Homeostatic Control

BIOL 2010, Anatomy and Physiology I

Homeostatic Control Mechanisms, Part I

Group Members:_______________

Part I:

Connie is a long distance runner. Her respiratory rate is based on the amount of CO2 (Carbon Dioxide) in her blood. The normal levels of CO2 are 35-45 mmHg. Chemoreceptors in major blood vessels detect blood CO2 levels and relay that information to the respiratory center in the medulla oblongata (part of the brain stem). The respiratory center controls the activity of the respiratory muscles (diaphragm and intercostals). When Connie exercises, her CO2 levels increase and her respiratory rate increases in an attempt to exhale the excess CO2.

Identify all parts of this homeostatic mechanism (variable, receptor, set point, control center, effector, response) and then diagram this mechanism using Fig 1-3 as a general guide. Note: fig. 1-3 does not properly separate effector from response, but you have to.

Variable: The variable is what is being maintained in homeostatic balance. These include pH, temperature and blood pressure

*variable: Connnies exercise

Receptor: The receptor is what detects the change in the variable

*Receptor: increase in Connies respiratory rate

Set point: The set point is the desired value

* Set-PointL 35-45mmHg

Control center: The control center receives the information from the receptors and initiates a response (by sending it to efferent pathway/effector). This maintains homeostasis.

* Control Center: Connies Brain

Effector: The efferent pathway sends output to effector from the control center and then the effector responds to the stimulus.

* The control of Connies respiratory muscles

Response: The response is the feedback to reduce the effect of the stimulus. It also returns the variable (balancing the variable).

• Connies extra Co2 is exhaled, helping her maintain her normal range and

homeostasis

BIOL 2010, Anatomy and Physiology I

Homeostatic Control Mechanisms,...