Lecture 6: Principles of the Muscular System

Question 1

what are the types of muscle

Answer 1

• smooth muscle e.g. gut and viscera
• cardiac muscle in heart
• skeletal muscle e.g. biceps

Question 2

what is the function of skeletal muscle

Answer 2

locomotion

Question 3

microstructure of skeletal muscle

Answer 3

• elongated multinucleated cells running parallel to one another
• nuclei sit on periphery of cells, not inside them

Question 4

structure of skeletal muscle

Answer 4

myofilaments –> myofibrils –> muscle fibres –> muscle fascicles –> muscle

Question 5

which connective tissue encloses each muscle fibre

Answer 5

endomysium

Question 6

which connective tissue encloses each fascicle

Answer 6

perimysium

Question 7

which connective tissue encloses the entire muscle

Answer 7

epimysium

Question 8

what is the sarcolemma

Answer 8

cell membrane of a muscle

Question 9

biceps brachi

Answer 9

origin: long head - supraglenoid tubercle of scapula
short head - corocoid process of scapula
insertion: radius
innervation: musculocutaneous nerve
action: flexion of elbow and shoulder, supination of radio-ulnar joints

Question 10

deltoid

Answer 10

origin: clavicle, acromiom process and spine of the scapula
insertion: deltoid tuberosity of humerus
innervation: axillary nerve
action: abduction of the shoulder joint

Question 11

how do muscle cells regenerate

Answer 11

• satellite cells run between sarcolemma and basement membrane
• normally dormant but proliferate in response to injury
• regenerate muscle fibres and more satellite cells
• only present in skeletal muscle