Homeostasis Homeostasis Stable internal environment Involves 1 Receptor

Homeostasis

Homeostasis �Stable internal environment �Involves 1. Receptor – senses stimulus 2. Control Center – receives and processes info 3. Effector – responds to stimulus 4. Pathways 1. 2. Afferent (receptor to control center) Efferent (control center to effector)

Homeostasis as Room Temp Thermometer (receptor) notices higher room temp (stimulus) 2. Thermostat (control center) receives and processes info 3. Air conditioner (effector) turns on 1.

Homeostatic Feedback �Negative Feedback: a variation outside normal limits triggers an automatic response that corrects the situation �ie: body temperature, hormone regulation, blood pressure �Positive Feedback: the initial stimulus produces a response that reinforces that stimulus �ie: clotting, birth contractions, lactation

Negative Feedback

Negative Feedback – Temp. Rises

Negative Feedback – Temp. Lowers

Negative Feedback

Positive Feedback

Review Feedback with Whiteboards �Define feedback �Define negative feedback �Define positive feedback �Compare and contrast negative and positive feedback �Which type of feedback is more common �List examples of negative feedback �List examples of positive feedback �Draw an example of feedback regarding temperature

Homework �Chapter 1 Coloring Workbook �Number 10, 24 and 25 from �An Introduction to Anatomy and Physiology – Chapter 1 �Objectives 5 -6