CHAPTER 1 PART 1
THE HUMAN BODY: AN ORIENTATION
Overview of Anatomy and Physiology

Anatomy
 Study
of the structure of body parts and their
relationship to one another

Subdivisions:
 Gross or macroscopic (e.g., regional, systemic, and
surface anatomy)
 Microscopic (e.g., cytology and histology)
 Developmental (e.g., embryology)
Overview of Anatomy and Physiology

Physiology
 Study
of the function of the body parts
 Subdivisions
based on organ systems
(e.g., renal or cardiovascular physiology)
 Often focuses on cellular and molecular level
 Body's
abilities depend on chemical reactions in individual
cells
1
Principle of Complementarity

Anatomy and physiology are inseparable
 Function
 What
always reflects structure
a structure can do depends on its specific
form
 Known
as the principle of complementarity of
structure and function
Complementarity of Structure and Function

Figure 1.1 Complementarity of structure and function.
Structural Organization

Human body is very organized, from the smallest chemical
level to whole organism level:






Chemical level: atoms, molecules, and organelles
Cellular level: single cell
Tissue level: groups of similar cells
Organ level: contains two or more types of tissues
Organ system level: organs that work closely together
Organismal level: all organ systems combined to make the whole
organism
2
Structural Organization
Human body is very organized, from the smallest chemical level to
whole organism level:
 Chemical


Atoms and molecules (chapter 2); and organelles (chapter 3)
Cellular

Cells (chapter 3)

Tissue

Organ

Organ System

Organismal




Groups of similar cells (chapter 4)
Contains two or more types of tissues
Organs that work closely together
All organ systems
Levels of Structural Organization (1 of 7)
Figure 1.2 Levels of structural organization.
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Levels of Structural Organization (2 of 7)
Figure 1.2 Levels of structural organization.
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3
Levels of Structural Organization (3 of 7)
Figure 1.2 Levels of structural organization.
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Levels of Structural Organization (4 of 7)
Figure 1.2 Levels of structural organization.
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Levels of Structural Organization (5 of 7)
Figure 1.2 Levels of structural organization.
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4
Levels of Structural Organization (6 of 7)
Figure 1.2 Levels of structural organization.
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Levels of Structural Organization (7 of 7)
Figure 1.2 Levels of structural organization.
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Requirements for Life
Necessary Life Functions:
 Maintaining boundaries
 Movement
 Responsiveness
 Digestion
 Metabolism
 Dispose of wastes
 Reproduction
 Growth
5
Necessary Life Functions

Maintaining boundaries between internal and
external environments
 Plasma
membranes
 Skin

Movement (contractility)
-Muscular system allows movement
 Of
 Of
body parts (skeletal muscle)
substances (cardiac and smooth muscle)
Necessary Life Functions

Responsiveness
 Ability
to sense and respond to stimuli
reflex
 Control of breathing rate
 Withdrawal

Digestion
 Breakdown
 Absorption
of ingested foodstuffs
of simple molecules into blood
Necessary Life Functions

Metabolism
 All
chemical reactions that occur in body cells
and anabolism
 Catabolism

Excretion
 Removal
 Urea,
of wastes from metabolism and digestion
carbon dioxide, feces
6
Necessary Life Functions

Reproduction
 Cellular
division for growth or repair (cell level)
of offspring (organismal level)
 Production

Growth
 Increase
in size of a body part or of organism
Interdependence of Body Cells

Humans are multicellular
 To
function, must keep individual cells alive
cells depend on organ systems to meet their survival
needs
 All


