Which blood vessels carry blood into and out of a kidney?

The renal artery brings blood in and the renal vein carries it away.

What is a kidney tubule and how many are there in a kidney?

It is the microscopic unit in which blood is filtered and useful substances are reabsorbed, and each kidney contains about a million of them.

What happens at the Bowman's capsule?

Blood in the knot of capillaries inside it is filtered under pressure, so water, glucose, urea and mineral ions pass into the capsule.

Why are proteins and blood cells absent from the filtrate in a healthy kidney?

Their molecules and cells are too large to pass through the filter at the Bowman's capsule, so they stay in the blood.

What happens in the proximal convoluted tubule?

All of the glucose and much of the water and mineral ions are reabsorbed from the filtrate back into the blood.

OCR GCSE Biology A J247

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Organism Level Systems

The kidney tubule and the effect of ADH

3 things to know
Paper 3

Overview

The cortex, medulla and renal pelvis, the renal artery and vein, what a kidney tubule is and how many a kidney holds, filtration at the Bowman's capsule, reabsorption in the proximal convoluted tubule, the loop of Henlé and the collecting duct, ADH from the pituitary and its effect on the collecting ducts, how it corrects blood concentration by negative feedback, and the effect of alcohol.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Process

Explain the sequence of events that corrects blood which has become too concentrated.

Key term

Explain what happens to ADH release after a person drinks a large volume of water.

Key term

Name the regions seen when a kidney is cut in half from top to bottom.

Questions from this subtopic

Each one with the model answer underneath.

1
Name the regions seen when a kidney is cut in half from top to bottom.
Model answer
The cortex on the outside, the medulla beneath it, and the renal pelvis in the middle where urine collects before entering the ureter.
2
Which blood vessels carry blood into and out of a kidney?
Model answer
The renal artery brings blood in and the renal vein carries it away.
3
What is a kidney tubule and how many are there in a kidney?
Model answer
It is the microscopic unit in which blood is filtered and useful substances are reabsorbed, and each kidney contains about a million of them.
4
What happens at the Bowman's capsule?
Model answer
Blood in the knot of capillaries inside it is filtered under pressure, so water, glucose, urea and mineral ions pass into the capsule.
5
Why are proteins and blood cells absent from the filtrate in a healthy kidney?
Model answer
Their molecules and cells are too large to pass through the filter at the Bowman's capsule, so they stay in the blood.
6
What happens in the proximal convoluted tubule?
Model answer
All of the glucose and much of the water and mineral ions are reabsorbed from the filtrate back into the blood.

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AThe blood becomes too dilute.

BLess ADH is released.

CThe collecting ducts become less permeable.

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Egestion means passing out of undigested food as faeces.

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