Skeletal Muscle Tissue Flashcards
Which muscle has the greatest stretch?
Smooth
What are the 3 layers that strengthen skeletal muscle?
Epimysium
Perimysium
Endomysium
Muscle tension
A force exerted on a single muscle fiber
Isometric contractions
Muscle tension doesn’t move the load
Isotonic contractions
Muscle tension moves the load and the muscle shortens
What are the properties of muscle tissue?
Excitability
Contractility
Extensibility
Elasticity
What is the all or none rule
All muscles in a motor unit contract and relax together
What does the total strength of contraction depend on?
The size of motor units
The number of motor units activated at a time
What is twitch muscle contraction?
Brief contraction of all muscle fibers in a motor unit from a single action potential
What is the latent period of a muscle twitch? (2msec)
When the action potential is propagated
What is the contraction period of a muscle twitch? (10-100 msec)
During cross bridging
What is the relaxation period of a muscle twitch? (10-100 msec)
Calcium ions are transported back to SR
contractile force decreases
Name the 6 patterns of muscle shapes.
Parallel Convergent Pennate Circular Spiral Fusiform
What is the shape of a parallel pattern and name an example
Evenly spaced, attached to a tendon the same width as the muscle
Strap like appearance
Ex: sartorious in thigh
What is the shape of a convergent pattern and name an example.
Broad muscle tapers to a single tendon
Ex: pectoralis in chest
What is the shape of a pennate pattern and name an example.
Muscle resembles a feather
Fascicles attach to a tendon at an angle
Ex: rectus femoris in thigh
What is the shape of a circular pattern and name an example.
Muscle encircles a structure
Ex: orbicularis oculi of eye
What is the shape of a spiral pattern and name an example.
Muscle wraps around the bone or twisted appearance
Ex: supinator in forearm
What is the shape of a fusiform pattern and name an example.
A muscle is thicker In The middle and is tapered at ends
Ex: biceps brachii
What does the agonist do?
Provides the most force for movement and it’s usually the largest muscle
What does the antagonist do?
Lies at the opposite side of a joint from the agonist and it slows the motion
What does the synergist do and who do the work with?
The work with the agonist and provide additional support to guide movement
What do fixators do?
Hold a bone in place and make movement more efficient to reduce the risk of an injury
What causes carpal tunnel syndrome and what can you do to treat it?
Caused by damage due to irritation of median nerve in wrist
Treatment: surgery or anti-inflammatory drugs
What causes muscular dystrophy and what can you do to treat it?
Caused by progressive degeneration and weakening of muscles
The fibers are replaced with fat and CT
Can be genetic
Treatment: inject muscles with immature muscle cells that produce dystrophin
What is myasthenia gravis and what can you do to treat it?
It is when the immune system mistakenly produces antibodies that destroy ACh receptors
Treatment: drugs that inhibit the enzyme that digests ACh
What causes fibromyalgia and what are its symptoms?
Cause is not known yet
Symptoms: pain, tenderness and stiffness of muscles. There is also inflammation
What is a spasm?
Sudden involuntary muscle contraction
What is a cramp
Strong and painful spasm of the leg and foot
What are facial tics?
Periodic spasms
What is a strain?
Stretching or tearing of a muscle
What is a sprain?
Twisting of a joint that damages muscles, tendons, ligaments, and blood vessels