All body functions spread among different organ
systems
Organ systems cooperate to maintain life
 Note
major organs and functions of the 11 organ
systems (fig. 1.4)
Figure 1.4 Examples of interrelationships among body organ systems.
Digestive system
Takes in nutrients, breaks them
down, and eliminates unabsorbed
matter (feces)
Respiratory system
Takes in oxygen and
eliminates carbon dioxide
Food
O2
CO2
Cardiovascular system
Via the blood, distributes oxygen
and nutrients to all body cells and
delivers wastes and carbon
dioxide to disposal organs
Blood
Heart
Nutrients
Interstitial fluid
CO2
O2
Urinary system
Eliminates
nitrogenous
wastes and
excess ions
Nutrients and wastes pass
between blood and cells
via the interstitial fluid
Feces
Integumentary system
Protects the body as a whole
Urine
from the external environment
7
Figure 1.4a The body’s organ systems and their major functions.
Hair
Skin
Nails
Integumentary System
Forms the external body covering, and
protects deeper tissues from injury.
Synthesizes vitamin D, and houses
cutaneous (pain, pressure, etc.)
receptors and sweat and oil glands.
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Figure 1.4b The body’s organ systems and their major functions.
Bones
Joint
Skeletal System
Protects and supports body organs,
and provides a framework the muscles
use to cause movement. Blood cells
are formed within bones. Bones store
minerals.
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Figure 1.4c The body’s organ systems and their major functions.
Skeletal
muscles
Muscular System
Allows manipulation of the
environment, locomotion, and facial
expression. Maintains posture, and
produces heat.
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8
Figure 1.4d The body’s organ systems and their major functions.
Brain
Spinal
cord
Nerves
Nervous System
As the fast-acting control system of
the body, it responds to internal and
external changes by activating
appropriate muscles and glands.
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Figure 1.4e The body’s organ systems and their major functions.
Pineal gland
Thyroid
gland
Pituitary
gland
Thymus
Adrenal
gland
Pancreas
Testis
Ovary
Endocrine System
Glands secrete hormones that
regulate processes such as growth,
reproduction, and nutrient use
(metabolism) by body cells.
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Figure 1.4f The body’s organ systems and their major functions.
Heart
Blood
vessels
Cardiovascular System
Blood vessels transport blood,
which carries oxygen, carbon
dioxide, nutrients, wastes, etc.
The heart pumps blood.
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9
Figure 1.4g The body’s organ systems and their major functions.
Red bone
marrow
Thymus
Lymphatic
vessels
Thoracic
duct
Spleen
Lymph
nodes
Lymphatic System/Immunity
Picks up fluid leaked from blood vessels and
returns it to blood. Disposes of debris in the
lymphatic stream. Houses white blood cells
(lymphocytes) involved in immunity.
The immune response mounts the attack
against foreign substances within the body.
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Figure 1.4h The body’s organ systems and their major functions.
Nasal
cavity
Pharynx
Larynx
Trachea
Bronchus
Lung
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.
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Figure 1.4i The body’s organ systems and their major functions.
Oral cavity
Esophagus
Liver
Stomach
Small
intestine
Large
intestine
Rectum
Anus
Digestive System
Breaks down food into absorbable units
that enter the blood for distribution to
body cells. Indigestible foodstuffs are
eliminated as feces.
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10
Figure 1.4j The body’s organ systems and their major functions.
Kidney
Ureter
Urinary
bladder
Urethra
Urinary System
Eliminates nitrogenous wastes from the body.
Regulates water, electrolyte, and acid-base
balance of the blood.
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Figure 1.4k The body’s organ systems and their major functions.
Prostate
Penis
Testis
Ductus
deferens
Scrotum
Male Reproductive System
Overall function is production of offspring. Testes produce
sperm and male sex hormone, and male ducts and glands
aid in delivery of sperm to the female reproductive tract.
Ovaries produce eggs and female sex hormones. The remaining
female structures serve as sites for fertilization and development
of the fetus. Mammary glands of female breasts produce milk to
nourish the newborn.
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Figure 1.4l The body’s organ systems and their major functions.
Mammary
glands (in
breasts)
Ovary
Uterus
Vagina
Uterine
tube
Female Reproductive System
Overall function is production of offspring. Testes produce
sperm and male sex hormone, and male ducts and glands
aid in delivery of sperm to the female reproductive tract.
Ovaries produce eggs and female sex hormones. The remaining
female structures serve as sites for fertilization and development
of the fetus. Mammary glands of female breasts produce milk to
nourish the newborn.
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11
Survival Needs

