 I WILL NOT BE TESTING YOU ON THE SPECIFIC DETAILS OF ANY SYSTEM. YOU NEED TO UNDERSTAND THE OVERALL FUNCTION OF THE SYSTEMS IN A VERY GENERAL, SUPERFICIAL SENSE. PLEASE DO NOT SPEND ANY TIME MEMORIZING THE FINE DETAILS ON ANY OF THE FOLLOWING SLIDES.

 The skeletal system includes all of the bones and joints in the body.  The skeleton acts as a scaffold by providing support and protection for the soft tissues that make up the rest of the body.  The skeletal system provides attachment points for muscles to allow movements at the joints.  The skeletal system in an adult body is made up of 206 individual bones.  The bone cells allow bones to: Grow and develop Be repaired following an injury or daily wear Be broken down to release their stored minerals  Looking at a bone in cross section, there are several distinct layered regions that make up a bone, some of which includes connective tissue and nervous tissue

 The main function of the muscular system is movement. Muscles are the only tissue in the body that has the ability to contract and therefore move the other parts of the body.  This system’s second function is the maintenance of posture and body position.  Another function is the movement of substances inside the body, such as blood or food from one part of the body to another.  The final function of muscle tissue is the generation of body heat.

 The cardiovascular system consists of the heart, blood vessels, and approximately 5 liters of blood (a liquid connective tissue).  This system is responsible for transporting oxygen, nutrients, hormones, and cellular waste products throughout the body,  There are 2 primary circulatory loops in the human body: Pulmonary circulation transports deoxygenated blood from the right side of the heart to the lungs, where the blood picks up oxygen and returns to the left side of the heart.. Systemic circulation carries highly oxygenated blood from the left side of the heart to all of the tissues of the body. Systemic circulation removes wastes from body tissues and returns deoxygenated blood to the right side of the heart.

 The system has 3 major functions Protection: White blood cells clean up cellular debris and fight pathogens that have entered the body. Platelets and red blood cells form scabs to seal wounds and prevent pathogens from entering the body and liquids from leaking out. Transportation: The blood delivers essential nutrients and oxygen and removes wastes and carbon dioxide to be processed or removed from the body. Hormones are transported throughout the body via the blood’s liquid plasma. Regulation: Blood vessels help maintain a stable body temperature by controlling the blood flow to the surface of the skin. Additionally albumins in blood plasma help to balance the osmotic concentration of the body’s cells by maintaining an isotonic environment.

 The digestive system is a group of organs working together to convert food into energy and basic nutrients to feed the entire body.  Food passes through a long tube inside the body known as the gastrointestinal tract (GI tract)  To achieve the goal of providing energy and nutrients to the body, six major functions take place in the digestive system: ingestion, secretion, mixing and movement, digestion, absorption and excretion

 The endocrine system includes all of the glands of the body and the hormones produced by those glands.  By regulating the functions of organs in the body, these glands help to maintain the body’s homeostasis.  The endocrine system is slow acting, but has very widespread, long lasting, and powerful effects.  Hormones are distributed by glands through the bloodstream to the entire body, affecting any cell with a receptor for a particular hormone.

 The nervous system consists of the brain, spinal cord, sensory organs, and all of the nerves that connect these organs with the rest of the body. Together, these organs are responsible for the control of the body and communication among its parts.  The approximately 100 billion neurons of the brain form the main control center of the body.  Nerves are bundles of axons that act as information highways to carry signals between the brain and spinal cord and the rest of the body. The wrapping of nerves with connective tissue helps to protect the axons and to increase the speed of their communication within the body.

The nervous system has 3 main functions:  Sensory. The sensory function of the nervous system involves collecting information from sensory receptors and passing them on to the central nervous system for further processing,  Integration. The process of integration is the processing of the many sensory signals. These signals are evaluated, compared, used for decision making, discarded or committed to memory as deemed appropriate.  Motor. Once the networks of interneurons in the central nervous system evaluate sensory information and decide on an action, they stimulate efferent neurons. The effector then releases a hormone or moves a part of the body to respond to the stimulus.

 The respiratory system provides oxygen to the body’s cells while removing carbon dioxide.  There are 3 major parts of the respiratory system: the airway, the lungs, and the muscles of respiration. The airway carries air between the lungs and the body’s exterior. The lungs pass oxygen into the body and carbon dioxide out of the body. The muscles of respiration, work together to act as a pump, pushing air into and out of the lungs during breathing.  The left and right lungs are slightly different in size and shape due to the heart pointing to the left side of the body. The left lung is therefore slightly smaller than the right lung and is made up of 2 lobes while the right lung has 3 lobes.  The interior of the lungs is made up of spongy tissues containing many capillaries and around 30 million tiny sacs known as alveoli. The alveoli are cup-shaped structures surrounded by capillaries. The alveoli are lined with thin simple epithelium that allows air entering the alveoli to exchange its gases with the blood passing through the capillaries.

 The lymphatic system is a system of capillaries, vessels, nodes and other organs that transport a fluid called lymph from the tissues as it returns to the bloodstream.  As blood passes through the tissues of the body, it enters thin-walled capillaries to facilitate diffusion of nutrients, gases, and wastes. To prevent the accumulation of excess fluids, small dead-end vessels called lymphatic capillaries extend into the tissues to absorb fluids and return them to circulation.  Lymph may also contain bacterial cells that are picked up from diseased tissues and the white blood cells that fight these pathogens.

 The integumentary system is an organ system consisting of the skin, hair, nails, and exocrine glands.  The skin is the largest organ in the body. The average person’s skin weighs 10 pounds and has a surface area of almost 20 square feet.  Skin forms a barrier to protect the body from chemicals, disease, UV light, and physical damage.  Hair and nails extend from the skin to reinforce the skin and protect it from environmental damage.  The exocrine glands of the integumentary system produce sweat, oil, and wax to cool, protect, and moisturize the skin’s surface.  In addition to secreting sweat to cool the body, eccrine sudoriferous glands of the skin also excrete waste products out of the body.

 The urinary system consists of the kidneys, ureters, urinary bladder, and urethra.  The kidneys filter the blood to remove wastes and produce urine. The ureters, urinary bladder, and urethra together form the urinary tract, which acts as a plumbing system to drain urine from the kidneys, store it, and then release it during urination.  Besides filtering and eliminating wastes from the body, the urinary system also maintains the balance of water, ions, pH, blood pressure, calcium and red blood cells.