Cell Specialization
SNC2D1 Cells, Tissues and Organs
Why Specialize?
• A single cellular organism performs all required functions in one cell.
• e.g., Amoeba.
Why Specialize?
• Multicellular organisms are much more complex.
• The body needs to supply food and nutrients, transport materials, remove wastes and fight infection.
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.
Cellular Differentiation
What Causes Specialization?
1. Cytoplasm Differences:• Asymmetric distribution of
organelles & other factors in zygote.
• Results in different daughter cells.
What Causes Specialization?
2. Environmental Conditions:• Variations in temperature and nutrients.
3. Neighbouring Cells: • Substances produced by nearby cells can
diffuse to nearby cells.
What Causes Specialization?
• The three factors listed may result in the expression of different genes within a cell.
Abnormal Development
• Chemical contamination of the environment can affect cellular development.
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. Watch This!!!
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.
Stem Cell Research
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.
Epithelial Tissue
• Line the internal and external surfaces of the body.
• Form a barrier by connecting adjoining cell membranes.
Muscular Tissue• Move the body or organ by contracting and
relaxing.
Connective Tissue• Strengthens, supports and protects other tissues.• Cells are in an extracellular matrix.
Nervous Tissue
• Made of neurons with long projections that send and receive signals.
• Coordinates body actions.
Tissues in the Arm
Tissues Assignment
1. Read the handout “Tissues of the Human Body” and learn the tissue subtypes.
2. Answer the questions on the handout.
