Chapter 1 Major Themes of Anatomy Physiology

1. Chapter 1Major Themes of Anatomy & Physiology Structure and Function Origins of Biomedical Science Scientific Method Human Evolution Nature of Life Homeostasis

2. Anatomy - The Study of Form Observation of surface structure Cadaver dissection is cutting & separation of tissues to study their relationships Comparative anatomy is the study of more than one species to analyze evolutionary trends Physical examination palpation, auscultation, percussion Gross anatomy is what is visible with naked eye Histology is examination of cells with microscope

3. Physiology - The Study of Function Study of bodily functions by use of methods of experimental science Comparative physiology involves the study of different species Basis for the development of new drugs and medical procedures

4. Beginnings of Medicine Physicians in Mesopotamia & Egypt 3000 years ago used herbal drugs, salts & physical therapy Greek physician Hippocrates established a code of ethics & urged physicians to seek causes of disease Aristotle called causes for disease physiologi & said that complex structures are built from simpler parts Galen, physician to the Roman gladiators, saw science as a method of discovery did animal dissections since use of cadavers banned wrote book advising followers to trust their own observation

5. Birth of Modern Medicine Little advancement during the Middle ages since medicine was taught as dogma with no new ideas Avicenna from Muslim world supported free inquiry over authority wrote The Canon of Medicine, used in medical schools until 16th century Vesalius accurately illustrated gross anatomy in 1543 Harvey realized blood flow out from heart & back in 1628 Leeuwenhoek invented microscope to look at fabrics (1632-1723) Hooke and Zeiss (1830)developed & improved compound microscope (wrote Micrographia in 1665) Schleiden & Schwann thought that all organisms were composed of cells -- cell theory of 1839 Clinical practice was in dismal state bleeding patients to remove toxins, operate with dirty hands, no anesthesia for amputations

6. Living in a Revolution Pioneers in establishing the scientific way of thinking occurred in 19th & 20th centuries germ theory of disease mechanisms of heredity & structure of DNA Now, on threshold of modern biomedical science Technology enhanced diagnostic ability & life-support strategies Verge of a genetic revolution due to library of the molecular structure of every human gene

7. Scientific Method Bacon (1561-1626) and Descartes (1596-1650) were not scientists but did invent new habits of scientific thought scientific method as habits of disciplined creativity, careful observations, logical thinking & analysis of observations way of seeking trends & drawing generalizations Convinced governments of England & France to form academies of science that still exist today Scientific way of thinking based on assumptions & methods that are reliable, objective & testable

8. Inductive Method First described by philosopher Francis Bacon Making observations until capable of drawing generalizations and making predictions anatomy is a product of inductive method Proof in science can not go past �proved beyond reasonable doubt� reliable methods of observation tested and confirmed repeatedly not falsified by any credible observation In science, all truth is tentative

9. Hypothetico-Deductive Method Physiological knowledge gained by this method Ask a question and formulate a hypothesis -- an educated possible answer Good hypothesis consistent with what is already known capable of being tested and falsified Falsifiability means that certain evidence would prove something wrong if nothing could prove it wrong, it is not a scientific belief

10. Proper Experimental Design Sufficient sample size to prevent chance event Control group receiving the same treatment except for the variable being tested Prevention of psychosomatic effects use of placebo in control group Experimenter bias prevented with double-blind study Statistical testing to be sure the difference between groups was not random, but was due to variable being tested

11. Peer Review Critical evaluation by other experts in the field Ensures honesty, objectivity & quality in science

12. Facts, Laws and Theories Scientific fact is information that can be independently verified by any trained person iron deficiency leads to anemia Law of nature is a generalization about the way matter and energy behave -- resulting from inductive reasoning & repeated observations first law of thermodynamics is that energy can be converted from one form to another but not destroyed Theory is an explanatory statement that makes predictions and suggests areas for further study sliding filament theory, fluid-mosaic theory, cell theory

13. Human Evolution Charles Darwin proposed the theory of natural selection to explain how species originate and change through time On the Origin of Species by Means of Natural Selection (1859) The Descent of Man (1871) discussed human evolution & our relationships to other animals Changed our view of our origin, our nature & our place in the universe Good understanding of our evolutionary history deepens our understanding of form & function

14. Evolution, Selection, and Adaptation Evolution is change in genetic composition of a population of organisms development of bacterial resistance to antibiotics, new strains of AIDS virus and new species Theory of natural selection some individuals have hereditary advantages (adaptations) enabling them to produce more offspring if they pass these characteristics on it brings about a genetic change in the population (evolution) forces that favor some individuals over others are called selection pressures -- climate, disease, etc.

