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We will study:
Why specialize cells?
What is cellular differentiation?
What causes specialization?
1.
Cell Specialization
SNC2D1
Cells, Tissues and Organs
2.
Why Specialize?
• A single cellular organism performs all
required functions in one cell.
• e.g., Amoeba.
3.
Why Specialize?
• Multicellular organisms are much more
complex.
• The body needs to supply food and nutrients,
transport materials, remove wastes and fight
infection.
4.
Cellular Differentiation
• The process of creating specialized cells.
• All cells in the body originated from the zygote
undergoing mitosis.
• As an embryo develops, cells change their
shape, contents and function.
5.
Cellular Differentiation
6.
What Causes Specialization?
1. Cytoplasm Differences:
• Asymmetric distribution of
organelles & other factors in
zygote.
• Results in different daughter
cells.
7.
What Causes Specialization?
2. Environmental Conditions:
• Variations in temperature and nutrients.
3. Neighbouring Cells:
• Substances produced by nearby cells can
diffuse to nearby cells.
8.
What Causes Specialization?
• The three factors
listed may result in
the expression of
different genes
within a cell.
9.
Abnormal Development
• Chemical contamination of the environment
can affect cellular development.
10.
Stem Cells
• Cells that can differentiate
into many different cell
types.
• The daughter cells
have the same DNA,
but different
genes
may be
turned on
or off.
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11.
Types of Stem Cells
1. Embryonic Stem Cells
– Differentiates into any cell type.
2. Adult Stem Cells
– Exists in some tissues but can only form specific
types of cells.
– E.g., bone marrow stem cells form white blood
cells, red blood cells and platelets.
13.
Tissue Types
• Tissues are a collection of similar cells that perform
specific functions.
• Animals have 4 types
of tissue:
1. Epithelial.
2. Muscular.
3. Connective.
4. Nervous.
14.
Epithelial Tissue
• Line the internal and
external surfaces of
the body.
• Form a barrier by
connecting adjoining
cell membranes.
15.
Muscular Tissue
• Move the body or organ by contracting and
relaxing.
16.
Connective Tissue
• Strengthens, supports and protects other tissues.
• Cells are in an extracellular matrix.
17.
Nervous Tissue
• Made of neurons with long projections that
send and receive signals.
• Coordinates body actions.
20.
Tissues Assignment
1. Read the handout “Tissues of the Human
Body” and learn the tissue subtypes.
2. Answer the questions on the handout.
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