The Muscular System Three types of muscle tissue
- Slides: 10
The Muscular System
Three types of muscle tissue n Skeletal n Smooth n Cardiac
Skeletal Muscle n n n Used for voluntary movement Attached to bones Cells are very large – Many nuclei per cell – Show light and dark bands
Smooth Muscle Involuntary muscles n Control digestion, blood flow etc. n Spindle shaped cells n – One nucleus per cell – Do not require nerves to function
Cardiac Muscle Involuntary heart muscle n Shared traits with skeletal and smooth n – – – n Banded One nuclei Doesn’t need nerves to function Branches
Muscle Contraction n Muscles have two types of fibers – Myosin – thick protein – Actin – thin protein n Contraction occurs when the actin slides along the myosin due to the formation of cross-bridges. n Requires ATP
Control of Muscular Contraction n Nerves and muscles connect at the neuromuscular junction n The nerve release acetylcholine (ACh). n ACh causes the muscle to contract. n The absence of Ach destroys the crossbridges and the muscle relaxes
Bone/Muscle Interaction n Tendons- connective tissues that attach muscles to bones n Bones act as levers for movement to occur. n Muscles can only contract, so every muscle is paired
Bone/Muscle Interaction n Example – Biceps pulls forearm towards the shoulder when contracted. – Triceps pulls forearm straight out when contracted. n ALWAYS train muscles in pairs.
Exercise and Muscles n Regular exercise keeps muscles healthy n Muscles that are not use will decrease in size or atrophy. n Strengthening muscles puts pressure on bones which causes the bones to become thicker and stronger.
