In this lesson we:
 Dissect a lamb’s kidney
 Look at kidney diseases: o Kidney failure o Bilharzia o Kidney stones o Kidney infections
 Examine the external structure of the kidney. Remove any fat if it is present.
 Note the position of the blood vessels and ureter if they are present.
 Measure the length and width of the kidney (through the mid-point) and record this information.
 Using a scalpel, cut the kidney in half longitudinally. Make sure that you don’t cut away the blood vessels or ureter if they are present.
 Arrange one of the cut halves on a dish.
 Identify the capsule, cortex, medulla, renal pyramids, pelvis, ureter, blood vessels and hilum.
Describe what each of these looks like in your specimen, mentioning colour and texture
(where relevant).
 Draw a diagram of the dissected kidney and label all the parts that you have identified (up to six labels). Make your drawing life size.
 Place the dissected kidney and diagram next to each other .
 If one kidney stops working, it does not matter too much. We can live a relatively normal life with just one kidney.
 Sometimes both kidneys stop working because of an infection that causes damage to the cells of the kidneys.
 If both kidneys stop working, excretion and water balance are affected. The following things happen: o Wastes are not removed from the blood. o The amount of urea in the blood increases day by day
 Excess water and salts are not removed from the blood. They accumulate in the tissues. This puts a strain on the heart.
 Methods to counteract these effects: o Dialysis o kidney transplant.

(Solutions for all Life Sciences, Macmillan, p260 )
(Solutions for all Life Sciences, Macmillan, p265)
 The kidney is easily damaged by a hard punch or blow to the side of the body or to the small of the back.
 People who are likely to experience this kind of injury are sportsmen and women and can protect their kidneys by wearing kidney belts.
 Over-use of painkillers such as aspirin and paracetamol may also lead to kidney failure. Not everyone is at risk.
 Diabetes and high blood pressure can cause kidney damage.
 So can various diseases.

 A disease caused by parasitic worms.
 The worms live in the blood vessels around the bladder and they lay their eggs in the blood.
The eggs pass into the bladder and then into the water in lakes or dams when urine comes into contact with this water.
 You can become infected with bilharzia when swimming in, washing in or touching contaminated water.
 Symptoms of bilharzia may include a fever, fatigue and blood in the urine.
 Bilharzia can be treated with oral pharmaceutical drugs.
 Long-term infection with bilharzia can lead to kidney damage.
The urinary system is also known as
A.
B.
C.
D. the endocrine system the renal system the reproductive system the gastric system
Internally both kidneys have three distinct regions:
A. the cortex, the medulla and the peritoneum
B.
C. the cortex, medulla and pelvis the carina, medulla and pelvis
D. the cortex, mediastinum and pelvis
Each kidney contains approximately:
A. 1 billion nephrons
B.
C.
1 thousand nephrons
1 million nephrons
D. 1 hundred nephrons
Glomerular capsule and convoluted tubules always lie within the …
A. renal pelvis
B.
C. renal medulla renal cortex
D. none of these

Glomerular filtrate passes from glomerular capsule into the
A. Loop of the nephron
B.
C.
D.
Proximal convoluted tubule
Glomerular capsule
Convoluted tubule
The hollow space at the centre of kidney where urine is collected after its formation is called
A. renal pelvis
B.
C.
D. glomerulus distal convoluted tubule urethra
The main nitrogen-containing waste excreted in urine is
A.
B.
C.
D. ammonia creatine phosphate nucleotides urea
The muscular tubes which take the urine from the kidneys to the bladder are
A.
B.
C.
D.
Urinary bladders
Ureters
Urethras
Nephrons
(Adapted from Solutions for all Life Sciences, Macmillan, p268 – 269)
The diagram below shows a longitudinal section though a human kidney.

1.1
1.2
1.3
1.4
1.5
Provide labels for A, B, C and D. (4)
In which part of the kidney does the filtration of blood occur (A, B, C or D)? (1)
About 180 l of glomerular filtrate is formed every day in the nephrons of the kidneys, but only
1,5 l of urine are formed. What happens to the rest of the liquid? (2)
Explain the difference between tubular reabsorption and tubular excretion. (2)
Answer the following questions:
1.5.1 How is the inner wall of the Bowman’s capsule specialised for the process of ultrafiltration? (3)
1.5.2 What features of the cells forming the walls of the proximal convoluted tubule do you think help the process of tubular reabsorption? (3)
1.5.3 What does the presence of many mitochondria in the cells tell you about the process of tubular reabsorption? (2)
1.7
1.6.1 What volume of water is reabsorbed into the blood?
1.6.2 What percentage of each substance is reabsorbed into the blood? Show your calculations.
(1)
(8)
1.6.3 Use the information in the table to explain why urea is more concentrated in the urine than it is in the filtrate. (2)
1.6.4 Draw a flow diagram to show the path of a molecule of urea from the time that it enters the kidney to the time that it leaves the body (only list organs or large visible structures). (5)
Explain why:
1.7.1 there is no glucose in the urine of a healthy person (2)
1.7.2 dialysis solution must have the same concentration of glucose as blood plasma. (2)
1.7.3 it is difficult for people in southern Africa who suffer from kidney failure to get a kidney transplant. (2)
 http://www.s-cool.co.uk/a-level/biology/gas-exchange/revise-it/gas-exchange-in-humans
 http://www.enotes.com/homework-help/what-process-gas-exchange-human-body-467185
 http://www.mrothery.co.uk/exchange/exchange.htm