kidney

Question 1

what is excretion

Answer 1

the removal of toxic materials and waste products of metabolism

Question 2

what are the organs of excretion?

Answer 2

• skin
• lungs
• kidney

Question 3

what does skin excrete?

Answer 3

sweat

Question 4

what does the water in sweat do?

Answer 4

helps keep the body cool in hot conditions, and it contains salts and urea

Question 5

what do lungs excrete?

Answer 5

excess carbon dioxide and some water vapour

Question 6

what do the kidneys excrete?

Answer 6

excess water, salt and urea

Question 7

why is homeostasis essential?

Answer 7

it keeps the conditions in our body constant

Question 8

what bodily conditions need to be kept constant?

Answer 8

• water
• salts
• glucose
• CO2 levels in blood
• pH of blood
• body temp

Question 9

what % of the body does water make up?

Answer 9

60-70%

Question 10

what is nitrogenous waste?

Answer 10

waste that contains nitrogen

Question 11

why is glucose reabsorbed?

Answer 11

used in respiration to release ATP

Question 12

why is water reabsorbed?

Answer 12

maintain concentration in blood

Question 13

what is osmoregulation?

Answer 13

control of water levels in the body

Question 14

what is the role of the aorta in the urinary system?

Answer 14

blood supply to the kidneys
straight from the aorta - high pressure

Question 15

what is the role of the kidneys in the urinary system?

Answer 15

homeostatic organ - controls water and salt concentration

excretory organ - concentrates nitrogenous waste to be removed

Question 16

what is the role of the ureter in the urinary system?

Answer 16

tube in which urine passes out of the kidneys

Question 17

what is the role of the vena cava in the urinary system?

Answer 17

removes the blood once filtered by the kidney

Question 18

what is the role of the bladder in the urinary system?

Answer 18

stores urine before release

Question 19

what is the role of the urethra in the urinary system?

Answer 19

tube to the outside
the wall contains two ring like muscles - sphincters

Question 20

what is the role of the nephron?

Answer 20

ultrafiltration/selective reabsorption

Question 21

what is the role of the renal artery?

Answer 21

brings blood to the kidney

Question 22

what is the role of the renal vein?

Answer 22

takes blood away from the kidney

Question 23

what is the role of the ureter?

Answer 23

takes urine from the kidney to the bladder

Question 24

what is the role of the renal pelvis?

Answer 24

when urine empties into from the tips of the pyramids
connects to the ureter which connects to the bladder

Question 25

what is the role of the renal pyramid?

Answer 25

parts that make up the medulla

Question 26

what is the role of the cortex?

Answer 26

contains tiny blood vessels microscopic tubes -> start of nephrons. filters large molecules from the blood

Question 27

what is the role of the medulla?

Answer 27

where tubules run into. tubules eventually meet up at the tip of the pyramid. contains loop of Henle

Question 28

what is filtered in the Bowmans capsule?

Answer 28

blood

Question 29

what process occurs in the Bowmans capsule?

Answer 29

ultrafiltration

Question 30

Ultrafiltration:

Answer 30

- blood enters the glomerulus from a high pressure - the blood vessel which removes blood from the glomerulus has a smaller diameter so the pressure is maintained - the pressure forces fluid into the Bowman's capsule - glomerular filtrate - the blood in the glomerulus and Bowman's capsule are separated by 2 layers of cells (with spaces between them to make them more permeable) and the basement membrane - these act as a filter, allowing water, ions and small molecules (glucose) through but not large molecules (proteins) and blood cells

Question 31

what gets selectively reabsorbed in the kidney?

Answer 31

- glucose - amino acids - urea - sodium ions - chlorine ions - water

Question 32

why does glucose get selectively reabsorbed?

Answer 32

want all glucose back for respiration which releases energy

Question 33

why do amino acids get selectively reabsorbed?

Answer 33

want all amino acids back to make proteins via protein synthesis

Question 34

what is the loop of Henle used for

Answer 34

used to concentrate the urine

Question 35

reabsorption in the loop of Henle:

Answer 35

- water is reabsorbed by osmosis in the descending limb - sodium and chloride ions are actively transported out of the ascending limb to create a lower water potential in the tissue fluid so water moves out by osmosis in the descending limb - ascending limb is impermeable to water

Question 36

why do animals that live in the desert have extremely long loop of Henle's?

Answer 36

to concentrate their urine and lose as little water as possible

Question 37

what is the distal convoluted tube used for?

Answer 37

to mop up any remaining reabsorption

Question 38

what is absorbed in the distal convoluted tube?

Answer 38

- more sodium and chloride ions reabsorbed - more water reabsorbed - ammonium ions secreted into the filtrate

Question 39

what happens in the proximal convoluted tube

Answer 39

reabsorption of glucose, amino acids, sodium and chloride ions, urea

Question 40

what happens in the collecting duct

Answer 40

selective reabsorption of water happens before the urine is collected in the pelvis and sent to the ureter

Question 41

what is the amount of water reabsorbed in the collecting duct dependant on?

Answer 41

ADH (anti-diuretic hormone) which controls the water level of the blood

Question 42

what happens if ADH is not present?

Answer 42

channels not open -> water not reabsorbed -> urine concentration decreases -> volume urine increases

Question 43

what happens if ADH is present?

Answer 43

open channels in collecting duct -> allows more water to be reabsorbed -> urine concentration increases -> volume urine decreases

Question 44

is there more or less ADH if more water is drank?

Answer 44

the more water drank, the less ADH

Question 45

how does the body know to produce more ADH?

Answer 45

water potential in the blood plasma is detected by hypothalamus, which sends a message to the pituitary gland to produce more or less ADH

Question 46

what does kidney failure mean?

Answer 46

the water and ion balance cannot be regulated, and the levels of toxic urea build up in the body

Question 47

what is one method of treatment of kidney failure?

Answer 47

kidney dialysis

Question 48

what does urine contain

Answer 48

urea, water and ions