Unit 5 Lesson 10

Lesson 10 - Other Tissues: Muscular and Nervous

Student Performance Objectives
1. List and state the locations of the 3 types of muscular tissue found in the human body.
2. Explain the basic functions of muscular tissue.
3. State the two major characteristics of nervous tissue. 
4. List the 4 basic functions of nervous tissue.

Lesson Outline
A. Other Tissues: to be examined more closely in subsequent lessons.
    1. Muscular Tissue - tissue capable of contraction and relaxation that brings about
        movement. There are three types of muscular tissue.
        a. Skeletal (striated) muscle - generally considered to be under voluntary, 
            conscious control, although many reflex activities involving these muscles
            occur automatically (unconsciously). The tissue is composed of elongated
            muscle fibers possessing many nuclei per fiber (multinucleate). This tissue
            forms much of the bulk of a human body, composing the muscles that are
            attached to and which move the skeleton, generally at the joints. The 
            contractile filaments within each fiber are arranged in a regular, repeating 
            pattern which presents the characteristic striated appearance under the light 
            microscope.
        b. Smooth muscle - involuntary muscle found in the walls of the body's hollow
            organs like the stomach and other digestive organs, the urinary bladder and 
            the blood vessels. Smooth muscle cells are mostly uninucleate; some are 
            multinucleate. The contractile filaments within this muscle type do not occur
            in the regular arrangement that would produce striations so that the muscle, 
            when viewed under the light microscope, appears non-striated, or smooth.
        c. Cardiac - the involuntary muscle tissue composing the heart's myocardium. 
            Its rhythmic contractions propel the blood through the cardiovascular
            system under pressure. Cardiac muscle fibers are striated, are "welded" to 
            each other through desmosomes (part of intercalated discs), and possess gap
            junctions that facilitate electrical signaling from one fiber to the next.
    2. Nervous Tissue - tissue possessing the properties of irritability (the ability to be 
        stimulated and to respond to such stimulation) and conductivity (the ability to transmit
        electrochemical signals over long distances along specialized cellular extensions - the 
        axons and dendrites. Its signals help to regulate and coordinate bodily functions. The 
        major organized regions of nervous tissue (brain, spinal cord, peripheral nerves, and 
        sensory receptors) carry out the following functions:
        a. Conduct sensory signals (information) from receptors into the central nervous
            system (CNS - which consists of the brain and spinal cord working as an 
            integrated unit).
        b. Analysis of incoming signals.
        c. Store incoming signal patterns as memory. 
        d. Conduct motor signals from the CNS to muscle and glands.