Transcript Anatomy and Physiology I BY 30

Anatomy and Physiology I
Bio 130
Professor Peter Smith D.P.T, ATC
http://www2.sunysuffolk.edu/smithpr/
Overview of Anatomy and
Physiology
• Anatomy – the study of the structure of
body parts and their relationships to one
another
• Physiology – the study of the function of
the body’s structural machinery
• Cytology – study of the cell
• Histology – study of tissues
Levels of Structural Organization
Smooth muscle cell
Molecules
2 Cellular level
Cells are made up of molecules
Atoms
Smooth
muscle
tissue
3 Tissue level
Tissues consist of
similar types of
cells
1 Chemical level
Atoms combine to
form molecules
Heart
Cardiovascular
system
Epithelial
tissue
Smooth
muscle
tissue
Connective
tissue
4 Organ level
Organs are made up of
different types of tissues
Blood
vessels
Blood
vessel
(organ)
6 Organismal level
The human organism is
made up of many organ
systems
5 Organ system level
Organ systems consist of different organs
that work together closely
Organ Systems Interrelationships
• Nutrients necessary for
energy production for all
the cells in the body are
absorbed in the digestive
system.
• O2 and CO2 are
exchanged by the
respiratory system and
distributed throughout
the blood by the
circulatory system.
• Metabolic wastes are
eliminated by the urinary
and respiratory systems
Homeostasis
• Homeostasis is the ability to maintain a relatively stable
internal environment in an ever-changing outside world
• The internal environment of the body is in a dynamic
state of equilibrium
– There is a tight regulation of hormones (chemical
messages), changes is body temperature and the
nervous system.
– The body is designed to maintain homeostasis!
• Diets fail because calorie restriction can promote a rapid drop
in body weight. Your physiology sees this as a threat to your
survival. To restore homeostasis metabolism is reduced.
Homeostatic Control Mechanisms
3 Input:
Information
sent along
afferent
pathway to
Control
center
4 Output:
Information sent
along efferent
pathway to
Effector
Receptor (sensor)
2 Change
detected
by receptor
1
Stimulus:
Produces
change
in variable
Variable (in homeostasis)
5 Response of
effector feeds
back to influence
magnitude of
stimulus and
returns
variable to
homeostasis
Negative Feedback
• In negative feedback systems, the output shuts off the
original stimulus.
Negative Feedback
• When the body temperature is higher than the set point the blood
vessels dilate bring the blood closer to the skin. Evaporated sweat
cools the body
• When the body is cold blood is shunted toward the internal organs
way from the skin to minimize heat lose. Shivering creates heat as a
byproduct of muscle metabolism
Negative Feedback
Positive Feedback
• In positive
feedback
systems, the
output enhances
or exaggerates
the original
stimulus
• Example:
Regulation of
blood clotting
Figure 1.6
Homeostatic Overview
• Under normal circumstances the body’s
homeostatic controls are maintained by negative
feedback loops.
• Diseases are often made worse because of
failure of the normal negative feedback
mechanisms. The creation of positive feedback
loops that further drive the body away from its
homeostatic mechanisms. Example:
– Diseased lungs reduce the body’s ability to bring in
oxygen to the cells. The body tries to adapt by make
more oxygen carrying red blood cells. The result is
thicker blood. This makes the heart work harder and
even get larger. The larger heart put pressure on the
lungs.