Muscles Flashcards
State the three types of muscle and which one is under voluntary control.
Smooth, cardiac, skeletal
Skeletal
Describe the relative abundance of each muscle type.
Smooth- in walls of viscera and blood vessels
Cardiac- heart and root of great vessels
Skeletal- most body muscle
State the function(s) of each muscle type
Smooth- move contents through viscera e.g. by peristalsis
Cardiac- product rhythmic contractions to pump blood round the body
Skeletal- locomotion by movement of bones and provide support
Describe the microstructure of smooth muscle.
spindle shaped
single central nuclei
no sarcomeres
proteins for focal density
Describe the microstructure of cardiac muscle.
central nuclei
branching pattern
intercalated discs
gap junctions to allow fast conduction of AP
fascia adhesions to allow coordination and contraction
less defined myofibril
Describe the microstructure of skeletal muscle.
multinucleated
elongated
arranged in fascicles (bundles of fibres)
Three connective tissue layers (endomysium, perimysium, epimysium)
satellite cells which enable regeneration
How do the contractions of the three muscle types compare?
Smooth- low force, rhythmic/wave like
Cardiac- intermediate force, resistant to fatigue
Skeletal- myofilaments pull closer together, shortening sarcomere and bringing origin and insertion closer.
Describe the innervation of three muscle types.
Smooth-autonomic NS, hormones
Cardiac- myogenic, visceral motor nerves
Skeletal- motor nerves at neuromuscular junctions
Describe the role of the sarcolemma.
T tubules (perpendicular extensions) conduct AP across entire length of muscle fibre for simultaneous contraction
Give an example of a a)flat muscle b) quadrate muscle c)fusiform muscle d) circular muscle e) pennate muscle.
a) anterolateral abdominal wall
b) hamstring
c) biceps brachial
d) eye (to squeeze shut)
e) muscle in quadriceps **rectors femoris
