1. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Human Anatomy & Physiology, Sixth Edition Elaine N. Marieb PowerPoint ® Lecture Slides prepared by Vince Austin, University of Kentucky 1 The Human Body: An Orientation Part B

2. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Today! We will learn about…….  Life functions and survival needs  Homeostasis and Feedback mechanisms  Anatomical position and directional terms

3. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Necessary Life Functions  Maintaining boundaries – the internal environment remains distinct from the external  Cellular level – accomplished by plasma membranes  Organismal level – accomplished by the skin

4. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Necessary Life Functions  Movement – locomotion, propulsion (peristalsis), and contractility  Responsiveness – ability to sense changes in the environment and respond to them  Digestion – breakdown of ingested foodstuffs

5. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Necessary Life Functions  Metabolism – all the chemical reactions that occur in the body  Excretion – removal of wastes from the body

6. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Necessary Life Functions  Reproduction – cellular and organismal levels  Cellular – an original cell divides and produces two identical daughter cells  Organismal – sperm and egg unite to make a whole new person  Growth – increase in size of a body part or of the organism

7. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Survival Needs  Nutrients – chemical substances used for energy and cell building  Oxygen – needed for metabolic reactions  Water – provides the necessary environment for chemical reactions

8. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Survival Needs  Maintaining normal body temperature – necessary for chemical reactions to occur at life-sustaining rates  Atmospheric pressure – required for proper breathing and gas exchange in the lungs

9. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Homeostasis  Homeostasis is the ability to maintain a relatively stable internal environment in an ever-changing outside world  The internal environment of the body is in a dynamic state of equilibrium  Chemical, thermal, and neural factors interact to maintain homeostasis

10. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Homeostatic Control Mechanisms  The variable produces a change in the body  The three interdependent components of control mechanisms are:  Receptor – monitors the environments and responds to changes (stimuli)  Control center – determines the set point at which the variable is maintained  Effector – provides the means to respond to the stimulus

11. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Stimulus: Produces change in variable 1 2 3 Change detected by receptor Input: Information sent along afferent pathway to 5 Response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis Variable (in homeostasis) Imbalance Receptor (sensor) Control center 4 Output: Information sent along efferent pathway to Effector Homeostatic Control Mechanisms Figure 1.4

12. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Negative Feedback  In negative feedback systems, the output shuts off the original stimulus  Example: Regulation of blood glucose levels

13. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Negative Feedback Figure 1.5

14. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Positive Feedback  In positive feedback systems, the output enhances or exaggerates the original stimulus  Example: Regulation of blood clotting Figure 1.6

15. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Homeostatic Imbalance  Disturbance of homeostasis or the body’s normal equilibrium  Overwhelming of negative feedback mechanisms allowing destructive positive feedback mechanisms to take over

16. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Anatomical Position  Body erect, feet slightly apart, palms facing forward, thumbs point away from body Figure 1.7a

17. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Directional Terms  Superior– toward the head  Inferior –away from the head

18. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Directional Terms  Anterior– toward the front of the body  Posterior – toward the back of the body

19. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Directional Terms  Medial– toward the midline  Lateral - away from the midline  Intermediate –between a more medial and lateral structure

20. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Directional Terms  Proximal – closer to the origin of the body  Distal – farther from the origin of the body

21. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Directional Terms  Superficial – toward the body surface  Deep –away from the body surface

22. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Directional Terms Table 1.1

23. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Directional Terms Table 1.1

24. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Regional Terms: Anterior View  Axial – head, neck, and trunk  Appendicular – appendages or limbs  Specific regional terminology Figure 1.7a

25. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Regional Terms: Posterior View Figure 1.7b

26. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Body Planes – next time  Sagittal – divides the body into right and left parts  Midsagittal or medial – sagittal plane that lies on the midline  Frontal or coronal – divides the body into anterior and posterior parts  Transverse or horizontal (cross section) – divides the body into superior and inferior parts  Oblique section – cuts made diagonally

27. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Anatomical Variability  Humans vary slightly in both external and internal anatomy  Over 90% of all anatomical structures match textbook descriptions, but:  Nerves or blood vessels may be somewhat out of place  Small muscles may be missing  Extreme anatomical variations are seldom seen

28. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Quiz next time over the material in this lecture! Work on study guide – Will be a check on pages 11-16