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Chapter 1: Introduction to Anatomy and
Physiology
© 2012 Pearson Education, Inc.
For the first lecture test, I should be able to…
• A. Define anatomy and physiology.
•
1.
Explain how they are related.
•
2.
Describe major specialties of each.
• B. Define homeostasis and explain its importance for
survival.
•
1.Compare/contrast intrinsic and extrinsic regulation
and provide an example of each.
•
2.Compare/contrast negative and positive feedback and
provide an example of each.
•
3.Discuss the relationship between homeostasis and
disease.
© 2012 Pearson Education, Inc.
• Anatomy
• Describes the structures of the
body
• What they are made of
• Where they are located
• Associated structures
• Physiology
• Is the study of:
• Functions of anatomical structures
• Individual and cooperative functions
• Biochemistry, Biology, Chemistry, Genetics
© 2012 Pearson Education, Inc.
Relationships between Anatomy and Physiology
• Anatomy
• Gross anatomy, or macroscopic
anatomy, examines large, visible
structures
• Surface anatomy: exterior features
• Regional anatomy: body areas
• Systemic anatomy: organ systems
• Developmental anatomy: from
conception to death
• Clinical anatomy: medical specialties
© 2012 Pearson Education, Inc.
Relationships between Anatomy and Physiology
• Microscopic anatomy examines cells and molecules
• Cytology: study of cells and their structures
• cyt- = cell
• Histology: study of tissues and their structures
© 2012 Pearson Education, Inc.
1-4 Relationships between Anatomy and
Physiology
• Physiology
• Cell physiology: processes within and
between cells
• Organ physiology: functions of specific
organs
• Systemic physiology: functions of an
organ system
• Pathological physiology: effects of
diseases
© 2012 Pearson Education, Inc.
1-5 Levels of Organization
• The Chemical (or Molecular) Level
• Atoms are the smallest chemical units
• Molecules are a group of atoms working together
• The Cellular Level
• Cells are a group of atoms, molecules, and organelles working
together
• The Tissue Level
• A tissue is a group of similar cells working together
• The Organ Level
• An organ is a group of different tissues working together
© 2012 Pearson Education, Inc.
1-5 Levels of Organization
• The Organ System Level
• An organ system is a group of organs working together
• Humans have 11 organ systems
• The Organism Level
• A human is an organism
© 2012 Pearson Education, Inc.
Figure 1-1 Levels of Organization
Cellular Level
Chemical and Molecular Levels
Heart muscle
cell
Protein filaments
Complex protein molecule
Atoms in combination
© 2012 Pearson Education, Inc.
Figure 1-1 Levels of Organization
Organ system
level
Organ Level
Tissue Level
Cardiac muscle
tissue
The heart
The
cardiovascular
system
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Organism
level
KEY CONCEPT
• The body is divided into 11 organ systems
• All organ systems work together
• Many organs work in more than 1 organ
system
© 2012 Pearson Education, Inc.
1-6 Homeostasis
• Homeostasis
• All body systems working together to maintain a
stable internal environment
• Systems respond to external and internal changes
to function within a normal range (body
temperature, fluid balance)
© 2012 Pearson Education, Inc.
1-6 Homeostasis
• Mechanisms of Regulation
• Autoregulation (intrinsic)
• Automatic response in a cell, tissue, or organ to some
environmental change
• Extrinsic regulation
• Responses controlled by nervous and endocrine
systems
© 2012 Pearson Education, Inc.
1-6 Homeostasis
• Receptor
• Receives the
stimulus
• Control center
• Processes the
signal and sends
instructions
• Effector
• Carries out
instructions
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CONTROL CENTER
Figure 1-2 The Control of Room Temperature
RECEPTOR
Normal
condition
disturbed
Thermometer
Information
affects
STIMULUS:
Room temperature
rises
Normal room
temperature
RESPONSE:
Room temperature
drops
Normal
condition
restored
EFFECTOR
Air conditioner
turns on
20° 30° 40°
Sends
commands
to
In response to input from a receptor (a thermometer), a thermostat
(the control center) triggers an effector response (either an air conditioner or a heater) that restores normal temperature. In this case,
when room temperature rises above the set point, the thermostat
turns on the air conditioner, and the temperature returns to normal.
© 2012 Pearson Education, Inc.
Room temperature (°C)
CONTROL CENTER
(Thermostat)
HOMEOSTASIS
Air
Air
conditioner conditioner
turns on
turns off
22
Normal
range
Time
With this regulatory system, room
temperature fluctuates around the
set point.
1-7 Negative and Positive Feedback
• The Role of Negative Feedback
• The response of the effector negates the stimulus
• Body is brought back into homeostasis
• Normal range is achieved
© 2012 Pearson Education, Inc.
Figure 1-3 Negative Feedback in the Control of Body Temperature
RECEPTORS
Temperature
sensors in skin
and
hypothalamus
Normal
temperature
disturbed
Information
affects
CONTROL
CENTER
STIMULUS:
Body temperature
rises
HOMEOSTASIS
RESPONSE:
Increased heat loss,
body temperature
drops
Normal
temperature
restored
EFFECTORS
• Sweat glands
in skin increase
secretion
• Blood vessels
in skin dilate
Sends
commands
to
Events in the regulation of body temperature, which are
comparable to those shown in Figure 12. A control center
in the brain (the hypothalamus) functions as a thermostat
with a set point of 37°C. If body temperature exceeds
37.2°C, heat loss is increased through enhanced blood flow
to the skin and increased sweating.
© 2012 Pearson Education, Inc.
Body temperature (°C)
Thermoregulatory
center in brain
Normal body
temperature
37.2
37
36.7
Vessels
Vessels
dilate,
constrict,
sweating sweating
increases decreases
Normal
range
Time
The thermoregulatory center keeps
body temperature fluctuating
within an acceptable range, usually
between 36.7 and 37.2°C.
1-7 Negative and Positive Feedback
• The Role of Positive Feedback
• The response of the effector increases change of the
stimulus
• Body is moved away from homeostasis
• Normal range is lost
• Used to speed up processes
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Figure 1-4 Positive Feedback: Blood Clotting
Clotting
accelerates
Positive
feedback
loop
Chemicals
Chemicals
Damage to cells in the
blood vessel wall releases
chemicals that begin the
process of blood clotting.
© 2012 Pearson Education, Inc.
The chemicals start chain
reactions in which cells,
cell fragments, and
soluble proteins in the
blood begin to form a clot.
As clotting continues,
each step releases
chemicals that further
accelerate the process.
Blood clot
This escalating process
is a positive feedback
loop that ends with the
formation of a blood clot,
which patches the vessel
wall and stops the bleeding.
1-7 Negative and Positive Feedback
• Systems Integration
• Systems work together to maintain homeostasis
• Homeostasis is a state of equilibrium
• Opposing forces are in balance
• Dynamic equilibrium — continual adaptation
• Physiological systems work to restore balance
• Failure results in disease or death
© 2012 Pearson Education, Inc.