Human Biology Week 1

• How does the body get so many individual cells to work together so perfectly? You can begin to answer this question by studying the organization of the human body.

• The levels of organization in a multicellular organism include cells, tissues, organs, and organ systems.

• Tissues are groups of similar cells that perform a single function, such as connecting a muscle to a bone. An organ is a group of tissues that work together to perform a complex function, such as sight.

• An organ system is a group of organs that perform closely related functions.

• The eleven organ systems of the human body work together to maintain homeostasis.

• Cells are the basic unit of structure and function in living things.

• Tissues are groups of cells that perform a single function.

• Organs are the group of different types of tissues that work together to perform a single function.

• Organ systems are a group of organs that perform closely related functions.

4 types of tissues

Homeostasis

Homeostasis

Circulatory System

THE HEART

• The heart muscle contracts on average 72 times a minute, pumping about 70 millimeters with each contract. This means that during one year an average person’s heart pumps enough blood to fill an Olympics size swimming pool.

• Dividing the left side of the heart from the right side is the septum.

Vein vs. Artery