necessary life functions

necessary life functions (def, why)

- 8 fns that must be maintained to support life
- whole science of physiology is based on how life is maintained
- internal environment from cells to the organism must be kept separate from the external environment�conditions for life are tightly balanced

necessary life functions (list)

1. maintaining boundaries between internal and external environments
2. movement 3. responsiveness: the ability to sense and respond to stimuli
4. digestion
5. metabolism: all chemical reactions that occur in body cells
6. excretion: the removal of wastes

maintaining boundaries between internal and external environments

- necessary life functions
- plasma membranes
- skin

movement

- necessary life functions
-(contractility)
- of body parts (skeletal muscle)
- of substances (cardiac and smooth muscle)

irritability

responsiveness

responsiveness

- necessary life functions
- irritability
- cell, organ, organism ability to sense and respond to stimuli
- withdrawal reflex
- control of breathing rate

digestion

- necessary life functions
- ATP must be made to stay alive: requires the uptake, breakdown, absorption of nutrients in food or molecules.
- breakdown of ingested foodstuffs
- absorption of simple molecules into blood

metabolism

- necessary life functions
- all chemical pathways n biochemical rxns that occur in body cells
- catabolism and anabolism

catabolism

- necessary life functions/ metabolism
- breaking down of larger substances eg.food particles into molecules small enuf to be used by the cells

anabolism

- necessary life functions/ metabolism
- uses small substances to build larger, more complex structures

excretion

- necessary life functions
- the removal of wastes from metabolism and digestion
- urea, carbon dioxide, feces

reproduction

- necessary life functions
- cellular division for growth or repair
- production of offspring

cellular division

- necessary life functions/ reproduction
- need for growth of newly formed cells, growth of the body from birth to adulthood
- wound repair during which cells must divide to fill in the and replace the wounded area

growth

- necessary life functions
- increase in size of a body part or of organism
- increasing the number of cells
- increase in size rather than number eg.muscle in response to weight lifting

contractility

movement