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Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Chapter 1Homeostasis: The Foundation of Physiology
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
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
Outline
• 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
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
Anatomy• Study of the structure of the bodyPhysiological mechanisms are possible
through structural designStructure-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
Functional Organization of the BodyLevels 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
1
2
3
4
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1 Chemical level
2 Cellular level
4 Organ level
3 Tissue level
5 Body system level
6 Organism level
Fig. 1.1, p.
3
Stepped art
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
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
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
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
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
Tissues• Nervous 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
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
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson LearningHyaline cartilage. X64.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson LearningCollagen or dense connective tissue. X155.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson LearningReticular fibers, silver preparation. X100.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson LearningHuman unilocular (white) fat and adipose (adult fat). H&E stain. LM X100.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Human pseudostratified columnar epithelium lining the bronchus of the lung. H&E stain. X180.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson LearningStratified squamous epithelium from mouth mucosa. H&E stain. LM X100.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson LearningSimple columnar epithelium. LM X140.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson LearningSimple Squamous Epithelium. LM X75.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson LearningAreolar (loose) connective tissue. LM X60.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Bone section showing osteocytes in lacunae arranged in concentric circles surrounding Haversian canals. LM X75.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson LearningMicroscopic technique series - Cheek cells. Nomarski view. LM X75.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson LearningMicroscopic technique series - Cheek cells. Phase view. LM X75.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson LearningMicroscopic technique series -Cheek cells. Darkfield view. LM X75.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
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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.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson LearningColony of undifferentiated human embryonic stem cells. LM X5.14
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson LearningSurface of a human fingertip with sweat droplets. SEM X120.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson LearningSweat gland duct in the skin. LM X5.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson LearningCardiomyocyte differentiated from human embryonic stem cells.
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Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
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
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
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
Body Systems
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Body Systems
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
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
Homeostasis
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
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
Homeostasis
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
HomeostasisFactors 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
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
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
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
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
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
Surface epithelium
Pocket epitheliumcells
Fig. 1.2a, p. 5
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Surface epithelium
Duct cells
Secretory exocrinegland cell
Fig. 1.2b, p. 5
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Surface epithelium
Connecting cellslost during development
Secretory exocrinegland cell
Blood vessels
Fig. 1.2c, p. 5
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
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
Role of Body Systems in Homeostasis
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
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
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
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
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
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
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
During the minute that it will take you to read this page
Your heart will beat 70 times,pumping 5 liters of blood to your lungs and another 5 liters to the rest of your body.
Your kidneys will produce 1 ml of urine.
Your eyes will convert the information on this page into electrical signals that will transmit to your brain.
Your digestive system will be processing your last meal for transfer into your bloodstream.
You will breathe in and out about 12 times.
Your cells will consume 250 ml of oxygen and produce 200 ml of carbon dioxide.
You will use about 2 calories of energy.
Your brain will send chemical messengers through your nerves to control your body.
Chapter Opener, p. 1
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Information from the external environment relayed through thenervous system
O2
CO2
Urine containingwastes and excess water and electrolytes
Nutrients, water,electrolytesFeces containingundigested foodresidue
Sperm leave maleSperm enter female
EXTERNALENVIRONMENT
BODY SYSTEMS
RESPIRATORY SYSTEM
NERVOUS SYSTEM
URINARY SYSTEM
DIGESTIVE SYSTEM
REPRODUCTIVE SYSTEM
Exchanges with all other systems
CIRCULATORY SYSTEM
Exchanges with all other systems
MUSCULAR AND SKELETAL
SYSTEM
IMMUNE SYSTEM
INTEGUMENTARY SYSTEM
ENDOCRINE SYSTEM
Body systemsmaintainhomeostasis
Keeps internalfluids in
Keeps foreignmaterials out
HOMEOSTASIS
Homeostasisessential forcell survival
CELLS
Cells makeup bodysystem
Enables thebody to interactwith the externalenvironment
Protects againstforeign invaders
Regulate
Fig. 1.6, p. 12
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Fig. 1-7a, p. 15
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Fig. 1-7b, p. 15
Chapter 1 Homeostasis: The Foundation of Physiology Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Fig. 1-7c, p. 15