1. HUMAN BODY

2. I. The Human Body A. Introduction Humans are the most complex organisms on Earth, and every cell in the human body must work together to keep functioning. There are many levels of organization: 1. Cell - basic unit of structure and function in ALL living things and usually are specialized for a particular function. 2. Tissues- group of cells that perform a single function.

3. 4 types of tissue

4. a. Epithelial covers body surfaces, lines cavities, organs, vessels. May contain glands for secretions or cells with cilia. Examples include thyroid gland, epicardium of heart, arteries & veins. Epidermissmall intestinekidney

5. b. Connective the most abundant and widespread tissue in the body. Used for support, transport, storage, and as connectors. Has a network of non- living material called a matrix. Ex. Bone, blood, cartilage.

6. c. Muscle able to generate electrical signals that create force and movement. Ex. Skeletal muscle, cardiac muscle, & smooth muscle.

7. d. Nerve specialized to generate and transmit electrical signals to transfer information. Examples include tissues of the brain and spinal cord. PNS – ganglion Blue stained Myelin sheath with red nuceli

8. 3. Organ - group of tissues working together for a particular function. 4. Organ system - Group of organs working together to perform a function.

9. B. Organ Systems All the parts of the body work together to maintain the internal conditions inside of a human. 1. Nervous system - Receives, processes, and responds to sensory information: coordinates all body functions 2. Endocrine System - regulates homeostasis with chemicals called hormones. 3. Skeletal System - protects and supports body parts. 4. Muscular System - produces movement. 5. Integumentary System- physical barrier against injury, dehydration, pathogens.

10. 6. Circulatory system - transports O 2 and CO 2, nutrients, and wastes. 7. Respiratory system - responsible for the exchange of O 2 and Co 2 8. Lymphatic System - destroys pathogens, fights infection. 9. Digestive System - breaks down food into absorbable monomers. 10. Urinary System - washes or cleans the blood; regulates blood volume. 11. Reproductive System – produces gametes; development of embryo in female

11. Organ systems work together in the body to maintain homeostasis. Homeostasis - the process by which organisms keep internal and physical conditions constant, or in internal harmony. This harmony is accomplished by negative feedback mechanisms. Negative feedback - the process in which a stimulus produces a response that opposes the original stimulus. (ex. House hold heater or AC(pg. 896) & thyroid hormones) This process is fulfilled by the endocrine and nervous systems working together. Endocrine system - may take hours to couple of days to affect the body. Nervous system - quick and rapid transmission to the body