Physiological Homeostasis

Question 1

Define homeostasis.

Answer 1

Dynamic maintenance of physiological variables within a predictable range.

Question 2

List some physiological variables and their importance.

Answer 2

Blood glucose level - Survival of cells
Blood CO2/O2 content - Survival of cells
Water intake/excretion
Ion content
Temperature - for functioning of enzymes
Metabolic rate - functioning of organs
GI secretion - fullfill dietary requirements
Steroid hormone levels - Enable reproductive capability

Question 3

What is negative feedback?

Answer 3

Response occurs when variable moves away from set point. Response moves variable back to set point.

Question 4

What is feed forward?

Answer 4

Anticipated response to a change in a variable. Acts as if the change has already occurred.

Question 5

What is positive feedback?

Answer 5

Response to change in a variable pushes the variable further from the set point. E.g. labour contractions.

Question 6

What is an integrating centre and what is its function?

Answer 6

Integrating centre is where signals from the sensor are compared to the set point to ellicit a response. E.g. hypothalamus, pons, medulla

Question 7

What is the role of the endocrine system in homeostasis?

Answer 7

Endocrine system secretes hormones into the blood stream which act of target tissue through specific receptors.
e.g. insulin secretion when plasma glucose concentration increase.