Excretion

Front 1

What makes up the urinary system?

Back 1

Kidneys, Ureter, Bladder, Urethra, Sphincter muscles.

Front 2

What do the sphincter muscles do?

Back 2

Contract to close the urethra and hold back the urine. Lower - voluntarily (consciously) controlled, Upper - involuntary. They're ring like.

Front 3

What is the bladder?

Back 3

Muscular bag that stores urine.

Front 4

What is excretion?

Back 4

The ability of an organism to release toxic waste products.

Front 5

What do humans excrete?

Back 5

Carbon dioxide and urea

Front 6

What is urea?

Back 6

Nitrogenous waster from excess amino acids in the diet.

Front 7

What do plants excrete?

Back 7

Carbon dioxide and oxygen

Front 8

What are the excretory organs in humans?

Back 8

Lungs, skin, kidneys

Front 9

What do the lungs excrete?

Back 9

CO2 when exhaling, through exhaled air

Front 10

What does the skin excrete?

Back 10

Excess water and salts, through sweat.

Front 11

What do the kidneys excrete?

Back 11

Urea, through urine.

Front 12

What does the urinary system do?

Back 12

Maintains the optimum water and salt levels in our blood.

Front 13

What happens if the water and salt levels in our blood aren't what they need to be?

Back 13

The kidneys act to adjust the levels back to normal.

Front 14

What do the kidneys do?

Back 14

Remove excess water from your blood, conserve it when needed.

Filter your blood.

Remove excess mineral ions (salts) from your blood, conserve them when needed.

Remove urea from your blood.

Help maintain homeostasis.

Front 15

What is homeostasis?

Back 15

Keeping the conditions in the internal environment constant.

Front 16

What is osmoregulation?

Back 16

Keeping the water and salt content of the internal environment stable.

Front 17

What is selective reabsorption?

Back 17

The reabsorption of some substances such as water as and when needed.

Front 18

What is ultrafiltration?

Back 18

The seperation of large molecules from small molecules under pressure (in the glomerulus).

Front 19

What happens in the nephron?

Back 19

Reabsorption of substances.

Blood from the aorta flows through the glomerulus at a high pressure, which causes water, urea, salts and glucose to diffuse out of the blood, through the basement membrane (acts like filter paper) into the Bowman's capsule. This is known as glomerular filtrate.

Front 20

What does glomerular filtrate contain?

Back 20

Glucose, water, urea, mineral ions/salts, (amino acids)

Front 21

What happens in the proximal convoluted tubule?

Back 21

ALL glucose is reabsorbed by active transport. It goes back into the blood.

Front 22

What happens in the loop of Henlé?

Back 22

Some mineral ions leave the ascending limb of the loop of Henlé by active transport. They go back into the blood (needed for nerve cells).

Front 23

What is the part of the nephron after the loop of Henlé called?

Back 23

The distal convoluted tubule

Front 24

What is the last bit of the nephron called?

Back 24

The collecting duct.

Front 25

What happens in the collecting duct?

Back 25

Some water is reabsorbed by osmosis and goes back into the blood. Urine is transported to the bladder.

Front 26

What does urine contain?

Back 26

Urea, excess water, excess mineral ions.

Front 27

What is the outer layer of the kidney called? Describe it.

Back 27

The cortex, Very dark red as there are lots of capillaries

Front 28

What layer surrounds the kidneys?

Back 28

The capsule

Front 29

What is the middle layer of the kidney called? Describe it.

Back 29

The medulla, contains the loops of Henlé from the nephrons.

Front 30

What are the 'bumps' in the medulla called? Describe them.

Back 30

Pyramids, a collection of tubules, collecting ducts and blood vessels.

Front 31

What is the centre of the kidney called? Describe it.

Back 31

Pelvis, the central chamber where the urine arrives from the collecting ducts.

Front 32

What tube comes off the pelvis? What does it do?

Back 32

The ureter, carries urine down to the bladder.

Front 33

What brings blood to the kidneys?

Back 33

The renal artery

Front 34

What carries filtered blood away from the kidneys?

Back 34

The renal vein.

Front 35

How do you work out the volume of urine?

Back 35

Volume of water taken in - volume of water lost by sweating and respiration.

Front 36

What condition may you have if you have protein in your urine?

Back 36

Kidney failure

Front 37

What condition may you have if you have glucose in your urine?

Back 37

Diabetes

Front 38

What condition may you have if you have bile salts in your urine?

Back 38

Jaundice (liver condition)

Front 39

Why might protein be in the urine of someone with kidney failure?

Back 39

The kidney is no longer filtering the blood. There is a problem with the basement membrane as it is letting large molecules into the Bowman's capsule. Kidney failure can also mean blood in the urine.

Front 40

Why might glucose be in the urine of someone with diabetes?

Back 40

They have a high concentration of glucose in their blood so have lots of glomerular filtrate. Only so much can be reabsorbed in the proximal convoluted tubule so lots stays in the urine.

Front 41

Why might bile salts be in the urine of someone with liver problems?

Back 41

The liver makes bile and should secrete it into the gall bladder. If bile is found in urine, it means it was in the blood and so the liver isn't functioning as it should.

Front 42

What is the function of the Bowman's capsule?

Back 42

It is the first part of the nephron where filtrate is collected.

Front 43

What is the function of the efferent arteriole?

Back 43

Removes blood from the nephron (minus filtered components).

Front 44

What is the function of the collecting duct?

Back 44

Feeds into ureter and is where water is selectively reabsorbed.

Front 45

What is the function of the afferent arteriole?

Back 45

Brings blood to the nephron to be filtered.

Front 46

What is the function of the proximal convoluted tubule?

Back 46

Where selective reabsorption of glucose occurs.

Front 47

What is the function of the glomerulus?

Back 47

Capillary tuft where filtration occurs.

Front 48

What is the function of the ascending loop of Henlé?

Back 48

Where salts are selectively reabsorbed.

Front 49

What is the anti-diuretic hormone (ADH)?

Back 49

Released by the pituitary gland. It causes the nephron to be more permeable to water i.e. more water is reabsorbed. This results in less water being in the urine so it is described as being more concentrated.

Front 50

What is negative feedback?

Back 50

A mechanism by which water levels are controlled i.e. when the level is not ideal (negative), the body responds to correct it back to the ideal (positive).

Front 51

What happens when you are dehydrated?

Back 51

Pituitary gland secretes more ADH, the collecting duct becomes more permeable to water, more water is reabsorped (out of urine), water level in blood increases, urine becomes more concentrated (volume reduces).

Front 52

What happens when you are over-hydrated?

Back 52

Pituitary gland secretes less ADH, the collecting duct becomes less permeable to water, less water is reabsorped, water level in blood decreases, urine becomes less concentrated (volume increases) ie. more dilute.

Front 53

What are diuretics?

Back 53

Substances which affect our ability to regulate our water levels (osmoregulation).

Front 54

What do diuretics do?

Back 54

They inhibit the secretion of ADH from the pituitary gland so urine volume increases, leaving the water level in blood too low. They dehydrate us.