1-1 Chapter 1 Lecture Outline Copyright (c) The McGraw-Hill Companies, Inc. Permission required for...

1-1

Chapter 1Lecture Outline

Copyright (c) The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

1-2

Major Themes of Anatomy and Physiology

• Form and Function

• Origins of Biomedical Science

• Scientific Method

Organism

Organ system Organ Tissue

Cell

OrganelleMacromolecule

MoleculeAtom

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Figure 1.7

1-3

• Human Originsand Adaptations

• Human Structure

• Human Function

• Language of Medicine

Major Themes of Anatomy and Physiology 2

Organism


Cell


MoleculeAtom


Figure 1.7

1-4

Anatomy - The Study of Form• Examining structure of the Human Body

– inspection– palpation– auscultation– percussion

• Cadaver dissection – cutting and separation of tissues to reveal their

relationships

• Comparative anatomy – study of more than one species in order to examine

structural similarities and differences, and analyze evolutionary trends

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• Exploratory Surgery– open body and take a look inside

• Medical imaging– viewing the inside of the body without surgery– Radiology – branch of medicine concerned with imaging

• Gross Anatomy– study of structures that can be seen with the naked eye

• Cytology– study of structure and function of cells

• Histology (microscopic anatomy)– examination of cells with microscope

• Ultrastructure– the molecular detail seen in electron microscope

• Histopathology– microscopic examination of tissues for signs of disease

Anatomy - The Study of Form

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Physiology - The Study of Function

• Subdisciplines– neurophysiology (physiology of nervous system)– endocrinology (physiology of hormones)– pathophysiology (mechanisms of disease)

• Comparative Physiology– limitations on human experimentation– study of different species to learn about bodily function

• animal surgery• animal drug tests

– basis for the development of new drugs and medical procedures

1-7

Greek and Roman Legacy

• Physicians in Mesopotamia and Egypt – 3000 years ago used herbal drugs, salts and

physical therapy

• Hippocrates - Greek physician – “father of medicine”– established a code of ethics (Hippocratic Oath)– urged physicians to seek natural causes of disease

rather than attributing them to acts of the gods and demons

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• Aristotle – one of the first philosophers to write about

anatomy and physiology

– believed that diseases had either supernatural causes or physical causes

• called supernatural causes of disease theologi• called natural causes for disease physiologi• this gave rise to the terms: physician and physiology

– believed that complex structures are built from simpler parts


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• Claudius Galen

– physician to the Roman gladiators

– did animal dissections since use of cadavers banned in his time

– saw science as a method of discovery not just a body of facts taken on faith

– wrote book advising followers to trust their own observation more than the teaching of dogma of the “ancient masters”


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Birth of Modern Medicine• Christian culture of Europe in Middle Ages

– science severely repressed– taught medicine primarily as dogmatic commentary on Galen and

Aristotle– crude medical illustrations

• In Jewish and Muslim cultures free inquiry was less inhibited

• Jewish physician Maimonides (Moses ben Maimon) – wrote 10 influential medical texts – was physician to Egyptian sultan, Saladin

• Avicenna (Ibn Sina) from Muslim world– “the Galen of Islam”– combined Galen and Aristotle findings with original discoveries– wrote The Canon of Medicine, used in medical schools for 500

years

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Birth of Modern Medicine around the 16th century

• Andreas Vesalius – taught anatomy in Italy– Catholic Church relaxed restrictions on dissection of cadavers and

permitting autopsies– barbering and surgery were considered ‘kindred arts of the knife’– performed his own dissections rather than the barber-surgeons– published first atlas of anatomy, Di Humani Corporis Fabrica (On the

Structure of the Human Body) in 1543

• William Harvey– early physiologist…contributions represent the birth of experimental

physiology– remembered for early studies on blood circulation– realized blood flows out from heart and back to it again– published book De Motu Cordis (On the Motion of the Heart) in 1628– Michael Servetus, along with Harvey, were the first Western

scientists to realize that blood must circulate continuously around the body, from the heart to other organs, and back to the heart again

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Early Medical Illustrations

Figure 1.3


Art Resource © SPL/Photo Researchers, Inc.


