Homeostasis Lecture

Question 1

What is homeostasis?

Answer 1

Maintenance of a constant environment

Question 2

Outline the body hierarchy

Answer 2

Cells → tissues → organs → organ systems → organism. All sections are linked by fluids.

Question 3

Describe the composition of the human body

Answer 3

60% is fluid - water (ions);

70% of fluid is ICF
30% of fluid is ECF.

Question 4

Define homeostasis medically

Answer 4

Physiological control of systems to maintain a relatively stable internal environment.

Question 5

What are the different types of feedback?

Answer 5

Feed-forward, closed loop and open loop

Question 6

What is feed-forward feedback?

Answer 6

Where the system anticipates change and adjusts before the problem occurs.

Question 7

What is closed loop feedback?

Answer 7

Where the output of the system feeds back and influences the controller: Positive and Negative feedback.

Question 8

What is positive feedback?

Answer 8

When the system produces more of the stimulus, a change in one direction. E.g. more oxytocin during birth → blood clotting → causes chemical release → more blood clotting

Question 9

What is negative feedback?

Answer 9

When the system adjusts to reduce the stimulus to maintain stability. E.g. when glucoreceptors detect high blood glucose concentration so the pancreas produces insulin to convert glucose to glycogen and reduce blood glucose concentration levels.

Question 10

What is open loop feedback?

Answer 10

Where the output is not influenced by the resulting conditions.