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Chapter 1

Lecture Outline

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Anatomy and Physiology

• The science of our own bodies

• Human structure and function, the biology of the human body

• Foundation for advanced study in health care, exercise physiology, pathology and other fields related to health and fitness

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Anatomy - The Study of Form

• Observation of surface structure

• Cadaver dissection – cutting and separation of organs to study

their relationships

• Comparative anatomy – study of more than one species to analyze

evolutionary trends

• Dissection- cutting and separation of tissues to reveal their relationships

• Anatomy and dissection both mean “cutting apart”

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• Physical examination– Palpation: feeling a structure w/ the hands– Auscultation: listening to natural sounds– Percussion: examiner taps the body

• Gross anatomy – visible with naked eye

• Histology– examination of cells with microscope

Anatomy - The Study of Form

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Physiology - The Study of Function

• Study of bodily functions – using methods of experimental science

• Comparative physiology– study of different species

• Basis for the development of new drugs and medical procedures

Scientific Knowledge

• Inductive Method: process of making numerous observations until one feels confident in drawing generalizations from them (anatomy)

• Hypothetico-deductive Method: start with hypothesis, make deduction (if, then prediction), experiment, results either support or do not support hypothesis (physiology)

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Scientific Method

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Hypothesis

• Consistent with what is already known

• Capable of being tested and possibly falsified by evidence

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

• If nothing could prove it wrong, it is not scientific

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• Is it better to treat seizures immediately or wait until epilepsy is well established?

• Early treatment of seizures will result in better seizure control than the same treatment when administered later in the development of epilepsy

• Collect data: animal model- produce rats with audiogenic seizures. Treat some with anti seizure meds immediately after first seizure (experimental group 1)

• Treat other group later after pattern of seizures is well established (experimental group 2)

• Compare both to another untreated group (control)

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Experimental Design

• Sample Size: adequate sample size controls for chance events and individual variations in response and enables us to place more confidence in the outcome

• Controls: Biomedical experiments require comparison between treated and untreated individuals so that we can judge whether the treatment has any effect– Control group: subjects are as much like the treatment

group as possible except with respect to the variable being tested

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• Psychosomatic effects: effects of subject’s state of mind on physiology, must control for this

• Give control group a placebo (substance with no physiological effect)

• Neither group must know which tablet it is getting

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Experimenter bias

Double-blind method: neither the subject to whom a treatment is given nor the person giving it and recording the results knows whether that subject is receiving the experimental treatment or placebo

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• Statistical testing: How great a difference must there be between experimental and control groups before we feel confident that it was due to treatment and not random variation? Expressed as probability

• Peer Review: when scientist applies for research funds or submits work for publication work is subject to peer review- a critical evaluation by other experts in that field. At every stage from planning to postpublication, scientists subject to scrutiny by their colleauges. Mechanism to ensure honesty, objectivity, and quality in science.

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What makes something alive?

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Characteristics of Life

• High level of Organization• Made of Cells• Metabolism• Responsiveness• Movement• Growth• Development• Reproduction

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Hierarchy of complexity

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Anatomical Variation

• No 2 humans are exactly alike– variable number of organs– variation in organ locations (situs inversus,

dextrocardia, situs perversus)

Organ Systems

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Organ Systems

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Homeostasis = body’s ability to detect change, activate mechanisms that oppose it,

and thereby maintain stable internal conditions

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

external conditions• Homeostasis

– Walter Cannon (1871-1945) coined the term– fluctuates within limited range around a set

point• Loss causes illness or death

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Feedback Mechanisms

• Receptor = senses change

• Afferent Pathway

• Control Center

• Efferent Pathway

• Effector = structures that restore homeostasis

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Negative Feedback Loop

• Body senses a change and activates mechanisms to reverse it

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Negative Feedback, Set Point

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

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Human Thermoregulation

• Brain senses change in blood temperature– if overheating, vessels dilate in the skin and sweating begins– if too cold, vasoconstriction in the skin and shivering begins

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Control of Blood Pressure

• Circulatory stretch receptors– detect a rise in BP

• Cardiac center in brainstem– sends out nerve signals

• Heart slowed and BP lowered

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Positive Feedback Loops

• Self-amplifying change– leads to change in the same direction

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

generation of nerve signals

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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