Homeostasis

Question 1

Define thirst.

Answer 1

The motivation to seek and ingest water; osmotic and hypovolemic.

Question 2

Define orexigenic and give examples of orexigenic hormones.

Answer 2

Increase food intake. Neuropeptide Y and AGRP.

Question 3

Define anorexigenic and give examples of anorexigenic hormones.

Answer 3

Decrease food intake. Pro-opiomelanocortin (POMC).

Question 4

Define programmed rheostasis.

Answer 4

Physiological changes that are obligatory at certain phases of life cycle (e.g. body weight cycles in hibernators, migration, ageing).

Question 5

Define reactive rheostasis.

Answer 5

Alterations in regulated physiology that occur in direct reaction to unpredictable events (e.g. fever, infertility in obesity).

Question 6

What is Krogh’s Principle?

Answer 6

For such a large number of problems there will be some animal of choice, or a few such animals, on which it can be most conveniently studied.

Question 7

What are the levels of analyses that Krogh’s Principle applies to?

Answer 7

• Chemical
• Cellular
• Tissue
• Organ
• Body system.

Question 8

Describe the female reproductive cycle in terms of positive and negative feedback control.

Answer 8

Hormone levels are low because negative feedback control is suppressing hormone production. Then the hypothalamus switches to positive feedback raising hormone levels for a few days before returning back to negative feedback control.

Question 9

What is vasopressin?

Answer 9

Otherwise known as ADH (antidiuretic hormone). The hormone responsible for water balance.

Question 10

What do high levels of insulin and leptin indicate and why?

Answer 10

High body fat. Adipose tissues secrete insulin and leptin which go back into the brain telling the individual to stop eating.