Lecture 9: Skeletal Muscle Neurophysiology 1 Flashcards
What is another name for skeletal muscle? Why is this?
striated muscle because of its striated appearance due to the thick and thin filaments
Flexion _________ the angle between joints and extension _______ the angle between the joints
decreases
increase
What is being activated and what is being relaxed during flexion?
activation of flexor muscles and relaxation of extensor muscles
What is being activation and what is being relaxed during extension?
activation of extensor muscles and relaxation of flexor muscles
Muscles need to span the joint. What is the name of the proximal attachment of the muscle to bone? What is the name of the distal attachment of muscle to bone?
the origin
the insertion
What do tendons connect?
muscle to bone
What do ligaments connect?
bone to bone
Both tendons and ligaments are made of what?
collagen
A group of muscle fibres is called a ________
fasciculus
What is a fasciculus made of?
lots of individual muscle fibres
What are muscle fibres?
the individual muscle cell
What do muscle fibres/cell have lots of?
nuclei
Muscle cells/fibres consist of lots of what?
myofibrils
What two things make up the myofibril? What does this cause?
thick and thin filaments (myosin and actin) which causes an ordered striated appearance
Which is the thick filament, actin or myosin?
myosin
Which is the thin filament, actin or myosin?
actin
What is an individual contractile unit of a myofibril called?
a sarcomere
What region makes up the sarcomere?
in between the two Z lines
What does the sarcomere consist of?
actin filaments going inwards from the Z line interlinked with the thick myosin filaments
What is the I band of the myofibril?
between the myosin filaments so it contains only actin
What is the A band of the myofibril?
between the regions of only actin filaments so this contains both the actin and myosin
What is the H zone of the myofibril?
the very middle part of the sarcomere which only contains myosin when resting
When the sarcomere is resting, there are balls of myosin right in the middle of the H zone which contains proteins. What are these proteins used for?
they organise and align myosin
When contracting, what changes in the sarcomere?
- the Z discs become closer together
- the myosin slides over the actin
- the H zone becomes much smaller and the actin is coming closer together
- I band becomes smaller as the myosin is coming closer together