Histology: muscle

Question 1

describe the features of skeletal muscle

Answer 1

striated, unbranched, multinucleated, long cylinder fibres

Question 2

what is the cell membrane in muscle fibres called

Answer 2

sarcolemma

Question 3

what are fascicles

Answer 3

a bundling together of parallel rod-like structures, muscle fibres are grouped into fascicles

Question 4

what is the connective tissue around the muscle called, around a fascicle called and around a single muscle cell called

Answer 4

whole muscle = epimysium
fascicle = perimysium
single cell = endomysium

Question 5

where are the nuclei located in skeletal muscle fibres

Answer 5

at the periphery of the cell

Question 6

where are myofibrils found

Answer 6

inside muscle cells/fibres

Question 7

what are myofibrils made up of

Answer 7

many sarcomeres placed end-to-end

Question 8

by definition, where does a single sarcomere extend from

Answer 8

one Z line to the next Z line

Question 9

briefly describe why skeletal muscles appear striated

Answer 9

due to the light(actin) and dark(myosin) bands across the myofibrils which are lined up with all the other myofibrils in the muscle, so appears striped

Question 10

what does a motor unit consist of

Answer 10

one motor neurone and all of the muscle fibres it innervates(can be a few or hundreds)

Question 11

describe the mitochondria content of slow twitch compared to fast twitch

Answer 11

slow = lots mitochondria and lots myoglobin
fast = few mitochondria and few myoglobin

Question 12

what are slow twitch and fast twitch muscle fibres also called

Answer 12

slow = ‘red’ fibres
fast = ‘white’ fibres
(due to myoglobin content)