PHTY100 Lecture Notes - Lecture 3: Internal Obturator Muscle, Greater Trochanter, Anterior Superior Iliac Spine
3. Introductory myology and muscles of the hip region
• 3.1 Identify and describe the major components of a skeletal muscle organ – belly,
attachments, connective tissue
o Belly - contractile cells, where the work happens
o Attachment to the skeleton
• Must cross a joint
• Proximal attachment called the 'origin'
• Distal attachment called the 'insertion'
o Connective tissue
o Muscle tissue
• Muscle cells called muscle fibres, which do the work
• Capillary network - requires a rich blood supply for the rapid delivery of
nutrients and removal of wastes
• Fibrous connective tissue
▪ Allows the work of the cell to be transferred to the muscle organ for
movement
▪ Consists of the epimysium, perimysium and endomysium
o Muscle structure
• Myofibres - muscle cells
▪ Cells fuse together
▪ Multi-nucleated
▪ Striations
• Myofilaments - strands of protein within the muscle cells
• Actin and myosin filaments slide over one another to bring about muscle
shortening
▪ Filaments do not shorten
▪ Receptor sites on the actin called troponin
▪ Calcium binds onto the troponin, changing its shape and opens the
binding site for myosin to latch onto the actin
▪ ATP releases energy to bind and drag the thin filament over the thick
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• 3.2 Describe the different types of attachments of skeletal muscle organs – tendinous,
fleshy, raphe
o Fleshy
• Muscle fibres attach directly to the bone, via a very small amount of
connective tissue
o Tendon
• Muscle fibres attach to a cord of connective tissue, which then attaches to the
bone
o Raphe
• Muscle fibres attach to a sheet of connective tissue, which attaches to
another muscle
• Gives muscles something to attach onto when there isn't a bone
o Aponeurosis
• Sheet of connective tissue from muscle to bone
• 3.3 Classify skeletal muscle on the basis of form, using the following terms:
o Parallel - fibres run in a straight line between attachments
• Maximum shortening of the muscle belly and therefore movement at the
associated joint
• Not great for force development
• More range of movement, less powerful
• Fusiform
▪ Narrowed fibres at each end
▪ Biceps brachii
o Oblique - fibres run on an angle between attachments
• Less shortening of the belly and so less movement at the associated joint
• More power, less range of movement
• Look like feathers
• Unipennate
▪ Fibres on one side of the tendon
• Bipennate
▪ Fibres coming from 2 directions to the axis
• Multipennate
▪ Sections of bipennate
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Document Summary
Fibrous connective tissue: allows the work of the cell to be transferred to the muscle organ for movement, consists of the epimysium, perimysium and endomysium, muscle structure, myofibres - muscle cells, cells fuse together, multi-nucleated. Striations: myofilaments - strands of protein within the muscle cells, actin and myosin filaments slide over one another to bring about muscle shortening. Fusiform: narrowed fibres at each end, biceps brachii, oblique - fibres run on an angle between attachments. Less shortening of the belly and so less movement at the associated joint: more power, less range of movement, unipennate. Fibres on one side of the tendon: bipennate. Fibres coming from 2 directions to the axis: multipennate. Sections of bipennate: circular - fibres run around an opening, 3. 4 identify examples of each type of skeletal listed in objective 3. 3 and the types of attachments listed in objective 3. 2, types of attachments.