Figure 1.2

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• Robert Hooke– made many improvements to the compound microscope -2 lenses-

ocular lens (eyepiece) and objective lens (near specimen)• invented specimen stage, illuminator, coarse and fine focus controls • his microscopes magnified only 30X• first to see and named ‘cells’

– published first comprehensive book of microscopy (Micrographia) in 1665

• Antony van Leeuwenhoek– invented a simple (single-lens) microscope with great magnification to

look at fabrics (200X)– published his observations of blood, lake water, sperm, bacteria from

tooth scrapings and many other things

Birth of Modern Medicine

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• Carl Zeiss & Ernst Abbe– greatly improved compound microscopes– added condenser and superior optics

• eliminated blurry edges (spherical aberration) and rainbow-like distortions (chromatic aberration)

• Matthias Schleiden and Theodor Schwann– with improved microscopes, examination of a wide variety of specimens followed– concluded that “all organisms were composed of cells”– first tenet of Cell Theory

• considered as the most important breakthrough in biomedical history• all functions of the body are interpreted as effects of cellular activity

Birth of Modern Medicine

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Early Compound Microscopes

The first cells seen were plant cell walls in a section of dried cork.

Figure 1.4

(a) (b)


a: Courtesy of the Armed Forces Institute of Pathology; b: © Corbis–Bettmann

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Living in a Revolution

• Modern biomedical science– technological enhancements

• advances in Medical Imaging have enhanced our diagnostic ability and life-support strategies

• Genetic Revolution• human genome is finished• gene therapy is being used to treat disease

• Early pioneers were important– established scientific way of thinking– replaced superstition with natural laws

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Scientific Method

• Francis Bacon, in England, and

Rene Descartes, in France– philosophers who invented new habits of scientific

thought– sought systematic way of seeking similarities,

differences, and trends in nature and drawing useful generalizations from observable facts

• Governments of England and France– established academies of science -- still exist today

• Science and scientific methods– set standards for truth

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Inductive Method

• Described by Francis Bacon– making numerous observations until one becomes

confident in drawing generalizations and predictions from them

– knowledge of anatomy obtained by this method

• Proof in science – reliable observations– tested and confirmed repeatedly– not falsified by any credible observation

• In science, all truth is tentative– “proof beyond a reasonable doubt”

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Hypothetico-Deductive Method• more physiological knowledge gained by this

method• investigator asks a question• formulates a hypothesis- an educated speculation or

possible answer to the question– characteristics of a good hypothesis

• consistent with what is already known• testable and possibly falsifiable with evidence

• Falsifiability – if we claim something is scientifically true, we must be able to specify what evidence it would take to prove it wrong

• Hypothesis - to suggest a method for answering questions - are written as ‘If-Then’ statements

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Experimental Design

• Sample size– number of subjects used in a study– controls for chance events and individual variation

• Controls– control group and treatment group– comparison of treated and untreated individuals

• Psychosomatic Effects – effects of the subject’s state of mind on his or her

physiology– use of placebo in control group

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• Experimenter bias – prevented with double-blind study

• Statistical testing – provides statements of probability – difference between control and test subjects

was not random variation– results due to the variable being tested

Proper Experimental Design

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Peer Review

• Critical evaluation by other experts in the field– done prior to funding or publication– done by using verification and repeatability of

results

• Ensures honesty, objectivity and quality in science

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Facts, Laws and Theories

• Scientific fact– information that can be independently verified by a trained

person

• Law of nature– generalization about the predictable way matter and

energy behave • results from inductive reasoning and repeated observations• written as verbal statements or mathematical formulae

• Theory– an explanatory statement or set of statements derived from

facts, laws, and confirmed hypotheses• summarizes what we know• suggests direction for further study

1-24

Human Origins & Adaptations

• Charles Darwin– On the Origin of Species by Means of Natural

Selection (1859) – ‘book that shook the world’– The Descent of Man (1871) – human evolution

• Theory of natural selection– how species originate and change through time– changed view of “our origin, our nature and our

place in the universe”– increases understanding of human form and

function

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Evolution, Selection, and Adaptation

