Muscle Tissue Flashcards
Slow Twitch Muscle
Type 1 Oxidative, Slow ATP Hi Mito Hi Myoglobin Aerobic Take Hold and Hold, relax slowly, shows up darker Myoglobin stores O2 in muscles In back, hips, costal, posture muscles
Intermediate Muscle
Type 2A Oxidative Fast ATP, Hi Mito Aerobic/Anaerobic ATPase burns faster In legs and arms
Fast Muscle
Type 2B Glycolytic
Fast ATP
Anaerobic
Limited range
Motor Endplate
Where muscle meets neuron
Very specialized tissue found only where neuron is
Myasthenia Gravis
Motor endplate receptors disappear (switch broken)
Smooth muscle calcium source
Extracellular, no SR calcium
Tonic flextion
Always flexed, ex holding mouth shut
What are the three kinds of muscle tissue?
Skeletal
Smooth
Cardiac
What make muscle cells different then others?
They are elongated and specialized for contraction and to exert force
What are the functions of muscle tissue?
Movement
Digestion, waste
Breathing, speech
Blood circulation
Explain skeletal muscle
Long unbrunched muscle fibers that are striated. It is voluntary controlled. Muscle fibers have multiple nuculi that are found at the edges of the cells. Muscle fibers are myofiber and they attach to the bone or skin
Explain cardiac muscle
It is only found in the heart and is striated. It is involuntary control with short branded cells. They have a central nuclei within each cell and they are cardiomyocytes.
Explain smooth muscle
It is found in blood vessels and hollow organs. It is unstriated with involuntary movement. They only have one nuclei per cell and the cell type is a myocyte.
What are the functions of muscle?
Movement Stability Control of bodies opening and passages Heat generation Glycemic control
What are the universal properties of muscles (skeletal)?
Excitability - responsiveness because of sodium potassium pumps. These send electrical charges across plasma membranes.
Conductivity - local electrical excitation initiates wave that travels along the muscle fiber, this leads to contraction
Contractility - shortens when stimulated, movement
Extensibility - capable of being straightened between contractions
Elasticity - return to its original rest length after being stretched.
Explain the construction or gross anatomy of muscle tissue. Deep to superficial.
Myofilaments that is made of think myosin and thin actin. These are what makes up the muscle fibers. Muscle fibers are wrapped in the endomysium. Muscle fibers are the actual muscle cells. Muscle fibers are then bundles together to make up the muscle focicle. Focicles are wrapped in perimysium. Many bundles of muscle focicles are the muscle. Muscle tissue is wrapped in epimysium.
Explain the importance of the muscle-nerve relationship.
Skeletal muscle never contracts unless stimulated by a nerve. If there is no nerve connection the muscle is paralyzed.
What does somatic mean?
Somatic is in relation to the muscle. So a somatic nerve is a nerve that stimulates skeletal muscles.
What is a motor unit?
Nerves and muscles that are all connected and work together. Some units are very strong and some are small that are used for fine motor skills.
What are the steps to muscle contraction?
Excitation
Excitation- contraction coupling
Contraction
Relaxation
What are the steps to muscle excitation?
A nerve signal goes to axon terminal
Synaptic vesicles release ACh which then defuses across the synaptic cleft and binds with receptors on the sarcolemma of the muscle fiber. This opens ion gates in the sarcolemma resulting in the sodium potassium movement through the membrane that electrically excite the muscle fibers.
Wave is made of excitation spreads down the length of the fiber and into the T tubule and into the cell.
What are the steps of excitation - contraction coupling?
Electrical events in the T tubule leads to the opening o calcium gates in the sarcolemic reticulum. The SR releases a flood of calcium ions into the cytosol.
Calcium ions bind to troponin molecules in the myofilaments.
Myosin was in the waiting position (like a bent elbow) with ATP bound to it. Energy is created by the breaking apart of ATP into ADP which straightens the myosin
What are the steps to contraction?
Myosin forms a link with an action binding site and released the ADP.
Myosin flexes and pulls the thin myofilament.
Contraction will continue to do these steps until the muscle is relaxed.
What are the steps to relaxation?
The motor neuron that started the excitation needs to stop firing. This will stop the release of ACh which will stop the electrical excitation.
The SR reabsorbs the calcium ions and stores them which then stops the binding of the troponin to the myofilaments.
What is found in the sliding filaments and what do they do when muscle contraction occurs?
The sarcomere shortens Z disc move closer together A band do not shorten I band narrow Think filaments slide toward the M line H band shortens or disappears
