3.6.4.1 Principles or Homeostasis and negative feedback

Question 1

Nerves cell vs endocrine nerves communication

Answer 1

Nerve cells pass electrical impulses along their length. A nerve impulse is specific to a target cell only because it releases a chemical messenger directly onto it, producing a response that is usually
- rapid, short-lived and localised.

In contrast, mammalian hormones stimulate their target cells via the blood system. They are specific to the tertiary structure of receptors on their target cells and produce responses that are usually
- slow, long-lasting and widespread.

Question 2

The nature of homeostasis

Answer 2

The maintenance of a more or less constant internal environment in organisms

Question 3

Negative feedback definition

E.g.

Answer 3

Restoring/ Corrective mechanisms to maintain the system at a set or optimum point

Body temperature

Question 4

Positive feedback definition
E.g.

Answer 4

Amplification mechanism to reinforce the disturbance of a system

Labour contraction

Question 5

Component of typical control system and definition (in cycle)

Answer 5

Input - change occurs in the system
Receptor
Receptor - change detected in the system
coordinator - storage of operational information used for onward communication
effector - produced a change in the system
output - change made to the system
feedback loop - change to produced leads to a new input to the system