unit 10 - muscular system Flashcards
1
Q
skeletal muscles
A
- striated
- tubular
- many nuclei
- voluntary
- attached to bone
2
Q
smooth muscles
A
- not striated
- spindle shaped
- 1 nuclei
- involuntary
- in walls of organs
3
Q
cardiac
A
- striated
- tubular + branched
- 1 nuclei
- involuntary
- walls of the heart
4
Q
primary functions of the muscular system
A
- supports the body
- helps maintain body temperature
- makes the bones move
- protects internal organs
5
Q
antagonistic muscles
A
if one muscle contracts the opposite relaxes
6
Q
hierarchy of muscle fibres
A
- muscle
- muscle-fibre bundle
- muscle fibre
- myofils
- myofilaments
7
Q
sarcolemma
A
muscle fibre membrane
8
Q
sarcoplasm
A
inner material surrounding fibres
9
Q
sarcoplasmic reticulum
A
used in transport (ie. calcium)
10
Q
myofibrils
A
individual parallel muscle fibres within sarcoplasm
11
Q
actin
A
- thin filaments
- 1 strand of protein
- other proteins: troponin + tropomyosin
- shorter
- no head
12
Q
myosin
A
- thick filaments
- 2 strands of protein
- longer
- double head
13
Q
how myofilaments contract
A
- when the myofilament contracts, the heads of the myosin move first
- actin is pulled along
- myosin heads flex on after another and myosin ‘walks’ along actin
- this requires 1 ATP molecule to reposition the myosin head so it can bind to the actin and flex again
- pulls the z lines closer together
14
Q
a muscle can contract when
A
- calcium ions have bonded to troponin, which is a part of the actin
- this causes the tropomyosin to reposition itself exposing the myosin bonding sites of actin
- the myosin head can bond to the actin and contraction occurs
- when a muscle fibre is stimulated it releases calcium from the SR, when it is no longer stimulated the calcium is returned to the SR
15
Q
ways to obtain energy for contraction - CP breakdown
A
- ATP is supplied by creatine phosphate
- duration of ATP is 8 seconds
- Anaerobic
