Transcript AP chapt One part one

Chapter One Part 1
Introduction to Anatomy and Physiology
Characteristics of Life
What is Anatomy and Physiology
Maintenance of Life
Ameoba –
Single
Celled
Organism
(Protist)
Can you remember the
characteristics of life?
Marvin the Martian steals a car from Earth
and takes it back to Mars as an example
of life on Earth. The Martians state that
this is not a good example of life.
Who is right? In your group, come up with
an argument for or against Marvin’s idea
that a car is a good example of Life from
Earth.
Characteristics of Life…
Death
Gas exchange
Water
Use energy
Eliminate waste
Responds to environment
Growth
Reproduce
Made of cells
Metabolism – all chemical changes within cells
considered all together; the chemical reactions in the
body's cells that convert the fuel from food into the
energy needed to do everything from moving to
thinking to growing.
What is required for life?
Make a list of all the
requirements for life with
your group…
What is Anatomy and Physiology?
Anatomy:
Branch of science that deals with the
structure (morphology) of body parts
Physiology
Concerns with the function of body parts –
what they do and how they work
Homeostasis
Balancing the internal environment
External vs. Internal
Environment
What is the difference?
Internal Environment
Conditions within the fluid surrounding its
body cells
Comprised of self-regulating control
systems – homeostatic mechanisms
Feeling Feverish?
Homeostatic Mechanisms
Have three common components:
Receptors – provides information about
specific conditions
Set point –
tells what a particular value
should be
Effectors - Cause the response that alter
conditions in the internal
environment.
Set Point
Control Center
Receptor
Homeostatic
Mechanism
Effectors
Stimulus – change in
external environment
Response – Change
Corrected
Negative vs. Positive
feedback mechanisms
Negative Feedback Systems
Deviation from the set point is corrected
Correction reduces the action of the
effectors
Homeostatic Regulation of Body Temperature through
Negative Feedback
Hyperthermia
Heat receptors
in the skin
Hypothalamus
Sensors
Control Center
Stress
Stress is reduced
shutting down
mechanism
Perspiration
evaporates
cooling the skin
Increased
activity of
sweat glands
Increased blood
flow to the skin
Effect
Effectors
Homeostasis Using a Neural Pathway
Control center
Many homeostatic
mechanisms use a
nerve pathway in which
to produce their effects.
These pathways
involve an afferent path
which brings sensory
messages into the
brain and an efferent
path which carries
outgoing nerve
messages to effectors.
Positive Feedback Systems
Change that occurs is in the same direction
as the initial disturbance.
Deviation from the set point is accelerated
No correction to the action of the effectors
Body will shut down, however some positive
feedback systems work in favor of the body
– ie. Childbirth.
Positive Feedback Mechanisms
Typical Positive Feedback Process
Stress
Intensifies
Sensor
Control Center
Effector
Homeostatic Regulation of Child Birth through
Positive Feedback
Pressure of Fetus on
the Uterine Wall
Nerve endings in the uterine
wall carry afferent messages
to the Hypothalamus
Intensifies
Increasing strength of
uterine contractions
Production and Release
of Oxytocin into the
Blood
The birth of the child will bring this process to a close. Other
examples of positive feedback regulation occur during milk
letdown and blood clotting.
Harmful Effects of Positive Feedback
Positive feedback can be harmful. A specific
example of these harmful outcomes would be:
Positive feedback is frequently a normal way of
producing rapid change. However, positive
feedback can be harmful to the body. For
example, if the body temperature rises above
108o F a dangerous positive feedback loop may
be created. This high temperature will increase
the metabolic rate, thus producing heat faster
than the body can get rid of it. Thus,
temperature rises still further, increasing
metabolic rate and heat production still more.
This becomes fatal at approximately 113o F.
Practice
http://www.mhhe.com/biosci/esp/2002_ge
neral/Esp/default.htm