Homeostasis

Question 1

What is homeostasis?

Answer 1

Homeostasis describes all of the processes that happen in a cell or organism to maintain optimal conditions.

This is needed to respond to changes in the internal and external environment.

Question 2

Why must humans regulate our body’s internal conditions?

Answer 2

Because humans are organisms that live in a changing environment, we must regulate our body’s internal conditions to make sure our enzymes and cells function well.

Question 3

What will happen if conditions are not optimal?

Answer 3

Our enzymes can denature (change shape). This reduces their ability to catalyse metabolic reactions.

Question 4

What conditions need to be regulated>

Answer 4

• Blood sugar levels
• Water levels
• Urea concentration (in urine)
• Carbon dioxide levels
• Internal body temperature

Question 5

What are control systems made up of?

Answer 5

• Receptors –> detect changes in the environment
• Coordination centres –> receive and process information arriving from receptor cells.
• Effectors (muscles or glands) –> carry out responses to stimuli (events or things) that help to restore optimum levels.

Question 6

What is negative feedback?

Answer 6

When our internal conditions are optimal, the body does not need to respond. If an internal condition changes and is no longer optimal, this stimulus is detected and the body works to counteract (reverse) the change and return conditions to the optimum. This process is called negative feedback and needs all of the components of the nervous system to work together.

Question 7

What is positive feedback?

Answer 7

Positive feedback is the opposite of negative feedback. It makes a small change even bigger. An example of positive feedback in the body is the release of oxytocin (hormone), which increases the number of contractions during childbirth.