1: Functions of Life and Homestasis

Question 1

Name the 8 Key Functions of Life

Answer 1

1. Maintain boundaries (skin)
2. Movement (locomotion + substances)
3. Responsiveness (NS + ES)
4. Digestion
   - breakdown (DS) and absorb nutrients (CVS)
5. Metabolism
6. Excretion
7. Reproduction (birth + cell division)
8. Growth

Question 2

Define metabolism

Answer 2

all chemical reactions within the body

• anabolism + catabolism
• ATP production

Question 3

What controls growth?

Answer 3

Endocrine system

• release growth hormone (GH)
• for growth to occur, constructive activities occur faster than destructive
• building > breakdown

Question 4

Name the 5 survival needs

Answer 4

1. Nutrients
2. Oxygen
   - aerobic organisms (O2 req for rxns)
3. Water (60-80%)
   - medium for metabolic rxn
4. Stable body temp (37)
5. Atmospheric pressure
   - maintain gas exchange

Question 5

What is homeostasis?

Answer 5

Body’s ability to maintain stable internal conditions regardless of changing external enviro
*Dynamic state of equilibrium

Question 6

What are the 3 homeostatic controls?

Answer 6

1. Receptor - afferent path
2. Control Centre (CNS) - efferent path
3. Effector

Question 7

What are the 2 types of feedback systems?

Answer 7

1. Negative Feedback

2. Positive Feedback

Question 8

Describe Negative Feedback System

Answer 8

Most homeostatic control mechanism
SHUTS OFF original stimulus/ reduces intensity
- stops response
ie: glucose and insulin response
- inc glu -> inc insulin (pancreas)-> gluc absorp -> dec gluc

Question 9

Describe Positive Feedback System

Answer 9

Increase original stimulus to push variable further

• encourage initial stimulus
  ie: blood clotting
• cut -> bleeding -> platelets w/ clotting a factors to site -> platelets keep coming until clot forms