BIOLOGY KIDNEY

Ultrafiltration

Allows small molecules to pass through e.g glucose and urea

Larger molecules e.g proteins remain in bloodsteam

What happens in selective reabsorption?

Mitochondria release ATP

Against concentration gradient

Selective reabsorption

Sodium ions and glucose are reabsorbed via active transport at a the proximal convoluted tubule

Loop of Henlé

Causes more water to be reabsorbed into the blood

Long loop of Henlé = more concentrated urine

Antidiuretic hormone

Hormone which controls the volume of urine produced

Cortex

Contains many blood vessels + nephrons

Nephrons

Microscopic tubules that produce urine

Adaptations of the nephron:

Many mitochondria to provide energy for active transport

Diabetes?

Cannot control glucose levels, often high

Not all glucose can be reabsorbed into blood

Glucose end ups in urine

Osmoregulation

The process by which organisms regulate the balance of water and salt in their bodies to maintain proper fluid balance and prevent dehydration or overhydration.

Excretion

The removal of metabolic waste from the body

If the body is dehydrated

More ADH is released

Collecting duct becomes more permeable to water

Water leaves into the bloodstream

Lower volume of concentrated urine

Filtrate

Urea

Glucose

Water

Salts

ADH

Controls water excreted

Travels in the plasma

Alcohol

• less ADH

• More urine

• Dehydrated

• Hangover

Ecstasy

• more ADH

• Less urine

• Thirsty

• Lungs drown

Dandelions

• less ADH

• More urine