1. Anatomy and Physiology
Chapter 1: Organization of the Body

2. Science and Society
Science involves logical inquiry based on experimentation (Figure 1-1)
Hypothesis—idea or principle to be tested in experiments
Experiment—series of tests of a hypothesis; a controlled experiment eliminates biases or outside influences
Theory—a hypothesis that has been proved by experiments to have a high degree of confidence
Law—a theory that has an unusually high level of confidence 2

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4. Science and Society
The process of science is active and changing as new experiments add new knowledge
Science is affected by culture and culture is affected by society

5. Anatomy and Physiology
Anatomy and physiology are branches of biology concerned with the form and functions of the body
Anatomy—science of the structure of an organism and the relationship of its parts
Gross anatomy—study of the body and its parts relying only on the naked eye as a tool for observation (Figure 1-2)

7. Anatomy and Physiology
Anatomy (cont.)
Microscopic anatomy—study of body parts with a microscope
Cytology—study of cells
Histology—study of tissues
Developmental anatomy—study of human growth and development
Pathological anatomy—study of diseased body structures
Systemic anatomy—study of the body by systems

8. Anatomy and Physiology
Physiology—science of the functions of organisms; subdivisions named according to:
Organism involved—human or plant physiology
Organizational level—molecular or cellular physiology
Systemic function—respiratory physiology, neurophysiology, or cardiovascular physiology

9. Language of Science and Medicine
Scientific terms are often based on Latin or Greek word parts
A terminology tool is provided in the pull- out section near the front of this textbook

10. Language of Science and Medicine
Terminologia Anatomica (TA) and Terminologia Histologica (TH)
Official lists of anatomical terms (TA, gross anatomy; TH, microscopic anatomy)
Terms listed in Latin, English, and by number
Avoids use of eponyms (terms based on a person’s name)
Physiology terms do not have an official list but follow the same principles as TA and TH

11. Characteristics of Life
A single criterion may be adequate to describe life, for example:
Autopoiesis—living organisms are self- organized and self-maintaining
Cell theory—if it is made of one or more cells, it is alive
Characteristics of life considered most important in humans are summarized in Table 1-1
Metabolism—sum total of all physical and chemical reactions occurring in the living body

12. Levels of Organization
Chemical level—basis for life
Organization of chemical structures separates living material from nonliving material
Organization of atoms, molecules, and macromolecules results in living matter—a gel called cytoplasm

14. Levels of Organization
Organelle level
Chemical structures organized to form organelles that perform individual functions
It is the functions of the organelles that allow the cell to live
Dozens of organelles have been identified, including:
Mitochondria
Golgi apparatus
Endoplasmic reticulum

15. Levels of Organization
Cellular level
Cells – smallest and most numerous units that possess and exhibit characteristics of life
Each cell has a nucleus surrounded by cytoplasm within a limiting membrane
Cells differentiate to perform unique functions

16. Levels of Organization
Tissue level
Tissue – an organization of similar cells specialized to perform a certain function
Tissue cells are surrounded by nonliving matrix
Four major tissue types
Epithelial tissue
Connective tissue
Muscle tissue
Nervous tissue

17. Levels of Organization
Organ level
Organ—organization of several different kinds of tissues to perform a special function
Organs represent discrete and functionally complex operational units
Each organ has a unique size, shape, appearance, and placement in the body

18. Levels of Organization
System level
Systems—most complex organizational units of the body
System level involves varying numbers and kinds of organs arranged to perform complex functions
Support and movement
Communication, control, and integration
Transportation and defense
Respiration, nutrition, and excretion
Reproduction and development

19. Levels of Organization
Organism level
The living human organism is greater than the sum of its parts
All of the components interact to allow the human to survive and flourish

20. Anatomical Position Reference position
Body erect with arms at sides, palms forward
Head and feet pointing forward

22. Anatomical Position
Bilateral symmetry—a term meaning that right and left sides of the body are mirror images
Bilateral symmetry confers balanced proportions
Remarkable correspondence of size and shape between body parts on opposite sides of the body
Ipsilateral structures are on the same side of the body in anatomical position
Contralateral structures are on opposite sides of the body in anatomical position

23. Body Cavities Ventral body cavity Thoracic cavity
Right and left pleural cavities
Mediastinum
Abdominopelvic cavity
Abdominal cavity
Pelvic cavity
Dorsal body cavity
Cranial cavity
Spinal cavity

