Exam 4 Study Guide - BIO 416K Human Physiology and...

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BIO 416K Human Physiology and Functional Anatomy I Study Guide – Lecture Exam 4 Fall 07 Muscles (Chapter 12) Skeletal Muscle Structure 1. Compare/contrast the location, function, gross, microscopic anatomical features of the 3 types of muscle tissue. Skeletal Smooth Cardiac Location Attached to bones Heart muscle Function Voluntary , Ca2+ & troponin, fibers indep . Involuntary, Ca2+ and CaM, electrically linked fibers Involuntary, Ca2+ & troponin, electrically linked fibers Fiber Arrange Sarcomeres Longitudinal bundles Sarcomeres Microscopic Striated Smooth Striated 2. Describe the three different connective tissue sheaths in skeletal muscle and discuss how they are important in muscle attachments to bone and for muscle contraction force. Endomysium – connective sheath around each individual muscle fiber Perimysium – a little thicker sheath; groups muscle cells into a fascicle Epimysium – “upon muscle”, dense irregular sheath that groups fascicles together 3. Briefly describe the organization of a muscle: Actin and myosin (protein molecules) myofilament (thick and thin) sarcomere (functioning unit) myofibril (intracellular structure) muscle fiber (cells) fascicle (grouping of cells) muscle (organ) 4. Discuss the following structures and describe the specializations associated with each: sarcolemma – cell membrane of a muscle fiber (cell) o abundance of voltage gated ion channels o t-tubules found here sarcoplasm – specialized cytoplasm myofibril – main intracellular structures; bundles of contractile and elastic proteins that carry out the work of contraction sarcoplasmic reticulum – modified endoplasmic reticulum that wraps around each myofibril like a piece of lace o consists of longitudinal tubules and terminal cisternae o stores Ca2+ and can signal Ca2+ release on demand t-tubules – a continuation of the muscle fiber membrane; release Ca2+ and makes myofibrils contract at the same time - triad: one t-tuble with its flanking terminal cisternae terminal cisternae – concentrates and sequesters Ca2+ longitudal tubules - ?? 5. Draw and label the molecular components of a sarcomere (A band, I band, H zone, Z disk, M line. A band – darkest of bands in a sarcomere; encompasses entire length of a thick filament o at edges, thick and thin filaments overlap 1
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I band – lightest color bands; region occupied only by thin filaments o a Z disk runs through middle of I band, each half of I band belongs to diff sarcomere H zone – central region of the A band – occupied by thick filaments only Z disk – zigzag structures made of proteins that serve as attachment site for thin filaments o One sarcomere is composed 2 Z disks M line – attachment site for thick filaments equivalent to Z disk for thin filaments o one A band is divided in half by an M line 6. Explain the sliding filament mechanism of skeletal muscle contraction. Sliding filament mechanism:
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This note was uploaded on 04/07/2008 for the course BIO 416K taught by Professor Findell during the Fall '08 term at University of Texas at Austin.

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Exam 4 Study Guide - BIO 416K Human Physiology and...

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