

each side of the spine, just below the lowest rib


From which vessels does the blood enter and leave the kidneys

From the renal artery and is drained by the renal vein


What is the role of the kidneys?

to remove waste products from the blood and produce urine.


Where does urine go once it has left the kidneys?

Down the ureter to the bladder where it is stored until it is ready to be releasedaaa


What can you see when you take a longitudinal section of the kidney?

- an outer region (cortex)
- an inner region (medulla)
- Central pelvis
Surrounded by a tough capsule


Where does the pelvis lead to?

the ureter


What does the bulk of the kidneys consist of?

tiny tubules called nephrons


How many nephrons are there in a kidney?

around 1 million


What are nephrons closesly associated with?

tiny blood capillaries


Where does each nephron start?

In the cortex


What is a nephron?

a functional unit of the Kidney
It is a microscopic tubule that receives fluid from the blood capillaries in the cortex and converts this to urine, which drains into the ureter


What is the glomerulus?

a fine network of capillaries that increases the local blood pressure to squeeze fluid out of the blood.
It is surrounded by a cup / funnel shaped capsule which collects the fluid and leads into the nephron


Where is the glomerulus found?

In the cortex


What is the Bowmans capsule?

The cup shaped structure surrounding the glomerulus


What is ultrafiltration?

The process by which fluid from the blood is pushed into the Bowmans capsule


What are the four parts of the nephron which the capsule leads into?

- proximal convoluted tube
- distal convoluted tube
- loop of Henle
- collectinf duct


What happens as the fluid moves along the nephron?

Its composition is altered due to seletive absorption


What is the proximal tubule?

The part of the nephron closest to the glomerulus


What is the distal tubule?

The part of the neurone furthest from the glomerulus


What is the convoluted tube?

The part of the nephron that is bent and coiled


What happens to the substances in the nephron as it passes through the convoluted tube?

The useful substances are reabsorbed back into the tissue fluid and blood capillaries surrounding the nephron tubule.


What is the final product in the collecting duct, after the fluid has passed through the nephron?



How does urine leave the kidneys?

It is the final product left in the distal convoluted tube, which then passes to the collection duct, which passes down into the pelvis and down the ureter to the bladder


What is the afferent arteriole?

The arteriole leading blood to the glomerulus


What is the efferent arteriole?

The arteriole leading away from the glomerulus


How does the composition of fluid change in the proximal convoluted tube?

sugars, most salts and some water are reabsorbed
85% of fluid is reabsorbed


How does the composition of fluid change in the descending limb of the loop of Henle? (in terms of water potential)

The water potential of the fluid is decreased by the addition of salts and the removal of water


How does the composition of fluid change in the ascending limb of the loop of Henle? (in terms of water potential)

Water potential is increased as salts are removed by active transport


How does the composition of the fluid change in the collecting duct? (in terms of water potential)

Decreases by the removal of water


Why is water removed to lower the water potential in the collecting duct?

To ensure that urine has a low water potential, and to ensure that urine has a higher concentration of solutes than is found in the blood and tissue fluid


What is selective reabsorption?

Where useful substances are reabsorbed from the nephron into the blood stream which other excretory substances remain in the nephron


Suggest why the nephrons are convoluted

To increase the length for greater SA for absorption


Why are there many capillaries round each nephron?

So that materials reabsorbed from the fluid in the tubule can re-enter the blood


Explain why reabsorption from the nephron must be selective

Some of the molecules in the nephron are waste and must be left in the fluid to be excreted
Other molecules are useful to the body and must be reabsorbed