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Chapter 1
The Human Organism
•The body is truly more than the sum of its parts and
understanding the connectedness of the human
structure and function is the real challenge.
Homeostasis is the “glue” and basis which explains
this relationship.
•Realize Anatomy and Physiology is a language.
Study it like a language.
Welcome to YOUR nursing career!
1-1
Overview of Anatomy and
Physiology
• Anatomy: scientific discipline that
investigates the body’s structure
• Physiology: scientific investigation of the
processes or functions of living things
1-2
Topics of Anatomy
• Gross or macroscopic: structures examined
without a microscope
– Regional: studied area by area
– Systemic: studied system by system
– Surface: external form and relation to deeper
structures as x-ray in anatomic imaging
• Microscopic: structures seen with the microscope
– Cytology: cellular anatomy
– Histology: study of tissues
1-3
Topics of Physiology
• Reveals dynamic nature of living things
• Considers operations of specific organ
systems
– Cell physiology: examines processes in cells
– Neurophysiology: focuses on the nervous
system
– Cardiovascular: the heart and blood vessels
1-4
Subjects That Encompass Both
Anatomy and Physiology
• Pathology: structural and functional
changes caused by disease
• Exercise Physiology: changes in structure
and function caused by exercise
1-5
Structural & Functional Organizations
• Chemical Level: interaction
of atoms
• Cell Level: functional unit of
life
• Tissue Level: group of
similar cells and the materials
surrounding them
• Organ Level: one or more
tissues functioning together
• Organ System Level: group
of organs functioning
together
• Organism Level: any living
thing.
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1-7
Homeostasis
• Homeostasis—maintenance of a stable
internal environment
– A dynamic state of equilibrium
• Homeostasis is necessary for normal body
functioning and to sustain life
• Homeostatic imbalance
– A disturbance in homeostasis resulting in
disease
1-8
Homeostasis
• Values of variables fluctuate
around the set point to
establish a normal range of
values.
• Set point: the ideal normal
value of a variable.
• What is the set point for
body temperature?
1-9
Homeostatic Control
Mechanisms
• Process for maintaining homeostasis
• How does the body maintain proper Oxygen
levels during exercise?
Maintaining Homeostasis
• The body communicates through neural and
hormonal control systems
• Receptor
• Responds to changes in the environment (stimuli)
• Sends information to control center
• Afferent pathway
Maintaining Homeostasis
– Control center
• Determines set point
• Analyzes information
• Determines appropriate response
– Effector
• Provides a means for response to the stimulus
• Efferent pathway
Feedback Mechanisms
• Negative feedback
– Includes most homeostatic control mechanisms
– Decreases the original stimulus, or reduces its
intensity
– inhibitory
– Works like a household thermostat
Feedback Mechanisms
• Positive feedback
– Increases the original stimulus to push the variable
farther
– In the body this only occurs in blood clotting and
during the birth of a baby
– Stimulatory
 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
Feedback Systems Summary
• Two types: negative and positive
• It is important to note that in science, negative means “to take
away” while positive means “to gain”
• Components
– Receptor: monitors the value of some variable
– Control center: establishes the set point
– Effector: can change the value of the variable
• Stimulus: deviation from the set point; detected by the receptor
• Response: produced by the effector
• Be able to give examples of BOTH
– (hint: what is the rule? and the few exceptions)
Levels
of
Homeostatic
Control
– 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)
Terminology and Body Plan
• Anatomical Position
– Body erect, face forward, feet
together, palms face forward
• Other Body Positions
– Supine: lying face upward
– Prone: lying face downward
• Directional Terms
– Superior (Cephalic) vs. Inferior
(Caudal) toward or away from the
head
– Medial vs. Lateral relative to the
midline
– Proximal vs. Distal used to
describe linear structures
– Superficial vs. Deep relative to the
surface of the body
– Ipsilateral vs. Contralateral same
or opposite side of the body
1-18
Terminology and Body Plan (cont.)
• Directional Terms
(cont.)
– Anterior (Ventral) vs.
Posterior (Dorsal).
Anterior is forward;
posterior is toward the
back.
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Intra: inside
Inter: between
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Body shapes and
Disease
- How structure and function are
interrelated
-Three body types:
1. Endomorph
2. Mesomorph
3. Ectomorph
- Apple shaped are at a higher risk of
heart disease, stroke, high blood
pressure and diabetes than those who
carry their weight around the hips and
thighs
1-21
Body Parts and Regions
1-22
1-23
Body Parts and Regions
1-24
Abdominal Subdivisions
Regions
Quadrants
1-25
Planes of Section Through an
Organ
• Longitudinal: cut
along the length of an
organ
• Cross/Transverse: cut
at right angle to length
of the organ
• Oblique: cut at any
but a right angle
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Terms Related to Organs
– Lumen (luminal)
hollow area within and organ
– Central and peripheral
near the center v near the boundary
– Medullary (medulla) and cortical (cortex)
inner region v outer region
– Apical (apex) and basal (base)
narrow tip v widest area of an organ
Body Planes
• Median (through
the midline) and
Sagittal (same
plane, but to the left
or right of median
• Frontal or Coronal
divides body into
anterior and
posterior sections
• Transverse / Cross
divides body into
superior and inferior
sections
• Oblique: Other
than at a right angle
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Body Cavities
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Trunk Cavities
• Diaphragm: divides body cavity into
thoracic and abdominopelvic cavities.
• Mediastinum: contains all structures of the
thoracic cavity except the lungs
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Serous Membranes
• Cover the organs of trunk
cavities & line the cavity
• Fist represents an organ
• Inner balloon wall represents
visceral serous membrane
• Outer balloon wall represents
parietal serous membrane
• Cavity between two
membranes filled with
lubricating serous fluid that is
produced by the membranes
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Serous Membranes:
Named for Their Specific Cavities and Organs
– Pericardium refers to heart.
– Pleura refers to lungs and thoracic cavity
– Peritoneum refers to abdominopelvic cavity
1-32
Review
1-33
Also…
• Mechanisms of Disease.
– pp.25-28 including Disease terminology in “Health
Matters”
1-34
What kind of feed back is this?
1-35
What plane is this?
1-36