25. Body Regions Axial subdivision Appendicular subdivision Head Neck
Torso, or trunk, and its subdivisions
Appendicular subdivision
Upper extremity and subdivisions
Lower extremity and subdivisions

27. Body Regions Abdominopelvic regions Right hypochondriac region
Epigastric region
Left hypochondriac region
Right lumbar region
Umbilical region
Left lumbar region
Right iliac (inguinal) region
Hypogastric region
Left iliac (inguinal) region

29. Body Regions Abdominal quadrants Right upper quadrant
Left upper quadrant
Right lower quadrant
Left lower quadrant

31. Terms Used in Describing Body Structure
Directional terms
Right superior and inferior
Anterior (ventral) and posterior (dorsal)
Medial and lateral
Proximal and distal
Superficial and deep

33. Terms Used in Describing Body Structure
Terms related to organs
Lumen (luminal)
Central and peripheral
Medullary (medulla) and cortical (cortex)
Apical (apex) and basal (base)
Many directional terms are listed inside the front cover of the book

34. Body Planes and Sections (Figures 1-9 and 1-10)
Planes are lines of orientation along which cuts or sections can be made to divide the body, or a body part, into smaller pieces
There are three major planes, which lie at right angles to each other:
Sagittal plane runs front to back so that sections through this plane divide the body (or body part) into right and left sides
If section divides the body (or part) into symmetrical right and left halves, the plane is called midsagittal median sagittal

36. Body Planes and Sections (Figures 1-9 and 1-10)
There are three major planes, which lie at right angles to each other (continued):
Frontal (coronal) plane runs lengthwise (side to side) and divides the body (or part) into anterior or posterior portions
Transverse (horizontal) plane is a “crosswise” plane and it divides the body (or part) into upper and lower parts

37. Interaction of Structure and Function
Complementarity of structure and function is an important and unifying concept in the study of anatomy and physiology
Anatomical structures often seem “designed” to perform specific functions because of their unique size, shape, form, or body location
Understanding the interaction of structure and function assists in the integration of otherwise isolated factual information

38. Homeostasis
Term homeostasis coined by American physiologist Walter B. Cannon
Homeostasis is used to describe the relatively constant states maintained by the body—internal environment around body cells remains constant
Body adjusts important variables to maintain a normal “set point” in an acceptable or normal range

40. Homeostasis Examples of homeostasis Temperature regulation
Regulation of blood carbon dioxide level
Regulation of blood glucose level

41. Homeostatic Control Mechanisms
Devices for maintaining or restoring homeostasis by self-regulation through feedback control loops
Basic components of control mechanisms
Sensor mechanism—specific sensors detect and react to any changes from normal
Integrating, or control, center—information is analyzed and integrated, and then if needed, a specific action is initiated

42. Homeostatic Control Mechanisms
Basic components of control mechanisms (cont.)
Effector mechanism—effectors directly influence controlled physiological variables
Feedback—process of information about a variable constantly flowing back from the sensor to the integrator

43. Homeostatic Control Mechanisms
Negative feedback control systems
Are inhibitory
Stabilize physiological variables
Produce an action that is opposite to the change that activated the system
Are responsible for maintaining homeostasis
Are much more common than positive feedback control systems

44. Homeostatic Control Mechanisms
Positive feedback control systems
Are stimulatory
Amplify or reinforce the change that is occurring
Tend to produce destabilizing effects and disrupt homeostasis
Bring specific body functions to swift completion

45. Homeostatic Control Mechanisms
Feed-forward control systems occur when information flows ahead to another process or feedback loop to trigger a change in anticipation of an event that will follow
Levels of control
Intracellular control
Regulation within cells
Genes or enzymes can regulate cell processes

47. Homeostatic Control Mechanisms
Levels of control (cont)
Intrinsic control (autoregulation)
Regulation within tissues or organs
May involve chemical signals
May involve other “built-in” mechanisms
Extrinsic control
Regulation from organ to organ
May involve nerve signals
May involve endocrine signals (hormones)

48. Cycle of Life: Life Span Considerations
Structure and function of body undergo changes over the early years (developmental processes) and late years (aging processes)
Infancy and old age are periods when the body functions least well
Young adulthood is the period of greatest homeostatic efficiency
Atrophy—term to describe the wasting effects of advanced age