• Evolution– change in genetic composition of population of organisms

• development of bacterial resistance to antibiotics• appearance of new strains of AIDS virus

• Natural Selection– some individuals within a species have hereditary

advantage over their competitors• better camouflage• disease resistance• ability to attract mates

– produce more offspring and advantage passed on

– Selection Pressures – natural forces that promotethe reproductive success of some individuals morethan others

1-26

Evolution, Selection, and Adaptation

• Adaptations – features of an organism’s anatomy, physiology, or behavior that have evolved in response to these selection pressures and enable the organism to cope with the challenges of its environment.– Model – animal species selected for research on a

particular problem

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Animal Relations

• Closest relative - chimpanzee– difference of only 1.6% in DNA structure – chimpanzees and gorillas differ by 2.3%

• Study of evolutionary relationships– help us chose animals for biomedical

research (the animal model)– rats and mice used extensively due to issues

involved with using chimpanzees

1-28

Vestiges of Human Evolution

• Vestigial Organs – remnants of organs that apparently were better developed and more functional in the ancestors of a species, and now serve little or no purpose– piloerector muscle– auricularis muscles

1-29

Life in the Trees• Primates – order of mammals to which humans, monkeys, and apes

belong

• Earliest Primates – squirrel-sized, arboreal, insect-eating African mammals– moved to trees due to safety, food supply and lack of competition

• Adaptations for arboreal (treetop) life style– mobile shoulders– opposable thumbs made hands prehensile to grasp branches and

encircle them with the thumb and finger– forward-facing eyes (stereoscopic vision)

• depth perception for leaping and catching prey– color vision

• distinguish ripe fruit and young, less toxic foliage– larger brains and good memory

• remember food sources and improved social organization

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Walking Upright

• African forest became grassland 4-5 million years ago– producing more predators and less protection

• Bipedalism - standing and walking on 2 legs

– helps spot predators, carry food or infants

• Adaptations for bipedalism– skeletal and muscular modifications– increased brain volume– family life and social changes

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• Australopithecus – oldest bipedal primate

• Homo genus (appeared 2.5 million years ago) • taller, larger brain volume, probable speech, tool-making

• Homo erectus (appeared 1.8 million years ago)– migrated from Africa to parts Asia

• Other Homo species discovered recently still matter of considerable debate

• Homo sapiens originated in Africa 200,000 years ago– sole surviving hominid species

• Evolutionary (darwinian) medicine traces some of our diseases and imperfections toour past

Walking Upright

1-32

Hierarchy of Complexity

• Organism is composed of organ systems

• Organ Systems composed of organs

• Organs composed of tissues

• Tissues composed of cells

• Cells composed of organelles

• Organelles composed of molecules

• Molecules composed of atoms

Organism


Cell


MoleculeAtom


Figure 1.7

Hierarchy of Complexity• Organism – a single, complete individual

• Organ System – human body made of 11 organ systems

• Organ – structure composed of two or more tissue types that work together to carry out a particular function

• Tissue – a mass of similar cells and cell products that form discrete region of an organ and performs a specific function

• Cells – the smallest units of an organism that carry out all the basic functions of life– Cytology – the study of cells and organelles

• Organelles – microscopic structures in a cell that carry out its individual functions

• Molecules – make up organelles and other cellular components

– macromolecules – proteins, carbohydrates, fats, DNA

• Atoms – the smallest particles with unique chemical identities1-33

Hierarchy of Complexity• Reductionism – theory that a large, complex system

such as the human body can be understood by studying its simpler components– first espoused by Aristotle– highly productive approach– essential to scientific thinking

• Holism – there are ‘emergent properties’ of the whole organism that cannot be predicted from the properties of the separate parts– humans are more than the sum of their parts– complementary theory to reductionism

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1-35

Anatomical Variation• No two humans are exactly alike

– 70% most common structure – 30% anatomically variant– variable number of organs

• missing muscles, extra vertebrae, renal arteries

– variation in organ locations (situs solitus, situs inversus, dextrocardia, situs perversus)

