Skeletal Muscle exam Flashcards
What are the different types of muscle tissue?
Cardiac, Smooth, Skeletal
What are myoblasts and satellite cells and what is their function?
Myoblasts are mult-nucleated-embryonic cells, build muscle cells.
myosatellite cell-stem cells that take part in repair of damaged muscle tissue.
What is epimysium layer?
connective tissue-Dense layer of collagen fibers that surrounds the entire muscle.
What is a perimysium layer?
Folds internal, seperates muscle into large sub-units called Fascicles.
What is a endomysium layer?
Wraps around and seperates each muscle fiber.
What is a muscle body?
Group of fascicles
What are bundles of fascicles?
made up of muscle cell
What are muscle fibers?
made up of myofibrils, multi-nucleiated
What are myofibrils?
made up of bundles of protien myo filaments
What is a sacrolemma?
muscle cell membrane
What is a sarcoplasma?
fluid that fills voids in the muscle cell
What are T-tubules?
Wraps around every myofibril and goes into cell to transmit Action/membrane Potential.
What is sarcoplasmic reticulum?
Wraps around each myofibril, stores lots of Calcium. Helps transmit Action potential
What is a Triad?
Formed by 1 T-tubule and 2 terminal cisternae/lateral sac.
What are myofilaments?
Responsible for muscle contraction.
Two types of myofilaments?
Thin-protein actin
Thick-protein myosin
What are sacromeres?
Sections of muscle fibers that contract.
What is titin?
Corkscrew elastic protein, restores sacromere length after contraction.
What is actin?
thin myofilament composed of troponin complex, and tropomyosin
What is myosin?
Thick filament that grabs the actin strand.
What are nerve and blood vessels?
Supply muscle cell with nutrients, blood. nerves in there as well.
What is a motor unit?
branch of a motor neuron and all the muscle cells it connects to.
what is the relationship between size of motor unit and power generation and level of control of movement?
Larger unit, more power & less control. Smaller unit less power, more control of the muscle cell.
What is a neuromuscular junction?
Where the nerve and muscle cell meet.
What toxin can interfere with muscle contractions and how does this toxin work?
Btx-blocks Vgated Sodium channels
TTx-Keeps Vgated Sodium channels open, stop Action P.
Curare-blocks Nicotinic chemical gated Sodium channels in the motor end plate
What are the five steps of the contraction cycle?
Active site exposure, Cross bridge formation, Pivot of Myosin head, Cross-bridge deatachment, myosin reactivation
Different types of skeletal muscle tissue and their functions.
Slow-endurance, lots of ATP & Myoglobin, Dark
Intermediate- in between
Fast-power, less ATP & Myoglobin, light.
are the same types of fibers found in a single motor unit?
In each motor unit the type of muscle fibers are the same.
In terms of muscle fiber organization, which has the greatest endurance, allows for variable movements and which produce the greatest force?
Parallel muscles have high endurance.
Convergent allow variable movement.
Pennate muscle produce greatest force
During the sliding filament theory, what is changing in size and what is not? And is the entire muscle fiber “contracting” or not
Muscle fiber and sacromere is changing shape. The entire muscle fiber is contracting because the muscle fiber is made up of sections of sacromeres.
What determines the duration of a muscle contraction?
Duration of the neural stimulus
# of free calcium ions in sacroplasm
ATP availability
Explain why Rigor Mortis happens and why it eventually goes away
No Oxygen, mitocondria cant make ATP, Myosin heads cant release, body becomes stiff. Lysomes rupture and dissolve protein, and muscle fibers release
What does the amount of force that a muscle fiber is capable of producing depend on?
Frequency of the stimulus, How much muscle is stretched, size of muscle fibers, amount of motor units
the different phases of a single muscle contraction and, why do we have the latent period – what is causing this?
Latent,
contraction-release of Calcium landing on troponin.
relaxation-pumping Calcium back into the lateral sacks.
Because the Action Potential has to happen
What is treppe?
completes relaxtion phase but a stimulus happens immediately after it ends
What is incomplete tetanus?
Stimulus is applied before relaxtion phase completes itself.
What is complete tetanus?
Before relaxation phase begins
Explain the concept of wave summation
Concept of a muscle contraction, the stimulus is applied before the relaxation phase has ended.
What toxin can interfere with muscle contractions and how does this toxin work?
Btx-blocks Vgated Sodium channels
TTx-Keeps Vgated Sodium channels open, stop Action P.
