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Muscular and Nervous Tissue Chapter 4.3 Human Anatomy & Physiology Muscular Tissue • Function • Contraction • Attachment by tendons to bones for movement • Movement: Voluntary and involuntary Muscular Tissue • Appearance – striated (striped) – Alternating light and dark bands • Location – Usually attached to skeleton • Each cell has a nucleus that is centrally located Types of Muscular Tissue • Types A. Skeletal B. Smooth C. Cardiac Characteristics of Skeletal Muscle • Appearance: striated • Location: Attached primarily to bones • Control: Voluntary (conscious) • Contracts quickly, tires easily (fatigable) • Allows for wide range of forces to be generated Skeletal Muscle Tissue - 400X Smooth Muscle • Appearance: spindleshaped • Location: wall of hollow organs – example: Intestines, urinary bladder, ureters, urinary bladder, blood vessels • Control: Involuntary • Contracts rhythmically and quickly, tires easily (fatigable) • Allows for wide range of forces to be generated Smooth Muscle Smooth Muscle Tissue - 400X Cardiac Muscle • Has features of both skeletal and smooth muscle - Strong contractions and striated appearance is similar to skeletal muscle - Involuntary control and rhythmic contraction is similar to smooth muscle • Appearance: striated and branched (like skeletal muscle) • Location: heart • Function: contraction of heart pumps blood and causes the heartbeat • Control: Involuntary (like smooth muscle) Cardiac Muscle Tissue - 400X Nervous Tissue • The ultimate control of all the organ systems is done by the nervous system. – The nervous system controls and coordinates functions throughout the body and responds to internal and external stimuli. Nervous Tissue • Found: brain, spinal cord, has specialized cells • The cells that transmit these impulses are called neurons. Structure of a Neuron Nucleus Dendrites Axon terminals Cell body Myelin sheath Nodes Axon Neuron Structure • The largest part of a typical neuron is the cell body. • It contains the nucleus and much of the cytoplasm. Neuron Structure • Dendrites extend from the cell body and carry impulses from the environment toward the cell body. 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.
