module 5 - 13.9 voluntary and involuntary muscles Flashcards
what are the 3 types of muscles in humans?
- skeletal muscle
- cardiac muscle
- smooth muscle
what are skeletal muscles?
- attached to tendons to the skeleton
- voluntary muscles controlled by somatic nervous system
what are cardiac muscles?
- only found in the heart
- involuntary muscle and is controlled by autonomic nervous system
what are smooth muscles?
- found in the walls of hollow organs, in blood vessels, in the respiratory system, in eyes, in the skin
- involuntary muscle and controlled by autonomic nervous system
what are features of skeletal muscles?
- striated appearance (looks stripy, stripes at right angles to length of cell)
- under conscious control of somatic nervous system
- muscle cells are called muscle fibres
- fibres are multicellular in origin and multinucleate (multi nucleus)
- fibres arranged to allow muscle to contact in one direction
- rapid contraction for short length of time
what are features of cardiac muscle cells?
- striated appearance but less pronounced
- under involuntary control of autonomic nervous system
- muscle cells are called muscle fibres/cadriomyocytes
- fibres arranged in branching pattern connected by intercalated discs
- intermediate contraction and length of time
what are features of smooth muscle?
- non-striated appearance
- involuntary control of autonomic nervous system
- muscle cells are called muscle fibres and are spindle shaped, with a wide middle and tapering ends
- fibres arranged in non-regular pattern
- slow contraction speed but can contract for long length of time
what is the structure of a skeletal muscle?
- extremely long, made from embryonic muscle cells fusing together to make a muscle fibre
- multinucleate
- has a sarcoplasm
- bundles of muscle fibres are covered by sarcolemma
- sarcolemma folds to form t-tubules
- many mitochondria to provide ATP for contraction
- ER is modified to form sarcoplasmic reticulum
- each muscle contains many myofibrils
what is a sarcolemma?
additional plasma membrane covering muscle fibres
what is a sarcoplasm?
cytoplasm in muscle fibre
what do t-tubules help with?
help spread electrical impulses throughout the muscle to allow it to contract as a whol
what does sarcoplasmic reticulum contain?
many Ca2+ ions for the muscle fibre to contract
what are myofibrils?
specialised organelles that allow the muscle fibre to contract longitudinally