IVMS- INTEGRATED HUMAN PHYSIOLOGY OVERVIEW-The Study of Body Function

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IVMS- INTEGRATED HUMAN PHYSIOLOGY OVERVIEW-The Study of Body Function

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IVMS- INTEGRATED HUMAN PHYSIOLOGY OVERVIEW-The Study of Body Function

  1. 1. INTEGRATED HUMAN PHYSIOLOGY OVERVIEW The Study of Body Function Prepared by Marc Imhotep Cray, M.D. Professor Basic Medical SciencesIVMS Intro to Anat. & Physio. Basics/ Video-Animations Anatomy and Physiology Tutorial http://www.le.ac.uk/pathology/teach/va/anatomy/frmst.htm 1
  2. 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. 2
  3. 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. 3
  4. 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. 4
  5. 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. 5
  6. 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. 6
  7. 7. Feedback Loops• Sensor: – Detects deviation from set point.• Integrating center: – Determines the response.• Effector: – Produces the response. 7
  8. 8. Negative Feedback• Defends the set point.• Reverses the deviation.• Produces change in opposite direction.• Examples: – Insulin decreases plasma [glucose]. – Thermostat. – Body temperature. 8
  9. 9. Negative Feedback (continued) 9
  10. 10. Positive Feedback• Action of effectors amplifies the changes.• Is in same direction as change.• Examples: – Oxytocin (parturition). – Voltage gated Na+ channels (depolarization). 10
  11. 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. 11
  12. 12. Muscle Tissues• Specialized for contraction.• 3 types of muscle tissue: – Skeletal. – Cardiac. – Smooth.• Skeletal and cardiac muscle have similar mechanisms of contraction. 12
  13. 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. 13
  14. 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. 14
  15. 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. 15
  16. 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. 16
  17. 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. 17
  18. 18. Epithelial Membranes• Squamous cells: – Flattened in shape. – Function: • Diffusion and filtration. –Line all blood vessels, pulmonary alveoli. 18
  19. 19. Epithelial Membranes• Cuboidal cells: – Cube-shaped cells. – Function: • Excretion, secretion and absorption. –Line kidney tubules, salivary and pancreatic ducts. 19
  20. 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. 20
  21. 21. Epithelial Membranes 21
  22. 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. 22
  23. 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. 23
  24. 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. 24
  25. 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. 25
  26. 26. Connective Tissue (continued)• Cartilage: – Chondrocytes. • Supportive and protective tissue. • Elastic properties to tissues. • Precursor to many bones. • Articular surfaces on joints. 26
  27. 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. 27
  28. 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. 28

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