Muscle Flashcards
Muscle surrounded by dense connective tissue.
Epimysium
What are muscle fiber bundles (fascicles) surrounded by?
Perimysium
Muscle fiber bundles consist of what?
Multinucleated muscle fibers that are 10-100um wide and up to 30 cm long.
What is endomysium made up of?
Basal lamina and reticular.
Where the shit do nuclei lie in muscle fibers?
Just beneath the sarcolemma.
Satellite cells found where?
Between sarcolemma and basal lamina.
When do cells proliferate from satellite cells?
After trauma.
List the order of muscle divisions from largest to smallest.
Muscle-> Fascicle-> Fiber->Myofibril->Myofilaments
What is the function unit of contraction!
Sarcomere
If I fold in a piece of the sarcolemma (plasma membrane) what do I call that?
T-tubule
What is the specialized endoplasmic reticulum called in muscle cells?
Sarcoplasmic reticulum
A T-tubule sandwiched between two portions of sarcoplasmic reticulum is called what?
A triad.
Where are triads found?
A and I band junctions.
What innervates muscle cells?
Motor end plate at the myoneural junction.
True or false? Axons going to muscle cells lose their myelin but are still covered by Schwann Cells?
True.
What name did people rename Schwann Cells that reach the motor end plate?
Teloglia
Acetylcholine crosses what to get from axon terminals to muscle receptors?
Synaptic cleft
What is the place acetylcholine receptors are located called?
Junctional folds (subneural clefts) of the sarcolemma
How many muscle fibers can a single nerve innervate? And what is this unit called?
One or more. Whatever an axon innervates is referred to as the motor unit
Where does Botulism bind to block Acetylcholine (Ach)?
Presynaptic membrane of axon. (Remember it like how botters are goddamn lazy so they don’t bother to go across synaptic cleft)
Where does Curare block Ach?
Ach receptor across synaptic cleft. (Remember how “Cur” like a villain will take your shit (receptors).
How does Myasthenia Gravis block Ach?
It’s an autoantibody so it attacks the Ach receptor itself. (Remember it as “My” (from Myasthenia) stupid body is attacking itself.)
How is action potential brought into the cell?
Via the transverse T tubule system and continuous with the sarcolemma.
If I depolarize the cell what will I release and from where?
Ca++ and from the terminal cisternae of the sarcoplasmic reticulum.
Describe Red Fiber muscles to me.
Known as type 1 slow twitch, they have high myoglobin, lots of mitochondria, and fatigue resistant.
Now do White Fibers.
Type 2, fast twitch, low myoglobin, more stored glycogen, more atpase activity.
If I decide to play Frankenstein and start switchin nerves that innervate red and white fibers what will happen?
I can change a red fiber to a white fiber or vice versa.
Where do muscle spindles run?
Parallel with the main muscle fibers.
And what do the muscle spindles do while we’re at it?
They sense changes in muscles length.
Intrafusal muscle fibers are skeletal muscle fibers that serve as specialized sensory organs (proprioceptors) inside muscle spindles that detect the amount and rate of change in length of a muscle. They constitute the muscle spindle and are innervated by two axons, one sensory and one motor.
I wasn’t asking anything, it was just something from the notes annoying me.
If a sensory nerve is stretched what will happen to the nerve discharge rate?
That shit’ll go up.
Actually, back to intrafusal fibers for a second what are the two types them?
Nuclear bag and nuclear chain.
