Chapter 1

Anatomy is the study of the structure and shape of the body and its parts and their relationship to one another.

Physiology is the study of how the body and its parts work or function.

Each part of the body has a unique job to do to make the body operate as a whole. Structure determines what functions can take place.

1. Chemical level - atoms combine to form molecules.

2. Cellular level - Molecules interact together to form microscopic cells

3. Tissue level - Similar microscopic cells that have the same function form tissue

4. Organ level - two or more tissue types that perform a specific function, join together to become an organ.

5. Organ system - groups of organs work together to accomplish a common purpose.

6. Organisimal level - The highest level of structural organization that is the sum total of all structural levels

• Integumentary System - The external covering of the
• body or the skin. It waterproofs the body and prevents injury to deeper tissues. It excretes salt and urea and helps regulate body temperature.

Skeletal System - Consists of bones, cartilages, ligaments, and joints. It supports the body and provides the framework that skeletal muscles use to perform movement. It is also used as a protective covering for the skull, and a storehouse for minerals. Hematopoiesis occurs within the cavities of the skeleton.

Muscular System - Only one function - to contract or shorten to produce movement. Skeletal muscles that are attached to the bones to produce movement. They maintain posture and produce heat.

Nervous System - Consists of the brain, spinal cord, nerves and sensory receptors. Sensory receptors detect changes and send messages via nerve impulses to the central nervous system - the brain and spinal cord. The CNS then assesses the information and reacts by activating muscles or glands.

Endocrine System - . The endocrine system controls body activities through endocrine glands that produce and release hormones into the blood to target organs. These endocrine glands are the pituitary, thyroid, parathyroid, adrenal, thymus, pancreas, pineal, ovaries and testes.

Cardiovascular System - The heart and blood vessels. The heart pumps the blood through the blood vessels that carries oxygen, nutrients, hormones and other substances to and from tissue cells.

Lymphatic System - Its organs include lymphatic vessels, lymph nodes, and other lymphoid organs such as the spleen and tonsils. The lymph nodes and lymph organs help cleanse the blood and store immunity cells.

Respiratory System - Keeps the body supplied with oxygen and removes carondioxide. It consists of the nasal passages, pharynx, larynx, trachea, bronchi, and lungs.

• Digestive System - Includes the mouth, esophagus, stomach, small and large intestines, and rectum, plus the liver, salivary glands, and pancreas. The purpose of these organs is to break down food and deliver nutrients to the
• blood.

Urinary System - Produces wastes of nitrogen (urea and uric acid) that results from the breakdown of proteins and nucleic acid. This excretory system is composed of the kidneys, ureters, bladder, and urethra. It also maintains the body's water and salt balance.

Reproductive System - Primarily to produce offspring. In the male - testes, scrotum, penis, accessory glands, and duct system. In the female - ovaries, the female duct system (uterine tubes, uterus, and vagina).

The stomach exhibits the organ level of structural organization.

The chemical level.

• 1. Maintain boundaries
• 2. Move
• 3. Respond to environmental changes
• 4. Take in and digest nutrients
• 5. Carry out metabolism
• 6. Dispose of wastes
• 7. Reproduce themselves.

• 1. Nutrients
• 2. Oxygen
• 3. Water
• 4. Normal body temperature
• 5. Atmospheric pressure

Survival also depends on the ability to maintain one's boundaries, to move, to respond to stimuli, and to reproduce.

Because all the chemical reactions that occur in the body and release food energy, require oxygen.

Anatomy

Molecules

Integumentary

Homeostasis

Forward

Midsagittal

Thoracic

Epigastric

Descending colon of the large intestine

Homeostasis is the body's ability to maintain relatively stable internal conditions even though the outside world is constantly changing. Our blood levels are constantly monitored for the proper nutrients and our blood pressure is constantly monitored and adjusted to assure that all body tissues are receiving the blood they require. Without homeostasis our bodies would become diseased and die.

• 1. Stimulus - produces change in the variable
• 2. Receptor - A sensor that monitors and responds to
• changes in the environment
• 3. Input - Information sent along the AFFERNT pathway to the control center
• 4. Control Center - Determines the level at which a variable is to be maintained, analyzes the information it receives and then determines the appropriate response or course of action.
• 5. Output - Information sent along the EFFERENT pathway to the effector
• 6. Response - The feedback that determines whether the stimulus is depressed or shut off(negative feedback) or whether the entire mechanism is enhanced (positive feedback) that allows the reaction to continue at an even faster rate.

A sagittal section cuts longitudinal, dividing the body into right and left parts. If the cut is down the median plane of the body and the right and left parts are equal in size it is called the midsagittal section.

Muscular system