Human Body: An Orientation
Anatomy & Physiology
Chapter 1
Life Functions
Maintaining Life
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Necessary Life Functions
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Maintain boundaries
Move
Respond to environmental changes
Take in and digest nutrients
Carry out metabolism
Dispose of waste
Reproduce themselves
Grow
Life Functions
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Maintain boundaries – an organism internal
environment must remain distinct from the external
environment
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Movement – all activities promoted by the muscular
system
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Responsiveness – the ability to sense changes in the
environment and then respond to them
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Digestion – process of breaking down ingested
foodstuffs to simple molecules that can be absorbed
into the blood
Life Functions
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Metabolism – all chemical reactions that occur within
the body cells
Excretion – process of removing wastes from the body
Reproduction –
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Cellular Level: original cell divides producing 2 identical
daughter cells that can be used for body growth or repair
Organismal Level: when sperm and egg unite producing a
fertilized egg which develops into a fetus within the mother’s
body
Growth – increase in size of a body part or the
organism
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Increase the number of cells
Survival Needs
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Survival Needs
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Nutrients
Oxygen
Water
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60 – 80% of body weight
Appropriate Temperature
Atmospheric Pressure
Homeostasis – dynamic state of equilibrium or
balance
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Internal conditions vary but within narrow limits
Variable – factor or event being regulated
Divisions of Anatomy
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Regional – all structures are in a
particular region of the body
Systemic– gross anatomy of the body
studied system by system
Microscopic– thin slices of body
tissues are examined under the
microscope
Pathological– studies structural
changes caused by disease
Homeostatic Control
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Homeostatic Control Mechanisms – have at least 3
interdependent components
1.
2.
3.
Receptor – some type of sensor that monitors the environment
and responds to changes (stimuli) by sending information to
the central center
Control Center – determines the set point at which a variable is
to be maintained, analyzes the input it receives, and
determines the appropriate response
Effector – provides the means for the central center’s response
to the stimulus
Homeostatic Control
Homeostatic Control
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Negative Feedback Mechanisms
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The goal is to prevent sudden, severe changes within the
body
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Maintaining blood glucose levels
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Regulation of body temperature by nervous system
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Examples: regulate heartbeat, rate and depth of breath, and
blood levels of oxygen, carbon dioxide, and minerals
Homeostatic Control
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Positive Feedback Mechanisms:
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Response enhances the original stimulus
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Change that occurs proceeds in the same direction as the
initial disturbance
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Control infrequent events that do not require continuous
adjustments
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Examples: blood clotting, contractions during the birth of a
baby
Homeostatic Imbalance: disruption of homeostasis causing
disease
Language of Anatomy
1.
Anatomical Position and Directional Terms
a.
Anatomical Position: reference point used to describe
body parts and position accurately (Standard body
position)
1.
Human body erect
2.
Arms at side
3.
Palms forward, thumbs pointed away from the body
4.
Feet together
* Right and Left – refers to the sides of the person being
viewed not those of the observer!
Language of Anatomy
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Anatomical Position
Language of Anatomy
2.
Directional Terms – explains where one body
structure is in relation to another
a.
b.
Superior: toward the head end or upper part;
above
Inferior: away from head end or toward the
lower part, below
Anterior: toward the front of the body
Posterior: toward the back of the body
Language of Anatomy
Language of Anatomy
c.
d.
Medial: toward or at the midline of the body
Lateral: away from the midline of the body
Intermediate: between a more medial and more lateral
structure
Proximal: closer to the origin of the body part or the point
of attachment of a limb to the body trunk
Distal: farther from the origin of a body part or the point of
attachment of a limb to the body trunk
e.
Superficial: toward or at the body surface
Deep: away from the body surface
Language of Anatomy
Language of Anatomy
Language of Anatomy
3.
Regional Terms – used to designate specific
areas within the major body divisions
a.
Major Body Divisions
1.
2.
4.
Axial – main axis of our body (i.e. head, neck, trunk)
Appendicular – consists of appendages or limbs
Body Planes and Sections
a.
Planes – cut along a flat surface
1.
Sagittal: vertical plane that divides the body into right
and left parts
Median/Midsagittal: sagittal plan that lies exactly in the
midline
Parasagittal: offset from the midline
Language of Anatomy
2.
Frontal/Coronal: divide the body into anterior and
posterior parts
3.
Transverse/Horizontal: runs horizontally from right to
left, divides the body into superior and inferior parts
- Also called a cross section
4.
Oblique: cuts made diagonally between the horizontal
and the vertical planes
Language of Anatomy
Language of Anatomy
5.
Body Cavities and Membranes
a.
Dorsal Body Cavity: protects the nervous system
organs
1.
2.
b.
Cranial Cavity – encases the brain
Vertebral Cavity – encases the delicate spinal column
Ventral Body Cavity : anterior
1.
Thoracic – Superior division, surrounded by the ribs
and muscles of the chest
a.
Pleural Cavity: houses a lung
b.
Mediastinum: contains the pericardial cavity which
encloses the heart, surrounds the esophagus, and
trachea
- separates the lungs into right and left cavities
Language of Anatomy
c.
d.
e.
Abdominopelvic Cavity:
1.
Abdominal Cavity – contains the stomach, intestines,
spleen, liver
2.
Pelvic Cavity – lies within the bony pelvis, contains
the bladder, reproductive organs, and rectum
Visceral Organs: group of internal organs collectively
called viscera
Diaphragm – dome shaped muscle important in
breathing. Separates the thoracic and abdominopelvic
cavities.
Language of Anatomy
Language of Anatomy
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Abdominopelvic Cavity Quadrants
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Because the abdominopelvic cavity is quite
large, it is often divided into four or more
equal regions called quadrants
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The Four Most Common Quadrants Are:
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Right Upper Quadrant
Right Lower Quadrant
Left Upper Quadrant
Left Lower Quadrant