Anatomy and the Organization of the Human Body Biology 2011

Defining Anatomy Anatomy = Body structure of an organism OR the study of the body structure of organisms In Biology, we’ll study the structures of the human body by focusing on a few main body systems. Examples: Circulatory System, Nervous System, Digestive System, Skeletal System, Muscular System (Sometimes Skeletal and Muscular systems are put together) We’ll relate structure (what it looks like) to function (what it does).

The organization of the body: From Cell to Organ System Cell – smallest unit Example: A cell in the lining of the stomach Tissue – group of cells working together to do a function Example: The cells in the lining of the stomach make up the epithelial (surface) tissue of the stomach. Organ – group of tissues working together to do a function Example: All of the different layers of tissue in the stomach make up the organ of the stomach. Organ System – group of organs working together to do a function Example: The stomach, along with the tongue, esophagus, small and large intestines make up the Digestive organ system.

4 Types of Tissue Remember: Tissue = group of cells working together for a function 1. Muscle tissue A. Internal Movement i. Veins and arteries (moving blood) ii. Stomach contractions B. External Movement i. skeletal muscles (legs, arms, fingers, etc.) 2. Epithelial tissue A. Covers surface of body i. Skin B. Covers inside of internal organs i. Heart chambers, blood vessels ii. Digestive tract iii. Glands like the salivary glands, pancreas, etc.)

Epithelial Tissue (top view)

Epithelial Tissue (side view)

Skeletal Muscle

4 Types of Tissue (continued) 3. Connective tissue A. Holds organs in place B. Holds different surfaces of the body together i. Tendons C. Pads and insulates the body 4. Nervous tissue A. Receives and sends messages to different parts of the body B. Controls heart beat

Loose Connective Tissue: Holds things together in the body

Nervous tissue (darker parts are cell bodies of neurons)

Tissues  Organs Many different types of tissue can make up one organ or organ system Examples: A. The muscular-skeletal system is made up of the muscles (muscular tissue), bones (connective tissue), tendons (connective tissue), nerves (nervous tissue). B. The Skin is made up of epithelial tissue (skin cells), nerves (nervous tissue), muscles – the ones that make your hair stand up when you get goose bumps (muscular tissue) C. The stomach is made up of connective tissue (to hold it together), epithelial tissue (on the inside surface), and muscular tissue (to contract and digestive the food).

Nervous System Basic cell type 1. Neuron – a nerve cell Main Structures 1. Brain 2. Spinal Cord 3. Peripheral Nerves Main Function 1. Coordinates body’s response to changes in internal and external environments.

The Neuron Function: Transmits information in the nervous system by signals called impulses. Main parts: 1. Dendrites -- Receives the signal, sends it to the cell body --Can have many dendrites 2. Cell body – largest part -- contains nucleus and most of cytoplasm -- control center of the neuron (does the “deciding” of where information should go). 3. Axon -- Sends the signal to the next neuron or body part -- Neurons usually have only one axon 4. Synapse -- The space between the axon and the next neurons’ dendrites

Neuron itself.xhtml

Drawing of a Neuron