Skeletal Muscle Flashcards
what type of muscle is being described?
many nuclei, striations, very big, has voluntary control, and is somatic innervation
Skeletal Muscle
what type of muscle is being described?
striations, nuculi, intercalated discs, no voluntary control, innervation is autonomic
Cardiac muscle
what type of muscle is being described?
no striations, singular nuclei, no voluntary control, innervation is autonomic
Smooth muscle
What are functions of skeletal muscle (5)
- movement and posture
- support of soft tissue
- regulate entry of food and exit of waste products
- thermoregulation
**Allow us to breathe by contraction of the diaphragm
What do muscle fibers begin as?
Myoblasts
What is the term called when some myoblasts do not fuse together?
Myosatellites
Connective tissue that is superficial and covers the whole muscle
Epimysium
Connective tissue that is intermediate and covers muscle fascicles
Perimysium
Connective tissue that is deep and covers individual fibers
Endomysium
Middle of sarcomere is called
M line
end of sarcomere is called
Z disc
this is where no overlap is present from the thin and thick filaments. Just the thick filament
H zone
the entire length of the thick filament is called the
A band
No overlap from the thick and thin filaments. Just the thin filaments are present
I band
What is the long protein called that attaches to the Thick Filament
Titin or Connectin
What is the thick filaments predominant protein?
Myosin
What is the thin filaments predominant protein?
Actin
What is the protein called that covers myosin binding sites on g-actin molecules
Tropomyosin
What is it called: three separate proteins; binds tropomyosin and Calcium
Troponin
What is the basic unit of a contractile muscle fiber called
sarcomere
what are the two main PROTEIN filaments that a sarcomere is composed of. which are active structures responsible for muscle contraction
Actin and Myosin
Region between 2 z discs
Sarcomere
How is muscle contraction produced?
Neurotransmitter, ACh gets to the muscle cell, ATP is produced, which elevated Calcium levels, and contraction occurs
What percentage do Myofibrils account for inside the cell?
80%
What are myofibrils surrounded by?
Think of mani’s marker and glove example
Sarcoplasmic Reticulum
What is the sarcoplasmic reticulum example Mani gave us?
Glove wrapped around many markers, which resembled the myofibrils and the SR
the pump that transports calcium ions from the cytoplasm into the sarcoplasmic reticulum
SERA
T-Tubules are ____ of the cell and sit ___ of the SR
Inside, On top
myofibrils contain:
thick and thin filaments
Thick filaments are contained of myosin which then have ( ) conformation
high or low
The myosin head allows for what to bind?
ATP and actin binding site
What is the rod shaped protein that sits on top of myosin binding sites?
Tropomyosin
Trimetric complex (TnI,TnC,TnT) are from
Troponin
do thick and thin filaments change shape? if no, what do they do
No
they slide over one another (Sliding Filament Theory)
Myosin pushes ___ filament over the ____ filament
thin over the thick
When the sliding of the filaments occur. What disappears?
H zone
How long will the cross bridging continue?
As long as the calcium levels remain high
how are sliding filaments caused?
A series of attachment and detachment cycles of myosin heads on actin binding sites
in a resting state does TnC have calcium bound to it?
no
how does Rigor Mortis occur? (Stiffness after death)
due to the depletion of ATP in muscles, therefore causing actin and myosin unable to detach from one another (Constant contraction)
During sliding filament theory – as the area shrinks what happens to the bands/zones
H and I zones get smaller
A zone does not change
HOW? Calcium
