Skeletal muscles Flashcards
Irritable
They are capable of receiving and responding to stimulation from nerves.
Contractible
Once they have received stimulation, the muscle is capable of actively shortening.
Extensible
With the application of force, muscle can be stretched without damage.
Elastic
whenever a muscle has been shortened or lengthened it has the ability to return to its resting shape and length
Adaptable
Muscle will hypertrophy ( enlarge) in response to increased work. Conversely, it will atrophy ( waste away) if deprived of work
Muscles are classified into which following types:
- Skeletal muscle ( striped or striated muscle)
- cardiac
- smooth
WHAT DO MUSCLES DO?
skeletal muscles
located beneath the layers of skin and fat. They connect to the bones via the tendons and respond (contract/ relax) to nerve stimulation, thus creating movement. skeleton muscles are under voluntary control.
Skeletal Muscle fatigues.
Generally contracts voluntarily ( via somatic nervous system) Although it can contract involuntary through reflexes. Skeletal muscle has four major functions:
Cardiac muscle
Only found in the heart. It is an involuntary muscle that contracts and relaxes rhythmically to pump blood throughout the body. Fatigue resistant
Smooth Muscle
forms the walls of most blood vessels, glads and organs. It contacts and relaxes to move blood and other fluids and materials through the body at varying rates. Its is and involuntary muscle.
Fatigue resistant
Name 3 types of muscle tissue and describe where they are found:
1- Skeletal: Found beneath fat and skin. Connect to bones via tendons. Create movement
2- Cardiac: Found only in the heart, contracts and relaxes.
3- Smooth: Found in the walls of most blood vessels, glands and organs. Contracts and relaxes to move blood and other fluid around the body.
What is skeletal muscle snd what does it do?
Skeletal muscles are attached to bones at either end by tendons.
The junction where the muscle joins the tendon is known as the tendo-musclar junction and the junction or the tendon with the bone (or outside layer of bone, “the periosteum”) is known as the tendons-periosteal junction.
What is the tendo-musclar junction?
This is the area where the muscle joins the tendon.
The Origin is:
The attachment end that is relatively fixed is known as the origin of the muscle. The origin is normally the proximal position (closer to the trunk)
The insertion is:
The attachment end that moves most is normally distal (further from the trunk) is known as the “insertion”
EXAMPLE: Bicep
Has two origins, one high on the humerus, the other on the scapula. When the muscle contracts and shortens, it pulls on the insertion points on the radius causing the elbow to flex.
Skeletal muscle
Generally contracts voluntarily ( via somatic nervous system) Although it can contract involuntary through reflexes. Skeletal muscle has four major functions:
Force generation for movement:
Skeleton muscle generates the force needed to move the body. Walking, running, swimming, pushing pulling, etc are all movements created by the contraction of skeletal muscles.
Skeletal muscles primarily responsible for movement are large and superficial muscles such as quadriceps, hamstrings, glutei and calves. The major superficial muscles (prime movers) are shown in anterior and poster muscles.
Force generation for breathing:
The skeletal muscles of the ribs and abdomen are responsible for the movements pessary for respiration, the intercostal muscles between the ribs relax and contract as does the diaphragm to enable the lungs to fill with air and then expel the air.
Force generation for postural support:
The skeletal muscles stabilise the joints of the body during movement and help maintain an “ideal” posture
person’s posture is ideal, the effects of gravity are minimal and the weight is evenly distributed throughout the load bearing joints of the body: between the vertebrae, the hips, knees and ankles.
When postural muscles become weak or fail to function, postural problems tend to occur and the body’s weight becomes unevenly distributed through the weight bearing joints and results in injury.
Skeletal muscles are sometimes categorised as inner or otter units. This inner unit refers to the posture stabilising muscles that lock joints in place, keep the joint safe, minimise stress on ligaments and provide a stable base for the outer unit muscles (called prime mover) to go to work and create movement.
Many injuries, both acute (from immediate impact or injury) and chronic (over time, such as tendonitis) can occur because of poor synergy between the inner and outer units.
Heat production:
When skeletal muscles contract they produce heat. When the body temperature drops, skeletal muscles can create heat to maintain the core body temperature. They do this either voluntarily or involuntarily by shivering, which is purely an involuntary contraction of large skeletal muscles to generate heat.
