Kidney structure

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  • Created by: Steff06
  • Created on: 28-02-16 11:39
Define the layers of the kidney.
Outer region of the kidney is called the cortex. The inner region is called the medulla. In the centre is the pelvis which leads into the ureter.
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What is the role of the kidney?
To remove waste products from the blood and to produce urine.
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What happens to the urine in the kidney?
It passes out of the kidney down the ureter to the bladder where it is stored before release.
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What is the nephron divided into?
The proximal convoluted tubule, the distal convoluted tubule, the loop of henle and the collecting duct.
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Describe nephrons and their pathway
Nephrons are tiny tubules. They start in the cortex where the capillaries form a knot called the glomerulus.
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What is the glomerulus surrounded by?
A cup-shaped structure known as the Bowman's capsule. Fluid from the blood is pushed into the Bowman's capsule by ultrafiltration.
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What happens to the fluid as it moves along the nephron?
Its composition changes. This is achieved by selective reabsorption.
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Where are substances reabsorbed and what is the final product?
Reabsorbed into the tissue fluid and blood capillaries. Urine is the final product in the collecting duct.
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What is reabsorbed and where?
All sugars, most salts and some water. 85% of reabsorption takes place in the proximal convoluted tubule.
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Changes in the descending limb of the loop of henle?
Water potential is decreased by the addition of salts and and the removal of water.
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Changes in the ascending limb of the loop of henle?
Water potential is increased as salts are removed by active transport.
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Changes to water potential in the collecting duct?
Decreases by removal of water to ensure urine has a low water potential.
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Describe the flow of blood in ultrafiltration
Blood flows into the glomerulus from the afferent arteriole. The afferent arteriole is wider than the efferent arteriole.
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Describe the pressure in the glomerulus and Bowman's capsule.
The pressure is higher in the glomerulus than the Bowman's capsule.
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Why is it important that the afferent arteriole is a different diameter to the efferent arteriole?
To ensure the blood in the capillaries of the glomerulus is under increased pressure.
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What does the glomerulus do to begin glomerular filtration?
Glomerulus brings a large SA of blood capillaries in close contact with the Bowman's capsule.
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What is filtered from the blood and what conditions are needed?
Liquid and small molecules are filtered from the blood under pressure.
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What is produced and what does it contain?
Glomerular filtrate is produced containing water, glucose, urea, salts, amino acids.
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What cannot pass into the tubule?
Proteins and blood cells as they are too big (over 69000).
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What are the 3 adaptions of the Bowman's capsule for ultrafiltration?
Endothelium of the capillary, basement membrane and the podocytes.
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How is the endothelium of the capillary adapted and why?
It is one cell thick and has narrow gaps. This provides a shorter diffusion distance and the gaps allow blood plasma and substances dissolved in it to pass through.
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Adaption of basement membrane and reasons for this
Made of a fine mesh of collagen fibres and glycoproteins. Acts as a filter to prevent the passage of molecules larger than 69000.
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How are the podocytes adapted and why?
They are specialised epithelial cells of the Bowman's capsule and have finger-like projections (major processes). These ensure there are gaps between cells so fluid from blood can pass into lumen of Bowman's capsule.
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What effect does the presence of proteins left in the capillary have?
Means the blood has very low water potential.
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Why is this good?
It ensures some fluid is retained in the blood and is important to help to reabsorb water later on.
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Other cards in this set

Card 2

Front

What is the role of the kidney?

Back

To remove waste products from the blood and to produce urine.

Card 3

Front

What happens to the urine in the kidney?

Back

Preview of the front of card 3

Card 4

Front

What is the nephron divided into?

Back

Preview of the front of card 4

Card 5

Front

Describe nephrons and their pathway

Back

Preview of the front of card 5
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