L1.4: Life Functions

• Essential life functions

  • Maintaining boundaries
  • Movement
  • Responsiveness
  • Digestion
  • Metabolism
  • Excretion
  • Reproduction
  • Growth
• • Separate the inside from the outside
  • Integumentary


  Maintaining boundaries
• • Locomotion
  • movement of substances
  • Muscular
  • Skeletal
  • Cardiovascular
  • Digestive
  • Urinary


  Movement
• • Irritability; the ability to sense changes and react
  • Nervous

  Responsiveness/Irritability
• • Breakdown and absorption of nutrients
  • Digestive


  Digestion
• • Breaks down complex molecules into smaller ones
  • Builds larger molecules from smaller ones
  • Produces energy (ATP)
  • Regulated by hormones
  • Digestive
  • Respiratory
  • Cardiovascular


  Metabolism
• • Eliminates excreta from metabolic reactions through urine, feces, or sweat
  • Digestive
  • Urinary


  Excretion
• • Occurs on cellular level or organismal level
  • On cellular level—new cells are used for growth and repair
  • On organismal level—the reproductive system handles the task

  Reproduction
• • Hormones play a major role in the increase of cell or body size through increasing the number of cell
  • Endocrine


  Growth
• Survival needs

  • Nutrients
  • Oxygen
  • Water
  • Normal body temperature
  • Atmospheric pressure
• • Chemicals used for energy and cell building.
  • Include carbohydrates, proteins, lipids, vitamins, and minerals.


  nutrients
• • Required for chemical reactions – Final electron acceptor in the electron transport chain (ETC) which is very very important in aerobic respiration.
  • Made available by the cooperation of the respiratory and cardiovascular systems.
  • Without it, human cells will die after a few minutes

  Oxygen
• • 60 to 80 percent of body weight.
  • Most abundant chemical in the human body.
  • Provides fluid base for body secretions and excretions.


  Water
• • 37 C (98.6 F).
  • Below this temperature (vasoconstriction), chemical reactions slow and stop.
  • Above this temperature (vasodilation), chemical reactions proceed too rapidly.


  Normal body temperature
• • Must be appropriate for gas exchange
  • If the altitude is high, the gas exchange is too slow to support the cellular metabolism
  • High altitude = low air pressure = less oxygen
  • This is why planes are cabin pressurized
  • Altitude and air are inversely proportional

  Atmospheric pressure