biology 1120 – anatomy & physiology chapter 1 major … 1120 – anatomy & physiology 2...
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Biology 1120 – Anatomy & Physiology
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Chapter 1 Major Themes of Anatomy & Physiology
Form (anatomy) fits function (physiology) History of Biomedical Science Scientific Method Human Origins and Adaptations Human Structure & function Homeostasis Language of Medicine Imaging
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Anatomy – the study of form
Describes the structures of the body: □ what they are made of □ where they are located □ associated structures
□ Example: the heart
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What is the difference between the heart of an athlete …
5 Couch potato – someone who sits around on the couch all day
and a couch potato?
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Anatomy
We study by Observation, palpation, auscultation,
percussion
Cadaver dissection □ cutting and separation of organs
Comparative anatomy □ study of more than one species to analyze
evolutionary trends
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Microscopic Anatomy □ Involves studying anatomical structures that
cannot be seen with the unaided eye • Cytology - cells • Histology – tissue
8 Vitruvian man - Leonardo da Vinci
Early Anatomical Drawings
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Unrealistic anatomy: human barbie – had ribs removed to have the same dimensions as barbie doll
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Physiology – the study of function
Describes □ functions of anatomical structures
- operation of the heart and blood vessels (eg blood pressure)
- kidney function - workings of the nervous system
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Physiology
We study by: Using methods of experimental science Comparative physiology □ study of different species (can’t test drugs on
humans) □ Basis for the development of new drugs and medical
procedures
Fields include: □ Pathophysiology □ Neurophysiology
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THE HISTORY OF MEDICINE
China □ Yin and yang □ Herbal remedies □ Channels in body through which energy (Qi) flows □ Acupuncture – based on opening channels
Ancient Egypt and Mesopotamia □ Knowledge from preparation of dead □ Heart weighed against feather by 42 divine judges
to allow person into world of gods
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Ancient Greeks □ Hippocrates (460-375 bce)
- believed there were natural causes of disease
- established basis for a code of ethics □ Aristotle
- Believed in natural (physici) or supernatural causes (theologi)
- Complex structures build from simpler, smaller components
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The Hippocratic Oath
I swear by Apollo the physician, and Asclepius, and Health, and All-heal, and all the gods and goddesses . . . to reckon him who taught me this Art equally dear to me as my parents, to share my substance with him, and relieve his necessities if required; to look upon his offspring in the same footing as my own brothers, and to teach them this art, if they shall wish to learn it, without fee or stipulation; and that by precept, lecture, and every other mode of instruction, I will impart a knowledge of the Art to my own sons, and those of my teachers, and to disciples bound by a stipulation and oath according to the law of medicine, but to none others. I will follow that system of regimen which, according to my ability and judgment, I consider for the benefit of my patients, and abstain from whatever is deleterious and mischievous. I will give no deadly medicine to any one if asked, nor suggest any such counsel; and in like manner I will not give to a woman a pessary to produce abortion. . . . Into whatever houses I enter, I will go into them for the benefit of the sick, and will abstain from every voluntary act of mischief and corruption; and, further from the seduction of females or males, of freemen and slaves. Whatever, in connection with my professional practice or not, in connection with it, I see or hear, in the life of men, which ought not to be spoken of abroad, I will not divulge, as reckoning that all such should be kept secret. 16
The Roman World (up to about 450 CE)
Claudius Galen of Pergamum (130-210) Physician to gladiators & Roman emperors □ Produced 500 books and other writings on medicine
and philosophy □ Galen’s understanding of the human body prevailed
for 1,500 years. □ Adopted the idea of four humors of the body
- Black bile, yellow bile, phlegm, blood □ Began bloodletting to balance these humors
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Dark Ages / Medieval (400 – 1450 CE)
Medieval Europe adopted Galen’s writings without question
Adopted bloodletting (barbers & leeches)
Abandoned sanitation
Dark Ages were dominated by the Church
Hospitalia established to provide shelter for pilgrims & evolved into places of refuge for the sick and dying.
Classical medical knowledge was preserved in the Muslim world.
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Canon of Medicine
Avicenna (980-1037) □ Studied ancient medicine – Greek, Persian, Indian □ Compiled the Canon of Medicine in 1025, including
his own experience - Body consists of organs, four humors, four elements
(earth, air, fire water) and vital force (link between body, spirit and soul)
- Developed treatments such as clearing airways with reeds or tubes of gold
- Toothache: dissolve opium seeds in rose-oil & drop in ear nearest painful tooth
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Renaissance / Enlightenment (post 1450)
A revival of interest in scientific enquiry Andreas Vesalius □ Displaced much of Galen’s work with cadaver
dissections William Harvey (1578-1657) □ published his views on the circulation of blood in
1628. René's Descartes (1590-1650) □ put forward the idea that the body was a machine
made up of parts (Cartesian view). Hospitals and medical schools established in
18th century. 20
James Lind (1716-1794) identified a cure for scurvy (citrus fruit) using a controlled experiment in 1747.
