Sliding Filament Theory and the Action of Paired Muscles Flashcards
1
Q
How do muscles work?
A
- muscles have properties of excitability, contractibility, extensibility and elasticity
2
Q
What do muscles have the ability to?
A
- be stimulated by nerve impulses
- shorten in length (contract)
- stretch in length (relax)
- go back to original shape
3
Q
What happens when muscles contract?
A
- the sarcomeres shorten
- actin and myosin filaments slide over each other
> this decreases distance of the sarcomere
4
Q
What happens when muscles relax?
A
- actin and myosin get pulled past each other in opposite directions
- muscle fibres return to their original shape
- at any given moment some muscle fibres can be relaxed while ither contract
5
Q
What does muscle contraction require?
A
energy (ATP)
6
Q
How are muscles connected to our bones?
A
- by fibrous, inelastic connective tissue called tendons
- tendons allow muscles to move bones
- muscles can only contract, so when muscles contract to pull a bone in one direction, another set of muscles must contract to pull the bone in the opposite direction
7
Q
How do skeletal muscles work?
A
- they work antagonistically
- flexion = bending joint
- extension = straightening
8
Q
What is an agonistic muscle?
A
muscle that causes the desired action, that contracts
9
Q
what is an antagonistic muscle?
A
the muscle that relaxes
10
Q
What is the relationship between the agonist and antagonist? + example
A
- when one muscle contracts (the agonist), its antagonist relaxes
- e.g. biceps contract and triceps relax (flexed position)
11
Q
What is a synergist?
A
- smaller muscles that assist the agonists
- stabilises the joint
12
Q
What is the origin of a muscle?
A
part that attaches to the immoveable bone
13
Q
What is the insertion of a muscle?
A
part of muscle that attaches to the moveable part of the bone
14
Q
What is muscle tone?
A
- partial contraction of the muscle that is not strong enough to cause movement
- muscle fibres take turns contracting