15. Evidence of Human Evolution DNA hybridization suggests a difference of only 1.6% in DNA structure between humans & chimpanzees Evolutionary developments help explain some aspects of our anatomy arrector pili muscle in the skin have no use auricularis muscles do not move in most people Evolutionary relationships help us chose animals for biomedical research rats & mice used extensively

16. Life in the Trees Origin of primates began 60 million years ago Squirrel-sized, insect-eating mammals became arboreal probably due to safety, food supply & lack of competition shoulder became more mobile (reach any direction) thumbs became opposable to be able to encircle branches with thumb & fingers (prehensile) forward-facing eyes provide (depth perception) judge distances accurately to jump & catch prey color vision to distinguish ripe fruit larger brains & good memory to remember food sources

17. Walking Upright African forest became grassland 5 million years ago Bipedalism (standing & walking on 2 legs) evolved spot predators, carry food or infants Adaptations for bipedalism pelvis, femur, knee, great toe, arch, skull, vertebrae, etc. Australopithecus (2.5mya) gave rise Homo habilis taller, larger brain volume, speech, tool-making Homo erectus (1.1mya) and Homo sapiens (.3mya) Homo sapiens include Neanderthal & Cro-Magnon

18. Primate Phylogeny

19. What is Life? Properties that distinguish from nonliving things: organization & cellular composition biochemical composition (DNA, proteins, etc) metabolism is transformation of molecules into others responsiveness is ability to sense & react to stimuli homeostasis is to maintain stable internal environment development is change over time (growth or differentiation) reproduction is producing copies of themselves evolution is genetic change between generations Clinical death is no brain waves for 24 hours

20. What is a Human? Phylum Chordata Subphylum Vertebrata Class Mammalia Order Primates Family Hominidae Genus Homo Species Homo sapiens

21. Our Chordate Characteristics Notochord flexible rod on upper side of body -- replaced by vertebral column during development Dorsal hollow nerve cord Gill pouches bulges in throat region develop into gills in fish & amphibians Postanal tail GI tracts end before end of tail tail in humans visible only in embryo

22. Our Vertebrate Characteristics Subphylum Vertebrata Characteristics of all internal skeleton jointed vertebral (spinal) column well developed brain & sense organs cranium to protect the brain

23. Our Mammalian Characteristics Class Mammalia Characteristics of all mammary glands for nourishment of young hair to retain body heat endothermy is ability to generate most of body heat heterodonty is possession of varied types of teeth single lower jawbone provides for better chewing 3 middle ear bones

24. Primate & Hominid Characteristics Order Primates Characteristics of all 4 upper and lower incisors for front cutting pair of clavicles (collarbones) only 2 mammary glands pendulous penis, attached only at base forward-facing eyes with stereoscopic vision flat nails in place of claws opposable thumbs Family Hominidae are only bipedal primates Homo sapiens are only surviving species

25. Structure - A Hierarchy of Complexity Subatomic particles compose atoms Atoms compose molecules Molecules compose organelles Organelles compose cells Cells compose tissues Tissues compose organs Organs compose organ systems Organ systems compose the organism

26. Homeostasis Hippocrates noted that body normally returns to a state of equilibrium by itself needs to detect the change & oppose it Walter Cannon (1871-1945) coined the term homeostasis indicating stable internal environment Internal environment described as dynamic equilibrium fluctuates within a range around a certain set point

27. Negative Feedback and Stability Mechanism to keep a variable close to its set point Body senses a change & activates mechanisms to reverse it

28. Negative Feedback, Set Point Room temperature does not stay at set point of 68 degrees -- it only averages 68 degrees

29. Human Thermoregulation Temperature sensing nerve cells in base of brain control shivering, sweating & vasomotor activity vasodilation & vasoconstriction Evaporation of water & heat radiation occur

30. Structures Needed for Feedback Loop Receptor = structure that senses change stretch receptors in heart & large blood vessels send information of an elevated BP to integrator Integrator = control center cardiac center in brainstem that signals heart to slow Effector = structures that carry out commands of the control center heart slows and BP decreases

31. Positive Feedback Loops Self-amplifying cycle in which a physiological change leads to an even greater change in the same direction Normal way of producing changes during birth, blood clotting, protein digestion & generation of nerve signals

32. Fever If temperature rises above 108 degrees metabolic rate increases causing body to produce heat faster still Temperature increases & cycle repeats again Fatal at 113 degrees

33. Review of Major Themes Unifying principles behind all aspects of human anatomy and physiology cell theory: all structure & function result from the activity of cells homeostasis: maintaining stable conditions within the body evolution: the body is a product of evolution, molded by years of natural selection hierarchy of structure: levels of complexity unity of form and function: physiology can not be separated from anatomy

34. Noninvasive Medical Imaging Radiography x-rays discovered by William Roentgen in 1885 penetrate soft tissues of body & darken photographic film on other side of the body Sonography handheld device produces high-frequency ultrasound waves and receives echoes back from internal organs obstetrics uses to locate placenta, evaluate fetal age, position and development used medically in the 1950s but little value until computers could develop differences in echoes

35. Noninvasive Medical Imaging Computed Tomography (CT scan) low-intensity X rays applied to the body computer analysis produces an image of a slice of the body about as thin as a coin from which a three-dimensional image of the body is constructed tumors, aneurysms, hemorrhages, kidney stones, etc Magnetic Resonance Imaging (MRI) magnetic field aligns hydrogen atoms; radio waves realign the atoms; when radio is turned off the atoms give off energy depending on tissue type computer analysis produces a �slice� type image

36. Noninvasive Medical Imaging Positron Emission Tomography (PET) assesses the metabolic state of a tissue injection of radioactively labeled glucose emits positrons; colliding positrons & electrons give off gamma rays that are analyzed by computer color image which tissue were using glucose at the moment extent of damaged heart tissue activity of brain of neurology patients