The Human Body: An Orientation

1. The Human Body: An Orientation

2. Overview of Anatomy and Physiology • Anatomy – the study of the structure of body parts and their relationships to one another • How things look • Physiology – the study of the function of the body’s structural machinery • How things work

3. Overview of Anatomy and Physiology • Anatomy can be divided up in many ways, but the main ways are: • Gross or macroscopic: what can be seen by the naked eye • Microscopic: what can be seen through a microsocope • Developmental: how the structure looks as it grows

4. Gross Anatomy • Regional – all structures in one part of the body (such as the abdomen or leg) • Systemic – gross anatomy of the body studied by system • Surface – study of internal structures as they relate to the overlying skin

5. Microscopic Anatomy • Cytology – study of the cell • Histology – study of tissues

6. Developmental Anatomy • Developmental: Traces structural changes throughout life • Embryology – study of developmental changes of the body before birth

7. Specialized Branches of Anatomy • Pathological anatomy – study of structural changes caused by disease • Radiographic anatomy – study of internal structures visualized by X ray • Molecular biology – study of anatomical structures at a subcellular level

8. Branches of Anatomy

9. Physiology • Focuses on the functions of the body, often at the cellular or molecular level • Considers the operation of specific organ systems • Renal – kidney function • Neurophysiology – workings of the nervous system • Cardiovascular – operation of the heart and blood vessels

10. Physiology • Understanding physiology also requires a knowledge of physics and chemistry, which explains electrical currents, blood pressure, and the way muscle uses bone for movement

11. Principle of Complementarity • Function always reflects structure • What a structure can do depends on its specific form • You only have a hammer if the hammer head is attached to the handle. • You must know the “anatomy” of the hammer

12. Which ventricle of the heart pumps blood to the entire body? Principle of Complementarity

14. Levels of Structural Organization Atoms Molecule Organelle Cell Tissue Organ Organ System Organism

15. Levels of Structural Organization Chemical Tissue Cell System

17. Organ Systems of the Body • Integumentary system • Forms the external body covering • Composed of the skin, sweat glands, oil glands, hair, and nails • Protects deep tissues from injury and synthesizes vitamin D

18. Organ Systems of the Body • Skeletal system • Composed of bone, cartilage, and ligaments • Protects body • Supports body • Provides the framework for muscles • Site of blood cell formation • Stores minerals

19. Organ Systems of the Body • Muscular system • Composed of muscles and tendons • Allows manipulation of the environment, locomotion, and facial expression • Maintains posture • Produces heat

20. Organ Systems of the Body • Nervous system • Composed of the brain, spinal column, and nerves • Is the fast-acting control system of the body • Responds to stimuli by activating muscles and glands

21. Organ Systems of the Body • Cardiovascular system • Composed of the heart and blood vessels • The heart pumps blood • The blood vessels transport blood throughout the body

22. Organ Systems of the Body • Lymphatic system • Composed of red bone marrow, thymus, spleen, lymph nodes, and lymphatic vessels • Picks up fluid leaked from blood vessels and returns it to blood • Disposes of debris in the lymphatic stream • Houses white blood cells involved with immunity

23. Organ Systems of the Body • Respiratory system • Composed of the nasal cavity, pharynx, trachea, bronchi, and lungs • Keeps blood supplied with oxygen and removes carbon dioxide

24. Organ Systems of the Body • Digestive system • Composed of the oral cavity, esophagus, stomach, small intestine, large intestine, rectum, anus, and liver • Breaks down food into absorbable units that enter the blood • Eliminates indigestible foodstuffs as feces

25. Organ Systems of the Body • Urinary system • Composed of kidneys, ureters, urinary bladder, and urethra • Eliminates nitrogenous wastes from the body • Regulates water, electrolyte, and pH balance of the blood

26. Organ Systems of the Body • Male reproductive system • Composed of prostate gland, penis, testes, scrotum, and ductus deferens • Main function is the production of offspring • Testes produce sperm and male sex hormones • Ducts and glands deliver sperm to the female reproductive tract

27. Organ Systems of the Body • Female reproductive system • Mammary glands, ovaries, uterine tubes, uterus, and vagina • Main function is the production of offspring • Ovaries produce eggs and female sex hormones • Sites for fertilization and development of the fetus • Mammary glands produce milk to nourish the newborn