Figure 1.8

Variations in branches of the aorta

Normal

Normal

Pelvic kidney Horseshoe kidney


1-36

Characteristics of Life• Organization

• Cellular composition

• Metabolism– anabolism, catabolism and excretion

• Responsiveness and movement– stimuli

• Homeostasis

• Development – differentiation and growth

• Reproduction

• Evolution– mutations

1-37

Physiological Variation

• Sex, age, diet, weight, physical activity

• Typical physiological values– reference man

• 22 years old, 154 lbs, light physical activity• consumes 2800 kcal/day

– reference woman• same as man except 128 lbs and 2000 kcal/day

• Overmedication of elderly

1-38

Homeostasis• Homeostasis – the body’s ability to detect change,

activate mechanisms that oppose it, and thereby maintain relatively stable internal conditions

• Claude Bernard (1813-78) – constant internal conditions regardless of external

conditions• internal body temperature ranges from 97 to 99 degrees despite

variations in external temperature

• Walter Cannon (1871-1945) – coined the term ‘Homeostasis’– state of the body fluctuates (dynamic equilibrium) within

limited range around a set point– Negative feedback keeps variable close to the set point

• Loss of homeostatic control causes illnessor death

1-39

Negative Feedback Loop

• Body senses a change and activates mechanisms to reverse it - dynamic equilibrium

(a) 3

4

5

6

1

2

Room temperaturefalls to 66°F (19°C)

Room cools down

Thermostat activatesfurnace

Thermostat shutsoff furnace

Room temperaturerises to 70°F (21°C)

Heat output


C 10° 15° 20° 25°

F 50° 60° 70° 80°

C 10° 15° 20° 25°

F 50° 60° 70° 80°

Figure 1.9a

1-40

Negative Feedback, Set Point

• Room temperature does not stay at set point of 68 degrees -- it only averages 68 degrees

(b)

Ro

om

te

mp

era

ture

(°F

)

Time

Furnace turnedoff at 70°F

Set point 68°F

Furnace turnedon at 66°F


75

70

65

60

Figure 1.9b

1-41

Negative Feedback in Human Thermoregulation

• Brain senses change in blood temperature– if to warm, vessels dilate (vasodilation) in the skin and sweating

begins (heat losing mechanisms)– if too cold, vessels in the skin constrict (vasoconstriction)

and shivering begins (heat gaining mechanism)

Time

Sweating

Set point

Vasoconstriction

Vasodilation

36.5°C(97.7°F)

37.0°C(98.6°F)

37.5°C(99.5°F)

Shivering

Co

re b

od

y te

mp

erat

ure


Figure 1.10

1-42

Negative Feedback Control of Blood Pressure

• Sitting up in bed causes a drop in blood pressure in the head and upper thorax

• Baroreceptors in the arteries near the heart alert the cardiac center in the brainstem

• Cardiac center sends nerve signals that increase the heart rate and return the blood pressure to normal

• Failure of this to feedback loop may produce dizziness in the elderly

1-43

Control of Blood Pressure

Blood drains fromupper body, creatinghomeostatic imbalance

Baroreceptors aboveheart respond to dropin blood pressure

Baroreceptors send signalsto cardiac center of brainstem

Blood pressure risesto normal; homeostasisis restored

Person risesfrom bed

Cardiac centeraccelerates heartbeat


Figure 1.11

1-44

3 Components of a Feedback Loop

• Receptor - senses change in the body

• Integrating (Control) Center - control center that processes the sensory information, ‘makes a decision’, and directs the response

• Effector – carries out the final corrective action to restore homeostasis

1-45

Positive Feedback Loops• Self-amplifying cycle

– leads to greater change in the same direction– feedback loop is repeated – change produces more change

• Normal way of producing rapid changes – occurs with childbirth, blood clotting, protein digestion, fever, and

generation of nerve signals

Head of fetus

pushes against cervix

2

3

4

1

Oxytocin stimulates uterine

contractions and pushes

fetus toward cervix

Nerve impulses

from cervix

Transmitted

to brain

Brain stimulates

pituitary gland to

secrete oxytocin


Figure 1.12

1-46

Harmful Positive Feedback Loop

• Fever > 104 degrees F– metabolic rate increases– body produces heat even faster– body temperature continues to rise– further increasing metabolic rate

