Specialized Animal
Cells
cell specialization/stem
cells/levels of organization
Unicellular Organisms
Made of only one non-specialized cell
 Some unicellular organisms have
organelles (like a nucleus and
mitochondria)

 Others do not
 Bacteria are
unicellular organisms
that do not have
organelles; there is
no nucleus and the
DNA can be found
anywhere in the cell
Multicellular Organisms
Organisms made of more than one cell
 Sometimes all of the cells are the same

Specialized Cells
Organisms with different types of cells
contain specialized cells
 Specialized cells usually have organelles
 Specialized cells look different

In the beginning…..



You began life as a
single fertilized egg
cell
This cell quickly
divided and produced
two cells
After about 10 days
and many cell
divisions the cells
started to differentiate
(become different
from each other)
Cell Specialization

Cells develop in different
ways to perform
particular functions
EX. Animal cells may
become lung cells or skin
cells
 Your body is a collection
of more than 200
different types of cells
doing specialized jobs
Each type of specialized cell is a
particular shape and size and has
unique features that let the cell perform
its special function.
Specialized Cells
and Hearing



Inside our ears are
cells with cilia
The cilia detect
vibrations that we
interpret as sound
Very loud noises can
permanently damage
these cells, leading to
hearing loss and
deafness
http://www.youtube.com/watch?v=1EJ4g3J6cJM
Question #1
Why are our bodies made up of specialized
cells?

We have over 200 different kinds of
specialized cells to perform all the
functions needed to keep us alive.
Growing New Cells from Stem Cells



Sometimes specialized
cells can no longer divide
Stem cells can often
replaced these damaged
cells
In some organs, like bone
marrow, stem cells divide
regularly. These bone
marrow stem cells can
become red blood cells,
white blood cells or
platelets
STEM CELLS



Are unspecialized
cells
They can divide
repeatedly
Can form specialized
cells
Types of Stem Cells

1.
2.
There are two types
of stem cells:
Embryonic stem
cells
Adult stem cells
Embryonic VS Adult Stem Cells


EMBRYONIC
Found in embryos (and to
a small extent in umbilical
cords and placentas)
Able to undergo
differentiation



ADULT
Found in adults
Can undergo limited
differentiation
Used by the body to
replace damaged tissue
Putting Stem Cells to Work
Many medical experts believe stem cells can be
used to treat a variety of illnesses and injuries
Ex. Bone regeneration, cancer, heart disease,
diabetes and Parkinson’s disease

The View of the Catholic Church


The preparation of
embryonic stem cells
from a living embryo
requires the destruction
of the embryo, which
the Church teaches is a
gravely immoral act.
The Catholic Church
has publicly supported
adult and umbilicalcord stem-cell
research.
Question #2
A.
B.
A.
B.
How do stem cells differ from other body
cells?
What is the Catholic Church’s View on
stem cell use?
They are not specialized and can divide
repeatedly.
The Catholic Church supports the use of
adult and umbilical cord stem cells, but
not the use of embryonic stem cells from
an embryo.
Levels of Organization1


Animals are
organized in a
hierarchy
The most simple level
of the hierarchy
consists of cells, the
basic unit of living
things
Levels of Organization2
Any group of
similar cells that
perform the same
specific function
is called a tissue
Ex. Muscle, bone,
blood and nerve
tissue

Types of Tissues

1.
2.
3.
4.
There are 4 main
types of animal
tissues
Epithelial
Connective
Nervous
Muscle
Epithelial Tissue

Tightly packed cells
that cover body
surfaces and line the
internal organs
Connective Tissue

Supports, protects
and connects the
body’s organs
Ex. Bone, blood,
cartilage
Nervous Tissue



Transmit signals
throughout the body
Most complex tissue
in the body
Makes up the brain,
spinal cord and
nerves
Muscle Tissue

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Made up of cells that
contract (get shorter)
Skeletal muscle
attaches bone to
bone so we can move
Smooth muscle
causes most body
organs to contract
Cardiac muscle
pumps blood through
the heart
Question #3

Why is it important that some types of
muscles can contract and relax without our
having to think about it?

If it were not involuntary, we would spend
all of our time thinking about things like
breathing and digesting food.
Levels of Organization3
Groups of tissues
(two or more types)
working together form
an organ
Ex. Stomach, heart

Levels of Organization4
An organ system
consists of one or
more organs and
other structures that
work together to
perform a body
function
Ex. circulatory system,
digestive system

Levels of Organization5
Many different organ
systems working
together makes an
organism
Ex. human

Question #4

Think of your circulatory system as
pictured above. Name one type of cell,
tissue and one organ found in this organ
system.
Cell – red blood cell
 Tissue – cardiac muscle
 Organ - heart

Reasoning for Specialized Features
of Some Cells
Type
of Cell
Special Feature(s)
Reasons
Red
Blood
Cell
• Disc-shaped,
concave in middle
Nerve
Cell
• Many long, thread- • Send and receive signals
like extensions
from other cells
• Arranged in
Muscle
sheets
Cell
• Many
mitochondria
• Made in bone marrow,
nucleus ejected
• Can carry more oxygen
• Need to lengthen and
contract
• Require large amounts
of energy