Muscles Flashcards
What is the main purpose of muscles?
Muscles are essentially responsible for all body movements due to their unique characteristic of being able to contract or shorten
What are the three types of muscles?
Skeletal, cardiac and smooth
What do all muscles have in common?
- All muscle cells are elongated and are called ‘fibres’
- They all consist of actin and myosin filaments, allowing muscles to shorten or contract
What are the key characteristics of smooth muscle?
- They compress organs, ducts, tubes
- They have a non-striated appearance (no stripped appearance)
- They are involuntary, which means we cannot consciously control them
Where is smooth muscle found?
They are found mainly in the walls of the hollow visceral organs, such as the stomach, urinary bladder and respiratory passages
what are the key characteristics of cardiac muscle?
- They contract the heart to propel blood through the body
- Cardiac muscle is unique to the heart
- They are striated, but involuntary, which means we cannot consciously control them
What are the key characteristics of skeletal muscle?
- They allow the movement of the whole body
- They attach directly to the skeleton
- They have a striated appearance
- They are voluntary, which makes them the only type of muscles that can be consciously controlled
What makes skeletal muscle so strong?
Although skeletal muscle fibres are soft and fragile, they can exert a tremendous amount of power because thousands of fibres are bundled together by connective tissues, which provide extra strength and support to the muscle as a whole
What is the structure of skeletal muscle?
- Each muscle fibre is enclosed in a sheath called endomysium
- A courser fibre called perimysium then wraps around several sheathed fibres to form a bundle called a fasicle
- Many fasicles are bound together by coating of connective tissue called epimysium, which covers the entire muscle
- The epimysium blends into a strong cord like tissue called a tendon, which then joins the muscle to the bone
What is the secondary function of skeletal muscle fibres?
They also provide durability and the ability to conserve space as they are made of tough collagen fibres, which are well suited to moving over the skeleton’s bony protrusions, as delicate muscle fibres would probably tear; because of their relatively small size, more tendons can pass over a joint at one time
What are the four main important roles of muscles in the body?
Produce movement, maintain posture, stabilise joints and generate heat
What is an origin of a muscle?
For any muscle to create movement they must attach at a bone that is stationary. This point is called the origin of the muscle.
What is meant by insertion?
To create movement the muscle must attach on another bone that moves this is called an insertion.
What are tendons?
muscles are attached by connective tissue called tendons.
What is the agonist or prime mover muscle?
The agonist, or prime mover, is the muscle that is primarily responsible for producing a specific movement. It contracts to create the desired motion. For example, during a bicep curl, the biceps brachii acts as the agonist because it is responsible for bending the elbow and lifting the weight.
What is the antagonist muscle?
The antagonist is the muscle that opposes the action of the agonist. While the agonist contracts to produce movement, the antagonist relaxes and lengthens to allow the movement to occur smoothly. In the case of the bicep curl, the triceps brachii serves as the antagonist, as it opposes the action of the biceps by extending the elbow.
What are fixator muscles?
Fixator muscles or stabilisers have the role to stabilise the origin so that the agonist can achieve maximum efficient contraction. A fixator is a muscle engaged in fixing a joint in a given position to make isolated movements in a different joint possible.
What are neutralisers or synergists?
Neutralisers or synergists prevent any undesired movement which may occur, particularly at the shoulder where the bicep works over two joints. Syngerists are kinds of muscles which perform, or assist in performing, the same set of joint motion as the agonists. Syngerists are muscles that act on movable joints. They are sometimes refered to as neutralisers as they help cancel out extra motion from the agonists to make sure that the force generated works within the desired plane of motion.
What movement do the muscles produce?
Body mobility is the sole product of skeletal muscles which are responsible for all locomotor movement. Smooth muscles of the blood vessels and cardiac muscle of the heart work together to circulate blood and maintain blood pressure. Smooth muscle also forces fluids like urine and other substances through internal body channels.
