Osmoregulation

Question 1

High water potential

Answer 1

•Well hydrated
•Large amount of water molecules that can move
•dilute: not much dissolved

Question 2

Low water potential

Answer 2

• not well hydrated
• smaller amount of water molecules that can move more dissolved substances
• concentrated

Question 3

What is osmoregulation?

Answer 3

The control of water and salt levels in the body

Question 4

Collecting duct

Answer 4

•passages that connect to multiple nephrons
•Amount of water reabsorbed depends on the permeability of the walls of the collecting duct due to the presence of ADH in the blood

Question 5

How is water gained?

Answer 5

From chemical reactions such as:
•food
•drink
•metabolism

Question 6

How is water lost?

Answer 6

•urine
•sweat
•water vapour in exhaled air
•feasies

Question 7

ADH characteristics

Answer 7

•ADH bind to receptors and cause a chain of enzyme controlled reactions inside the cell
• end result is to insert vesicles containing water permeable channels (aquapourins) into the cell surface membrane
• make walls more permeable to water

Question 8

Over hydration

Answer 8

1. detected by hypothalamus
2. Pituitary gland releases more of ADH which travels in the blood
3. When ADH reaches the kidney it causes less water to be reabsorbed into the blood
4. Less urine is made

Question 9

Dehydration

Answer 9

1. Detected by hypothalamus
2. Pituitary gland releases ADH which travels in the blood
3. When ADH reaches the kidneys it causes more water to be reabsorbed into the blood
4. More urine is made

Question 10

Hypertonic solution

Answer 10

If a cell is placed in hypertonic solution, water will leave the cell and the cell will shrink because:
• the red blood cell plasma has a higher water potential than the surrounding solution
• creates an osmotic gradient
• dehydrated or high levels of salt and sugar in the blood

Question 11

Hypotonic meaning

Answer 11

When a cell is placed in hypotonic environments, water will enter the cell and the cell will swell and eventually burst (lysis) this is because:
• red blood cell plasma has a lower water potential than the surrounding solution
• creates an osmotic gradient
• over hydrated

Question 12

Isotonic meaning

Answer 12

• equal amounts
•no net flow of water into or out of cell
• Cells volume will remain stable