Muscle types are dependent upon _____ and ________
speed and level of oxidation and glycolysis
_____surrounds an entire muscle
Epimysium
_____ surrounds the muscle bundle called fascicles
Perimysium
______surrounds individual myofibers
Endomysium
Myofilaments make up _________
myofibrils
_____ are multinucleated, while ______ and ______ are uninucleated.
Skeletal: multinucleated;
cardiac and smooth
Where is the nuclei located? specifically _____of the sarcolemma.
Below the surface of sarcolemma
What kind of neurons innerate muscle fibers? And ______gives rise to such neurons
alpha motor neurons; ventral horn
_______use ATP for the myosin-head region that provides the energy for the sliding
inter-myofibril mitochondria
The ________keeps the Na+/K+ active transport pump going
Subsarcolemmal mitochondria
What is a triad inside of a myofiber?
Which one opens to the extracellular environment?
What is the terminal ends of the t-tubule called?
Two sarcoplasmic retinculum and 1 transverse tubule; The transverse tubule is open to the extracellular environment;
terminal cisternae
Which myofilament protein type contains a tail region and a cross-bridge region?
Myosin
What region of the myosine contains an active binding site and ATPase binding site, located on the A band?
Cross-bridge region
T/F: actin is present in the light H zone.
False
What renders the dark spot on the H line?
M line protein
What is the DISC called in the middle of the I bands?
Z-disc
What are the points called that define the boundaries of each sarcomere?
Z discs
Draw a complete sarcomere
What kind of protein forms the filament actin (F-actin)?
Globular actin proteins
The smallest functional unit of contraction is called a ______
Sarcomere
T/F: Titin is thought to aid in centering the thick filament equidistant between the thin actin filaments and also aiding in relaxation
True
What protein is used to mediate interactions between the sarcoplastmic reticulum and myofibrils?
obscurin
Nebulin is in thick or thin filaments?
thin filaments; structural in nature
mutations in _____, a type of support protein, leads to muscular dystrophy and even inbibitins; it's located under the sarcolemma
dystrophin
Describes the process leading to disuse atrophy attributed by a cut in axon:
1.Ach..
2.membrane...
3. receptors... (and what kind of receptors?)
1. Ach is no longer release
2. Membrane tends to flatten
3. receptors drift into the sarcolemma
*nicotinic receptors
T/F: motor end plate includes the terminal bouton.
False
T/F: Motor-end plate is the specialized post-synaptic region of the sarcolemma that is part of the neuromuscular junction.
True.
A motor unit includes______
The somatic motor neuron and myfibers it innervates
_____ ______ is the synapse betwen the nerve fiber and muscle fiber
Neuromuscular junction
Excitation-contraction coupling:
Two different types of Ca+ channels that are coupled. Where are they?
The voltage gated calcium channels are on the transverse tubule (They only respond to membrane depolarization), and the other one that's coupled to it is the sarcoplasmic reticulum calcium release channels
*CRC receptors are calcium release channel receptors on the SR
The DHP receptors are ______ located on _______; the Ryanodine receptors are _____ and located on ______
Voltage gated calcium channels on the t-tubules;
SR calcium release channels; on SR
T/F: Calcium activated ATPase pump on t-tuble
No, the ATPase pump is on the SR
T/F: Changing permeabiltiy allows calcium to flood out
Yes
T/F: Calsequestrin is a calcium binding protein that aids the pump in concentrating calcium
True
_____lies on top of the active site on the globular-actin molecule;
Troponin complex:
______: regulatory molecule that binds to calcium
______ binds to the tropomysin
Tropomyosin;
Troponin C
Troponin T
T/F: When Ca+ binds to troponin C, causing a conformational change that will move the tropomyosin out of the way for actin to attach to the cross-bridge, undergoing a powerstroke
True
Just remember:
Calcium: binding the two
ATP: releases the two
Breaking ATP to ADP and ior. phosphate for cross bridge to recock
In details:
After the cross bridge binds to actin: Pi gets released
Then Powerstroke:
ADP gets released
Explain rigor mortis;
In order for body to relax, Ca+ has to be pumped back into the SR
Since the body can't produce any more ATPs, the APTase can no longer pump the Ca+ in the cytoplasm into the SR, hence, the Ca+ just hanging around are keeping the myosin attached to the actin;
and no more ATP can unbind the actin;
--->the muscle is in the stiffened form
T/F: The strength of a muscle contraction can be graded.
True
What do you call the phenomenon when a second electric shock is delievered immediately after the first that the twitch may partially ride piggyback on the first?
Summation
In an isometric contraction, ___ changes, ____ does not.
In an isotonic contraction, ____ change, _____ does not.
