life functions & homeostasis. necessary life functions 1.maintain boundaries 2.movement ...
TRANSCRIPT
Life Functions & Homeostasis
Necessary Life Functions
1. Maintain boundaries
2. Movement
Locomotion
Movement of substances
3. Responsiveness
Ability to sense changes and react
4. Digestion
Break-down and absorption of nutrients
Necessary Life Functions
5. Metabolism—chemical reactions within the body
Produces energy
Makes body structures
6. Excretion
Eliminates waste from metabolic reactions
7. Reproduction
Produces future generation
8. Growth
Increases cell size and number of cells
Survival Needs
1. Nutrients
Chemicals for energy and cell building
Includes carbohydrates, proteins, lipids, vitamins, and minerals
2. Oxygen
Required for chemical reactions
Survival Needs
3. Water
60–80% of body weight
Provides for metabolic reaction
4. Stable body temperature
5. Atmospheric pressure
Must be appropriate
Interrelationships Among Body Systems
Figure 1.3
Homeostasis
Homeostasis—maintenance of a stable internal environment
A dynamic state of equilibrium
Homeostasis is necessary for normal body functioning and to sustain life
Homeostatic imbalance
A disturbance in homeostasis resulting in disease
Homeostasis - Fishbowl Model
Fishbowl Human Body Function
Water
Glass bowl
Fish
Air Pump
Filter
Heater
Feeder
Everything working together Homeostasis!
Bodily Fluids
Skin
Cells
Lungs
Kidneys
Muscles
Digestive System
Internal env’t
Barrier
Maintain life
Keep high O2 level
Remove wastes
Constant temp
High nutrients
Figure 1.4
Changedetectedby receptor
Stimulus:Produceschangein variable
Input:Informationsent alongafferentpathway to
Receptor (sensor) Effector
Variable(in homeostasis)
Response ofeffector feedsback toinfluencemagnitude ofstimulus andreturns variableto homeostasis
Controlcenter
Imbalance
Imbalance
Output:Information sentalong efferentpathway to activate
Figure 1.4, step 1a
Variable(in homeostasis)
Figure 1.4, step 1b
Stimulus:Produceschangein variable
Variable(in homeostasis)
Imbalance
Imbalance
Figure 1.4, step 2
Changedetectedby receptor
Stimulus:Produceschangein variable
Receptor (sensor)
Variable(in homeostasis)
Imbalance
Imbalance
Figure 1.4, step 3
Changedetectedby receptor
Stimulus:Produceschangein variable
Input:Informationsent alongafferentpathway to
Receptor (sensor)
Variable(in homeostasis)
Controlcenter
Imbalance
Imbalance
Figure 1.4, step 4
Changedetectedby receptor
Stimulus:Produceschangein variable
Input:Informationsent alongafferentpathway to
Receptor (sensor) Effector
Variable(in homeostasis)
Output:Information sentalong efferentpathway to activate
Controlcenter
Imbalance
Imbalance
Figure 1.4, step 5
Changedetectedby receptor
Stimulus:Produceschangein variable
Input:Informationsent alongafferentpathway to
Receptor (sensor) Effector
Variable(in homeostasis)
Response ofeffector feedsback toinfluencemagnitude ofstimulus andreturns variableto homeostasis
Output:Information sentalong efferentpathway to activate
Controlcenter
Imbalance
Imbalance
Maintaining Homeostasis
The body communicates through neural and hormonal control systems
Receptor
Responds to changes in the environment (stimuli)
Sends information to control center
Maintaining Homeostasis
Control center
Determines set point
Analyzes information
Determines appropriate response
Effector
Provides a means for response to the stimulus
Feedback Mechanisms
Negative feedback
Includes most homeostatic control mechanisms
Shuts off the original stimulus, or reduces its intensity
Works like a household thermostat
Positive feedback
Increases the original stimulus to push the variable farther
In the body this only occurs in blood clotting and during the birth of a baby
Homeostasis Video
QuickTime™ and a decompressor
are needed to see this picture.