This document provides an overview of integrated human physiology. It discusses the study of body function and homeostasis through feedback loops. The four primary tissues - muscle, nervous, epithelial and connective tissue - are examined, as well as the scientific method and development of new drugs. Physiological processes and their alterations in disease are explored.

1. INTEGRATED HUMAN PHYSIOLOGY OVERVIEW
The Study of Body Function
Prepared by Marc Imhotep Cray, M.D.
Professor Basic Medical Sciences
IVMS Intro to Anat.
& Physio. Basics/
Video-Animations
Anatomy and Physiology Tutorial
http://www.le.ac.uk/pathology/teach/va/anatomy/frmst.htm
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2. Human Physiology
• Study of how the human body functions.
• How organisms accomplish tasks essential for
life.
• Pathophysiology:
– How physiological processes are altered in
disease or injury.
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3. Scientific Method
• Confidence in rational ability, honesty and humility.
• Specific steps in scientific method:
– Formulate hypothesis:
• Observations.
– Testing the hypothesis:
• Quantitative measurements.
– Analyze results:
• Select valid statistical tests.
– Draw conclusion.
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4. Development of New Drugs
• Cellular research:
– Cells in tissue culture used to develop new drugs.
• Animal models:
– Laboratory animals, genetically susceptible to a
particular disease, are given doses of new drug.
• Phase I clinical trials:
– Drug tested on healthy human volunteers.
• Determine pharmacokinetics.
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5. Development of New Drugs (continued)
• Phase II clinical trials:
– Drug tested on target population.
• Phase III clinical trials:
– Occur in research centers across country to increase
number of participants.
• If passes trials, goes to FDA for approval.
• Phase IV:
– Test for other uses of the drug.
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6. Homeostasis
• Maintaining constancy of internal environment.
– Dynamic constancy.
• Within a certain normal range.
• Maintained by negative feedback loops.
• Regulatory mechanisms:
– Intrinsic:
• Within organ being regulated.
– Extrinsic:
• Outside of organ, such as nervous or hormonal systems.
• Negative feedback inhibition.
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7. Feedback Loops
• Sensor:
– Detects deviation from
set point.
• Integrating center:
– Determines the
response.
• Effector:
– Produces the response.
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8. Negative Feedback
• Defends the set point.
• Reverses the deviation.
• Produces change in opposite direction.
• Examples:
– Insulin decreases plasma [glucose].
– Thermostat.
– Body temperature.
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9. Negative Feedback (continued)
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10. Positive Feedback
• Action of effectors amplifies the changes.
• Is in same direction as change.
• Examples:
– Oxytocin (parturition).
– Voltage gated Na+ channels
(depolarization).
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11. Primary Tissues
• The body composed of 4 different primary tissues:
– Muscle, nervous, epithelial, connective.
• Organs:
– Composed of at least two primary tissues.
– Serve different functions of the organ.
• Systems:
– Organs that are located in different regions of the body
and perform related functions.
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12. Muscle Tissues
• Specialized for contraction.
• 3 types of muscle tissue:
– Skeletal.
– Cardiac.
– Smooth.
• Skeletal and cardiac muscle have similar
mechanisms of contraction.
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13. Skeletal Muscles
• Voluntary, striated.
• Attached to bones by
tendons:
– Produce skeletal
movement.
• Muscle fibers arranged in
bundles, fibers arranged in
parallel.
• Produce graded
contractions.
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14. Cardiac Muscles
• Striated, found only in the
heart.
• Myocardial cells are
interconnected to form
continuous fabric.
• Intercalated discs couple
cells together mechanically
and electrically.
– Syncytium.
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15. Smooth Muscles
• Not striated.
• Do not contain sarcomeres.
• Ca2+ combines with
calmodulin, activating
contraction process.
• Contain gap junctions.
• Found in GI tract, blood
vessels, bronchioles, ducts
of urinary and reproductive
systems.
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16. Nervous Tissue
• Neurons (nerve cells):
– Specialized for action potential
conduction.
• Dendrites:
– Receive input.
• Cell body:
– Nucleus.
– Metabolic center.
• Axon:
– Conducts nerve impulses.
• Supporting cells
(neuroglia/glia):
– Provide anatomical and
functional support.
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17. Epithelial Tissue
• Cells that form membranes:
– Provide barrier between external and internal environments.
– Classified according to number of layers and shape of the
cells in upper layer.
• Simple:
– One cell layer thick.
– Specialized for transport.
• Stratified membranes:
– Composed of a number of layers.
– Specialized for protection.
– Squamous, columnar, cuboidal.
– Glands:
• Exocrine, endocrine glands.
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18. Epithelial Membranes
• Squamous cells:
– Flattened in shape.
– Function:
• Diffusion and
filtration.
–Line all blood
vessels,
pulmonary
alveoli.
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19. Epithelial Membranes
• Cuboidal cells:
– Cube-shaped cells.
– Function:
• Excretion, secretion
and absorption.
–Line kidney
tubules, salivary
and pancreatic
ducts.
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20. Epithelial Membranes
• Columnar cells:
– Taller column shaped cells.
– Function:
• Excretion, secretion and
absorption.
• May contain cilia.
– Line digestive tract,
uterine tubes, and
respiratory
passageways.
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21. Epithelial Membranes
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22. Exocrine Glands
• Derived from cells of epithelial membranes.
• Secretions are released through ducts.
– Simple tubes or modified as acini.
• Examples:
– Tear glands.
– Sweat glands.
– Prostate glands.
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23. Endocrine Glands
• Lack ducts.
• Secrete hormones into
capillaries/lymphatic system within
the body.
• May be discrete organs:
– Primary functions are the production and
secretion of hormones.
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24. Connective Tissue
• Large amounts of extracellular material in the
spaces between connective tissue cells.
• 4 types of connective tissue:
– Connective tissue proper.
– Cartilage.
– Bone.
– Blood.
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25. Connective Tissue Proper
• Loose connective tissue:
– Scattered collagen and tissue fluid.
• Dermis of skin.
• Dense fibrous connective tissue:
– Regularly arranged.
• Collagen oriented in same direction.
– Tendons.
– Irregularly arranged.
• Resists forces applied in many directions.
– Capsules and sheaths.
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26. Connective Tissue (continued)
• Cartilage:
– Chondrocytes.
• Supportive and protective tissue.
• Elastic properties to tissues.
• Precursor to many bones.
• Articular surfaces on joints.
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27. Connective Tissue (continued)
• Bone:
– Hydroxyapatite crystals.
• Osteoblasts:
– Bone-forming cells.
– Osteocytes:
• Trapped osteoblasts: less
active.
– Osteoclasts:
• Bone resorbing cells.
Rubin, Essentials of Pathophysiology,2001
• Blood:
– Classified as connective tissue.
• Half its volume is plasma.
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28. Body-Fluid Compartments
• 65-75% of total body weight is H20.
• Intracellular compartment:
– Fluid inside the cell.
• 2/3 of H20.
• Extracellular compartment:
– 2 Subdivisions:
• Blood plasma.
• Interstitial fluid.
• 1/3 H20.
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