• Cycle continues to reinforce itself

• Becomes fatal at 113 degrees F

1-47

Anatomical Terminology

• Standard International Anatomical Terminology– Terminologia Anatomica was codified in 1998

by professional associations of anatomists

• About 90% of medical terms from 1,200 Greek and Latin roots

• Naming confusion during the Renaissance– same structures with different names in different countries– structures named after people (eponyms)

• 1895 Nomina Anatomica (NA) – rejected all eponyms– each structure given a unique Latin name to be used worldwide

1-48

Analyzing Medical Terms• Terminology based on word elements

– lexicon of 400 word elements on the inside the back cover of textbook

• Scientific terms – one root (stem) with core meaning– combining vowels join roots into a word– prefix modifies core meaning of root word– suffix modifies core meaning of root word

• Acronyms formed from first letter, or first few letters of series of words– Calmodulin comes from the phrase - calcium

modulating protein

1-49

Useful Tables in Textbook

1-50

Plural, Adjectival, and Possessive Forms

• Plural forms not always easy– ovary – ovaries, cortex – cortices, corpus – corpora, epididymis – epididymides

• Adjectival form of same word– brachium denotes ‘arm’ - digits – fingers and toes– brachii denotes ‘of the arm’ - digiti – of a single finger or toe

- digitorum – of multiple fingers or toes

• 3 examples of positive, comparative, and superlative degrees of comparison

• English – large, larger, and largest• Latin - magnus means large, major means larger of 2, while maximus is largest of 3

being compared

• Adjectives often follow the noun in a name• foramen magnum or pectoralis major

1-51

Importance of Precision

• Be precise in your terms

• Spell correctly

• Health Care professions demand the same type of precision

• People’s lives will be in your hands

1-52

Review of Major Themes• Cell Theory

– All structure and function result from the activity of cells

• Homeostasis– The purpose of most normal physiology is to maintain stable

conditions within the body

• Evolution– The human body is a product of evolution

• Hierarchy of Structure– Human structure can be viewed as a series of levels of complexity

• Unity of Form and Function– Form and function complement each other; physiology cannot be

divorced from anatomy

1-53

Medical Imaging

• Radiography (x rays)– William Roentgen - 1885– penetrate tissues to

darken photographic film beneath the body

– dense tissue appears white

– over half of all medical imaging

– until 1960’s, it was the only method widely available

1-54

Medical Imaging

• Radiopaque substances– injected or swallowed – fills hollow structures

• blood vessels• intestinal tract

(b) Cerebral angiogramCustom Medical Stock Photo, Inc.


Figure 1.13b

1-55

Medical Imaging

• Computed Tomography (CT scan)– formerly called a CAT

scan– low-intensity X rays

and computer analysis• slice type image• increased

sharpness of image

Figure 1.13c

(c) Computed tomographic (CT) scan© CNR/Phototake


1-56

Medical Imaging - Nuclear Medicine

• Positron Emission Tomography (PET scan)– assesses metabolic state of tissue– distinguished tissues most active at a

given moment– mechanics

• inject radioactively labeled glucose– positrons and electrons collide

– gamma rays given off

– detected by sensor

– analyzed by computer

– image color shows which tissues

were using the most glucose at that moment

– damaged tissues appear dark

1-57

Medical Imaging

• Magnetic Resonance Imaging (MRI)– slice type image– superior quality to CT scan– best for soft tissue– mechanics

• alignment & realignment of hydrogen atoms with magnetic field & radio waves

• varying levels of energy given off used by computer to produce an image

(e) Magnetic resonance image (MRI)


© Monte S. Buchsbaum, Mt. Sinai School of Medicine, New York, NY

Figure 1.13e

1-58

Medical Imaging

• Sonography– second oldest & second

most widely used

– mechanics• high-frequency sound

waves echo back from internal organs

– avoids harmful x rays• obstetrics• image not very sharp

Figure 1.14

(a)

(b)© Alexander Tsiaras/Photo Researchers, Inc.; (inset): Ken Saladin


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