Homestasis

State the ways in which water is lost from the body?

Lungs, urine, skin (sweat)

Sweat contains mostly water. What else can be found in sweat?

Ions and urea

What is removed via the kidneys in the urine?

Excess water, ions and urea

What is a hypertonic solution?

More concentrated solution than it the cellls eg concerntrated sugar solution

What is an isotonic solution?

Same concentration as the solution in the cell

What is a hypotonic solution?

More dilute than the solution in the cells. E.g. water or dilute sugar solution

What happens to animal cells when they are put in water?

Water enters the cell by osmosis and as the volume increases this puts pressure on the cell membrane and it bursts. This is called lysis.

What happens to animal cells when they are put in a concentrated sugar solution?

Water leaves the cell by osmosis and the cells shrink and the membrane wrinkles. This is called cremation

HT: What happens to excess proteins in the diet?

They are transported to the liver and converted into urea

HT: What does deaminated mean?

An amino group is removed from an amino acid

HT: What is ammonia converted to in the liver?

Urea

Name the structures in the kidneys where the blood is filtered

Kidney tubules (nephrons)

What are the 3 steps in the blood filtering process

Filteration, selective re absorption, excretion

Describe what happens in each of the 3 steps of the blood filtering process

Filteration of glucose urea ions (salts) and water from the blood. Selective re absorption of all glucose, some I ones (salts) and some water into the blood. Excretion of all urea, excess ions (salts) and excess water into the ruin

HT: where in the body are the water levels in the blood monitored

Pituitary gland in the brain

HT: name the hormone that controls the water levels in the blood

Ain’t-diuretic hormone (ADH)

What effect does increased levels of this hormone have on the kidneys?

Kidney tubules to become more permeable to water. Increased levels of ADH cause the kidneys to re absorb more water.

Describe what happens in the body when the water content of the blood is too low?

Describe what happens in the body when the water content of the blood is too high