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 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
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
5
6
4
3
1 Chemical level
2
2 Cellular level
3 Tissue level
4 Organ level
5 Body system level
1
6 Organism level
Chapter 1 Homeostasis: The Foundation of Physiology
Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Fig.
1.1, p.
Stepped art
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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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
©2007 Brooks/Cole-Thomson
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H&E stain.
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Chapter
1 Homeostasis:
The Foundationof
of Physiology
Human pseudostratified columnar epithelium
lining
the bronchus
the lung. H&E stain.
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Chapter 1 Homeostasis: The Foundation of Physiology
Human
Physiology
by Lauralee Sherwood
©2007 Brooks/Cole-Thomson
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mouth
mucosa.
H&E stain.
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Chapter 1 Homeostasis: The Foundation of Physiology
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Chapter
1 Homeostasis:
Foundation of Physiology
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arranged
inThe
concentric
circles surrounding
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Chapter 1 Homeostasis: The Foundation of Physiology
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Learning
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Chapter 1 Homeostasis: The Foundation of Physiology
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Sherwood
©2007
Brooks/Cole-Thomson Learning
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Phase
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Learning
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A long bone showing the compact bone (yellow) surrounding the spongy or cancellous bone
Chapter
1 Homeostasis:
The Foundation
of Physiology
(orange). Compact bone consist of a dense
matrix
resembling
a solid
mass. The spongy
Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
region consists of a network of bony spicules called trabeculae. SEM X40.
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Chapter 1 Homeostasis: The Foundation of Physiology
Human Physiologystem
by Lauralee
Sherwood
©2007
Brooks/Cole-Thomson Learning
Colony of undifferentiated human embryonic
cells.
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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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Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
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Chapter 1 Homeostasis: The Foundation of Physiology
Physiology
by Lauralee Sherwood
©2007 Brooks/Cole-Thomson Learning
Cardiomyocyte differentiated from Human
human
embryonic
stem cells.
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 lifesustaining 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
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
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 epithelium
cells
Chapter 1 Homeostasis: The Foundation of Physiology
Human Physiology by Lauralee Sherwood ©2007 Brooks/Cole-Thomson Learning
Fig. 1.2a, 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
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
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 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 kidneys will produce
1 ml of urine.
Your cells will consume 250 ml
of oxygen and produce 200 ml
of carbon dioxide.
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
BODY SYSTEMS
Information from
the external
environment relayed
through the
nervous system
O2
CO2
Urine containing
wastes and
excess water and
electrolytes
NERVOUS
SYSTEM
Regulate
RESPIRATORY
SYSTEM
ENDOCRINE
SYSTEM
INTEGUMENTARY
SYSTEM
Sperm leave male
Sperm enter
female
EXTERNAL
ENVIRONMENT
Keeps internal
fluids in
HOMEOSTASIS
Keeps foreign
materials out
URINARY
SYSTEM
IMMUNE SYSTEM
Nutrients, water,
electrolytes
Feces containing
undigested food
residue
Body systems
maintain
homeostasis
DIGESTIVE
SYSTEM
REPRODUCTIVE
SYSTEM
MUSCULAR AND
SKELETAL
SYSTEM
Exchanges with
all other systems
Exchanges with
all other systems
Protects
against
foreign
invaders
Enables the
body to
interact
with the
external
environment
Homeostasis
essential for
cell survival
CELLS
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
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