musculoskeletal system Flashcards
1
Q
what are the three types of muscle?
A
- skeletal muscles
- smooth muscles
- cardiac muscle
2
Q
what is skeletal muscle?
A
- move bones and enable us to walk, run and carry out a wide range of voluntary physical activities
- muscles are under conscious control and are attached to the bones of the skeleton
3
Q
what are smooth muscles?
A
involuntary muscles (not under conscious control), control movement within internal organs such as the stomach and intestines
4
Q
what is cardiac muscle?
A
heart muscle
- When cardiac muscle contracts, it reduces the space in the chambers of the heart and pushes the blood from the heart into the blood vessels.
5
Q
what are myofibrils?
A
- thread-like structures within the sarcoplasm
- that run parallel to each other along the length of the fibre
- composed of many smaller myofilaments
6
Q
what gives muscle its banded effect?
A
- the arrangement of the thick and thin myofilaments give the muscle cells its striations
- striations allow myofibrils to be divided into sarcomeres
7
Q
what is extensibility?
A
ability for a muscle to be stretched or extended
8
Q
what is perimysium?
A
- connective tissue
- holds bundles of muscle cells
- allows adjacent bundles to slide easily over one another as they contract
9
Q
what is sarcolemma?
A
muscle cell membrane
10
Q
what are bundles in muscles?
A
composed of muscle cells that lie parallel to each other
11
Q
what are the characteristics of skeletal muscle fibres?
A
- many nuclei
- thin membrane
- 10- 100 micrometres in diameter
- dark bands of myosin
- light bands of actin
12
Q
what are myofilaments and the 2 types
A
- makeup myofibrils
- made of protein
- thick myofilaments = myosin
- thin myofilaments = actin
13
Q
what is the A band?
A
- runs the length of the myosin
- dark due to myosin and actin overlapping
14
Q
what is the I band?
A
- from each end of the myosin.
- contains only actin so is light and thin
- can overlap z line
15
Q
what is the M line?
A
- middle of sarcomere
