KINE 2031 Lecture Notes - Lecture 2: Relaxed Muscle, Peptide, Cytoskeleton
2 Jul 2018
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Muscle Physiology
Muscles are contraction specialist in body. Skeletal muscles attach to skeleton. Contraction of
skeletal muscles moves bones to which they are attached, allowing body to perform variety of
motor activities. Skeletal muscles include chewing, swallowing, heat generation. Smooth
muscles found in walls of hallow organs & tubes.
Controlled contraction of smooth muscle regulates movement of blood through blood vessels,
food through digestive tract, air through respiratory airways & urine to exterior.
Cardiac muscle found only in walls of heart, whose contraction pumps life-sustaining blood
throughout body
-Muscle cells can develop tension & shorten- contractions
-Three types of muscle:
oSkeletal muscle
oCardiac muscle
oSmooth muscles
-Categories of muscles based on characteristics:
oStraited (skeletal & cardiac)
oUnstraited (smooth)
oVoluntary (skeletal) intervated by somatic nervous system
oInvoluntary (cardiac & smooth muscle) innervated by autonomic nervous
system
Structure of Skeletal Muscle
-Single skeletal muscle is a muscle fibre. Number of muscle fibres lie parallel to one
another
-During embryonic development, huge skeletal muscle fibers are formed by fusion of
smaller cells called myoblasts multiple nuclei in one muscle cell. Also, abundant
mitochondria present in muscle fibers for high energy demands
-Myofibrils are contractile element that consists of organized cytoskeleton elements:
oThick filaments myosin
oThin filaments actin filament
find more resources at oneclass.com
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Document Summary
Contraction of skeletal muscles moves bones to which they are attached, allowing body to perform variety of motor activities. Smooth muscles found in walls of hallow organs & tubes. Controlled contraction of smooth muscle regulates movement of blood through blood vessels, food through digestive tract, air through respiratory airways & urine to exterior. Cardiac muscle found only in walls of heart, whose contraction pumps life-sustaining blood throughout body. Muscle cells can develop tension & shorten- contractions. Three types of muscle: skeletal muscle, cardiac muscle, smooth muscles. Categories of muscles based on characteristics: straited (skeletal & cardiac, unstraited (smooth, voluntary (skeletal) intervated by somatic nervous system, involuntary (cardiac & smooth muscle) innervated by autonomic nervous system. Number of muscle fibres lie parallel to one another. During embryonic development, huge skeletal muscle fibers are formed by fusion of smaller cells called myoblasts multiple nuclei in one muscle cell. Also, abundant mitochondria present in muscle fibers for high energy demands.
