Page 9 - ASOP ROT Study Guide

2 . 3 Tissue Level

Tissues are organized groups of similar cells performing a specific function. Cells in a tissue are
surrounded by non-living material referred to as matrix. For example, blood is a tissue consisting of
blood cells (red and white cells and platelets) in a liquid matrix (plasma). The functions of blood
are to transport substances around the body and protect the body from disease. There are four
basic types of human tissues: epithelial, muscle, nervous, and connective tissues. These four
tissue types, which are shown in Figure 2 below.

2 . 4 Organ Level

Organs are organizations of several types of tissue arranged to work together to perform a specific
function. For instance the heart consists of muscle, blood, nervous and connective tissues all
working together to pump blood round the body.

2 . 5 System Level

An organ system is a group of anatomical structures that work together to perform a specific
function or task. Although we learn about each organ system as a distinct entity, the functions of
the body's organ systems overlap considerably, and your body could not function without the
cooperation of all of its organ systems. In fact, the failure of even one organ system could lead to
severe disability or even death. The human body is composed of 11 different organ systems.
These include the following:

Integumentary Lymphatic
Muscular Respiratory
Skeletal Endocrine
Nervous Urinary/excretory
Circulatory Reproductive
Digestive