(3) Homeostatic Mechanisms.Anatomy and physiology

Homeostasis system of Anatomy and physiology

1. BS Nursing (1st Samester) SESSION: 2023-2027 Topic:Hemeostasis LECTURER: Dr. Zulifqar Baloch

2. Homeostatic Mechanisms and Cellular Communication

3. Homeostasis The term was introduced in 1930 by Harvard Physiologist Walter B Cannon. Greek words for "same" and " steady (fixed)” Homeo = Same Stasis = Standing

4. Any process that living things use to actively maintain fairly stable conditions necessary for survival. State of steady internal, physical, and chemical conditions maintained by living systems.  The ability or tendency to adjust to achieve a stable internal environment.

5. Examples: Body Temperature Regulation Blood Pressure Regulation Blood Sugar Regulation Fluid Balance Hormone Balance pH  of  extracellular fluid T he concentrations of  sodium ,  potassium , and  calcium   ions Being kept within certain pre-set limits (homeostatic range)

6. R egulated above all variables despite changes in the… Environment Diet Level of activity Each of these variables is controlled by homeostatic mechanisms, which together maintain life

7. Basis of Physiology is Homeostatis : Why? Because it explains ….. Why various physiological functions are to be maintained within a normal range If any function deviates from this range how it is brought back to normal So the concept of Homeostatis forms the basis for clinical diagnostic procedures

8. Homeostatic Regulation Body recognizes the deviation of any physiological activity from the normal limits. Adjustment of physiological systems within the body is called homeostatic regulation.

9. Components of   Homeostatic System: Homeostatic system in the body acts through self- regulating devices, which operate in a cyclic manner:   Detectors or Sensors or Receptors …… Sense deviation Integration/control center ……. Alert, send information to the concerned effector Effectors ……. Accelerate or inhibit activity/response to restore normalcy

10. Mechanism of Homeostatic System Homeostasis is maintained through Feedback Control Systems . A feedback mechanism involves ….. A biological process A signal A mechanism that tends to initiate (or accelerate) or to inhibit (or slow down) a process

11. Types Of Feedback Mechanism There are two feedback mechanisms : Negative feedback mechanisms Positive feedback mechanisms

12. Negative Feedback Mechanisms The most common is the  negative feedback mechanism . Negative feedback mechanisms, or loops, are inhibitory in nature, meaning they oppose the change from the “set point” causing the opposite effect or reverse the direction of change.

13. Negative feedback serves to reduce an excessive response and to keep a variable within the normal range. Examples: Control body temperature Blood glucose level

14. Positive Feedback Mechanisms It is less common. In this system reacts in such a way as to increase the intensity of the change in the same direction. It has its own significance particularly during emergency conditions. Examples : Blood clotting Contraction of Uterus in Parturition (child birth)