| Muscle contraction trigger words | Ca2+ release
Tropomyosin
Activate
Cross bridge
Bend/ pull |
| Muscle contraction trigger words and theory | CA 2+ RELEASE from the sarcoplasmic reticulum
TROPOMYOSIN Ca2+ attach to Tropomyosin clearing actin binding site
ACTIVATE Calciuk ions activate atp hydrolyse to break ATP into adp plus pi releasing energy . This exposes the myosin head.
CROSS BRIDGE - myosin attaches to actin forming actinomyosin cross bridge . The previous energy caused myosin head to bend and pull actin over . |
| What are antagonistic muscles | Antagonistic muscles work in pairs.
Work in opposition to each other.
One muscle contracts, and the other muscle relaxes.
Allows movement in both directions.
When a muscle contracts it shortens and produces a ‘pulling’ force.
When a muscle relaxes it lengthens. |
| If one muscle shortens... | it creates a pull force lengthening the opposing one |
| Muscles structure | Each muscle fibre is actually a giant muscle cell.
•Each muscle fibre is cylindrical in shape.
•Muscle fibres are surrounded by a membrane called a sarcolemma.
•The sarcoplasm (cytoplasm) contains many nuclei and mitochondria.
•Muscle fibres also contain sarcoplasmic reticulum which is a store of calcium ions
•Each muscle fibre contains many smaller muscle fibres called MYOFIBRILS.
•Myofibrils are made up of sections called sarcomeres.
•Each sarcomere is made up of many proteins (called actin and myosin). |
| What does the Z line contain | end of sacromere |
| M line | mysosin filaments |
| light band | only actin filaments |
| dark band | myosin , outer regions of dark band are overlap |
| H zone | centre of the dark band |
| What is a neuromuscular junction | Action potential arrives at the pre-synaptic knob.
This causes the ___CA2+__ ion channels to ______OPEN_______.
This causes ___________ containing acetylcholine to fuse with the _______PRE SYPAPTIC MEMBRANE__________________.
Acetylcholine is released. Acetylcholine ___DIFFUSES___________ across the ___SYNAPTIC CLEFT___________ and binds to the ____RECEPTORS_________ on the _________________.
This stimulates ___NA+_____ ion channels to open.
_NA+_________ ions diffuse ___IN____ causing depolarisation. If the _____THRESHOLD________ is passed, action potentials will occur in the muscle membrane (sarcolemma).
The action potentials move along the muscle membrane deep within the muscle.
This stimulates calcium ions to diffuse out of the sarcoplasmic reticulum.
Calcium ions causes the muscle contraction (remember the 7 steps of muscle contraction). |
