Anatomy and
Physiology
Sam Rhodes, Ph.D.
Professor of Biology
What is it?
Anatomy: Structure and Nomenclature
of the Body Parts
Physiology: Function, Chemistry and
Physics of the Body Systems
So what do we expect you to learn in
this class (and all college classes)?
1. Learn/memorize specific facts
2. Communicate effectively in writing and
orally
3. Use the information you learned to
solve problems.
Anatomy and Physiology Are Sciences
• Science relies on empirical evidence. If you
can’t measure something then it is out of the
realm of science.
• Scientists accept uncertainty. We never know
something as “absolutely true.”
• Scientists use controlled experiments and
repetitions to reduce uncertainty and increase
confidence.
The Scientific Method
Hypothesis: Should attempt to explain
what is observed. “Why did the
observation happen?”
The Experiment: Produces new empirical
evidence that may support or refute the
hypothesis.
The hypothesis may have to
be refined or completely
changed.
The Scientific Method is
Comparable to a Court of Law
A crime is committed
(observation of fact)
The prosecutor states that the
defendant is guilty
(hypothesis)
Both lawyers present new
evidence (experiments)
The jury examines the
evidence and draws a
conclusion (the hypothesis is
accepted or rejected).
Important Note: just because the jury draws a conclusion doesn’t mean it is correct.
Example of the Scientific Method
The Scientific Community
• Relies on many repetitions to build confidence
• Uses controlled experiments
Experimental Condition: the individuals
are treated with variable stated in the
hypothesis
Control Condition: the individuals are
treated exactly like the experimental EXCEPT
for the variable in the hypothesis.
• Publishes and distributes results for peer
review
What is a theory?
• A hypothesis that is supported by
a great deal of experimental
evidence from a variety of different sources.
• A hypothesis that has been examined by a
large number of different scientists and is
accepted as the best explanation for the
existing data.
• Only subject to change if new data or a
substantially different, and equally valid,
explanation is given.
Homeostasis: Central Theme of
Physiology
• How do we define homeostasis?
• “Maintaining a relatively constant internal
environment, despite changes in the external
environment.”
• How does the body maintain homeostasis?
• Receptors, Integrator/Controller, Effector,
Feedback.
Receptor: cells that detect a change in a specific
physiological parameter
Integrator/Controller: receives input from the
receptor and compares the input to an ideal setpoint.
If input differs from setpoint, then an efferent signal is
sent to an effector.
Effector: tissue or organ that can directly change
(increase or decrease) the specific physiological
parameter. It directly EFFECTS the parameter.
Feedback: A change in the the specific parameter
that is detected by the receptor. “Tells the receptor”
that the parameter has changed.
Goal of Glucose Homeostasis
• Glucose is an essential nutrient needed by all tissues.
• Maintain blood glucose close to 100 mg/100 mL
• When glucose levels are low, release glucose from
body stores.
• When glucose is high, take glucose out of blood and
store in the liver and muscle.
Glucose Homeostasis
Homeostasis of Resting Blood Pressure
• Large blood vessels contain nerve endings that detect when
blood pressure is low
• The nerve endings send signals to the “cardiac center” in the
brain that compares the information to the normal set-point
of blood pressure.
• If blood pressure is too low, the cardiac center will signal the
heart to beat at a faster rate.
• The increased heart rate will cause blood pressure to
increase.
• The increased blood pressure is detected by the nerve
endings in the large arteries.
3. Cardiac center compares
blood pressure to the set
point.
2. Signal sent to the cardiac
center in the brain
4. Cardiac center sends
signal to increase
heart rate.
1. Nerve endings detect that
blood pressure is low.
5. Increased heart rate
causes blood pressure to
return toward set point.
6. The increased blood pressure provides
negative feedback to the nerve endings.
Analysis
• What is the Receptor in the cardiac control
system?
• What is the Controller?
• What is the Effector?
• What is the Negative Feedback?
Understanding the Organization of
the Body
Cells: fundamental units of all living organisms. Cells are specialized to
specific functions in the body. There is a division of labor. Some cells produce
mineral for bone, some cells produce protein for muscle contraction, etc.
Tissues: Tissues are groups of similar cells that function together. There are
four major categories of tissues - epithelium (coverings and linings),
connective tissue (strength, support), muscle (contraction), and nerve (control
and communication).
Organs: Combinations of two or more tissues. The skin is an organ because
it is composed of epithelium, connective tissue and small amounts of nerve
and muscle.
Organ Systems: Combinations of organs that together serve a general
function for the body. For example, the circulatory system pumps blood and
carries nutrients, wastes and gases to cells throughout the body.
Introduction to Chemistry
The Study of Changes in Matter.
Gain & Release of Energy
Changes in Physical State
(solid, liquid, gas)
Changes in Physical Properties:
Elasticity, Density,
Color, Smell
The world is made up of 92 naturally
occurring substances which can not
be reduced to a simpler state by
chemical reactions. These
substances are called elements.
Important biological elements
include:
Carbon: C
Hydrogen: H
Oxygen: O
Nitrogen: N
Sodium: Na
Potassium: K
Chloride: Cl
Phosphorous: P
Sulfur: S
Calcium: Ca
Magnesium: Mg
Each Element Has Unique Physical
and Chemical Properties
Carbon: a crumbly, black solid
Magnesium: a shiny, highly
reactive metal
Chlorine: A green corrosive gas
When Two Elements React, They
Form Compounds That May Have
Completely Different Properties
Magnesium Metal
Magnesium Chloride
A white Powder That
Dissolves in Water
Chlorine Gas
Simplified Atomic Structure
All Atoms of the Same Element
Have the Same Number of Protons
and Electrons
Radioactive Decay
Spontaneous Decomposition of an
Unstable Atom
Alpha Particle = two protons and two neutrons
Beta Particle = electron
Uses of Radioactive Isotopes
Radiation Therapy for Cancer
Radioactive Tracers
Chemical Reactions Involve an Exchange of Energy
and a Rearrangement of Chemical Bonds.
2 H2 + O2
H-H
H-H
 2 H2O
O-O 
O
H H
O
H H
Two hydrogen molecules and one oxygen molecule react to form two water molecules
A hydrogen bond forms when a polar Hydrogen on one molecule is attracted to a
partial negative charge (polar) on another atom.