Chapter 3: Homeostasis Lecture PDF

CHAPTER III HOMEOSTATIS HOMEOSTASIS - Homeostasis is the body’s ability to maintain relatively stable internal conditions even the outside environment or world is constantly changing. - Homeostasis – unchanging - Home...

CHAPTER III HOMEOSTATIS HOMEOSTASIS - Homeostasis is the body’s ability to maintain relatively stable internal conditions even the outside environment or world is constantly changing. - Homeostasis – unchanging - Home – the same - Stasis – standing still - It indicates a dynamic state of equilibrium or balance. - Internal conditions change but managed to adjust within normal limits. - The organ systems are responsible in maintaining equilibrium by doing their respective functions. - Example: Circulatory System (blood-oxygen levels, normal heart activity, blood pressure & distribution of nutrients). - Communication within the body is essential for homeostasis. - Nervous and Endocrine System. - Electrical signals were sent then hormones were released in the bloodstream. 1. RECEPTOR - It is a type of sensor that monitors and responds to changes in the environment. - It is very sensitive to change. - The information flows from the receptor – control center – afferent pathway. 2. CONTROL CENTER - It determines the level or set point at which a variable is to be maintained. - It analyzes information it receives. - Determines the appropriate response or course of action. 3. EFFECTOR - Provides the means for the control center’s response (output) to the stimulus. - Information flows from the control center – effector – efferent pathway. - It will reduce the amount of change (negative feedback). – It will increase the amount of change (positive feedback) COMPONENTS OF HOMEOSTATIC CONTROL SYSTEM - All homeostatic control mechanism have at least three components: receptor, control center and effector. FEEDBACK MECHANISM - Most homeostatic control mechanism are negative feedback mechanism. - The effect of the response to stimulus: shut off the original stimulus or reduce its intensity. Negative feedback mechanisms - is a mechanism that reverse a deviation from the set point. Positive feedback mechanisms- are rare because they tend to increase the original stimulus. Example: blood clotting & childbirth HOMEOSTATIC IMBALANCE - Homeostasis is important because most disease can be regarded as a result of its disturbance. - As we age our organs becomes less efficient. - Internal condition becomes less stable. - These conditions will place us at an increasing risk for illness and produces the changes we associate with aging. - Homeostasis is important because most disease can be regarded as a result of its disturbance. - As we age our organs becomes less efficient. - Internal condition becomes less stable. FIGHT OR FLIGHT RESPONSE - The fight or flight response is the automatic physiologic reaction to an event that is perceived as stressful or frightening. - The perception of threat – activate the sympathetic nervous system – acute stress response – prepares the body for “fight or flight”. - These responses are evolutionary adaptations to increase the chances of survival. - Intense or inappropriate activation of the fight or flight response is implicated in a range of clinical conditions including most anxiety disorders. WHAT HAPPENS DURING FIGHT OR FLIGHT? - Sympathetic nervous system is activated to release hormones. - SNS stimulates the adrenal glands – release catecholamines - Adrenaline and noradrenaline - Increase in heart rate, blood pressure and breathing. - After the threat is gone (20-60 minutes) for the body to recover and return in its pre-arousal state. WE EXPERIENCE FIGHT OR FLIGHT DURING: - Imminent physical danger - Psychological threat - Preparing to give a big presentation at school or work. PHYSICAL SIGNS: FIGHT OR FLIGHT - Dilated pupils (allows more light for better vision) - Pale or flushed skin (blood rushes to the brain and head) - Clotting ability increases to prevent injury. - Rapid heart rate (to increase oxygen supply to fuel a rapid response to danger) - Trembling (tense muscles) WHY IS IT IMPORTANT TO UNDERSTAND FIGHT OR FLIGHT? - It plays a critical role on how we deal with stress and danger in the environment. - By priming your body for action, you are better prepared to perform under pressure. - The stress created by the situation can be helpful, making it more likely that you will cope up effectively with threat.