Chapter 1 *Lecture Powerpoint Major Themes of Anatomy and Physiology

Chapter 1 *Lecture PowerPoint Major Themes of Anatomy and Physiology

*See separate FlexArt PowerPoint slides for all figures and tables preinserted into PowerPoint without notes.

• Anatomy and physiology (A&P) is about human structure and function—the biology of the human body • We want to know how our body works! • A&P is a foundation for advanced study in health care, exercise physiology, pathophysiology, and other health-care-related fields • Considers the historical development and a central concept of physiology—homeostasis

1-2 The Scope of Anatomy and Physiology

• Expected Learning Outcomes – Define anatomy and physiology and relate them to each other. – Describe several ways of studying human anatomy. – Define a few subdisciplines of human physiology.

1-3 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 Figure 1.1 – Study of more than one species in order to examine structural similarities and differences, and analyze evolutionary trends 1-4

Anatomy—The Study of Form • 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 – View molecular detail under electron microscope • Histopathology – Microscopic examination of tissues for signs of disease 1-5 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 1-6 The Origins of Biomedical Sciences • Expected Learning Outcomes – Give examples of how modern biomedical science emerged from an era of superstition and authoritarianism. – Describe the contributions of some key people who helped to bring about the transformation.

1-7 Greek and Roman Legacy

• Physicians in Mesopotamia and Egypt – 3,000 years ago used herbal drugs, salts, and physical therapy

• Hippocrates, the 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

1-8 Greek and Roman Legacy

• 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

1-9 Greek and Roman Legacy

• Claudius Galen

– Physician to the Roman gladiators – Did animal dissections since use of cadavers was banned in his time – Saw science as a method of discover, 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‖

1-10 The 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 1-11 The Birth of Modern Medicine

• 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, De Humani Corporis Fabrica (On the Structure of the Human Body) in 1543

1-12 The Birth of Modern Medicine

• 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, they 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

1-13 Early Medical Illustrations

Figure 1.2 Figure 1.3

1-14 The Birth of Modern Medicine

• Robert Hooke – Made many improvements to the compound microscope— two 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 name ―cells‖ – Published first comprehensive book of microscopy (Micrographia) in Figure 1.4 1665 1-15 The Birth of Modern Medicine

• 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

• Carl Zeiss and Ernst Abbe – Greatly improved compound microscopes – Added condenser and superior optics • Eliminated blurry edges (spherical aberration) and rainbowlike distortions (chromatic aberration)

1-16 The Birth of Modern Medicine

• 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

1-17 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

1-18 Scientific Method

• Expected Learning Outcomes – Describe the inductive and hypothetico– deductive methods of obtaining scientific knowledge. – Describe some aspects of experimental design that help to ensure objective and reliable results. – Explain what is meant by hypothesis, fact, law, and theory in science.

1-19 Scientific Method

• Francis Bacon, in England, and René 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 that still exist today • Science and scientific methods – Set standards for truth 1-20 The 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‖

1-21 The 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

1-22 The Hypothetico–Deductive Method

• 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: written as ―if–then‖ statements

1-23 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

1-24 Experimental Design

• 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

1-25 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

1-26 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 1-27 Human Origins and Adaptations

• Expected Learning Outcomes – Explain why evolution is relevant to understanding human form and function. – Define evolution and natural selection. – Describe some human characteristics that can be attributed to the tree-dwelling habits of earlier primates. – Describe some human characteristics that evolved later in connection with upright walking.

1-28 Human Origins and Adaptations

• Charles Darwin – On the Origin of Species by Means of Natural Selection (1859)—‟the book that shook the world‖ – The Descent of Man (1871)—human evolution, anatomy and behavior, relationship to other animals

• Theory of natural selection – How species originate and change through time – Changed prevailing view of our origin, nature and our place in the universe – Increases understanding of human form and function

1-29 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

– Selection pressures—natural forces that promote the reproductive success of some individuals more than others 1-30 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

1-31 Evolution, Selection, and Adaptation • 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

1-32 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

1-33 Our Basic Primate Adaptations

• 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

1-34 Our Basic Primate Adaptations

• Adaptations for arboreal (treetop) lifestyle – 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

1-35

Our Basic Primate Adaptations

Human

Figure 1.5 Figure 1.6 1-36 Walking Upright

• African forest became grassland 4 to 5 million years ago – Producing more predators and less protection • Bipedalism—standing and walking on two legs – Helps spot predators, carry food or infants • Adaptations for bipedalism – Skeletal and muscular modifications – Increased brain volume – Family life and social changes

1-37 Walking Upright

• 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

1-38 Walking Upright

• 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 to our past

1-39 Human Structure

• Expected Learning Outcomes – List the levels of human structure from the most complex to the simplest. – Discuss the value of both reductionistic and holistic viewpoints to understanding human form and function. – Discuss the clinical significance of anatomical variation among humans.

