Homeostasis

Question 1

adrenaline and how it affects blood glucose concentration (5)

Answer 1

Hormone that increases blood glucose concentration
1. Secreted from adrenal glands when blood glucose concentration is low (exercising / stressed)
2. Binds to receptors in the cell membrane of liver cells, activates glycogenolysis (via a second messenger), inhibits glycogenesis
3. Activates glucagon secretion, inhibits insulin secretion to increase glucose concentration
4. Gets body ready for action by making more glucose available for muscles to respire

Question 2

how does antidiuretic hormone (ADH) increase blood water potential

Answer 2

1. Water content of blood drops so water potential drops
2. Detected by osmoreceptors in the hypothalamus, so the posterior pituitary gland is stimulated to release more ADH
3. More ADH means the distal convoluted tubule + collecting duct become more permeable, so more water is reabsorbed into the blood
4. A small amount of highly concentrated urine is produced and less water is lost

Question 3

how does antidiuretic hormone (ADH) decrease blood water potential

Answer 3

1. Water content of blood rises so water potential rises
2. Detected by osmoreceptors in the hypothalamus, so the posterior pituitary gland is stimulated to release less ADH
3. Less ADH means the distal convoluted tubule + collecting duct become less permeable, so less water is reabsorbed into the blood
4. A large amount of dilute urine is produced and more water is lost

Question 4

Type I diabetes

Answer 4

immune system attacks beta cells in the islets of Langerhans so they cannot produce insulin - genetic + develops during childhood
after eating: blood glucose levels remain high (hyperglycaemia) + can result in death if untreated
kidneys cannot reabsorb all glucose so some is in urine

treated with insulin therapy - injections/pump - needs to be controlled to avoid hypoglycaemia
control simple carbohydrate intake

Question 5

Type II diabetes

Answer 5

beta cells do not produce enough insulin or cells do not respond to insulin because receptors do not work properly - acquired later in life, obesity, lack of exercise, poor diet, age, family history

treated with healthy diet, regular exercise, losing weight