The Kidneys And The Excretory System - Part 4 (T2)

Question 1

What is the name of the area that the kidney tubules or nephrons run through?

Answer 1

The medulla

Question 2

Describe the medulla on a human kidney…

Answer 2

• the kidney tubules or nephrons run through it
• the medulla contain bulges called pyramids, pointing towards the concave side of the kidney
• the tubes in the medulla join up and lead to the tips of the pyramids, where they empty urine into a space called the pelvis

Question 3

What is the pelvis on the human kidney?

Answer 3

• where the tips of the pyramids empty urine

- the pelvis connects with the ureter, carrying urine to the bladder

Question 4

How does the blood get into the kidneys and through the the glomerulus?

Answer 4

• blood enters the kidneys through each of the two renal arteries
• these divide into smaller and smaller arteries called arterioles
• the arterioles lead to he capillaries of the glomerulus

Question 5

How is blood transferred from the glomerulus to the bowman’s capsule?

Answer 5

• the glomerulus cause resistance to blood flowing into them so there is very high pressure in the arteriole blood leading to the glomerulus
• this high pressure forces fluid from the blood through the capillary walls and the bowman’s capsule into the space in the middle of the bowman’s capsule

Question 6

Once blood has entered the bowman’s capsule, it is separated from the blood in the glomerulus by three layers of what? And what is their function?

Answer 6

• the capillary wall (made of cells)
• the wall of the capsule (made of cells)
• the basement membrane (not made of cells)

These layers acts like a filter, allowing water, ions and small molecules to pass, but preventing blood cells and larger molecules like proteins from passing

Question 7

The process within the three layers between the bowman’s capsule and the glomerulus that separates the different sized molecules under pressure is called…

Answer 7

Ultrafiltration

Question 8

Explain in detail what happens once the glomerular filtrate has entered the tubules of the nephron…

Answer 8

• immediately, all the glucose is reabsorbed back into the blood capillaries
• there are two coiled regions in the cortex; the proximal convoluted tubule and the distal convoluted tubule
• they are separated by a ‘u’ shaped loop which runs down into the medulla, known as the loop of henle

Question 9

What is the collecting duct and how does it work?

Answer 9

• after passing the second coiled tubule (the distal convoluted tubule) several nephrons join together to form a collecting duct, from which the urine passes out into the pelvis of the kidney

Question 10

The kidneys produce around ……. of glomerular filtrate per minute, or about ……. per day

Answer 10

The kidneys produce around 25 cm3 of glomerular filtrate per minute, or about 180 dm3 per day