the urinary system

Question 1

function of the kidney

Answer 1

osmoregulation
filters the blood
removes waste such as urea, salt and water

Question 2

function of the bladder

Answer 2

stores urine

Question 3

function of the renal artery

Answer 3

carries the blood that needs to be filtered into the kidneys
originates from the aorta

Question 4

function of the renal veins

Answer 4

carries clean filtered blood out of the kidneys
connects to the vena cava

Question 5

function of the ureter

Answer 5

carries urine to the bladder for storage

Question 6

function of the urethra

Answer 6

carries urine from the bladder out of the body

Question 7

location of the kidneys

Answer 7

below the diaphragm

Question 8

what is osmoregulation

Answer 8

-kidneys control the level of salt and water in the blood
-if we don’t drink enough water only a small volume of urine will be produced
-if we eat a lot of salty food a low volume of concentrated urine will be produced

Question 9

renal artery

Answer 9

-aorta divides into two renal arteries when it reaches the kidneys
-one renal artery enters each kidney
-the blood blood is under very high pressure and needs to be filtered (it comes from the aorta)
-when the renal artery enters the kidney it splits up into smaller vessels called arterioles which then split into capillaries

Question 10

renal vein

Answer 10

-emerges from both kidneys and connects to the vena cava
-the blood has been cleaned and filtered to remove excess salt, water and urea
-blood is under low pressure

Question 11

the nephron

Answer 11

-each kidney contains millions of nephrons
-provide a huge surface area so that the blood can be filtered and urine removed efficiently

Question 12

urine production

Answer 12

three parts to urine production in the nephron of the kidney
1. filtration
2. reabsorption
3. secretion

Question 13

what is filtration

Answer 13

-blood enters the glomerulus (bunch of blood capillaries) which sit in the bowmans capsule
-blood is filled with waste and small substances pass out of the glomerulus and into the bowmans capsule
-it is based on size and any substance small enough will get passed out of the glomerulus

Question 14

glomerular filtrate

Answer 14

vitamins and hormones that enter the bowmans capsule

Question 15

how does filtration happen

Answer 15

-high blood pressure in the glomerulus
-the diameter of the efferent arteriole is much less than the diameter of the afferent arteriole
-glomerulus provides a large surface area
-the glomerulus capillaries are more porous than normal and only one cell thick
-the wall of the bowmans capsule is one cell thick

Question 16

what are the large substances that do not get filtered into the bowmans capsule

Answer 16

red blood cells
platelets
antibodies
clotting proteins

Question 17

what is reabsorption

Answer 17

-beyond the bowmans capsule water, most salts and useful substances are reabsorbed into the blood, about 99% of the glomerular filtrate is reabsorbed
-a combination of diffusion, osmosis and active transport

Question 18

diffusion

Answer 18

movement of a substance from a high concentration to a low concentration
(passive process, no energy required)

Question 19

osmosis

Answer 19

movement of water from a high concentrate of water to a low concentrate of water through a semi permeable membrane like a cell membrane or visking tube
(passive process, no energy required)

Question 20

active transport

Answer 20

movement of a substance from a region of low concentration to a region of high concentration with the use of energy

Question 21

reabsorption in the proximal convoluted tubule

Answer 21

-most of the water is reabsorbed by osmosis
-all of the useful molecules such as glucose, amino acids and vitamins are reabsorbed by diffusion and active transport
-most salts reabsorbed by active transport or diffusion

Question 22

what helps the process of reabsorption in the proximal tubule

Answer 22

-is thin walled, only one cell thick
-is long (14mm)
-has numerous infoldings (microvilli) in its cells
-high concentration of mitochondria to provide energy for active transport
-surrounded by a blood capillary

Question 23

reabsorption in the loop of henle (descending limp)

Answer 23

-permeable to water
-water is reabsorbed into the blood capillaries surrounding the nephron
-this happens by osmosis

Question 24

reabsorption in the loop of henle (ascending limp)

Answer 24

-permeable to salts
-salts move out into the fluid of the medulla by diffusion
-at the top of the ascending limp salt is pumped out by active transport
-this increases the concentration of salt in the medulla causing osmosis to happen from the descending limp and collecting duct

Question 25

what is the main function of the loop of henle

Answer 25

the reabsorption of water back into the blood

Question 26

reabsorption in the distal convoluted tubule

Answer 26

-controls the water, salt and pH values of the blood
-some water and salt are reabsorbed into the blood in the dct

Question 27

the collecting duct

Answer 27

-permeable to water
-small amount of water is reabsorbed from the filtrate
-occurs by osmosis due to high concentration of salt in the medulla
-the liquid that passes is called urine
-flows into the pelvis of the kidney and onto the bladder through the ureters

Question 28

what is secretion

Answer 28

-when some substances pass from the blood into the nephron (opposite direction of reabsorption)
-secretion happens in the distal convoluted tubule
-potassium ions and hydrogen ions are passed from the blood into the dct

Question 29

what is the main function of secretion and the distal convoluted tubule

Answer 29

keep the pH of the blood constant

Question 30

how is urine volume controlled

Answer 30

-controlled by anti-diuretic hormone (vasopresin)

Question 31

where is adh produced and stored

Answer 31

-produced by the hypothalamus
-stored in the pituitary gland

Question 32

anti-diuretic hormone

Answer 32

-travels in blood from pituitary gland to the nephron
-makes the dct and collecting duct permeable to water
-controls osmoregulation

Question 33

what happens if you drink a lot of water or have a low salt diet

Answer 33

-the hypothalamus in the brain detects the diluted blood and pituitary gland does not release adh
-dct and collecting duct become impermeable to water
-no water reabsorbed from dct or collecting duct
-large volume of urine is produced
-concentration of blood plasma does not change