The Human Body An Overview PDF

THE HUMAN BODY AN OVERVIEW Prepared by: Casiano, F.  OBJECTIVES Define anatomy and physiology. Explain how anatomy and physiology are related Identify the levels of structural organization. Identify and understand the function of different body systems....

THE HUMAN BODY AN OVERVIEW Prepared by: Casiano, F.  OBJECTIVES Define anatomy and physiology. Explain how anatomy and physiology are related Identify the levels of structural organization. Identify and understand the function of different body systems. List 8 functions that humans must perform to maintain life. List the 5 survival needs of the human body. Define homeostasis and explain why it is important for proper body function.  Anatomy is the study of the structure (physical form) and shape of the body and its parts and their relationships to one another. The function, or physiology, of each body part and the body as a whole is dependent on the anatomy of those parts; in other words, structure determines function. It will help you learn structures and functions so you can understand the role of individual organs and body systems and how they interact to support life. LEVELS OF STRUCTURAL ORGANIZATION The human body is structured from the simplest to the most complex levels. WHAT IS OUR BODY CAPABLE OF? ORGAN SYSTEMS OVERVIEW INTEGUMENTARY SYSTEM Forms the external body covering (skin). Protects deeper tissue from injury. Synthesizes vitamin D Location of sensory receptors and sweat and oil glands.  SKELETAL SYSTEM Protects and supports body organs. Provides a framework the muscles use to cause movement. Blood cells are formed within bones. Stores minerals. MUSCULAR SYSTEM Allows manipulation of the environment, locomotion, and facial expression. Maintains posture Produces heat  NERVOUS SYSTEM Fast-acting control system of the body. Responds to internal and external changes by activating appropriate muscles and glands. ENDOCRINE SYSTEM Glands secrete hormones that regulate processes such as growth, reproduction, and nutrient use by body cells. CARDIOVASCULAR SYSTEM Blood vessels transport blood, which carries oxygen, nutrients, hormones, carbon dioxide, wastes, etc. The heart pumps blood. LYMPHATIC SYSTEM Picks up fluid leaked from blood vessels and returns it to blood. Disposes of debris in the lymphatic stream. Houses white blood cells involved in immunity. RESPIRATORY SYSTEM Keeps blood constantly supplied with oxygen and removes carbon dioxide. The gaseous exchanges occur through the walls of the air sacs of the lungs. DIGESTIVE SYSTEM Breaks food down into absorbable nutrients that enter the blood for distribution to body cells. Indigestible foodstuffs are eliminated as feces.  URINARY SYSTEM Eliminates nitrogen- containing wastes from the body. Regulates water, electrolyte, and acid-base balance of the blood. REPRODUCTIVE SYSTEM Overall function of the reproductive system is production of offspring. Testes produce sperm and male sex hormone. Ducts and glands aid in delivery of sperm to the female reproductive tract. REPRODUCTIVE SYSTEM Ovaries produce eggs and female sex hormones. Remaining structures serve as sites for fertilization and development of the fetus. Mammary glands of female breasts produce milk to nourish the newborn. NECESSARY LIFE FUNCTIONS 1. MAINTAINING BOUNDARIES Making the “inside” distinct from the “outside”. Keeps the body protected from constant threat of the external environment. 2. MOVEMENT Includes all the activities promoted by the muscular system. Includes skeletal muscle movement (e.g. running, manipulation of fingers) Also occurs when substances such as blood, food, and urine are propelled through the internal organs. 3. RESPONSIVENESS Also "irritability" Ability to sense changes (stimuli) in the environment and then to react to them. Although all body cells are responsive to some extent, nerve cells are the most irritable. 4. DIGESTION The process of breaking down ingested food into simple molecules that can then be absorbed into the blood. The nutrient-rich blood is then distributed to all body cells that will utilize the molecules for energy. 5. METABOLISM A broad term that refers to all chemical reactions that occur within the body and all of its cells. Includes breaking down complex substances into simpler molecules, making larger structures from smaller ones. 6. EXCRETION The process of removing excreta or wastes from the body. The digestive system rids the body of indigestible food residues in feces, the urinary system disposes of nitrogen-containing wastes in urine, and the skin disposes of waste products as components of sweat. 7. REPRODUCTION The production of offspring, can occur on the cellular or organismal level. In cellular level - original cell divides, producing two identical daughter cells. 8. GROWTH Can be an increase in cell size or an increase in body size that is usually accomplished by an increase in the number of cells. Cell-formation > cell death  Growth Maintaining boundaries Reproduction Movement NECESSARY LIFE FUNCTIONS Excretion Responsiveness Metabolism Digestion  Examples of interrelationships among organ systems that illustrate life functions: REVIEW QUESTIONS: What structures / organ system are responsible for maintaining boundaries? This necessary life function involves propelling digested food along your intestines. Can digestion occur in the mouth? How? Give at least 3 excretion processes we undergo. A developmental process we undergo over time. SURVIVAL NEEDS 1. NUTRIENTS Contain the chemicals used for energy and cell building. e.g. carbohydrates, proteins, fats, minerals, and vitamins. 2. OXYGEN The chemical reactions that release energy from foods require oxygen. Cells can only survive a few minutes without it. 3. WATER Accounts 60-80% of the body weight. Provides fluid base for body secretions and excretions. 4. NORMAL BODY TEMPERATURE If 37°C, metabolic reactions become rapid and proteins start to break down. 5. ATMOSPHERIC PRESSURE Refers to the force exerted on the surface of the body by the weight of air. Breathing and gas exchange depend on AP. At high altitude, where air is thin and AP is low, gas exchange can be too slow. HOMEOSTASIS HOMEOSTASIS Maintenance of relatively stable internal conditions. A dynamic state of equilibrium, or balance. HOMEOSTASIS Main controlling systems: Nervous system Endocrine system Homeostatic imbalance A disturbance in homeostasis results in disease. HOMEOSTASIS All homeostatic control mechanisms have at least three components: RECEPTOR CONTROL CENTER EFFECTOR Responds to Determines set Provides a means changes in the point, analyzes for response to environment information, and the stimulus. (stimuli)and sends determines information to appropriate control center. response. FEEDBACK MECHANISMS Feedback mechanisms are processes that the body uses to maintain homeostasis. There are two types: 1. NEGATIVE FEEDBACK Includes most homeostatic control mechanisms. Shuts off the original stimulus or reduces its intensity. e.g. body temperature regulation and control of blood glucose. FEEDBACK MECHANISMS 1. POSITIVE FEEDBACK Rare in the human body Increases the original stimulus to push the variable farther. In the body, positive feedback occurs in blood clotting and during the birth of a baby.