homeostasis.gif Content Summary:

This chapter gives a general overview of the study of biological function within the body. It discusses negative feedback loops, positive feedback, and a brief rundown of human body makeup beginning with atoms through systems.

Summary #1: Homeostasis controls the internal environment within the human body. Doctors can diagnose a patient's illness through monitoring functions that have a dynamic constancy. Functions that deviate from that constancy indicate changes within. Homeostasis is maintained through negative feedback loops that contain sensors, integrating centers and effectors. There are also positive feedback systems that amplify changes-such as triggering ovulation within females and uterine contractions during labor.

Summary #2: Organs are comprised of four major types of tissues-muscle, nervous, epithelial and connective and have distinct features and specialization of use.
  • Muscle tissue contracts
  • Nervous tissue coordinates body functions through nerve impulses
  • Epithelial tissue covers body surfaces, forms linings of cavities and organs, and forms secretory portions of glands
  • Connective tissue connects organs, provides support and protection for organs and the body

Summary #3: Skin is the largest organ of our bodies because of it's surface area. It is comprised of epithelial and connective tissues. It has three layers-cornified epidermis that protects against water loss and disease penetration, dermis that provides strength, stretchability and elasticity and hypodermis that provides attachment to tissues and organ. The skin is also an endocrine gland because it synthesizes and secretes Vitamin D.


Studying Physiology will help me understand how our bodies function and this will definitely benefit me as an OTA. Every time I provide services to a patient or client, I must be aware of what is going on with them physically, and need to be able to judge how their treatment session is affecting them. Also, patients receiving OT services do so because something has been altered in their body function, so having an understanding of that alteration will benefit me in giving them the correct treatment. OT deals with Pathophysiology everyday, and knowledge in all areas of Physiology will help me be a better OTA. I certainly will not remember everything but having a base of knowledge and knowing how and where to find more information regarding my patient will help me help them. Knowledge allows for understanding, and understanding allows for successful treatment.

Essential Question:
Negative Feedback is an internal regulatory system that allows homeostasis to be maintained. A negative feedback loop is made up of sensors that monitor any changes in the set points within the human body. Set points are norms for functions such as body temperature, blood pressure, and blood glucose . If a sensor detects a change in a set point, a message is sent to an integrating center, which in turn sends the message to an effector. The effector makes the change needed to bring the set point back into balance or a normal range. When the normal range is achieved, the negative feedback loop's job is finished until called on again for another set point deviation. My understanding of insulin control by negative feedback inhibition is this--the sensor detects a rise in blood glucose and sends that information to the integrating center which stimulates the effector to produce insulin. Insulin production decreases the level of blood glucose and also the need for further insulin secretion. Insulin and other molecules need to be regulated so homeostasis can be maintained. If they were not regulated, the body processes would not be kept in check per se, and their functions would run out of control, causing organs to shut down or malfunction. Negative feedback inhibition is a built in protection system for the human body.
References: Human Physiology by Stuart Ira Fox, Anatomy and Physiology by Stanley E Gunstream