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Muscular and Nervous Tissue Chapter 3 Human Anatomy & Physiology Muscular Tissue • Function • Contracts to produce movement • Movement can be voluntary or involuntary Types of Muscular Tissue • 3 Types 1. Skeletal 2. Smooth 3. Cardiac Characteristics of Skeletal Muscle • Appearance: striated (striped) and column-shaped cells (muscle fibers) – Alternating light and dark bands make striations • Location: Attached primarily to bones • Control: Voluntary (conscious) • Contracts quickly, tires easily (fatigable) Skeletal Muscle Tissue - 400X Smooth Muscle • Appearance: spindleshaped • Location: wall of hollow organs – example: Intestines, urinary bladder, ureters, blood vessels • Control: Involuntary • Contracts rhythmically and quickly Smooth Muscle Smooth Muscle Tissue - 400X Cardiac Muscle • Has features of both skeletal and smooth muscle - Like skeletal muscle, it has strong contractions and striated appearance - Like smooth muscle, it is under involuntary control and has rhythmic contraction • Appearance: striated and branched • Location: heart • Function: contraction of heart pumps blood and causes the heartbeat • Control: Involuntary Cardiac Muscle Tissue - 400X Nervous Tissue • The ultimate control of all the organ systems is done by the nervous system. – Function: controls and coordinates all bodily functions and responds to internal and external stimuli. THINK… COMMUNICATION! Nervous Tissue • Found: brain, spinal cord, and peripheral nerves • The cells that transmit messages (impulses) are called neurons. Structure of a Neuron Nucleus Dendrites Axon terminals Cell body Myelin sheath Nodes Axon Neuron Structure • Dendrites extend from the cell body and carry impulses from the environment toward the cell body. Neuron Structure • The largest part of a typical neuron is the cell body. • It contains the nucleus and much of the cytoplasm. Neuron Structure • The axon is the long fiber that carries impulses away from the cell body. Neuron Structure • The axon is sometimes surrounded by an insulating membrane called the myelin sheath. Neuron Structure There are gaps in the myelin sheath, called nodes, where the membrane is exposed. • Impulses jump from one node to the next. Neuron Structure Impulses are then passed to the next cell by the axon terminals.