Edward Jenner (1749-1823) noticed that milkmaids who caught coxpox rarely developed smallpox. □ Innoculated a boy with cowpox in 1796. He then
unsuccessfully attempted to infect him with smallpox. □ Jenner’s vaccination was much safer than smallpox
inoculation, became popular and did much to reduce smallpox mortality.
Vaccinia
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The 19th Century (1)
Girolamo Fracastoro (1478-1553) had suggested that diseases were caused by invisible ‘seminaria’ (germs).
Prevailing view in early 19th century was that diseases were caused by ‘miasmas’.
French investigation of yellow fever epidemic in Barcelona in 1822 ‘proved’ contagion was not possible (people not in contact with other contracted it – but they didn’t know about mosquito carriers)
We know now that germ theory is correct.
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The 19th Century (2)
Ignaz Philipp Semmelweiss (1818-1865) reduced deaths from fever in Vienna & Budapest by insisting that anyone delivering a baby should wash in chlorinated lime.
Joseph Lister (1827-1912) reduced mortality from infections after surgery from 50% to 15% in 1861 using antiseptics.
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Florence Nightingale
1820 – 1910 Founded the modern
nursing profession Nightingale School of
Nursing Nightingale Research
Foundation (Canada) Florence Nightingale
Effect
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The 19th Century (3)
Louis Pasteur (1822-1885) published his germ theory in 1861. Devised method for agents to use as vaccines.
Robert Koch (1843-1910) identified causal agents of tuberculosis (1882) and cholera (1883).
By 1900 miasmatic theory was totally discredited.
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Scientific Method
Bacon (1561-1626) and Descartes (1596-1650) Invented new habits of scientific thought □ scientific method as habits of disciplined creativity,
careful observations, logical thinking & analysis □ way of seeking trends & drawing generalizations
Scientific way of thinking based on assumptions & methods that are reliable, objective & testable
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Two scientific methods: Inductive and Deductive
Inductive: Making observations until generalizations
can be drawn and prediction made □ Anatomy is a product of inductive method □ Specific observations lead to generalizations
Deductive: Observations lead to questions □ Q. what causes uterine contractions in childbirth?
Form an hypothesis □ Oxytocin causes uterine contractions
Test the hypothesis with an experiment □ Isolate muscle tissue and apply oxytocin
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Experimental Design
Sufficient sample size to prevent chance event
Control group and treatment group receive 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
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Peer Review
Critical evaluation by other experts in the field
Ensures honesty, objectivity & quality in science
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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 description of the way matter and energy behave □ resulting from inductive reasoning & repeated observations □ written as verbal statements or mathematical formulae □ first law of thermodynamics
Theory is a summary of conclusions drawn from observable facts □ it provides explanations and predictions □ sliding filament theory of muscle contraction
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Human Origins and Adaptations
Charles Darwin’s theory of natural selection explains 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
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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 emergence of 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.