1-40 The Hierarchy of Complexity

• Organism is composed of

organ systems Organism

• Organ systems composed of organs

• Organs composed of tissues

• Tissues composed of cells Tissue Organ system Organ • Cells composed of organelles Cell Macromolecule • Organelles composed of Organelle molecules

Atom • Molecules composed of Molecule atoms Figure 1.7 1-41 The 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

1-42 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)

Normal

Pelvic kidney Horseshoe kidney

Figure 1.8

Normal 1-44 Variations in branches of the aorta Human Function

• Expected Learning Outcomes – State the characteristics that distinguish living organisms from nonliving objects. – Explain the importance of defining a reference man and woman. – Define homeostasis and explain why this concept is central to physiology. – Define negative feedback, give an example of it, and explain its importance to homeostasis. – Define positive feedback and give examples of its beneficial and harmful effects.

1-45

Characteristics of Life

• Organization—living things exhibit a higher level of organization than the nonliving world around them • Cellular composition—living matter is always compartmentalized into one or more cells • Metabolism—sum of all internal chemical change: anabolism, catabolism, and excretion • Responsiveness and movement—sense and react to stimuli (responsiveness, irritability, or excitability)

1-46

Characteristics of Life

• Homeostasis—maintaining relatively stable internal conditions • Development—differentiation and growth • Reproduction—producing copies of themselves; pass genes to offspring • Evolution—mutations: changes in genetic structure

1-47 Physiological Variation

• Sex, age, diet, weight, physical activity • Typical physiological values – Reference man • 22 years old, 154 lb, light physical activity • Consumes 2,800 kcal/day – Reference woman • Same as man except 128 lb and 2,000 kcal/day • Failure to consider variation can lead to overmedication of elderly or medicating women on the basis of research done on men 1-48 Homeostasis and Negative Feedback

• 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°–99°F despite variations in external temperature

1-49 Homeostasis and Negative Feedback

• 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 illness or death

1-50 Negative Feedback Loop

• Body senses a change and activates mechanisms to reverse it— dynamic equilibrium • Because feedback mechanisms alter the original changes that triggered them (temperature, for example), they are called feedback loops Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 Room temperature fallsto66°F(19°C)

C1015° °20 °25 ° 6 Room cools down

F5060° °70 °80 °

2 Thermost atactivates furnace C1015° °20 °25 °

F5060° °70 °80 ° 5 Thermostat shuts Figure 1.9a off furnace

4 Room temperature rises to 70°F (21°C)

3 Heat output 1-51 (a) Negative Feedback

75 Furnace turned

off at 70 oF

F) o 70

Set point 68 oF

Furnace turned on at 66 oF Room Room temperature ( 60 Time Figure 1.9b (b) • Example: Room temperature does not stay at set point of 68°F—it only averages 68°F 1-52 Negative Feedback

Sweating

37.5 oC (99.5 Vasodilation oF)

o 37.0 C Set point (98.6 oF) Vasoconstriction Core bodytemperature Core 36.5 oC (97.7 oF) Time Figure 1.10

Shivering • Example: Brain senses change in blood temperature – If too warm, vessels dilate (vasodilation) in the skin and sweating begins (heat-losing mechanism) – If too cold, vessels in the skin constrict (vasoconstriction)

and shivering begins (heat-gaining mechanism) 1-53 Homeostatis and Negative Feedback

• Sitting up in bed causes a drop in blood pressure in the head and upper torso region (local imbalance in homeostasis); detected by baroreceptors

• Baroreceptors (sensory nerve endings) in the arteries near the heart alert the cardiac center in the brainstem. They transmit to the cardiac center

1-54 Homeostatis and Negative Feedback

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

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

1-55 Postural Change in Blood Pressure

Person rises from bed Blood pressure rises Blood drains from to normal; homeostasis upper body, creating is restored homeostatic imbalance