28. Organ Systems of the Body • Endocrine System • Composed of the pituitary gland, thyroid gland, pancreas, adrenal glands, gonads, distributed in other tissues. • Functions in long-term changes such as metabolism and reproduction

29. Organ Systems Interrelationships • I encourage you to appreciate the interrelationships of the organ systems. The body is quite elegant at using a variety of systems to accomplish its goals. Some of those goals may be… • Generating heat • Regulating blood pressure • Excretion • Breathing • Eating

31. Necessary Life Functions and Survival Needs Living organisms must do certain things in their environment … … these are called necessary life functions Living organisms must get certain things from the environment… …these are called survival needs.

32. Necessary Life Functions I • Maintain boundaries – the internal environment remains distinct from the external • Cellular level – accomplished by plasma membranes • Organismal level – accomplished by the skin • Movement – locomotion, propulsion (peristalsis), and contractility • Responsiveness – ability to sense changes in the environment and respond to them • Digestion – breakdown of ingested foodstuffs

33. Necessary Life Functions II • Metabolism – all the chemical reactions that occur in the body • Excretion – removal of wastes from the body • Reproduction – cellular and organismal levels • Cellular – an original cell divides and produces two identical daughter cells • Organismal – sperm and egg unite to make a whole new person • Growth – increase in size of a body part or of the organism

34. Survival Needs • Nutrients – chemical substances used for energy and cell building • Oxygen – needed for metabolic reactions • Water – provides the necessary environment for chemical reactions • Maintaining normal body temperature – necessary for chemical reactions to occur at life-sustaining rates • Atmospheric pressure – required for proper breathing and gas exchange in the lungs

36. Homeostasis • Homeostasisis the ability to maintain a relatively stable internal environment in an ever-changing outside world • Maintain body temperature • What is your body temperature if the room is 55 or 110? • Maintain glucose levels so you can feed your cells. • The internal environment of the body is in a dynamic state of equilibrium • Often breakdowns in health involve breakdowns in ability to maintain homeostasis.

37. Homeostatic Control Mechanisms • The variable produces a change in the body (temp, pH, glucose levels) • The three interdependent components of control mechanisms are: • Receptor – monitors the environments and responds to changes (stimuli) • Control center – determines the set point at which the variable is maintained • Effector – provides the means to respond to the stimulus

38. Homeostatic Control Mechanisms

39. Homeostatic Control Mechanisms Keep in mind that breakdowns in homeostasis can involve any of the three parts. Thus, breakdowns in health can involve any of the three parts.

40. Homeostatic Control Mechanisms • Receptor: Can’t sense the problem • Control Center: Can sense the problem but do not initiate a correction. • Effector: Sense and attempt to correct but the correction cannot be carried out by the effector. Keep in mind that breakdowns in homeostasis can involve any of the three parts. Thus, breakdowns in health can involve any of the three parts.

41. Negative Feedback • Homeostatic mechanisms involve sensing that something is moving out of normal range (temp is rising too high). • The body deals with this by trying to turn that movement out of range back around. So, this control is called negative feedback. • In negative feedback systems, the output shuts off the original stimulus

42. Negative Feedback

43. Positive Feedback • Another type of feedback is positive feedback. • Positive feedback is a self-amplifying cycle • i.e., change leads to an even greater change in the same direction, things build up to a climax • Normal way of producing changes during • birth • blood clotting • protein digestion • generation of nerve signals

44. Positive Feedback • In positive feedback systems, the output enhances or exaggerates the original stimulus • Example: Regulation of blood clotting

46. Anatomical Position • Anatomists need a standard position to refer to. This is called Anatomical Position. • Body erect, feet slightly apart, palms facing forward, thumbs point away from body • “Why me?”

47. Directional Terms • Superior and inferior • Anterior and posterior • Medial, lateral, and intermediate • Superficial and deep • Proximal and distal • Axial and Appendicular

48. Directional Terms Superior and inferior – toward and away from the head, respectively

49. Directional Terms Anterior and posterior – toward the front and back of the body

50. Directional Terms Medial, lateral, and intermediate – toward the midline, away from the midline, and between a more medial and lateral structure