Appropriate amounts necessary for life
 Too





little or too much harmful
Nutrients
Oxygen
Water
Normal body temperature
Appropriate atmospheric pressure
Survival Needs

Nutrients
 Chemicals
for energy and cell building
fats, proteins, minerals, vitamins
 Carbohydrates,

Oxygen
 Essential
for energy release (ATP production)
Survival Needs

Water
Most abundant chemical in body
Environment of chemical reactions
 Fluid base for secretions and excretions



Normal body temperature



37° C
Affects rate of chemical reactions
Appropriate atmospheric pressure

For adequate breathing and gas exchange in lungs
12
Homeostasis

Homeostasis
 Maintenance
of relatively stable internal conditions
despite continuous changes in environment
 A dynamic state of equilibrium
 Maintained by contributions of all organ systems
Homeostatic Control Mechanisms


Involve continuous monitoring and regulation of all
factors that can change (variables)
Communication necessary for monitoring and
regulation
 Functions

of nervous and endocrine systems
Nervous and endocrine systems, as well as other
systems, play a major role in maintaining
homeostasis
Components of a Control Mechanism
Homeostatic control of variables involves three
components: receptor, control center, and effector
 Receptor (sensor)



Monitors environment
Responds to stimuli (something that causes changes in
controlled variables)
Control center
Determines set point at which variable is maintained
Receives input from receptor
 Determines appropriate response


13
Components of a Control Mechanism
(cont’d)

Effector
Receives output from control center
Provides the means to respond
 Response either reduces (negative feedback) or enhances
stimulus (positive feedback)


Homeostatic Controls
• Example of negative feedback:
– Receptors sense increased blood glucose
(blood sugar)
– Pancreas (control center) secretes insulin
into the blood
– Insulin causes body cells (effectors) to absorb
more glucose, which decreases blood
glucose levels
Negative Feedback

Most feedback mechanisms in body
Response reduces or shuts off original stimulus

Examples

 Variable
changes in opposite direction of initial change
 Regulation
of body temperature (a nervous system
mechanism)
 Regulation of blood volume by ADH (an endocrine
system mechanism)
14
Slide 1
Figure 1.5 Interactions among the elements of a homeostatic control system maintain stable internal conditions.
3 Input: Information
sent along afferent
pathway to control
center.
2 Receptor
Receptor
Control
Center
Afferent
pathway
Efferent
pathway
4 Output: Information
sent along efferent
pathway to effector.
Effector
detects change.
1 Stimulus
produces
change in
variable.
BALANCE
5 Response
of effector feeds
back to reduce
the effect of
stimulus and
returns variable
to homeostatic
level.
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Figure 1.5 Interactions among the elements of a homeostatic control system maintain stable internal conditions.
1 Stimulus
produces
change in
variable.
Slide 2
BALANCE
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Figure 1.5 Interactions among the elements of a homeostatic control system maintain stable internal conditions.
2 Receptor
detects change.
Slide 3
Receptor
1 Stimulus
produces
change in
variable.
BALANCE
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15
Slide 4
Figure 1.5 Interactions among the elements of a homeostatic control system maintain stable internal conditions.
3 Input: Information
sent along afferent
pathway to control
center.
2 Receptor
detects change.
Receptor
1 Stimulus
produces
change in
variable.
Control
Center
Afferent
pathway
BALANCE
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Slide 5
Figure 1.5 Interactions among the elements of a homeostatic control system maintain stable internal conditions.
3 Input: Information
sent along afferent
pathway to control
center.
2 Receptor
Receptor
Control
Center
Afferent
pathway
Efferent
pathway
4 Output: Information
sent along efferent
pathway to effector.
Effector
detects change.
1 Stimulus
produces
change in
variable.
BALANCE
© 2016, 2016, 2013 Pearson Education, Inc.
Slide 6
Figure 1.5 Interactions among the elements of a homeostatic control system maintain stable internal conditions.
3 Input: Information
sent along afferent
pathway to control
center.
2 Receptor
Receptor
Control
Center
Afferent
pathway
Efferent
pathway
detects change.
1 Stimulus
produces
change in
variable.
BALANCE
4 Output: Information
sent along efferent
pathway to effector.
Effector
5 Response
of effector feeds
back to reduce
the effect of
stimulus and
returns variable
to homeostatic
level.
© 2016, 2016, 2013 Pearson Education, Inc.
16
Figure 1.6 Body temperature is regulated by a negative feedback mechanism.
Control Center
(thermoregulatory
center in brain)
Afferent
pathway
Efferent
pathway
Receptors
Temperature-sensitive
cells in skin and brain
Effectors
Sweat glands
Sweat glands activated
Response
Evaporation of sweat
Body temperature falls;
stimulus ends
Body temperature
rises
BALANCE
Stimulus: Heat
Stimulus: Cold
Response
Body temperature rises;
stimulus ends
Body temperature
falls
Receptors
Temperature-sensitive
cells in skin and brain
Effectors
Skeletal muscles
Shivering begins
Efferent
pathway
Afferent
pathway
Control Center
(thermoregulatory
center in brain)
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Negative Feedback:
Regulation of Blood Volume by ADH



