Transcript The Human Body: An Orientation

Chapter 1
Anatomy
 The study of the structure and shape of body parts in
their relation to each other
 Gross Anatomy-study of large, easily observable
structures
 Microscopic Anatomy-study of parts that can only be
seen with a microscope
Physiology
 Study of how the body and its parts work or function
 Many subdivisions: neurophysiology, cardiac
physiology, muscular physiology, etc.
Relationship between anatomy and
physiology
 Parts are a well-formed unit, each with its own job
 Structure determines the functions that occur
Levels of organization
 Atoms – building blocks of matter
 cells- smallest living unit of all living things
 Tissues – groups of similar cells doing a common
function
 Organ – two or more tissue types performing a specific
function together
 Organ system – group of cooperating organs that
accomplish a common purpose
 Organism – 11 organ systems making up the living,
working body
Organ system overview:
Integumentary System
 External covering of the body
 Skin
 Waterproof, cushions, protects from injury
 Excretes salts and urea (sweat)
 Regulates body temperature
 Contains temperature, pressure, and pain receptors
Organ system overview:
Skeletal system
 Bones, cartilage, ligaments, and joints
 Supports the body
 Framework for skeletal muscles and movement
 Protects brain and internal organs
 Hematopoiesis occurs (formation of blood cells)
 Stores minerals, like calcium
Organ system overview:
Muscular System
 One function: contraction
 Large, fleshy muscles attached to bone are skeletal
muscles
 Allow movement
Organ system overview:
Nervous System
 Fast-acting control system
 Brain, spinal cord, nerves, sensory receptors
 Must detect changes in the body and control the
responses
Organ system overview:
Endocrine System
 Helps control body activities such as growth and
reproduction
 Glands release hormones in the blood that travel to
target organs
 Pituitary, thyroid, parathyroids, adrenals, thymus,
pancreas, pineal, ovaries, and testes
Organ system overview:
Cardiovascular System
 Heart and blood vessels
 Blood is a transport fluid
 Carries oxygen, nutrients, and other substances to cells
 Picks up waste materials from cells
 Produces WBCs to help with immune response
Organ system overview:
Lymphatic System
 Lymphatic vessels, lymph nodes, and other lymphoid
organs (spleen and tonsils)
 Return fluid to the blood vessels that leaked out
 Cleanses blood
 Helps with immunity
Organ system overview:
Respiratory System
 Keep body supplies with oxygen and get rid of carbon
dioxide
 Nasal passages, pharynx, larynx, trachea, bronchi, and
lungs
Organ system overview:
Digestive System
 Oral cavity, esophagus, stomach, small and large
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intestines, and rectum
Breaks down food and delivers nutrients to the blood
for dispersal to cells
Reabsorbs water
Anything undigested is excreted
Liver and pancreas help with digestion
Organ system overview:
Urinary System
 Nitrogen – containing wastes are flushed from the
body in urine
 Kidneys, ureters, bladder, and urethra
 Maintains water and salt balance
 Maintains pH balance in blood
Organ system overview:
Reproductive System
 For production of offspring
 Males
 Sperm (made in testes), scrotum, penis, accessory
glands and duct system
 Females
 Ovaries, ova (eggs), uterine tubes, uterus, and vagina
Characteristics of Life
 Maintain boundaries-keep the inside separate from
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the outside; protect against invading chemicals,
sunlight and “germs”
Movement-activities by the muscular system
Digestion-breaking down food into simpler substances
that can be absorbed by blood and transported to cells
Metabolism-all chemical reactions that occur in cells
Excretion-removing waste materials
Reproduction-producing viable offspring
Characteristics of Life
 Growth-increase in size due to an increase in the
number of cells
 Development-changing from juvenile to adult
Survival needs
 Nutrients – take in with food provide the materials
needed for energy and building cells (carbohydrates,
proteins, minerals, lipids)
 Oxygen-need to convert food to energy (ATP) in all
cells; carried by respiratory and circulatory systems
 Body temperature-must be maintained; low temp.
results in slower metabolism and possibly death; high
temp. causes metabolism to speed up which breaks
down proteins and can also cause death
 Atmospheric pressure-helps exchange O2 and CO2
Homeostasis
 Maintaining the internal environment regardless of
what occurs outside the body
 Dynamic state in which internal conditions may
fluctuate but only within very defined limits
Homeostatic controls
 3 components
 Receptor-monitors and responds to changes in the
environment (responds to stimuli) by sending
information to the control center
 Control center-determines the appropriate response or
course of action required
 Effector-provides the means for the control center to
respond through the efferent pathway resulting in a
feedback mechanism
Feedback mechanisms
 Negative feedback-result of the response will shut off
the stimulus or reduce the intensity (ex: AC
thermostadt)
 Positive feedback (very rare)-increases the original
stimulus (blood clotting, child birth)
Body cavities
 Provide different degrees of protection to internal organs
 Dorsal Body Cavity
 2 subdivisions
 Cranial cavity-inside the skull
 Spinal cavity-extends from the cranium to the end of the
vertebral column
 Ventral Body Cavity
 2 subdivisions
 Thoracic Cavity-superior area above the diaphragm
 Abdominopelvic Cavity-inferior area below the diaphragm
Body cavities
 Small Cavities
 Oral cavity-within the mouth
 Nasal cavity-inside the nose
 Orbital cavities-hold the eyes
 Middle ear cavities-in the skull, used to transmit sound
Language of Anatomy
 Anatomical Position
 Body is erect
 Feet parallel
 Arms hanging at sides
 Palms facing forward
 Thumbs pointing away from the body
Language of Anatomy
 Directional terms
 Allow explanation of the location of body structures in
relations to others
 See Figure 1.2, p. 6
Body planes
 Sagittal plane (midsagittal or median)-a cut made
lengthwise that divides the body into right and left
halves
 Frontal plane-a cut made lengthwise that divides the
body into anterior and posterior parts
 Transverse plane (cross section)-a cut made along a
horizontal line that divides the body into superior and
inferior sections
 See Fig. 1.1, p. 5
Kinetics
 The analysis of actions of forces acting on the human
body
Force
 Force is push or pull acting on a structure.
 Net force is single force resulting form summation of
all forces acting on a structure (size and directi0n of all
acting forces)
Mass and Weight
 Mass-anything with matter that takes up space
 Weight-gravitational acceleration exerted on an
object’s mass
Pressure
 Force distributed over a given area
Torque
 When force causes a structure to rotate, rotary force
is=torque
 For the human body: the size of the muscle force
multiplied by the distance between the muscle
attachment and the joint center=torque generated
Directional force
 Compression – squeezing force
 Tension (tensile force) – pulling force that creates
tension in the object
 Shear – acts perpendicular to the length of the object
(or bone) causing sliding or shearing with respect to
another portion of the object
Mechanical stress
 Resulting force distribution inside the body
 Size of the force divided by the area over which the
force acts
Combined loads
 Bending – combination of off center forces
 Torsion – a structure twists bout the length but one
end is fixed
 Combined loading – simultaneous action of 2 or more
forces