1-55 Muscle Histology

Question 1

Types of muscle

Answer 1

1. Skeletal muscle: thin layer of fascia, layers of parallel fibers in concentric fashion
   
   • skeletal muscle cell: myocyte
   • made up of longitudinal pink fiber filled with myofibrils and multiple nuclei that are pushed to the edge of cell
   • myocyte contains many myofibrils (back to back arrangements of sarcomeres), sarcomeres are regions of alternating thick/thin fibers that act as contrictlie unit of fibril
     
     • thin filaments: actin, troponin, tropomyosin
     • thick filaments: myosin
2. Cardiac muscle
   
   • striated but myofibers are shorter and branched
   • nuclei central, one per fiber
   • cell attached to each other by specialized junctions called intercalated discs
3. Smooth muscle: different architecture, instead of striations has a network of actin/myosin filaments connected by “dense bodies” which are involved in cell contration
   
   • bright pink (eosinophilic cytoplasm)
   • blunt-ended nuclei (cigar-shaped)

Question 2

Answer 2

skeletal muscle

Question 3

Answer 3

Cardiac muscle

Question 4

Answer 4

Smooth muscle