Skip Navigation Links
About
Admissions
Academics
Continuing ED
Alumni
Community
Donate
Skip Navigation LinksKCC Home > Academic Departments > Biological Sciences > 11New > Webpages > Unit 4, Lesson 13

Skip Navigation Links
Anatomy and Physiology I
Unit 1: Introduction to Human Anatomy and PhysiologyExpand Unit 1: Introduction to Human Anatomy and Physiology
Unit 2: The Cell and It’s EnvironmentExpand Unit 2: The Cell and It’s Environment
Unit 3: Cellular ChemistryExpand Unit 3: Cellular Chemistry
Unit 4: Biomolecules, Cell Architecture and Cellular Molecular FunctionExpand Unit 4: Biomolecules, Cell  Architecture and Cellular Molecular Function
Unit 5: Tissues, Membranes and GlandsExpand Unit 5: Tissues, Membranes and Glands
Unit 6: Integumentary SystemExpand Unit 6: Integumentary System
Unit 7: Skeletal System
Unit 8: Muscular System
Unit 9: Nervous System Introductory Concepts
Unit 10: The Central Nervous System - The Spinal Cord
Unit 11: The Central Nervous System - The Brain
Unit 12: The Autonomic Nervous System and Smooth Muscle


Lesson 13 - Taking a Deeper Look at Cellular Structure
(An optional lesson about the cellular cytoskeleton)

Student Performance Objectives

1. List and describe the locations of the 3 major types of cytoskeletal elements found in cells.
2. Describe the functions of the microfilaments, intermediate filaments and the microtubules
    found in the cell's cytoplasm.

Lesson Outline
A. A cell is not a watery soup with organelles floating around at random.
B. Cells have a cytoskeleton composed of:
    1. Microfilaments, of which actin is the specific protein type. About 6/1000 of a micron
        thick.
http://www.biology.arizona.edu/cell_bio/tutorials/cytoskeleton/page1.html
        a. Microfilaments form a network at the junction of the outermost border of the
            cytoplasm and the inner border of the cell membrane phospholipids. The
            association of microfilaments and phospholipids holds the inner membrane
            in place thus acting as a membrane stabilizing force. Appropriately, this band
            of microfilaments underlying the cell membrane is called the membrane
            skeleton.
        b. Microfilaments extend upward from the cytoplasm into microvilli, those
            cellular extension seen best in intestinal epithelial cells and kidney tubular
            epithelial cells where they increase absorptive surface area. The filaments can
            then pull down on the microvillus, physically propelling absorbed materials
            deeper into the cell for processing.
    2. Intermediate filaments, of which keratin is a major type, are seen in epidermal cells.
        Slightly thicker than microfilaments - about 8-10/1000 of a micron thick.
        
http://www.cytochemistry.net/Cell-biology/filam.htm
        http://www.cytochemistry.net/Cell-biology/intermediate_filaments.htm
        a. Extend throughout the cytoplasm like a spider's web.
        b. Help to maintain cell shape by resisting mechanical stresses placed on the cell.
    3. Microtubules, which are more complex structures composed of the protein, tubulin. Significantly
        larger than the other cytoskeletal elements: 25/1000 of a micron.

        
http://www.ruf.rice.edu/~bioslabs/studies/invertebrates/microtubules.html
        a. Each microtubule is composed of the globular protein, tubulin, arranged into 13 tiny filaments that
           form a cylinder.
        b. The cylinders radiate from the cell's centrosomal region throughout the cell like the intermediate
            filaments, only they are larger.
        c. Functions:
            (1) Anchor organelles in place in specific cytoplasmic regions.
            (2) Allow organelles, like chromosomes during mitosis, to glide to
                 different locations as required. The mitotic spindle and centrioles are composed of
                 microtubules.
                 (3) Work with the intermediate filaments to help maintain cell shape.
                 (4) Make up the inner structure of cilia and flagella and are responsible
                      for their movements.

       
















kccFacebook KCCTwitter
Privacy Statement | GAINFUL EMPLOYMENT | Disclaimer | Text Only | Make This Website Talk

Kingsborough Community College
2001 Oriental Boulevard, Brooklyn, NY 11235-2398 | (718)-368-5000
Kingsborough is CUNY