The Hierarchy of Structure in Animals

1. The Hierarchy of Structure in Animals

2. Learning Goals • I know the structure and levels of the hierarchy of organization in the animal body. • I understand the importance of the hierarchy and how each level contributes to the overall function of the organism. • I know the four main types of tissues.

3. How is Your Body Organized? • Hierarchy – An organizational structure with the simplest unit on the bottom and the most complex unit at the top. • Let’s look at one example of a hierarchical structure

4. Levels of Organization in the Body Organism Organ Systems Organs Tissues Cells

6. Importance of the Hierarchy of Organization The functioning of the entire organism relies on the hierarchy of organization. • The circulatory system needs to deliver oxygen and nutrients throughout the body and eliminate waste • This requires the heart to pump blood throughout the arteries, veins and capillaries of the body. • The heart needs muscle tissue to be able to be able to contract and nerve tissue to keep a regular beat. • Muscle tissue is made up of muscle cells and nervous tissue is made up of nerve cells.

7. Organ Systems The organ systems have three main purposes: • Obtain oxygen and other nutrients (food) and eliminate waste. • Sense and respond to their environment • Grow, repair damage and reproduce • The organism must be able to perform these functions in order to survive. • We will learn about the different organ systems throughout this chapter.

8. The Organ Systems • Musculoskeletal System: Provides support and allows the body to move. • Nervous System: Sends messages throughout the body and regulates most functions. • Circulatory System: Transports substances like oxygen and nutrients throughout the body. • Respiratory System: Takes in oxygen from the air and eliminates carbon dioxide from the body.

9. The Organ Systems, Continued • Digestive System: Breaks down food and distributes throughout the body. • Reproductive System: Produces sperm (in males) and eggs (in females), and allows for development of a fetus in females. • Urinary System: Responsible for excreting waste and regulating water in the body.

10. Organs • Organ systems are composed of highly specialized organs that work together to perform the overall function of the system. • For example, the digestive system is made up of several organs including the mouth, esophagus, stomach and intestines. Food is pushed through organs that perform different functions and ultimately results in the digestion of our food. • Some organs play a role in more than one type of organ systems. The pancreas is involved in the digestive system and in the endocrine system (produces and releases hormones).

11. Tissues Animals are made up of four different types tissues that are found in most organ systems: • Epithelial Tissue: A thin layer of tightly packed cells that line the surfaces, organs and cavities within the body. • Connective Tissue: Supports and protects parts of the body • Muscle Tissue: Contracts to allow movement and conducts electrical impulses. • Nerve Tissue: Conducts electrical signals throughout the body.

12. Cells The smallest structural unit of an organism. Each type of tissue is composed of groups of similar specialized cells that perform a common function. • Epithelial tissue contains a variety of different forms of epithelial cells that form tight barriers (skin). • The cells of connective tissue exist in a matrix and are widely spread out. Can include white blood cells. • Muscle cells (or muscle fibres) contain proteins that allow for contraction. • Neurons in the nerve tissue transmit the electrical signals.

13. Summary • Animal’s bodies are organized in a hierarchy (cells  tissues  organs  organ systems) • Organ systems perform specific functions through their specialized organs. • Tissues are made up of groups of similar cell types that perform a common function. • There are four main types of tissues: epithelial, connective, muscle and nerve.

14. Homework • Worksheet • Chapter 3.1 page 76 #2, 3