6.3 - Skeletal muscles Flashcards
1
Q
Describe features of skeletal muscles (sometimes called striped or striated)
A
- voluntary
- joined to bones by tendons
2
Q
What feature do all muscles share?
A
pairs are antagonistic
3
Q
Name the two main proteins present in a myofibril and describe them
A
actin: thin and myosin: thick
4
Q
What is the sarcolemma?
A
membrane of a muscle fibre
5
Q
What is the sarcoplasm?
A
cytoplasm of a muscle fibre
6
Q
What is the sarcomere?
A
one contractile unit of a muscle fibre
7
Q
What is the A band?
A
total width of myosin
8
Q
What is the H zone?
A
where there is myosin only
9
Q
What is the I or light band?
A
where there is actin only
10
Q
What is the M line?
A
middle point of myosin
11
Q
What do Z lines indicate?
A
the parameters of one sarcomere
12
Q
Describe what happens to the parts of a myofibril during contraction
A
- A band stays same
- H zone and I band shorten
- Z lines move closer together
13
Q
Does the A band ever change?
A
no, it always stays constant
