Muscle structures and pathologies

Question 1

Describe the key features of skeletal muscle

Answer 1

• cylindrical cells
• Striated (i.e formed from sarcomeres with contractile proteins arranged in parallel)
• multinucleate
• limited regenerative capacity (satellite cells)
• cm in length
• Voluntary control

Question 2

Define the key features of cardiac muscle

Answer 2

• Branched cells with intercalated discs (cardiomyocytes joined by intercalated discs, leads to coordination of contraction as a synctium)., connected by desmosomes and gap junctions).
• Striated muscle (formed of sarcomeres with contractile proteins in parallel)
• bi or mono nucleate
• no regenerative capacity
• 100 um length
• Spontaneous contraction

Question 3

define the key features of smooth muscle

Answer 3

• spindle shaped cells with central nucleus
• 20-200um long
• regenerate
• line vessels, hollow organs, glands
• under control of ANS, endocrine system

Question 4

Describe the makeup of skeletal muscle from the smallest unit to the actual muscle

Answer 4

• Myofilaments are actin and myosin = contractile elements of muscle
• Myofilaments form the muscle cell, muscle cells fused their cell membranes (sarcolemma) together to form one large multinucleat skeletal muscle fibre.
• Many muscle fibres are bundled together and form a muscle fascicle
• Many muscle fascicles are bound together and form the skeletal muscle

Question 5

Describe the coverings and makeup of skeletal muscle components