1. Homeostasis: The Foundation of Physiology
Chapter 1
Homeostasis: The Foundation of Physiology
Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

2. Outline Physiology Levels of organization Basic Cell function
Tissues/ organs/systems
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

3. Outline Homeostasis Disruptions of homeostasis Fluid compartments
Variables controlled
contributions of systems
Control systems
intrinsic/extrinsic
Feedfoward/ feedback
Positive/negative
Disruptions of homeostasis
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

4. Physiology Study of body functions
Two processes explain body functions
Teleological
Explanations are in terms of meeting a bodily need
Mechanistic
Explanations are in terms of cause and effect sequences
Body is viewed as a machine
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

5. Anatomy Study of the structure of the body
Physiological mechanisms are possible through structural design
Structure-Function relationships of the body include
Heart receiving and pumping blood
Teeth tearing and grinding food
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

6. Functional Organization of the Body
Levels of organization
Chemical
Molecules composed
of atoms
Cellular
Cells are basic unit
of life
Tissue
Organ
Body system
Organism
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

7. Fig. 1.1, p. 3 5 6 4 3 1 2 2 3 4 5 1 6 Chemical level Cellular level
Tissue level 4
Organ level 5
Body system level 6
Organism level
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Stepped art
Fig. 1.1, p. 3

8. Basic Cell Functions
Obtain nutrients and oxygen from surrounding environment
Perform chemical reactions that provide energy for the cell
Eliminate carbon dioxide and other wastes to surrounding environment
Synthesize needed cellular components
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

9. Basic Cell Functions
Control exchange of materials between cell and its surrounding environment
Sensing and responding to changes in surrounding environment
Reproduction
Exception
Nerve cells and muscle cells lose their ability to reproduce during their early development
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

10. Tissues
Groups of cells with similar structure and specialized function
Four primary types of tissues
Muscle tissue
Nervous tissue
Epithelial tissue
Connective tissue
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

11. Tissues Muscle tissue Specialized for contracting and generating force
Three types of muscle tissue
Skeletal muscle
Moves the skeleton
Cardiac muscle
Pumps blood out of the heart
Smooth muscle
Encloses and controls movement of contents through hollow tubes and organs
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

12. Tissues Nervous tissue Epithelial tissue
Consists of cells specialized for initiating and transmitting electrical impulses
Found in brain, spinal cord, and nerves
Epithelial tissue
Consists of cells specialized for exchanging materials between the cell and its environment
Organized into two general types of structures
Epithelial sheets
Secretory glands
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

13. Tissues Connective tissue
Connects, supports, and anchors various body parts
Distinguished by having relatively few cells dispersed within an abundance of extracellular material
Examples
Tendons
Bone
Blood
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

14. The following photos are from Visuals Unlimited
The following photos are from Visuals Unlimited. An instructor using a Thomson Learning textbook has the right to use these photos for the duration of the adoption in the classroom or on instructor’s course website so long as the credit specified here is visible on or under the photo at all times, and images are displayed at no larger than 1/4 screen at 72 dpi (web-ready JPGs available in folder “Bonus_Photos_JPGs” in “Media” folder). Instructors do not become the owners of these photos and do not have the right to grant permission to third parties to use this material. See the ReadMe for details.
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

15. Credit: © Dr. Fred Hossler/Visuals Unlimited
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Credit: © Dr. Fred Hossler/Visuals Unlimited
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Hyaline cartilage. X64.

16. Credit: © Dr. David Phillips/Visuals Unlimited
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Credit: © Dr. David Phillips/Visuals Unlimited
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Collagen or dense connective tissue. X155.

17. Credit: © Dr. Richard Kessel/Visuals Unlimited
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Credit: © Dr. Richard Kessel/Visuals Unlimited
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Reticular fibers, silver preparation. X100.

18. Credit: © G.W. Willis, MD/Visuals Unlimited
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Credit: © G.W. Willis, MD/Visuals Unlimited
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Human unilocular (white) fat and adipose (adult fat). H&E stain. LM X100.

19. Credit: © G.W. Willis, MD/Visuals Unlimited
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Credit: © G.W. Willis, MD/Visuals Unlimited
Human pseudostratified columnar epithelium lining the bronchus of the lung. H&E stain. X180.
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

20. Credit: © G.W. Willis, MD/Visuals Unlimited
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Credit: © G.W. Willis, MD/Visuals Unlimited
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Stratified squamous epithelium from mouth mucosa. H&E stain. LM X100.

21. Credit: © Carolina Biological/Visuals Unlimited
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Credit: © Carolina Biological/Visuals Unlimited
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Simple columnar epithelium. LM X140.

