1 / 8

MUSCLES

MUSCLES. Microstructure of Skeletal Muscle. Skeletal Muscle. There are 3 main components:. Muscle fibres (cells): arranged in bundles running the length of the muscle. Myofibrils : run the length of the muscle fibres and cause the muscle to contract.

braith
Télécharger la présentation

MUSCLES

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. MUSCLES

  2. Microstructure of Skeletal Muscle

  3. Skeletal Muscle There are 3 main components: • Muscle fibres (cells): arranged in bundles running the length of the muscle. • Myofibrils: run the length of the muscle fibres and cause the muscle to contract. • Sarcomeres: each contain protein filaments called myosin and actin. • Myosin have tiny projections called cross bridges that reach across and pull the actin towards each other causing contraction.

  4. Muscle ContractionSliding filament Theory In order for a muscle to contract, the following happen: • Nerve impulses reach muscle fibres. It stimulates a reaction in each sarcomere • Cross bridges reach forward and pull actin toward the centre. • This results in shortening of muscle causing contraction. • At the end of the process, the cross bridges uncouple causing muscle relaxation.

  5. Type of muscles fibres • There are two types of muscle fibres • The major differences between the two are related to : • Speed of contraction - slow-twitch (red) fibres contract at a much slower rate than fast-twitch (white) fibres. 2. Muscle endurance – red contract slower but are able to do so repeatedly, whereas white fibres are fatigued easily.

  6. Muscle fibre force – white fibres are larger than red fibres and therefore generate greater force and more powerful contractions. • It has been shown that fibre distribution is inherited. • Whilst you can not change the number in particular muscles, they can be trained. • Therefore we have varying abilities eg. A person with a higher proportion of red fibres is better suited to endurance activities eg. Long distance running.

  7. Websites • www.ptcentral/muscles • http://muscle.ucsd.edu/musintro/jump.shtml • www.estrellamountain.edu/faculty/farabee/biobk/biobooktoc.html • http://innerbody.com/htm/body.html • http://www.klbschool.org.uk/interactive/science/skeleton_function.htm • http://www.botany.uwc.ac.za/sci_ed/

More Related