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PHYSIOLOGY

PHYSIOLOGY. Ch. 1. THE STUDY OF BODY FUNCTION. 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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PHYSIOLOGY

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  1. PHYSIOLOGY Ch. 1 THE STUDY OF BODY FUNCTION

  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.

  3. History of PhysiologyAncient Greeks • Aristotle (384 - 322 BC) • Blood flows between arteries and veins • The heart is the seat of intellect and a furnace that heats the blood • The lungs ventilate the furnace and air acts as a cooling agent

  4. History of PhysiologyAncient Greeks • Herophilus (335 - 280 BC) • Identified pulse as a function of heartbeat, and showed that it varied when disease was present • Arteries are thicker walled than veins • The brain is the seat of intellect

  5. History of PhysiologyAncient Greeks • Erasistratus (310 - 240 BC) • Postulated the existence of capillaries • The brain is the origin of all nerves • Blood is made in the liver from food, and air (pneuma) is a living force that is transformed into a “vital spirit”.

  6. History of Physiology • Galen (130 - 201 AD) • Dissection of Barbary apes was basis for his book of human anatomy - stood as the authority for 1400 years • Known for his voluminous writings about philosophy, medicine, and physiology.

  7. Galen's physiological teaching (after C.Singer Greek Biology and Greek Medicine)

  8. "In the universe there are four elements - fire, air, water and earth; and in the living body there are four humours, black bile, yellow bile, sanguine and phlegm. Out of the excess or deficiency or misproportion of these four humours there arise disease; by restoring the correct proportion diseases are cured"

  9. History of PhysiologyRenaissance Physiologists • Andreas Vesalius (1514 - 1564) • Dissected human cadavers while he lectured. Introduced anatomical drawings. • De Humanis Corporis Fabrica (The Structure of the Human Body) was the first anatomy text based on human dissection.

  10. History of PhysiologyRenaissance Physiologists • William Harvey (1578 - 1657) • Proposed that the heart is a pump (not a furnace) and that blood circulates (does not return along the same pathways. • The blood flows from the right ventricle of the heart to the lungs

  11. Robert Hooke (1635 - 1703) British physicist who first observed and described cells

  12. Schleiden & Schwann Cell Theory: 1839 • All living things are • comprised of cells. Matthais Schleiden Theodor Schwann (1804-1881) German microscopist (1818-1882) German physiologist 2. All cells come from pre-existing cells.

  13. History of PhysiologyModern Physiologists • Claude Bernard (1813 - 1878) • The advent of the thermometer allowed physiologists to determine that the internal temperature of all healthy human beings fell withina narrow range • Bernard developed the concept of the milieu interieur - a constant internal state

  14. History of PhysiologyModern Physiologists • Walter Cannon (1871 - 1945) • In his book The Wisdom of the Human Body, Cannon coined the term homeostasis to describe this internal constancy.

  15. 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.

  16. Feedback Loops • Sensor: • Detects deviation from set point. • Integrating center: • Determines the response. • Effector: • Produces the response. Fig 1.1 P. 7

  17. Negative Feedback • Defends the set point. • Reverses the initial deviation. • Produces change in opposite direction. • Examples: • Insulin decreases plasma glucose. • Body temperature. Fig 1.3 P. 8

  18. Negative Feedback Fig 1.4 P. 8 Fig 1.6 P. 10

  19. Positive Feedback • Action of effectors amplifies the changes. • Is in same direction as change. • Examples: • Oxytocin (parturition). • Voltage gated Na+ channels (depolarization).

  20. Hierarchy of Life Atom Molecule Cell Tissue Organ Organ System Organism

  21. Muscle • Elongated cells are highly specialized to contract and produce most types of body movement • Three types of muscle tissue: • Skeletal Muscle • Cardiac Muscle • Smooth Muscle

  22. Nervous Tissue • Found in the central nervous system (brain and spinal cord) or peripheral nervoussystem (nerves, sensory receptors, ganglia) • Two major cell populations: • Neurons – specialized for the generation and conduction of electrical impulses • Neuroglia –supporting cells; serve to protect, support, and insulate neurons

  23. Epithelial Tissues • Cells fit closely together to form membranes or sheets • Covers surfaces; the tissue has one free surface • Avascular • Functions include: protection, absorption, filtration and secretion

  24. Epithelial Tissues • Classified by two criteria • Cell shape • Squamous - scale-like • Cuboidal - cube-like • Columnar - column-shaped

  25. Epithelial Tissues • Number of layers • Simple = one cell layer • Stratified = two or more layers

  26. Fig 1.14 P. 15

  27. Connective Tissue • The most abundant and widely distributed of the tissue types • Large amount of noncellular material (matrix) between the cells • With few exceptions (cartilages, tendons and ligaments), connective tissues have a rich supply of blood vessels • Functions include protection, support, and binding together other tissues of the body

  28. Fig 1.21 P. 18

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