SB7i The Kidneys

Question 1

nephrons? 3

Answer 1

~ include the Bowman’s capsule, convoluted tubules, the loop of Henle and the collecting duct
~some substances are absorbed through the walls of the nephron back into the blood, such as glucose, which is useful for the body. This is called selective reabsorption.​
~water is also reabsorbed through osmoregulation

Question 2

glomerulus? 3

Answer 2

~blood flows along the renal artery and into a network of capillaries called the glomerulus ~small molecules such as glucose can pass out of the glomerulus whilst large molecules such as blood cells and proteins remain inside.​
~the cells of the glomerulus have spaces between them, making them let small molecules through.​

Question 3

bowman’s capsule? 3

Answer 3

~bowman’s capsule surrounds the glomerulus and contains tiny holes that allow small molecules such as water, urea and glucose into the nephron. ~large molecules like proteins and blood cells, stay in the blood.​
~This is filtration

Question 4

first convoluted tubule? 4

Answer 4

~selective reabsorption - useful substances such as glucose and mineral ions are reabsorbed here ~substances are pumped into the blood through proteins in the cell membrane via active transport
~cells in the first convoluted tubule are adapted by having microvilli which increases surface area for proteins. ~cells contain many mitochondria which release energy to actively transport the glucose back into the blood.​

Question 5

loop of henle and collecting duct?

Answer 5

~water is reabsorbed here, via osmosis
~remaining fluid flows into the collecting duct and travels to the bladder via the ureter
~the fluid contains excess water that the body doesn’t need as well as urea. The fluid is now called urine. ​

Question 6

3 adaptations of the nephron?

Answer 6

~large surface area, increase contact between nephron and capillaries
~microvilli, increase surface area:volume area of the cells
~cells contain many mitochondria, provide the energy needed for active transport

Question 7

what does the kidney alter and what is this controlled by?

Answer 7

how much water it reabsorbs
controlled by pituitary gland

Question 8

what does ADH alter?

Answer 8

the permeability of the collecting duct, increasing the concentration of urine

Question 9

what does the pituitary gland do when there is lots of water in urine?

Answer 9

stops producing ADH