Chapter 1
ANATOMY : The study of structure
PHYSIOLOGY: The study of function.
Levels of organization
CHEMICAL LEVEL: includes Atoms ( C,O, H, N), the smallest units of matter. These 4 are essential to life. Atoms bond together to form MOLECULES.
CELLULAR LEVEL: Molecules combine to form Organelles. Organelles function together to form a CELL, the smallest unit of life. There are different types of cells with different functions. A cell consists of about 70-95% water.
TISSUE LEVEL: Similar cells join together to perform a specific function. There are 4 different classifications of tissue: epithelial tissue, connective tissue, muscle tissue, nervous tissue.
ORGAN LEVEL: 2 or more different types of tissue come together to perform a specific function. Example = the STOMACH is composed of epithelial tissue + muscle + nervous + connective tissue.
ORGAN SYSTEM LEVEL: Organs work together . ex. The stomach joins with other organs like the intestines and the liver to digest food, forming the DIGESTIVE SYSTEM.
These SYSTEMS join together to form an ORGANISM, a living individual.
Homeostasis
With all of the activities going on in the organism, there must be guidelines and limits that the body must follow in order to preserve health. The body must maintain a STABLE INTERNAL ENVIRONMENT, even when external environment is changing. The term used to describe the body‟s ability to maintain these stable conditions is HOMEOSTASIS. ( Ex. thermostat and heater and temp regulation in the hypothalamus.)
Homeostasis regulated by feedback:
Compare NEGATIVE FEEDBACK and POSITIVE FEEDBACK
Examples of negative feedback are B.P control
Mechanism of B.P. Control happens the following way.
First the Baroreceptors in the walls of the blood vessels detect a decrease in the blood pressure. Signals are sent to the control center that now starts comparing the actual B.P to the normal B.P value. Detecting a change the