"The organization of complex animals includes organ systems, such as nervous, digestive, respiratory, and circulatory systems. In turn the organ systems consist of organs including brain, stomach, lungs, and heart. Organs are composed of tissues, and each tissue has like cells that perform specific duties within the organism. Organs and organ systems function best if the internal environment stays within normal limits. Working in harmony and under the coordination of the nervous and endocrine systems, healthy organisms are capable of maintaining homeostasis, a dynamic equilibrium of the internal environment.

"Structure suits function means that the function of an organ is reflected in its structure. For example, the function of the heart is to pump blood, and therefore it contains chambers for holding blood and has thick, muscular walls for pumping blood. Homeostasis refers to the relative constancy of the internal environment. In complex animals, the internal environment is blood and tissue fluid."

1. Describe human histology including a survey of basic tissue types, their structure, and function.
2. Apply general concepts to selected topics in human biology.

To master the competencies, you should seek to understand how:

1. Animals have cells-tissues-organs-organ systems.
2. Four types of tissues are common in the animal body and carry out distinct functions.
3. The structure of tissues suits their function.
4. Organs, composed of tissues, work together in organ systems.
5. All organ systems contribute to homeostasis in animals.
6. Homeostasis is the dynamic equilibrium of the internal environment.
7. The heart, arteries, capillaries, and veins operate to transport blood which exchanges substances with cells.