1 The Human Body: An Orientation Part 1

2 Anatomy Ana- (apart) -tomy (to cut) The study of internal & external structures of the body and the physical relationships between body parts

3 Anatomy Gross Anatomy study of large and easily observable structures considers features visible with the unaided eye surface anatomy Microscopic anatomy study of very small structures with the use of microscope or magnifying lens considers structures that cannot be seen without magnification e.g. cells, tissues

4 Physiology Derived from physio = nature; ology = the study of The study of how living organisms perform their vital functions. It considers the physical & chemical processes responsible for the characteristics of life.

5 Relationship Between Anatomy & Physiology The parts of the body form a well-organized unit and each of these parts has a job to do to make the body operate as a whole Structure determines what functions can take place

6 Levels of Structural Organization From Atoms to Organisms Chemical level Atoms and molecules Cellular level Cells are the smallest units of all living things Cells vary according to their function Tissue level Tissues consist of group of similar cells that have a common function Epithelial, connective, muscular and neural

7 Levels of Structural Organization From Atoms to Organisms Organ level Organ is a structure composed of 2 or more tissue types that performs a specific function for the body Complex functions are possible Organ System Group of organs that operate to accomplish a common purpose Organismal level Highest level of structural organization

8

9 Organ System Overview Integumentary System forms the waterproof skin or the external body covering cushions and protects the deeper tissues from injury helps regulate body temperature excretes salts and urea in perspiration contains temperature, pressure and pain receptors synthesizes vitamin D

10 Organ System Overview Skeletal System consists of bones, cartilages, ligaments and joints supports and protects body organs provides leverage for locomotion site of hematopoiesis or blood cells formation storehouse of minerals

11 Organ System Overview Muscular System formed by skeletal muscles allows manipulation of the environment, locomotion and facial expression helps to maintain posture produces heat

12 Organ System Overview Nervous System composed of brain, spinal cord, nerves, sensory receptors the body’s fast-acting control system responds to internal and external changes by activating appropriate effectors (muscles and glands)

13 Organ System Overview Endocrine System consists of ductless glands that secrete hormones to regulate bodily processes such as growth, reproduction and metabolism includes the pituitary, thyroid, parathyroids, adrenals, thymus, pancreas, pineal, ovaries and testes not connected anatomically

14 Organ System Overview Cardiovascular System the heart and blood vessels are the primary organs carries oxygen, nutrients, hormones and other substances to and from the tissues cells where exchanges are made protection from foreign invaders

15 Organ System Overview Lymphatic System includes lymphatic vessels, lymph nodes and other lymphoid organs returns leaked fluids from blood to the blood vessels so that blood can be kept continuously circulating through the body cleanses the body and contains cells involved in immunity

16 Organ System Overview Respiratory System consists of nasal passages, pharynx, larynx, trachea, bronchi and lungs keeps blood constantly supplied with oxygen and removes carbon dioxide

17 Organ System Overview Digestive System basically a tube running through the body from the mouth – esophagus – stomach – intestines – rectum – anus also includes the liver and pancreas breaks down food and delivers the product to the blood for dispersal eliminates undigested food as feces reclaims water in the large intestine

18 Organ System Overview Urinary System / Excretory System composed of kidney, ureters, bladder and urethra eliminates nitrogenous wastes from the body regulates water, electrolytes and acid-base balance of the blood

19 Organ System Overview Reproductive System for the production of offspring Male Reproductive System Testes, scrotum, penis, accessory glands and duct system Female Reproductive System Ovary, uterine tubes, uterus and vagina

20 Necessary Life Functions Maintaining Boundaries Membranes Keep the inside distinct from the outside Skin Protects internal organs from drying out, from bacteria and from damaging effects of heat, sunlight and chemical substances

21 Necessary Life Functions Movement Propelling oneself from one place to another Manipulating the external environment Propelling blood, foodstuffs and urine through the organs

22 Necessary Life Functions Responsiveness / Irritability ability to sense changes in the environment and then to react to them Digestion process of breaking down ingested food into simpler molecules that can then be absorbed into the blood for delivery

23 Necessary Life Functions Metabolism Chemical reactions that occur within the body cells Catabolism  Breaking down complex substances into simpler building blocks Anabolism  Making larger structures from smaller ones Regulated chiefly by hormones secreted by the glands of the endocrine system

24 Necessary Life Functions Excretion process of removing wastes from the body get rid of the useless substances produced during digestion and metabolism Reproduction the production of offspring cellular or organismal level mitosis/ meiosis

25 Necessary Life Functions Growth increase in size brought about, usually, by an increase number of cells cell-constructing activities must occur at a faster rate than cell-destroying ones

26 Maintaining Life Survival Needs Nutrients Carbohydrates, Fats, Proteins, vitamins and minerals Oxygen Needs for release of energy from food Water 60-80% of body weight Blood Temperature (37 0 C or 98 0 F) Atmospheric pressure Force exerted on the surface of the body by weight of air

27 Homeostasis The body’s ability to maintain relatively stable internal conditions even though the outside world is continuously changing Indicates a dynamic state of equilibrium Imbalances will lead to development of diseases and illnessess

29 Feedback Mechanisms Negative Feedback Mechanism the net effect of the response to the stimulus is to shut off the original stimulus or reduce its intensity thermostat action of hypothalamus, heart rate, BP, etc. Positive Feedback Mechanism rare in the body causes an increase in the intensity of the original stimulus blood clotting and birth of a baby