Turn on thread page Beta
    • Thread Starter
    Offline

    0
    ReputationRep:
    I'm just refreshing my memory on all chapters in F214 and there's just something I'm a bit confused about in the Excretion chapter.

    You know how the afferent arteriole supplies the glomerulus with blood, well in the book it says it is wider than the efferent arteriole to maintain the high pressure of the blood in the glomerulus so it remains higher than in the Bowman's capsule.

    What I don't understand is, why is the afferent arteriole wider? In order for increased pressure shouldn't it be smaller, i.e. less wide? Like for arteries - blood is under high pressure so the lumen is a lot smaller than that of the veins which is under low pressure.

    Help is appreciated, thanks in advance
    • Thread Starter
    Offline

    0
    ReputationRep:
    Bump! Help needed please


    This was posted from The Student Room's iPhone/iPad App
    Offline

    4
    ReputationRep:
    (Original post by laauurraa)
    I'm just refreshing my memory on all chapters in F214 and there's just something I'm a bit confused about in the Excretion chapter.

    You know how the afferent arteriole supplies the glomerulus with blood, well in the book it says it is wider than the efferent arteriole to maintain the high pressure of the blood in the glomerulus so it remains higher than in the Bowman's capsule.

    What I don't understand is, why is the afferent arteriole wider? In order for increased pressure shouldn't it be smaller, i.e. less wide? Like for arteries - blood is under high pressure so the lumen is a lot smaller than that of the veins which is under low pressure.

    Help is appreciated, thanks in advance
    Pressure is maintained because it travels from a wider space to a narrower space.

    Imagine squirting water out of a bottle. If you take the lid off, it doesn't go very far. Put the lid on but prick a hole in the top and it squirts very far because the pressure is higher.

    It is wider relative to the efferent arteriole. It is still narrow but the efferent arteriole is narrower.
    • Thread Starter
    Offline

    0
    ReputationRep:
    Ah I see, makes sense. Thank you!


    This was posted from The Student Room's iPhone/iPad App
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: April 8, 2013
Poll
Do you think parents should charge rent?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.