Homeostasis and Disease HAP Susan Chabot Lemon Bay High School

Maintenance of Life HOMEOSTASIS Keeping a constant internal environment. Feedback Mechanism 1. Receptors gather info Special senses (external) Internal sensors (temp., blood pressure, water levels, etc) 2. Control Center decides what to do Brain and spinal cord 3. Effectors create a response Muscles and/or glands

Example of a Feedback Mechanism Body Temperature control Normal body temperature is 98.6* F or 37* C. When temperature is too hot or too cold, the body responds to bring it within a normal range.

Feedback Mechanisms Negative Feedback Reverses the original stimuli MOST normal body processes If its HIGH, it becomes LOW If its LOW, it becomes HIGH Positive Feedback Enhances the original stimuli USUALLY associated with disease or pain If its HIGH, it goes HIGHER. If its LOW, it goes LOWER

Homeostasis and Disease Disease is defined as a failure to maintain homeostatic conditions. ANY deviation from normal limits can lead to disease. When adaptation fails in one system, it can impact other systems. Homeostatic systems must adapt to: Gradual changes Sudden, rapid changes Disease may result from: Pathogens Inherited genetic mutations Loss of regulatory control (cancer) Degenerative changes Trauma, toxins, or environmental hazards Nutritional factors

Diagnosing Disease Symptom: patient’s perception of a change in body function. Difficult to measure Dependent on patient description/opinion Ex: nausea, fatigue, pain Pain: indication of tissue damage Pain classification: chart page 6 Sign: physical manifestation of disease Can be measured Can be observed by health provider Ex: lumps, color changes

Steps in Diagnosis Medical History: Summary of past medical issues Chief complaint History of present illness Review of all body systems Physical Exam Inspection: sight Palpation: touch Percussion: tapping Auscultation: listen Diagnostic Procedures MRI, CT, radiography, EKG, EEG Laboratory testing on fluids and tissues

Purpose of Diagnosis S: Subjective O: Objective A: Assessment P: Plan