Chapter 1
Organization of the Body
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Slide 1
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
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Slide 2
Scientific Method
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Slide 3
Science and Society
• Theory—a hypothesis that has been proven
by experiments to have a high degree of
confidence
• Law—a theory that has an unusually high
level of confidence
• The process of science is active and
changing as new experiments add new
knowledge
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Slide 4
Science and Society
• Science is affected by culture and culture is
affected by society
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Slide 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
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Slide 6
Anatomy and Physiology
• Gross anatomy—study of the body and its
parts using only the naked eye (Figure 1-2)
• Microscopic anatomy—study of body parts
using a microscope

Cytology—study of cells

Histology—study of tissues
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Slide 7
Anatomy and Physiology
• Developmental anatomy—study of human
growth and development
• Pathological anatomy—study of diseased
body structures
• Systemic anatomy—study of the body
by systems
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Slide 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, neurovascular, or
cardiovascular physiology
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Slide 9
Language of Science and Medicine
• Scientific terms are often based on Latin or
Greek word parts
• Terminology tool is provided in pull-out
section near the front of this textbook
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Slide 10
Language of Science and Medicine
• Terminologia anatomica

Official list of anatomical terms

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
Terminologia Anatomica
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Slide 11
Characteristics of Life
• A single criterion may be adequate to
describe life, as in following examples:

Autopoiesis—living organisms are self-organized
and self-maintaining

Cell theory—if it is made of one or more cells,
it is alive
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Slide 12
Characteristics of Life
• Characteristics of life considered most
important in humans:

Responsiveness

Absorption

Conductivity

Secretion

Growth

Excretion

Respiration

Circulation

Digestion

Reproduction
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Slide 13
Characteristics of Life
• Metabolism—sum total of all physical and
chemical reactions occurring in the living
body
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Slide 14
Levels of
Organization
within the
body
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Slide 15
Levels of Organization (Figure 1-3)
• 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
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Slide 16
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 the
following:
• Mitochondria
• Golgi apparatus
• Endoplasmic reticulum
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Slide 17
Levels of Organization
• Cellular level

Cells—smallest and most numerous units that
possess and exhibit characteristics of life

Cell—nucleus surrounded by cytoplasm within a
limiting membrane

Cells differentiate to perform unique functions
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Slide 18
Levels of Organization
• Tissue level

Tissue—an organization of similar cells specialized to
perform a certain function

Tissue cells surrounded by nonliving matrix

Four major tissue types:
• Epithelial tissue
• Connective tissue
• Muscle tissue
• Nervous tissue
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Slide 19
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
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Slide 20
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 (Table 1-1):
•
•
•
•
•
Support and movement
Communication, control, and integration
Transportation and defense
Respiration, nutrition, and excretion
Reproduction and development
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Slide 21
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
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Slide 22
Anatomical Position (Figure 1-4)
• Reference position
• Body erect with arms at sides and palms
forward
• Head and feet pointing forward
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Slide 23
Anatomical Position (Figure 1-4)
• Bilateral symmetry is a term meaning that right and
left sides of 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
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Slide 24
Body Cavities (Figure 1-5; Table 1-2)
• Ventral body cavity

Thoracic cavity
• Right and left pleural cavities
• Mediastinum

Abdominopelvic cavity
• Abdominal cavity
• Pelvic cavity
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Slide 25
Body Cavities
• Dorsal body cavity

Cranial cavity

Spinal cavity
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Slide 26
Body Regions (Figure 1-6; Table 1-3)
• Axial subdivision

Head

Neck

Torso, or trunk, and its subdivisions
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Slide 27
Body Regions
• Appendicular subdivision

Upper extremity and subdivisions

Lower extremity and subdivisions
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Slide 28
Body
Regions
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Slide 29
Body Regions
• Abdominal regions (Figure 1-7)

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
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Slide 30
Body Regions
• Abdominopelvic quadrants (Figure 1-8)

Right upper quadrant

Left upper quadrant

Right lower quadrant

Left lower quadrant
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Slide 31
Terms Used in Describing Body Structure
• Directional terms (Figure 1-9)

Superior – toward the head

Lateral – toward the side

Inferior - lower or below

Proximal – toward trunk

Anterior (ventral) - front

Distal – away from trunk

Posterior (dorsal) - back

Superficial – near surface

Medial – toward midline

Deep – farther from surface
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Slide 32
Terms Used in Describing Body Structure
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Slide 33
Terms Used in Describing Body Structure
• Terms related to organs

Lumen (luminal) – hollow area of organ

Central – near the center

Peripheral – around the boundary

Medullary (medulla) – inner region

Cortical (cortex) – outer region

Apical (apex) – narrow tip of an organ

Basal (base) – base or widest part of organ
• Many directional terms are listed inside the front
cover of the book
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Slide 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
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Slide 35
Body Planes and Sections
(Figures 1-9 and 1-10)
• 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 body (or body part) into right and left sides
• If section divides body (or part) into symmetrical right and left
halves, the plane is called midsagittal or median sagittal

Frontal (coronal) plane runs lengthwise (side to side) and
divides body (or part) into anterior and posterior portions

Transverse (horizontal) plane is a “crosswise” plane—it
divides body (or part) into upper and lower parts
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Slide 36
Body Planes and Sections
What plane is this section taken
from?
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Slide 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 integration of otherwise
isolated factual information
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Slide 38
Body Type and Disease (Figure 1-11)
• Somatotype—category of body build or physique
• Endomorph—heavy, rounded physique with
accumulation of fat

“Apple-shaped” endomorph has more accumulation of fat in
the waist than hip
• Waist-to-hip ratio >0.9 for women and >1.0 for men
• Higher risk for health problems than “pear shape”

“Pear-shaped” endomorph has more accumulation of fat in
hips than in waist
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Slide 39
Body Type and Disease (Figure 1-11)
• Mesomorph—muscular
physique
• Ectomorph—thin, often fragile
physique with little fat
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Slide 40
Homeostasis (Figure 1-14)
• Term homeostasis coined by the American
physiologist Walter B. Cannon
• Homeostasis is the term used to describe the
relatively constant states maintained by the
body—internal environment around body
cells remains constant
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Slide 41
Homeostasis (Figure 1-14)
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Slide 42
Homeostasis (Figure 1-14)
• Body adjusts important variables from a
normal “set point” in an acceptable or normal
range
• Examples of homeostasis:

Temperature regulation

Regulation of blood carbon dioxide level

Regulation of blood glucose level
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Slide 43
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

Effector mechanism—effectors directly influence controlled
physiological variables

Feedback—process of information about a variable constantly
flowing back from the sensor to the integrator
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Slide 44
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
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Slide 45
Homeostatic
Control
Mechanisms
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Slide 46
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
• Feed-forward occurs when information flows ahead
to another process or feedback loop to trigger a
change in anticipation of an event that will follow
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Slide 47
Homeostatic Control Mechanisms
Positive Feedback
Control
-stretch receptors
trigger pituitary to
secrete oxytocin (OT)
which stimulates
stronger contractions
of uterus, hence
stimulating more OT to
be released.
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Slide 48
Homeostatic Control Mechanisms
• Levels of control (Figure 1-15)

Intracellular control
• Regulation within cells
• Genes or enzymes can regulate cell processes

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)
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Slide 49
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 of time when
the body functions least well
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Slide 50
Cycle of Life:
Life Span Considerations
• Young adulthood is period of greatest
homeostatic efficiency
• Atrophy—term to describe the wasting effects
of advancing age
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Slide 51