Receptors sense decreased blood volume
Control center in hypothalamus stimulates pituitary
gland to release antidiuretic hormone (ADH)
ADH causes kidneys (effectors) to return more water
to the blood
Positive Feedback



Response enhances or exaggerates original stimulus
May exhibit a cascade or amplifying effect
Usually controls infrequent events that do not
require continuous adjustment
 Enhancement
of labor contractions by oxytocin (chapter
28)
 Platelet plug formation and blood clotting
17
A Positive Feedback Mechanism Regulates
Formation of a Platelet Plug (1 of 5)
Figure 1.7 A positive feedback mechanism regulates formation of a platelet plug.
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A Positive Feedback Mechanism Regulates
Formation of a Platelet Plug (2 of 5)
Figure 1.7 A positive feedback mechanism regulates formation of a platelet plug.
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A Positive Feedback Mechanism Regulates
Formation of a Platelet Plug (3 of 5)
Figure 1.7 A positive feedback mechanism regulates formation of a platelet plug.
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18
A Positive Feedback Mechanism Regulates
Formation of a Platelet Plug (4 of 5)
Figure 1.7 A positive feedback mechanism regulates formation of a platelet plug.
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A Positive Feedback Mechanism Regulates
Formation of a Platelet Plug (5 of 5)
Figure 1.7 A positive feedback mechanism regulates formation of a platelet plug.
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Homeostatic Imbalance

Disturbance of homeostasis


Increases risk of disease
Contributes to changes associated with aging


Control systems less efficient
If negative feedback mechanisms overwhelmed

Destructive positive feedback mechanisms may take over
(e.g., heart failure)
19
CHAPTER 1 PART 2
THE HUMAN BODY: AN
ORIENTATION
Anatomical Position

Standard anatomical body position
 Body
erect
slightly apart
 Palms facing forward
 Feet



Thumbs point away from body
Always use directional terms as if body is in
anatomical position
Right and left refer to body being viewed, not those
of observer
Table 1.1-1 Orientation and
Directional Terms
Table 1.1-1 Orientation and Directional Terms
20
Table 1.1-2 Orientation and
Directional Terms
Table 1.1-2 Orientation and Directional Terms
Table 1.1-3 Orientation and
Directional Terms
Table 1.1-3 Orientation and Directional Terms
Regional Terms

