Muscle Flashcards
Myo and sarco mean what?
muscle
What are the tree types of muscle groups?
Striated: Skeletal= voluntary
Cardiac= involuntary
Non-striated: Smooth= invountary
Muscles are bunches of _______, which are bunches of muscle fibers.
Fascicles
Sarcoplasm is muscle ________, has a lot of mitochondria.
cytoplasm
Each muscle fiber is a long thin cell with multiple _______ and many ______.
nuclei
myofibrils
Each myofibril consists of many ________ wurrounded by the sarcoplamic reticulum and t-tubule system.
sarcomeres
_________ proteins are thick and thin filaments.
Contractile
Thick filaments are _______. Intertwind heavy chains with globular heads.
myosin
What are 2 strands of F actin in a helix?
Actin
F actin is made up of many _____ molecules and has _____ binding sites.
G actin
myosin
What is a double stranded helix around actin. Covers the myosin binding site.
Tropomyosin
What is bound to tropomyosin?
Troponin complex
This connects sarcomere to sarcolemma and ECM.
Dystrophin, mutations cause the most common form of Muscular dystrophy
This holds thin filaments apart from one another?
Nebulin
This holds thin filaments to z-disc.
Alpha- actinin
This is a spring that runs through heavy chain and connects it to the z-disc.
Titan
This bisects the sarcomere and bare zone.
M-line
__________ is the functional unit of muscle.
Sarcomere
Smallest part of muscle that can still perform its function.
Sarcomere contraction
A band thick or thin filaments?
Both. Dark striation
I band thick or thin filaments?
Only thin, light striation
Holes of the sarcolemma membrane allows crosses of myocyte between myofibrils.
T-tubules
Smooth ER that has been massively modified to function as Calcium store. How does it run?
Sarcoplasmic Reticulum (SR) Parallel along myobfibrils
More of a ligand gated calcium release channel.
Ryanodine receptor
True/False: In skeletal muscle the DHPR, RyR and SR are all far apart along the T-tubule system.
False, very close together,
so close that changes in DHPR shape can affect RyR shape
AP begun in the NMJ depolarizes down sarcolemmal membrane and down T-tubule system.
Excitation contraction coupling
IMPORTANT: RyR allows Ca++ from ___ into _______.
Sarcoplasmic Reticulum
Cytosol
____________ is how myosin binds to actin and then pulls Z discs together toward the M-line.
Cross bridge cycling
At rest ________ cover myosin binding site on actin.
Tropomyosin
Myosin has bound ___ so it is cocked and has high affinity for actin, but it can’t because Tropomysoin is in the way.
ATP
Calcium binds TnC, this does what?
Moves tropomyosin off actin’s myosin binding pocket, and is excited, then it can bind to actin. Goes through power stroke, pulling on actin, and releases ADP. ATP binds to myosin, releases ADP, hydrolyzes ATP and is recocked and cycle repeats. (as long as there is ATP and Ca++ available)
Motor neurons synapse on varying number of _________.
myocytes
-neuron and all synapsed myocytes make a motor unit
True/False: Fewer cells per nerve lead to fine movements.
True
Each time a motor neuron fires, you get a single __________.
muscle twitch
Recruit more motor units is what?
Spatial summation
Stimulate the same unit numerous times.
Temporal summation
