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Name _______________________________________________ Period _______ Date ____________ LAB 2: CONNECTIVE, MUSCULAR, NERVE TISSUES PURPOSE: To use a microscope to examine the similarities and differences between connective, muscular, and nervous tissues in Homo sapiens (humans). ESSENTIAL QUESTION: How does the structure of each type of tissue relate to its function? Background (source: HASPI): Connective tissue is the most abundant tissue type in the body. It is not as dense as epithelial tissue, and is made up of cells, fibers, and extracellular components embedded in fluid. This structure allows connective tissue to provide ample support, while also staying pliable. Cells called fibroblasts are responsible for producing connective tissues. Blood, bone, cartilage, tendons, ligaments, adipose (fat), and lymph are all examples of connective tissue. The extracellular portion of connective tissue primarily includes the following: Interstitial fluid – fluid that contains proteins and cells Adhesion proteins – allow cells to bind to each other and to structural fibers Proteoglycans – proteins that act to filter fluids through the ground substance Collagen – extremely strong fibers that provide support Elastin – fibers that are able to stretch and return to their original shape, much like a rubber band Reticular fibers – fine networking fibers Connective tissue functions to protect, store energy, support, transport, insulate, and connect all body tissues. These tissues can be highly vascular, but can also be avascular, such as with cartilage. In the avascular tissues, they tend to be made up of more extracellular (non-living) matrices, or substances, rather than of cellular components. http://pharmaworld.pk.cws3.my-hosting-panel.com/products/stimg_43_344.jpg Types of Connective Tissues Areolar Adipose Reticular Regular Irregular Hyaline Elastic Fibrocartilage Bone Blood Loose Connective Tissue Binds cells and fibers together, but also allows movement Fat; stores nutrients, insulates, and protects organs Much like dense spider webbing; allows for structure and flow of substances Dense Connective Tissue Make up tendon and ligaments; tightly organized bundles of collagen Make up the dermis; tight bundles of collagen that are unorganized Cartilage Provides support while still being pliable; most abundant form of cartilage Provides support while still able to stretch Provides strong support and handles heavy pressure Other Tissues Support; hard tissue of collagen fibers and calcium surrounding osteocytes Tissue that contains red blood cells, proteins, and fluid called plasma MUSCULAR, NERVOUS TISSUES BACKGROUND (Source: HASPI): The cells of muscle tissue are extremely long and contain protein fibers capable of contracting to provide movement. The bulk of muscle tissue is made up of two proteins, myosin and actin. These proteins are organized into muscle fibers called myofilaments, and can be arranged into even larger bundles to create muscles. Muscle tissues are separated into three main types depending on the arrangement of these myofilaments. These include skeletal muscle tissue, smooth muscle tissue, and cardiac muscle tissue. Skeletal Muscle Tissue Skeletal muscle is also considered “voluntary muscle” and makes up the muscles that are attached to our skeleton by tendons. These muscles can be contracted voluntarily and function in movement and maintenance of posture. About 35-45% of the human body is made up of skeletal muscle tissue. When skeletal muscle tissue is observed, there are visible striations, or lines that can be seen. Smooth muscle is also known as “involuntary muscle” and makes up the lining of most of the organs of the body. This includes the gastrointestinal tract, respiratory tract, blood vessels, bladder, and uterus just as a few examples. These muscles do not contract voluntarily and do not have visible striations. For example, in a process called peristalsis smooth muscle contracts in waves to push food from the esophagus all the way through until it is expelled out the anus. Cardiac muscle makes up the heart, and is an extremely dense strong tissue. Cardiac muscle tissue has a very large number of mitochondria to provide the energy source for the continuous contracting action of the heart. Cardiac muscle tissue is striated like skeletal muscle tissue, but also has myofilaments arranged into larger striations called intercalated discs that join cardiac muscle fibers together. Smooth Muscle Tissue Cardiac Muscle Tissue Nervous Tissue Nervous tissue is found in the brain, spinal cord, and nerves and is responsible for communication. There are two main cells that make up nervous tissue: neurons and neuroglia cells. Neurons are responsible for sending and receiving messages while neuroglia provide support and nutrients for neurons. MATERIALS: Compound light microscope, Prepared slides, Computer with Wi-Fi, Pencil and colored pencils PROCEDURE: Part A. Identify the Connective Tissue Use the tissue charts on the class website to review connective tissue types. Then identify the following tissue samples A-O. Write your answers on the line in each box. A. ___________________ B.