Two major divisions of body
 Axial
 Head,
neck, and trunk
 Appendicular


Limbs
Regional terms designate specific areas within body
divisions
21
Figure 1.7a Regional terms used to
designate specific body areas.
Cephalic
Frontal
Orbital
Nasal
Oral
Mental
Cervical
Upper limb
Acromial
Brachial (arm)
Antecubital
Thoracic
Sternal
Axillary
Mammary
Antebrachial
(forearm)
Carpal (wrist)
Abdominal
Umbilical
Manus (hand)
Pelvic
Inguinal
(groin)
Palmar
Pollex
Digital
Lower limb
Coxal (hip)
Femoral (thigh)
Patellar
Pubic (genital)
Crural (leg)
Fibular or peroneal
Pedal (foot)
Tarsal (ankle)
Thorax
Abdomen
Metatarsal
Digital
Hallux
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Anterior/Ventral
Figure 1.7b Regional terms used to
designate specific body areas.
Cephalic
Otic
Occipital (back
of head)
Upper limb
Acromial
Brachial (arm)
Cervical
Olecranal
Antebrachial
(forearm)
Back (dorsal)
Scapular
Vertebral
Lumbar
Manus (hand)
Metacarpal
Sacral
Gluteal
Digital
Perineal (between
anus and external
genitalia)
Lower limb
Femoral (thigh)
Popliteal
Sural (calf)
Fibular or peroneal
Pedal (foot)
Calcaneal
Back (Dorsum)
Plantar
Posterior/Dorsal
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Anatomical Variability

Humans differ externally and internally
 90%
of all structures present in body match description
in textbook
 Nerve or blood vessel may be out of place
 Small muscle may be missing

Extreme variations inconsistent with life
22
Body Planes and Sections

Body plane
 Flat
surface along which body or structure may be cut
for anatomical study
– Three most common planes:
• Sagittal plane
• Frontal (coronal) plane
• Transverse (horizontal) plane

Sections
 Cuts
or sections made along a body plane
Sagittal Plane

Sagittal plane
 Divides
body vertically into right and left parts
a sagittal section if cut along this plane
 Produces
 Midsagittal

(median) plane
Lies on midline
 Parasagittal
plane
• Cut was off-centered, not on midline
Body Planes



Frontal (coronal) plane

Divides body vertically into anterior and posterior parts

Produces a frontal or coronal section
Transverse (horizontal) plane

Divides body horizontally (90° to vertical plane) into
superior and inferior parts

Produces a cross section
Oblique section

Result of cuts at angle other than 90° to vertical plane
23
Figure 1.8 Planes of the body with
corresponding magnetic resonance
imaging (MRI) scans.
Median (midsagittal) plane
Vertebral
column
Frontal (coronal) plane
Right
lung
Rectum Intestines
Liver
Heart
Left
lung
Stomach
Transverse plane
Liver
Spleen
Aorta
Pancreas
Spleen
Spinal
Subcutaneous
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cord
fat layer
Body Cavities

Two sets of internal body cavities
 Closed



to environment
Provide different degrees of protection to organs
Dorsal body cavity
Ventral body cavity
Dorsal Body Cavity


Protects nervous system
Two subdivisions:
 Cranial

cavity
Encases brain
 Vertebral

cavity
Encases spinal cord
24
Figure 1.9 Dorsal and ventral body
cavities and their subdivisions.
Cranial
cavity
Cranial
cavity
(contains
brain)
Vertebral
cavity
Dorsal
body
cavity
Thoracic
cavity
(contains
heart and
lungs)
Vertebral
cavity
(contains
spinal
cord)
Superior
mediastinum
Pleural
cavity
Pericardial
cavity within
the mediastinum
Diaphragm
Abdominal cavity
(contains digestive
viscera)
Abdominopelvic
cavity
Ventral body
cavity
(thoracic and
abdominopelvic
cavities)
Pelvic cavity
(contains urinary
bladder, reproductive
organs, and rectum)
Dorsal body
cavity
Ventral body
cavity
Lateral view
Anterior view
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Ventral Body Cavity


Houses internal organs (viscera)
Two subdivisions (separated by diaphragm)
 Thoracic
cavity
 Abdominopelvic
cavity
Ventral Body Cavity

Thoracic cavity subdivisions
 Two
pleural cavities
 Each
houses a lung
 Mediastinum