22. Credit: © Carolina Biological/Visuals Unlimited
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Credit: © Carolina Biological/Visuals Unlimited
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Simple Squamous Epithelium. LM X75.

23. Credit: © Carolina Biological/Visuals Unlimited
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Credit: © Carolina Biological/Visuals Unlimited
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Areolar (loose) connective tissue. LM X60.

24. Credit: © Carolina Biological/Visuals Unlimited
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Credit: © Carolina Biological/Visuals Unlimited
Bone section showing osteocytes in lacunae arranged in concentric circles surrounding Haversian canals. LM X75.
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

25. Credit: © David Phillips/Visuals Unlimited
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Microscopic technique series - Cheek cells. Nomarski view. LM X75.

26. Credit: © David Phillips/Visuals Unlimited
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Microscopic technique series - Cheek cells. Phase view. LM X75.

27. Credit: © David Phillips/Visuals Unlimited
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Microscopic technique series -Cheek cells. Darkfield view. LM X75.

28. Credit: © Dr. Richard Kessel & Dr. Randy Kardon/Tissues & Organs/
228388
Credit: © Dr. Richard Kessel & Dr. Randy Kardon/Tissues & Organs/
Visuals Unlimited
A long bone showing the compact bone (yellow) surrounding the spongy or cancellous bone (orange). Compact bone consist of a dense matrix resembling a solid mass. The spongy region consists of a network of bony spicules called trabeculae. SEM X40.
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

29. 306457
Credit: © UMW
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Colony of undifferentiated human embryonic stem cells. LM X5.14

30. Credit: © Dr. Wolf Fahrenbach/Visuals Unlimited
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Surface of a human fingertip with sweat droplets. SEM X120.

31. Credit: © Carolina Biological/Visuals Unlimited
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Sweat gland duct in the skin. LM X5.

32. 301276
Credit: © Geron
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Cardiomyocyte differentiated from human embryonic stem cells.

33. Organs
Consist of two or more types of primary tissues that function together to perform a particular function or functions
Example
Stomach
Inside of stomach lined with epithelial tissue
Wall of stomach contains smooth muscle
Nervous tissue in stomach controls muscle contraction and gland secretion
Connective tissue binds all the above tissues together
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

34. Body Systems
Groups of organs that perform related functions and interact to accomplish a common activity essential to survival of the whole body
Do not act in isolation from one another
Human body has 11 systems
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

35. Body Systems Circulatory System Digestive System Respiratory System
Urinary System
Skeletal System
Muscular System
Integumentary System
Immune System
Nervous System
Endocrine System
Reproductive System
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

36. Body Systems
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

37. Body Systems
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

38. Homeostasis
Defined as maintenance of a relatively stable internal environment
Does not mean that composition, temperature, and other characteristics are absolutely unchanging
Homeostasis is essential for survival and function of all cells
Each cell contributes to maintenance of a relatively stable internal environment
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

39. Homeostasis
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

40. Homeostasis
Body cells are in contained in watery internal environment through which life-sustaining exchanges are made
Extracellular fluid (ECF)
Fluid environment in which the cells live (fluid outside the cells)
Two components
Plasma, interstitial fluid
Intracellular fluid (ICF)
Fluid contained within all body cells
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

41. Homeostasis
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

42. Homeostasis Factors homeostatically regulated include
Concentration of nutrient molecules
Concentration of O2 and CO2
Concentration of waste products pH
Concentration of water, salt, and other electrolytes
Volume and pressure
Temperature
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

43. Contributions of Body Systems to Homeostasis
Circulatory system
Carries materials from one part of the body to another
Digestive system
Breaks down dietary food into smaller molecules that can be distributed to body cells
Transfers water and electrolytes from external environment to internal environment
Eliminates undigested food residues to external environment in the feces
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

44. Contributions of Body Systems to Homeostasis
Respiratory system
Gets O2 from and eliminates CO2 to the external environment
Important in maintenance of proper pH of internal environment
Urinary system
Removes excess water, salt, acid, and other electrolytes from plasma and eliminates them in urine
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

45. Contributions of Body Systems to Homeostasis
Skeletal system
Provides support and protection for soft tissues and organs
Serves as storage reservoir for calcium
Along with muscular system enables movement of body and its parts
Bone marrow is ultimate source of all blood cells
Muscular system
Moves the bones
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

46. Contributions of Body Systems to Homeostasis
Integumentary system
Serves as outer protective barrier
Important in regulating body temperature
Immune system
Defends against foreign invaders and against body cells that have become cancerous
Paves way for repairing or replacing injured or worn-out cells
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

