Chapter 14: Bones,
Muscles and Skin
Section 1: Body Organization
and Homeostasis
p. 468 – p.473
Body Organization
• How the body systems work
together to keep you alive
Levels of Organization in the
Body
•
The levels of organization in the human body consist of:
– Cells – the basic unit of structure and function in living
things
– Tissues – a group of similar cells that work together to
perform the same function
– Organ – A structure in the body that processes materials
necessary for the body to survive
– Organ system – A group of organs that work together to
perform a major function in the body
– Organism – A complete, living thing
homeostasis
• Our internal environment stays
the same in spite of changes on the
outside
• Keeping things in balance
Homeostasis
• The maintenance of stable
internal condition in an organism
even when the outside
environment changes
• Like body temperature
• Sugar
• Iron
• Calcium
Cell
• The basic unit of
structure and
function in a
living things.
• A human being
contains 100
trillion cells.
Cell Membrane
• The cell
membrane forms
the outside
boundary of the
cell.
• It is picky about
what it allows into
and out of the cell.
• One could say, “It is
selectively
permeable.”
Nucleus
• It is the control
center of the cell.
• It directs all the
cell’s activities.
• It contains the
information that
determines the
cell’s form and
function.
Cytoplasm
• The material
within the cell
apart from the
nucleus. The
clear, jellylike
substance
containing the
cell’s structures
and organelles.
Tissue
• A group of similar
cells that perform
the same function.
The human body
contains four basic
types of tissue:
–
–
–
–
Muscle Tissue
Nervous Tissue
Connective Tissue
Epithelial Tissue
Muscle Tissue
• Muscle tissue can
contract or
shorten.
• By doing this,
muscle tissue
makes parts of
your body move.
Nervous Tissue
• Nervous tissue
carries electrical
messages back
and forth
between the
brain and other
parts of the body.
• It controls the
brain messages
and responses
from the brain.
Connective Tissue
• Connective tissue
provides support
for your body and
connects all its
parts.
• Bone tissue and
fat are connective
tissues.
Epithelial Tissue
• The surfaces of your
body, inside and out
are covered by
epithelial tissue.
• Some epithelial tissue,
such as your skin,
protects the delicate
structures that lie
beneath it.
• The lining of your
digestive system
consists of epithelial
tissue that allows you
to absorb the nutrients
in your food.
Organ
• An organ is a
structure that is
composed of
different kinds of
tissue.
• Your stomach,
heart, brain and
lungs are all
organs.
• An organ performs
a specific job.
Organ System
• Each part of your
body is part of an
organ system.
• An organ system is
a group of organs
that work together
to perform a major
function to sustain
the body.
• Check page 471 in
your textbook 
Stress
• The reaction of
your body to
potentially
threatening,
challenging, or
disturbing events.
Summary
• What information was helpful to
me?
• Is there something interesting that
I may look back at in this section?