Contains pericardial cavity
Surrounds thoracic organs (i.e. trachea, esophagus, etc.)
 Pericardial

cavity
Encloses heart
25
Ventral Body Cavity

Abdominopelvic cavity subdivisions
 Abdominal

 Pelvic

cavity
Contains stomach, intestines, spleen, and liver
cavity
Contains urinary bladder, reproductive organs, and rectum
Figure 1.9 Dorsal and ventral body
cavities and their subdivisions.
Cranial
cavity
Cranial
cavity
(contains
brain)
Dorsal
body
cavity
Vertebral
cavity
Thoracic
cavity
(contains
heart and
lungs)
Vertebral
cavity
(contains
spinal
cord)
Dorsal body
cavity
Ventral body
cavity
Superior
mediastinum
Pleural
cavity
Pericardial
cavity within
the mediastinum
Diaphragm
Abdominal cavity
(contains digestive
viscera)
Abdominopelvic
cavity
Ventral body
cavity
(thoracic and
abdominopelvic
cavities)
Pelvic cavity
(contains urinary
bladder, reproductive
organs, and rectum)
Lateral view
Anterior view
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Clinical – Homeostatic Imbalance
1.1

Whereas the pelvic bones provide limited
protection to the pelvic cavity, the walls of
abdominal cavity are formed by muscle only, so
organs in this area are most vulnerable to trauma
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Inc.
26
Membranes in Ventral Body Cavity

Serous membrane or serosa
 Thin,
double-layered membranes
Parietal serosa lines internal body cavity walls
 Visceral serosa covers internal organs (viscera)

 Layers
separated by slit-like cavity filled with serous
fluid

Fluid secreted by both layers of membrane
Serous Membranes

Named for specific cavity and organs with which
associated
Each has parietal and visceral layers
Pericardium

Pleurae

Peritoneum





Heart
Lungs
Abdominopelvic cavity
Figure 1.10 Serous membrane
relationships.
Outer balloon wall
(comparable to parietal serosa)
Air (comparable to serous cavity)
Inner balloon wall
(comparable to visceral serosa)
A fist thrust into a flaccid balloon demonstrates
the relationship between the parietal and visceral
serous membrane layers.
Heart
Parietal
pericardium
Pericardial
space with
serous fluid
Visceral
pericardium
The serosae associated with the heart.
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27
Clinical – Homeostatic Imbalance
1.2



Serous membranes can become inflamed as a result
of infection or other causes
Normally smooth layers can become rough and
even can stick together, resulting in excruciating
pain
Examples: pleurisy and peritonitis
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Inc.
Abdominopelvic Quadrants

Divisions used primarily by medical personnel
 Quadrants
are divisions used primarily by medical
personnel

Abdominopelvic region is sectioned into quarters




Right upper quadrant (RUQ)
Left upper quadrant (LUQ)
Right lower quadrant (RLQ)
Left lower quadrant (LLQ)
Figure 1.11 The four
abdominopelvic quadrants.
Right upper
quadrant
(RUQ)
Left upper
quadrant
(LUQ)
Right lower
quadrant
(RLQ)
Left lower
quadrant
(LLQ)
© 2016 Pearson Education, Inc.
28
Abdominopelvic Regions

Nine divisions used primarily by anatomists.
Right hypochondriac region
Epigastric region
 Left hypochondriac region
 Right lumbar region
 Umbilical region
 Left lumber region
 Right Iliac (inguinal) region
 Hypogastric region
 Left iliac (inguinal) region


Figure 1.12 The nine
abdominopelvic regions.
Liver
Right
hypochondriac
region
Right
lumbar
region
Epigastric
region
Umbilical
region
Left
hypochondriac
region
Left
lumbar
region
Gallbladder
Ascending colon
of large intestine
Small intestine
Cecum
Right iliac
(inguinal)
region
Hypogastric
(pubic)
region
Left iliac
(inguinal)
region
Nine regions delineated by four planes
Appendix
Diaphragm
Spleen
Stomach
Transverse colon
of large intestine
Descending colon
of large intestine
Initial part of
sigmoid colon
Urinary bladder
Anterior view of the nine regions showing the
superficial organs
© 2016 Pearson Education, Inc.
Other Body Cavities

Exposed to environment
 Oral
and digestive cavities
cavity
 Orbital cavities
 Middle ear cavities
 Nasal

Not exposed to environment
 Synovial
cavities
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