1. Principles of Anatomy and Physiology
14th Edition
CHAPTER 1
An Introduction to the Human Body
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Introduction
The purpose of the chapter is to:
Introduce the disciplines of anatomy and physiology
Discuss the organization of the human body
Reveal shared properties of all living things
Discuss the concept of homeostasis
Why This Matters:
Learning and understanding anatomical terminology allows you to communicate accurately with your colleagues in the health sciences.
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Anatomy vs. Physiology
Anatomy is the study of structure of body parts and their relationship to one another. Physiology is the study of how body structures function and how they work to carry out life- sustaining activities.
Word is derived from the Greek and means “to cut” or “cutting backwards” (putting things together from slices).
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4. Anatomy and Physiology
Another Name for Cell Biology is Cytology.
To study anatomy, one must know anatomical terminology and be able to observe, manipulate, palpate, and auscultate.
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5. Complementarity of Structure and Function
Anatomy and physiology are inseparable
Function always reflects structure
What a structure can do depends on its specific form
Known as the principle of complementarity of structure and function
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6. Levels of Structural Organization & Body Systems
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Requirements for Life
All living things have certain characteristics that distinguish them from nonliving things
Life processes in humans include maintaining boundaries, digestion, metabolism, responsiveness, movement, growth, excretion, differentiation, and reproduction
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8. Necessary Life Functions
Maintaining Boundaries
Separation between internal and external environments must exist.
Plasma membranes separate cells.
Skin separates organisms from the external environment.
Movement
Muscular system allows movement of body parts via skeletal muscle and of substances via cardiac muscle (blood) and smooth muscle (digestion)
Contractility refers to movement at the cellular level.
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9. Necessary Life Functions
Responsiveness
Ability to sense and respond to stimuli
Withdrawal reflex prevents injury
Control of breathing rate, which must change in response to different activities
Digestion
Breakdown of ingested foodstuffs, followed by absorption of simple molecules into the blood.
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10. Necessary Life Functions
Metabolism
All chemical reactions that occur in body cells
Sum of all catabolism (breakdown of molecules) and anabolism (synthesis of molecules) reactions.
Excretion
Removal of wastes from metabolism and digestion.
Urea (from the breakdown of proteins)
Carbon Dioxide (from metabolism)
Feces (unabsorbed foods)
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11. Necessary Life Functions
Reproduction
At the cellular level, reproduction involves division of cells for growth or repair
At the organismal level, reproduction is the production of offspring.
Growth
Increase in size of a body part
Increase in the number of cells in order for the organism to grow
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12. Systems of the Human Body
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13. Systems of the Human Body
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14. Systems of the Human Body
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15. Systems of the Human Body
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16. Systems of the Human Body
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17. Systems of the Human Body
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18. Systems of the Human Body
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Survival Needs
Humans need several factors for survival that must be in the appropriate amounts; too much or too little can be harmful:
Nutrients
Oxygen
Water
Normal Body Temperature
Appropriate Atmospheric Pressure
Nutrients
Chemicals for energy and cell building
Carbohydrates: major source of energy
Proteins: needed for cell building and cell chemistry
Fats: long-term energy storage
Minerals and vitamins: involved in chemical reactions as well as for structural purposes
Oxygen
Essential for release of energy from foods
The body can survive only a few minutes without oxygen
Water
Most abundant chemical in body; provides the watery environment needed for chemical reactions
Also is fluid base for secretions and excretions
Normal body temperature
If body temp falls below or goes above 37°C, rates of chemical reactions are affected
Appropriate atmospheric pressure
Specific pressure of air is needed for adequate breathing and gas exchange in lungs
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20. Clinical Connection: Noninvasive Diagnostic Techniques
Palpation, auscultation, and percussion are used to assess certain aspects of body structure and function
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21. Clinical Connection: Autopsy
An autopsy is a postmortem examination of the body and dissection of its internal organs to confirm or determine cause of death
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Homeostasis
Homeostasis is the maintenance of relatively stable internal conditions despite continuous changes in the environment
a dynamic state of equilibrium, always readjusting as needed
Homeostasis is maintained by regulatory processes of all organ systems
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23. Homeostasis & Body Fluids
The survival of our body cells is dependent on the precise regulation of the chemical composition of their surrounding fluid
This fluid is known as extracellular fluid
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Homeostasis
Interactions Animation:
Communication, Regulation, and Homeostasis
You must be connected to the Internet and in Slideshow Mode to run this animation.
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Homeostatic Controls
Body must constantly be monitored and regulated to maintain homeostasis
Nervous and endocrine systems play a major role in maintaining homeostasis
Variables are factors that can change (blood sugar, body temperature, blood volume, etc.)
Homeostatic control of variables involves three components: receptors, control center, and effector.
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26. Control of Homeostasis
Receptor (sensor)
Monitors environment
Responds to stimuli (things that cause changes in controlled variables)
Control center
Determines set point at which variable is maintained
Receives input from receptor
Determines appropriate response
Effector
Receives output from control center
Provides the means to respond
Response either reduces stimulus (negative feedback) or enhances stimulus (positive feedback)
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27. Control of Homeostasis: Negative Feedback
Most-used feedback mechanism in body
Response reduces or shuts off original stimulus
Variable changes in opposite direction of initial change
Examples
Regulation of body temperature (a nervous system mechanism)
Regulation of blood glucose by insulin (an endocrine system mechanism)
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Interactions Among Elements of A Homeostatic Control System Maintain Stable Internal Conditions
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29. Body Temperature – Negative Feedback Mechanism
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30. Control of Homeostasis: Positive Feedback
Response enhances or exaggerates the original stimulus
May exhibit a cascade or amplifying effect as feedback causes variable to continue in same direction as initial change
Usually controls infrequent events that do not require continuous adjustment, for example:
Enhancement of labor contractions by oxytocin
Platelet plug formation and blood clotting
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31. Platelet Plug Formation – Positive Feedback Mechanism
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32. Homeostatic Imbalances
Disturbance of homeostasis
Increased risk of disease
Contributes to changes associated with aging
Control systems become less efficient
If negative feedback mechanisms become overwhelmed, destructive positive feedback mechanisms may take over
Heart failure
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