47. Contributions of Body Systems to Homeostasis
Nervous system
Controls and coordinates bodily activities that require rapid responses
Detects and initiates reactions to changes in external environment
Endocrine system
Secreting glands of endocrine regulate activities that require duration rather than speed
Controls concentration of nutrients and, by adjusting kidney function, controls internal environment’s volume and electrolyte composition
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

48. Fig. 1.2a, p. 5 Surface epithelium Pocket epithelium cells
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Fig. 1.2a, p. 5

49. Fig. 1.2b, p. 5 Surface epithelium Duct cells Secretory exocrine
gland cell
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Fig. 1.2b, p. 5

50. Fig. 1.2c, p. 5 Surface epithelium Connecting cells
lost during development
Secretory exocrine
gland cell
Blood vessels
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Fig. 1.2c, p. 5

51. Contributions of Body Systems to Homeostasis
Reproductive system
Not essential for homeostasis (not essential for survival of individual)
Is essential for perpetuating the species
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

52. Role of Body Systems in Homeostasis
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

53. Homeostatic Control Systems
In order to maintain homeostasis, control system must be able to
Detect deviations from normal in the internal environment that need to be held within narrow limits
Integrate this information with other relevant information
Make appropriate adjustments in order to restore factor to its desired value
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

54. Homeostatic Control Systems
Control systems are grouped into two classes
Intrinsic controls
Local controls that are inherent in an organ
Extrinsic controls
Regulatory mechanisms initiated outside an organ
Accomplished by nervous and endocrine systems
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

55. Homeostatic Control Systems
Feedforward
Term used for responses made in anticipation of a change
Feedback
Refers to responses made after change has been detected
Types of feedback systems
Negative
Positive
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

56. Homeostatic Control Systems
Negative feedback system
Primary type of homeostatic control
Opposes initial change
Components
Sensor
Monitors magnitude of a controlled variable
Control center
Compares sensor’s input with a set point
Effector
Makes a response to produce a desired effect
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

57. Homeostatic Control Systems
Positive feedback system
Amplifies an initial change
Do not occur as often as negative feedback system
Example
Uterine contractions become increasingly stronger until the birth of the baby
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

58. Disruptions in Homeostasis
Can lead to illness and death
Pathophysiology
Abnormal functioning of the body associated with disease
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning

59. During the minute that it will take you to read this page
Your eyes will convert the
information on this page
into electrical signals that
will transmit to your brain.
Your brain will send chemical
messengers through your
nerves to control your body.
Your heart will beat 70 times,
pumping 5 liters of blood to
your lungs and another
5 liters to the rest of your
body.
You will breathe in and out
about 12 times.
Your cells will consume 250 ml
of oxygen and produce 200 ml
of carbon dioxide.
Your kidneys will produce
1 ml of urine.
Your digestive system will
be processing your last meal
for transfer into your
bloodstream.
You will use about 2 calories
of energy.
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Chapter Opener, p. 1

60. Fig. 1.6, p. 12 BODY SYSTEMS Body systems maintain homeostasis NERVOUS
ENDOCRINE
SYSTEM
Information from
the external
environment relayed
through the
nervous system
Regulate O2
RESPIRATORY
SYSTEM
Keeps internal
fluids in
INTEGUMENTARY
SYSTEM
HOMEOSTASIS
CO2
Keeps foreign
materials out
Urine containing
wastes and
excess water and
electrolytes
URINARY
SYSTEM
Protects
against
foreign
invaders
IMMUNE SYSTEM
Homeostasis
essential for
cell survival
Nutrients, water,
electrolytes
DIGESTIVE
SYSTEM
Feces containing
undigested food
residue
MUSCULAR AND
SKELETAL
SYSTEM
Enables the
body to
interact
with the
external
environment
REPRODUCTIVE
SYSTEM
Sperm leave male
CELLS
Sperm enter
female
Exchanges with
all other systems
Exchanges with
all other systems
EXTERNAL
ENVIRONMENT
CIRCULATORY SYSTEM
Cells make
up body
system
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Fig. 1.6, p. 12

61. Fig. 1-7a, p. 15 Figure 1.7: Negative feedback.
(a) Components of a negative-feedback control system.
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Fig. 1-7a, p. 15

62. Fig. 1-7b, p. 15 Figure 1.7: Negative feedback.
(b) Negative-feedback control of room temperature.
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Fig. 1-7b, p. 15

63. Fig. 1-7c, p. 15 Figure 1.7: Negative feedback.
(c) Negative-feedback control of body temperature.
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Fig. 1-7c, p. 15