The Human Organism

Anatomy and Physiology 1

The Human Organism

Chapter 1

Many branches of science will help in the understanding of the human body. Our focus this semester will be in the study of ANATOMY and PHYSIOLOGY.

ANATOMY : The study of structure

PHYSIOLOGY: The study of function.

It is possible to study these disciplines separately, but they really are inseparable from each other. The function of a structure depends upon its anatomy.

Ex. The area in the lungs that allows for gas exchange to occur (physiology) will have very thin walls( anatomy).

LEVELS OF ORGANIZATION

The human body has several different levels of organization, starting small.

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.

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.

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...