Excretion

Question 1

What are the metabolic processes in plants?

Answer 1

Photosynthesis:
6CO2 + 6H2O—> C6H12O6 + 6O2

Respiration:
C6H12O6 + 6O2—> 6CO2 + 6H2O + Energy as ATP.

Question 2

What is excretion?

Answer 2

The removal of waste from metabolic reactions. E.g. The skin excretes water, kidneys excrete water, urea, excess minerals and other waste, the lungs excrete carbon dioxide and water.

Question 3

How are kidneys involved in osmoregulation?

Answer 3

When your body’s water level has dropped below normal levels, your body works to reduce the amount of water loss. When this happens, your hypothalamus detects this and sends a message to the pituitary gland to release ADH into your blood stream and target the kidney cells. This makes your collecting duct more permeable, so more water is reabsorbed back into the blood.

Question 4

How are kidneys involved in excretion?

Answer 4

• Dirty blood enters the kidney by the renal artery and enters a bundle of capillaries called the GLOMERULUS.
• blood entering leaves at a higher pressure as the renal vein is smaller than its artery.
• high pressure forces small substances out of the holes in the capillary walls, leaving behind large substances.
• small substances move into the bowman’s capsule and then into the first convoluted tubule where selective reabsorption takes place.
• SR is where all the glucose and other useful substances are released back into the blood by active transport.
• whatever isn’t few sorbet goes to the loop of henlé and eventually leaves the body as urine.

Question 5

What is urine and what does it contain?

Answer 5

Urine is nitrogenous waste. It contains water, urea and salts.

Question 6

Where is water reabsorbed back into our blood?

Answer 6

Collecting duct

Question 7

Where does selective reabsorption take place?

Answer 7

First convoluted tubule

Question 8

What term do we use to refer to the role of ADH?

Answer 8

Osmoregulation