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EXAM III REVIEW LOCOMOTION Type of movement seen in the lining of the respiratory tract: Ciliary and Flagellar Seen in lymphocytes: Amoeboid Seen in sperm: Flagellar 4 characteristics of muscle cells: 1. Contractile (shortens) 2. Excitability: can receive and respond to stimulus 3. Extensibility: can be stretched 4. Elasticity: returns to original shape Which type of muscle is? In voluntary? Smooth, Cardiac, Autorhythmic? Cardiac Voluntary?: Skeletal Which evolved first? Smooth The functional unit of a muscle fiber: Sarcomere (sarcomere=area between 2 adjacent Z-lines) Characteristics of cardiac muscle: Involuntary: not under conscious control Found in the heart of vertebrates and invertebrates. Fibers are bifurcated (branched), and interlocking Provides strength to tissue. Autorhythmic (self-exciting): generates its own impulse to contract (SA Node) Heart Contractions (strength, rate) are influenced or modified by hormones and nervous system, but basic impulse originates within heart Characteristics of skeletal muscle: Characteristics : Voluntary Capable of more force than smooth muscle Greater energy requirements than smooth muscle Many mitochondria Fatigues more quickly than smooth muscle
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Formation of fibers: Skeletal muscle fibers are formed by end-to-end fusion of several cells during development. Results in many nuclei per fiber: multinucleate Striated (striped) appearance: Comes from highly ordered arrangement of contractile fibers. What is the main point of Huxley's hypothesis? Contraction of Skeletal Muscle: *During contraction, both the thick (myosin) and thin (actin) filaments retain their original length . Since shortening of individual filaments does not cause contraction , it must be the result of an increase in the amount of overlapbetween the filaments . What does acetylcholinesterase do? enzyme released into the synaptic cleft, which breaks down acetylcholine What chemical/ion causes muscles to contract by triggering an interaction between actin and myosin? Calcium diffuses into myofibrils of the muscle fiber: causes interaction between myosin “heads” and actin filaments by exposing binding sites on actin filaments What is the advantage to cardiac muscle of having branched/interlocking fibers? Provides strength to tissue. Why are skeletal muscle fibers multinucleate (several nuclei)? Skeletal muscle fibers are formed by end-to-end fusion of several cells during development. Part of the sarcomere to which actin filaments is anchored: Z-line membrane **********What chemical ion do we use to trigger muscular contraction? Calcium NERVOUS SYSTEM What is meant by cephalization? Development of a brain and true nervous system; Well-developed sensory structures located in the anterior region What is the function of dendrites? Receives communication (impulse) from other neurons or sensory receptors What are interneurons? where might you find them? (between other neurons); Sorts impulses (somewhat): Allows one sensory or motor neuron to communicate with more than one other neuron What are the nodes of Ranvier? Describe the impulse conduction along axons
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This note was uploaded on 04/22/2008 for the course BIO 103 taught by Professor Philipjones during the Spring '08 term at University of South Dakota.

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