Cardiac center accelerates heartbeat Baroreceptors above heart respond to drop in blood pressure Figure 1.11

Baroreceptors send signals to cardiac center of brainstem Homeostasis and Negative Feedback

• Receptor—senses change in the body (e.g., stretch receptors that monitor blood pressure)

• Integrating (control) center—control center that processes the sensory information, ―makes a decision,‖ and directs the response (e.g., cardiac center of the brain)

• Effector—carries out the final corrective action to restore homeostasis (e.g., cell or organ)

1-57 Positive Feedback and Rapid Change

• 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

1-58 Positive Feedback and Rapid Change • During birth, the head of the fetus pushes against the cervix and stimulates its nerve endings – Hormone oxytocin is secreted from the pituitary gland – Oxytocin travels through the bloodstream to the uterus stimulating it to contract – This action pushes the fetus downward toward cervix, thus stimulating the cervix more, causing the positive feedback loop to be repeated

3 Brain stimulates pituitary gland to secrete oxytocin

4 Oxytocin stimulates uterine 2 Nerve impulses contractions and pushes from cervix fetus toward cervix transmitted to brain

1 Head of fetus pushes against cervix

1-60 Positive Feedback and Rapid Change

• Fever > 104°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°F

1-61 The Language of Medicine

• Expected Learning Outcomes – Explain why modern anatomical terminology is so heavily based on Greek and Latin. – Recognize eponyms when you see them. – Describe the efforts to achieve an internationally uniform anatomical terminology. – Break medical terms down into their basic word elements. – State some reasons why the literal meaning of a word may not lend insight into its definition. – Relate singular noun forms to their plural and adjectival forms. – Discuss why precise spelling is important in anatomy and physiology. 1-62 The History of Anatomical Terminology

• Standard international anatomical terminology – Terminologia Anatomica (TA) was codified in 1998 by professional associations of anatomists

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

1-63 The History of Anatomical Terminology

• 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

1-64 Analyzing Medical Terms

• Terminology based on word elements – Lexicon of 400 word elements on the inside 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

1-65 Analyzing Medical Terms

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

1-66 Plural, Adjectival, and Possessive Forms

1-67 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‖ – Brachii denotes ―of the arm‖ – Digiti—of a single finger or toe – Digits—fingers and toes – Digitorum—of multiple fingers or toes

1-68 Plural, Adjectival, and Possessive Forms

• Three examples of positive, comparative, and superlative degrees of comparison • English: large, larger, and largest • Latin: magnus means ―large,‖ major means ―larger of two,‖ while maximus means ―largest of three being compared‖

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

1-69 Pronunciation

• Simple pronunciation guides for many terms are given when terms are first introduced

• Go to the Anatomy & Physiology/Revealed website for this book to hear pronunciation of most anatomical terms! – http://www.mhhe.com/sem/apr/

1-70 The 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

1-71 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 1-72 Medical Imaging

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Radiography (X-rays) – William Roentgen’s discovery in 1885 – Penetrate tissues to darken photographic film beneath the body – Dense tissue appears white – Over half of all medical imaging – Until 1960s, it was the only method widely available

(a) X-ray (radiograph)

Figure 1.13a 1-73 Medical Imaging

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Radiopaque substances – Injected or swallowed – Fills hollow structures • Blood vessels • Intestinal tract

Figure 1.13b

(b Cerebral angiogram Custom Medical Stock Photos, Inc. 1-74 Medical Imaging

• Computed Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. tomography (CT scan) – Formerly called a CAT scan – Low-intensity X-rays and computer analysis • Slice-type image • Increased sharpness of image

1-75 Medical Imaging—Nuclear Medicine

• Positron emission tomography

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (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 (d) Positron emission tomographic • Image color shows tissues using (PET) scan Tony Stone Images/Getty Images the most glucose at that moment Figure 1.13d • Damaged tissues appear dark 1-76 Medical Imaging

• Magnetic resonance Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. imaging (MRI) – Slice-type image – Superior quality to CT scan – Best for soft tissue – Mechanics • Alignment and realignment of hydrogen atoms with magnetic field and radio waves • Varying levels of energy given off used by computer

to produce an image (e) Magnetic resonance image (MRI)

• Sonography – Second oldest and 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

1-78