Homeostasis A state of balance in the body Whoa. Maintenance of a stable internal environment = a...
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Transcript of Homeostasis A state of balance in the body Whoa. Maintenance of a stable internal environment = a...
Homeostasis
A state of A state of balance balance
in the bodyin the body WhoaWhoa
Homeostasis
Maintenance of a stable internal environment = a dynamic state of equilibrium
Homeostasis must be maintained for normal body functioning and to sustain life
Homeostatic imbalance – a disturbance in homeostasis resulting in disease
Overview of Homeostasis
Maintaining Homeostasis The body communicates through neural
and hormonal control systems The primary systems responsible for
maintaining homeostasis are the nervous and endocrine systems.
Components of Feedback Mechanisms
Variable-factor or event being regulated.
Set point-ideal normal value 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
Human Example of Negative Feedback Human example: shivering in response
to cooling of body during cold weather or sweating when their core temperature gets too hot.
Homeostasis allows an organism to remain in balance with its environment.
If homeostasis is not maintained, it can harm or kill the organism.
Feedback Mechanisms
Positive feedback Increases the original stimulus to
push the variable farther In the body this only occurs in blood
clotting and birth of a baby
High-Wire Artist Model
With your elbow partner,With your elbow partner,identify the following:identify the following:
VariableVariable SetpointSetpoint ReceptorsReceptors Control CenterControl Center EffectorsEffectors
WhoaWhoa
High-wire Artist Model
Variable: position of bodySetpoint: directly over the wireReceptors (Sensors): nerve
receptors (eyes, inner ears, muscle stretch receptors, etc.)
Control Center: brainEffectors: skeletal muscles
High-wire artist uses negative feedback to maintain relatively constant position on wire.