Homeostasis: The Essence of Life
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Transcript Homeostasis: The Essence of Life
Human Physiology
A short introduction
to the field of human
physiology
Introduction
Living systems possess a special
organization
Physiology studies two related
aspects of that organization:
structure and function
For this reason physiology is
closely related to Anatomy and
Biochemistry
Homeostasis
This is the name for the
processes which keep the
condition and environment
of the tissues in the proper
condition to sustain life.
Cells
Cells are the basic units of life
they make up tissues and organs
in the body
Cells can only come from other
cells (The CELL THEORY)
Tissues
muscle
nervous
epithelial
connective
Glands
Epithelial tissue
Specialized for secretion
Exocrine glands: secrete through
ducts to the outside of the body
Endocrine glands: ductless glands
which produce hormones which
are released into the blood
Organs
Two or more types of primary
tissue
Organized to perform a particular
function
Examples of Organs
Stomach
Heart
Liver
Kidneys
brain
many others
Homeostasis: The
Essence of Life
Cells live in a fairly constant
environment
The cells, in turn, constitute the
tissues which provide that
environment
Homeostasis
Body systems
Cells
Body Systems
Nervous
Endocrine
Immune
Circulatory
Muscle/skeletal
Integument
Respiratory
Urinary
Digestive
Reproductive
Negative Feedback
Fall in temperature
-
+
Thermostat
Connecting
Circuit
Heat
Furnace
+
Negative Feedback
Fall in blood pressure
-
+
Pressure sensors
Increase in
blood pressure
Nerves
Heart and blood
vessels
+
Failure of Homeostasis
Often leads to sickness and
eventually death