Microscopic Anatomy and Organization of Skeletal Muscle
Skeletal Muscle Cells and Their Packaging into Muscles
1. Use the items in the key to correctly identify the structures described below. g; perimysium c; fascicle
a. b. c. endomysium epimysium fascicle fiber myofibril myofilament perimysium sarcolemma sarcomere sarcoplasm tendon
1. 2. 3. 4. 5. 6. 7.
connective tissue ensheathing a bundle of muscle cells bundle of muscle cells contractile unit of muscle
i; sarcomere d; fiber a; endomysium h; sarcolemma e; myofibril
d. a muscle cell thin reticular connective tissue surrounding each muscle cell plasma membrane of the muscle fiber a long filamentous organelle with a banded appearance found within muscle cells actin- or myosin-containing structure e. f. g. h.
cord of collagen fibers that attaches a muscle to a bone
2. List three reasons why the connective tissue wrappings of skeletal muscle are important.
The connective tissue wrappings (a) bundle the muscle fibers together, increasing coordination of their activity; (b) add strength to the muscle; and (c) provide a route for entry and exit of blood vessels and nerves to the muscle fibers.
3. Why are there more indirect-that
attachments to bone than there are direct attachments?
They conserve space (less bulky than fleshy muscle attachments) and are more durable than muscle tissue where bony prominences must be spanned.
4. How does an aponeurosis differ from a tendon structurally? a tendon is a band or cord of the same tissue.
An aponeurosis is a sheet of white fibrous connective tissue;
t_o_o_t_h_er_m_u_sc_l_es_. _ How is an aponeurosis functionally similar to a tendon? _B_o_t_h_s_e'_II_e_t_o_a_tt_a_ch_m_u_s_c_le_s_to_b_o_ne_s_o_,_'
S. The diagram illustrates a small portion of several myofibrils. Using letters from the key, correctly identify each