Quiz 1 ( structure and function of muscle) Flashcards
What is Epimysium?
Connective tissue that surrounds ENTIRE muscle/ gives it shape
What is Perimysium?
Connective tissue that surrounds each fascicle individually.
What is a fascicle?
small bundle of fibers wrapped in Perimysium
What is Endomysium?
Connective tissue that covers EACH muscle fiber
What is the correct order from SMALLEST TO LARGEST ? peri, endo, epi?
ENDO- PERI-EPI
what is a myocyte?
multi nucleated cells
tube like structure
What are satellite cells?
Undifferentiated cells of musclefibers
what/how is muscular membrane damage created?
Resistance training which ACTIVATES satellite cells which plays a key role with muscle growth/repair
How many stimuli activate the satellite cells which leads to myogenesis of any specific fiber type?
Seven
What does tintin do?
provides elasticity and stabilizes myosin
What are the two binding sites of myosin?
Actin binding site
ATPase site
what is the excitation-contraction coupling?
Calcium binds to troponin
Cooperative conformational changes takes place in troponin-tropomyosin system
The Inhibition of actin and myosin interaction is released
Crossbridges of myosin filaments are attached to actin filaments
Tension is exerted and/or the muscle shortens by sliding filament mechanism
What is the Z line
Actin molecules are bound to the Z line, which forms the borders of the sarcomere. Other bands appear when the sarcomere is relaxed
After the power stroke of the crossbridge that causes the sliding of the thin filaments, what happens next in contraction?
The binding of ATP to the crossbridge, which results in the crossbridge disconnecting from the actin
The hydrolysis of ATP, which leads to the re-energising and repositioning of the crossbridge
Cessation of AP- reuptake of Ca2+ into Sarcroplasmic reticulum
relaxation
What are the two components of muscle fibers?
Sarcolemma and Plasmalemma
What is the Sarcolemma
A structure that is made up of the plasmalemma and basement membrane
What is the Plasmalemma
A plasma membrane that surrounds EACH muscle fiber
What does the plasmalemma assist in?
The transmission of the action potential from the motor neuron to the muscle fiber
What is the motor unit?
motor neuron and all the muscle fibers it innervates
Where are satellite cells located?
between plasmalemma and basement membrane
What is the sarcoplasm
Gelatin like substance that fills the space between MYOFIBRILS
contains dissolved proteins, minerals, glycogen, fats an organelles ( mitochondria and others that promote muscle growth/ repair)
What are transverse tubules
T tubules
Extension of plasmalemma, located in sarcoplasm that presses along muscle fiber
What is the sacroplasmic reticulum
longitudinal network of tubules that parallel the myofibrils and loop them around
What is stored in the sarcoplasmic reticulum
calcium
What is a myofibril
smaller than the whole muscle fiber
contains two contractile proteins - actin ( thin) myosin (thick)
How are cross bridge’s formed
many myosin heads
crossbridge interacts with thin filaments
What are the three proteins that make up thin filaments
Actin, tropomyosin and troponin
what is the tropomyosin strand also known as
Protein strand
What binds to Tnc to make myosin?
Calcium
What is the sliding filament theory
When each sacromere which contains thin and thick filaments overlap and SLIDE PAST eachother when the muscle contracts ( shortening of muscle)
Cross bridge cycling creates the molecular basis for this to happen
When is muscle contraction initiated?
when muscle fibers are stimulated by a nerve impulse AND calcium ions are released
What are the three types of muscle action
isometric, concentric and eccentric
What is isometric muscle movement
Muscle tension= muscle load
no change in length of muscle when tension is developed
what is concentric muscle movement
muscle tension > muscle load
muscle shortens while developing tension
think of CONSTRICTING both start with CON so muscle is shortening like constricting
what is eccentric muscle movement
muscle tension > muscle load
muscle trying to shorten but is being forced to lighten
ex- think of doing a bicep curl ( when lowering the dumbbell)