Curare-blocks Nicotinic chemical gated Sodium channels in the motor end plate
What are the five steps of the contraction cycle?
Active site exposure, Cross bridge formation, Pivot of Myosin head, Cross-bridge deatachment, myosin reactivation
Different types of skeletal muscle tissue and their functions.
Slow-endurance, lots of ATP & Myoglobin, Dark
Intermediate- in between
Fast-power, less ATP & Myoglobin, light.
Are the same types of fibers found in a single motor unit?
In each motor unit the type of muscle fibers are the same.
In terms of muscle fiber organization, which has the greatest endurance, allows for variable movements and which produce the greatest force?
Parallel muscles have high endurance.
Convergent allow variable movement.
Pennate muscle produce greatest force
During the sliding filament theory, what is changing in size and what is not? And is the entire muscle fiber “contracting” or not
Muscle fiber and sacromere is changing shape. The entire muscle fiber is contracting because the muscle fiber is made up of sections of sacromeres.
What determines the duration of a muscle contraction?
Duration of the neural stimulus
# of free calcium ions in sacroplasm
ATP availability
Explain why Rigor Mortis happens and why it eventually goes away
No Oxygen, mitocondria cant make ATP, Myosin heads cant release, body becomes stiff. Lysomes rupture and dissolve protein, and muscle fibers release
What does the amount of force that a muscle fiber is capable of producing depend on?
Frequency of the stimulus, How much muscle is stretched, size of muscle fibers, amount of motor units
the different phases of a single muscle contraction and, why do we have the latent period – what is causing this?
Latent,
contraction-release of Calcium landing on troponin.
relaxation-pumping Calcium back into the lateral sacks.
Because the Action Potential has to happen
What is treppe?
completes relaxtion phase but a stimulus happens immediately after it ends
What is incomplete tetanus?
Stimulus is applied before relaxtion phase completes itself.
What is complete tetanus?
Before relaxation phase begins
Explain the concept of wave summation
Concept of a muscle contraction, the stimulus is applied before the relaxation phase has ended.
Explain the concept of recruitment
smooth motion and increasing tension are produced by slowly increasing the size or number of motor units stimulated.
What is Isotonic contraction
muscle changes in length resulting in motion
What is Concentric contraction
Force greater than load muscle shortens
What is eccentric contraction
Force is less than load, muscle lengthens
What is isometric contraction
same length
In terms of relative amounts which do we have more and less of - ATP, CP or glycogen stores?
More of glycogen, some Creatine Phospate, and less ATP.
What are the different types of fuels (substrates) that can be used by the body to generate ATP?
Fatty acids, glucose, amino acids
How do we generate more Creatine Phospahte, where in the muscle cell does this take place?
ATP, created by mitochondria, with creatine, converts creatine to “Creatine Phosphate”, takes place in the sarcoplasm.
During aerobic and anaerobic metabolism what are we using as “fuel” to produce ATP?
Aerobic m. in the mito., O2, fatty acids, pyruvic acid, amio acids.
Anerobic m. in the sacroplasm, no O2,glucose to pyruvic acid, and use of creatine.
In what regions/parts of a cell do we find aerobic and anaerobic metabolism taking place?
aerobic- in mitochondria
anaerobic-takes place in the cytoplasm of the cell.
What determines the metabolic pathway that a muscle cell uses to generate energy, and, what are those different pathways?
Activity level. Metabolic pathway-Cellular respiration-mito. makes ATP, Glycoloysis-Glucose to Pyruvic acid, Gluconeogenesis-Pyruvate to glucose from Lactate.
What do mitochondria use and produce as they make ATP?
Mito. use Fatty acids,Glucose,amino acids,O2.Produce:ATP, CO2, H2O.
Explain the Cori Cycle, and why is this not a very efficient pathway?
Glucose is converted to Pyruvate Acid by glycolysis, excess Pyruvate is converted to Lactic acid, lactic acid is sent to the liver, by the bloodstream, and through gluconeogensis, lactate is converted back to Pyruvate. It takes 6 ATP to convert Pyruvate back to glucose, and only getting 2ATP.
What are the two different metabolic pathways for pyruvic acid?
Glycolysis, Gluconeogensis
Define gluconeogenesis and what are examples of this process?
Define: Turning compound into glucose. Example Converting 2 Pyruvate to 1 glucose in the liver.
Define hypertrophy an atrophy
hypertrophy:Lots of nourishment, muscles cells increase in diameter.
Atrophy:No nourishment to muscle cells,no movement.
