Cells Form Tissues

Cells Form Tissues Name: ______

Cells specialization refers to the fact that different cell types have different structures and abilities to perform specific function efficiently. As we know all cells originate from a single cell, this makes copies of itself. The cells that have not yet decided its function is called a stem cell.

At some point, cells get some sort of signal that tells them what type of cell to become. The process which a stem cell undergoes to become a specialized cell is called cell differentiation.

Can you think of a reason why this is so interesting to scientists?______

______

Scientists are in fact very interested in studying cell differentiation because they feel they can find clues on how to treat many diseases. They hope to figure out how to trigger the stem cells to develop into the type of cell to repair tissues damaged by the disease. Or even to trigger stem cells to grow into the type of tissue they may need to replace.

Some specialized cells:

When we have many specialized cells grouped and working together to do one function, they are called a tissue. There are 4 major groups: (You need to know the tissue types)

1.  Muscle

¨  Enables a body part to move, exert force, or change shape

§  Long muscles (in arms or legs)

§  Stomach muscles ( to help move and digest)

§  Heart muscles (to push blood through our veins and arteries)

2.  Epithelial (skin or outer layer of cells)

¨  Covers external and internal body surfaces

§  Outer skin (that we can see)

§  In intestine (digestive cavity)

3.  Connective Tissues

¨  Strengthens and supports and connects cells and tissue

§  Bone connective tissue (around living bone cells – very hard)

§  Other types - ligaments (elastic connectors between bones)

-  tendons (inelastic connectors between bone and muscle)

-  cartilage ( acts as a cushion between bones)

§  blood (considered a connective tissue since it connects different body systems, it delivers oxygen and nutrients and removes wastes.)

4.  Nervous

¨  Senses, conducts and transmits information

§  Sensory neurons – transmit senses to the brain (how hot etc)

§  Motor neurons – carry instructions from brain to body parts

§  Interneurons – connect sensory neurons to motor neurons (mostly in spinal cord and brain)

Viewing Specialized Human Cells

Instructions:

1.  Look at prepared slides of human cells (Muscle, epithelial, connective and Nervous)

2.  Make sure to use the information on the cards and the slides to determine which type of cell you are looking at.

3.  Sketch two of the cells on one page. Include all the details that you can see including the structures inside of the cell.

4.  Try to use the description to identify the different organelles of the cell. (Use the sheets provided by Mrs. Forrest as a guide – they may be hard to find and skin cells probably will only have a nucleus, and cell membrane that you can identify)

5.  Use the checklist below to make sure you have done your drawing correctly.

Scientific Drawing Checklist Name: ______

Requirements:

□  Drawing done on Blank paper

□  Drawing done with a sharp pencil

□  Firm clear Lines (no sketching)

□  No Shading/colour (stippling allowed)

□  Only relevant & easily seen details included

□  Large Drawing (1/2 page or 1/3 page if two)

□  Labels are neatly printed

□  Labels are located at the right side of the drawing

□  Labels are listed in an even column

□  Label lines are parallel & done with a ruler

□  Label lines do not cross

□  Name & date Located at the top right corner

□  Appropriate Title located under the drawing

□  Title underlined

□  Total magnification is located in the bottom right corner

Hand In your drawing by Tuesday Nov 27