____________________ C. ____________________ D. ___________________ E. ___________________ F. ____________________ G. ___________________ H. ___________________ I. _____________________ J. ____________________ K. ___________________ L. ____________________ M. ___________________ N. ___________________ O. ___________________ Identify the Muscle and Nervous Tissue Use the tissue charts and “Types of Tissues” slide set on the class website to review muscular and nervous tissue types. Then identify the following tissue samples A-F. Write your answers on the line in each box. A. ___________________ B.____________________ C. ____________________ D. ___________________ E. ___________________ F. ____________________ Part B. Practice Identification of Normal Tissues Use the prepared slides and your computer and the following website to choose slides to view: http://medsci.indiana.edu/c602web/602/c602web/virtual_nrml/nrml_lst.htm For each type of tissue, choose a listed organ and find that type of epithelial tissue on that organ slide. • REMEMBER there may be multiple tissue types on many of the slides. • Start by searching at the edges of the slide sample for the epithelial tissues, and focus at the cell level. • You may need to move the slide around to find a good example • You may need to look up/research the organ function if it is unfamiliar (use PubMed Health Topics) • Use blue for the nucleus, yellow for the cytoplasm, and red for the cell membrane. a. Connective tissue proper: loose connective tissue, areolar Slide Choices: areolar tissue slide, under epithelium, mucous membranes, surrounding capillaries Tissue Function Draw an example. Use colored pencils. b. Connective tissue proper: loose connective tissue, adipose Slide Choices: Fat or adipose slide, under skin, around kidneys, around eye, breast, abdomen Tissue Function Draw an example. Use colored pencils. c. Connective tissue proper: loose connective tissue, reticular Slide Choices: Reticular tissue slide, lymph nodes, bone marrow, spleen Tissue Function Draw an example. Use colored pencils. d. Connective tissue proper: dense connective tissue, dense regular Slide Choices: Dense regular tissue slide, tendons, ligaments Tissue Function Draw an example. Use colored pencils. e. Cartilage: hyaline Slide Choices: Hyaline cartilage, embryo skeleton, end of long bones, costal cartilage, nose, trachea, larynx Tissue Function Draw an example. Use colored pencils. i. Bone (osseous tissue) Slide Choices: Bone Tissue Function Draw an example. Use colored pencils. j. Blood Slide Choices: Blood, red blood cell smear Tissue Function Draw an example. Use colored pencils. a. Skeletal muscle Slide Choices: Skeletal muscle Tissue Function Draw an example. Use colored pencils. b. Cardiac muscle Slide Choices: Heart Tissue Function Draw an example. Use colored pencils. c. Smooth muscle Slide Choices: Smooth muscle, wall of any hollow organ Tissue Function Draw an example. Use colored pencils. d. Nervous tissue: neurons Slide Choices: Brain, spinal cord, nerve Tissue Function Draw an example. Use colored pencils. ANALYSIS (attach extra sheets as needed): 1. What is the difference between loose and dense connective tissue? ________________________________________________________________________________ ________________________________________________________________________________ 2. What is the difference between areolar, adipose, and reticular tissue? ________________________________________________________________________________ ________________________________________________________________________________ 3. What is the difference between regular and irregular dense tissue? ________________________________________________________________________________ ________________________________________________________________________________ 4. What is the difference between hyaline, elastic, and fibrocartilage? ________________________________________________________________________________ ________________________________________________________________________________ 5. What is the difference between compact and spongy bone? ________________________________________________________________________________ ________________________________________________________________________________ 6. What is the difference between skeletal, smooth, and cardiac muscle? ________________________________________________________________________________ ________________________________________________________________________________ 7. What are the lines in skeletal and cardiac muscle? ________________________________________________________________________________ ________________________________________________________________________________ 8. What is an intercalated disc? Why are these not seen in skeletal muscles? ________________________________________________________________________________ ________________________________________________________________________________ 9. How is the shape of a neuron suited to its purpose? ________________________________________________________________________________ ________________________________________________________________________________