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Adaptations
Adaptations are useful features that evolved in response to selection pressures
DNA hybridization suggests a difference of only 1.6% in DNA structure between humans & chimpanzees
Evolutionary relationships help us choose animals for biomedical research □ rats & mice used extensively
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Adaptations
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Wisdom teeth
Third eyelid Vomeronasal organ Extrinsic ear
muscles
Darwin’s point
Neck rib
Palmaris muscle
Erector pili
Body hair
Thirteenth rib
Pyramidalis muscle
Male uterus
Female vas deferens
Fifth toe Plantaris muscle
Appendix
Male nipples
Subclavius muscle
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Primate Adaptations
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Primate Adaptations
Some human features can be traced to the earliest primates
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 encircle branches with
thumb & fingers (prehensile) □ forward-facing eyes provide depth perception
- judge distances accurately for leaping & catching prey □ color vision to distinguish ripe fruit □ larger brains & good memory to remember food
sources
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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 Evolutionary medicine traces our diseases to
evolutionary past 40
Primate Phylogeny
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Human Structure
Hierarchy of complexity □ organ systems □ organs □ tissues □ cells □ organelles □ molecules □ atoms
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Anatomical Variation
No 2 humans are exactly alike Missing organs □ palmaris longus or plantaris muscles
More or less organs than normal □ 2 spleens, single kidney, 6 or 4 lumbar vertebrae
Variation in organ locations (situs inversus, dextrocardia, situs perversus)
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Human Function
Characteristics of life □ organization □ cellular composition □ excretion □ metabolism □ responsiveness and movement □ homeostasis □ development (growth or differentiation) □ reproduction □ evolution
Clinical death is no brain waves for 24 hours 44
Physiological Variation
Differs with sex, age, diet, weight, degree of physical activity
Typical human values □ reference man
- 22 years old, 154 lbs, light physical activity - 2800 kcal/day
□ reference woman - same as man except 128 lbs and 2000 kcal/day
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Homeostasis
Internal environment described as dynamic equilibrium □ fluctuates within a range around a certain set point
Loss of homeostatic control causes illness or death
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Human Thermoregulation
Blood temperature sensing nerve cells in base of brain control shivering, sweating & vasomotor activity □ vasodilation with heat & vasoconstriction with cold
Evaporation of water & heat radiation occur
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History of Anatomical Terminology
Most medical terms are formed from Greek and Latin roots
Fast-paced anatomical discoveries during the Renaissance resulted in naming confusion □ different countries naming same structures with different
names □ structures being named after people (eponyms)
Anatomy meetings in 1895 began search for uniform international terminology □ Nomina Anatomica (NA) rejected all eponyms
- gave each structure a unique Latin name to be used worldwide □ Terminologia Anatomica was codified in 1998 48
Analyzing Medical Terms
Medical terminology based on word elements □ lexicon of 400 common word elements in back of
book Scientific terms are composed of the
following elements □ at least one root (stem) that bears the core meaning □ combining vowels that join roots together □ prefix that modifies the core meaning of the word □ suffix that modifies the core meaning of the word
acronyms – words composed of the first few letters of a series of words
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Useful Tables in Textbook
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Review of Major Themes
Cell theory □ activity of cells determine structure and function
Homeostasis □ maintaining stable internal conditions
Evolution □ our body evolved by natural selection
Hierarchy of structure □ levels of complexity
Unity of form and function □ physiology is inseparable from anatomy
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Medical Imaging
Radiography (x rays) □ William Roentgen - 1885 □ penetrate soft tissues and
darken photographic film □ dense tissue remains white
Radiopaque substances □ injected or swallowed □ hollow structures
– blood vessels – intestinal tract
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Medical Imaging
Computed Tomography (CT scan) □ low-intensity X rays and computer analysis
- slice type image - increased sharpness
Magnetic Resonance Imaging (MRI) □ slice type image □ best for soft tissue □ Mechanics
- magnetic field aligns atoms - radio waves realign the atoms - radio turned off - atoms realign to the magnetic field - energy given off depending on tissue type
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Medical Imaging
Positron Emission Tomography (PET scan) □ assesses metabolic state □ mechanics
- inject labeled glucose – positrons and electrons collide – gamma rays given off
- analyzed by computer – image glucose usage
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Medical Imaging
Sonography □ mechanics
- high-frequency sound waves echo back from internal organs
□ avoids harmful x rays □ obstetrics □ 2nd most commonly used
technique
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Summary (1)
Anatomy & physiology intimately related (form fits function)
Gross (naked eye) & micro (histology) Two contexts in which to place A&P: □ Evolutionary adaptations of humans □ Health and wellness
History of medicine □ Science emerged in Greece, disappeared during the
dark ages (in Europe), and remerged in the Renaissance
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Summary (2)
Technology and new discoveries intimately related □ Especially the microscope and imaging techniques
Francis Bacon and Renee Descartes helped propagate scientific thought □ Inductive and deductive reasoning □ Experimental design & rigorous testing □ Peer review
Facts, laws and theories
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Summary (3)
Human origins & adaptations □ Adaptive traits are selected by environmental
pressures – called natural selection – resulting in disproportionate survival
□ Hereditary traits passed on to next generation □ Results in descent with modification (evolution), and
speciation
Primate adaptations and phylogeny □ Our ancestors went from quadripedalsim to
bipedalism, from forest & trees to grasslands 58
Summary (4)
Gives context to current human anatomy & physiology (vestigial organs, fight or flight response)
Human structure □ Hierarchy of complexity, simple level entrains into
next level. - Cells together form tissue, which can perform functions
cells cannot on their own (eg muscles)
Human function – all functions to support life □ Energy, growth, response, reproduction
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Summary (5)
Homeostasis (property of life) □ Negative & positive feedback loops
Medical terminology Medical imaging Orientation □ Anatomical position, planes, directional terms □ Body regions □ Body cavities and membranes
Organ systems