Organization of Skeletal Muscle
What is the name for Smooth ER in skeletal muscle and what are its functions?
What are the two proteins of the myofibril and their alternate names?
Actin - thin filament
Myosin - thick filament
What does the sarcoplasmic reticulum store?
What type of contraction does smooth muscle use
involuntary
What is this
Skeletal muscle
What is the cell shape of skeletal muscle, and what is a characteristic of its nucleus?
Reid make a bowl of cereal and post it on your chef instagram and play it off as gourmet
Cylindrical, and skeletal muscle is multinucleated
+400
How many heads does myosin have and what does it bind?
2 - ATP binding site and actin binding site
What has to bind in order to form a cross bridge?
Myosin to actin
What process does smooth muscle use to regenerate?
Tony post ultra 85 on your snapchat story saying "10/10 must read" and give a breakdown of why you liked it. Keep it up for 2 minutes
mitosis
+600 for doing it, -100 if you dont
What is this
Smooth muscle
The perimysium layer surrounds a ______?
fasicle
Actin is made of individual __ actin, which polymerizes to form __ actin
+200 - what two regulatory proteins does actin associate with?
Tory has to call Abby and use a witawy accent to explain why he's an alpha
G-actin, F-actin
Troponin and Tropomyosin
+400 for Tory
What is a t tubule?
downward extension of the sarcolemma
Where is smooth muscle found in the body
In the walls of hollow organs
What is circled
epimysium
What is the outermost ct layer of skeletal muscle?
For +100, what type of collagen makes up this ct layer
Epimysyium
type 1 and type 3
What three things together make up the thin filament?
F-actin, troponin and tropomyosin
What is known as the triad?
+100 - Where on the myofibril is the triad?
the t tubule along with the terminal cisternae of the sarcoplasmic reticulum on either side
Where the A and I band meet
Describe the nucleus location and number, and what is the shape of the fiber?
Tig, call Sam and tell her you miss her
Just kidding. Pick someone to make you a shot with stuff from the fridge.
central mononucleated, elongated tapering spindle shaped cells
+400 for Tig
what is circled
the triad
Name and explain the bands/discs/lines/zones of a myofibril
+100 - What does a sarcomere span to and from?
A band - mainly myosin, overlaps with some actin
I band - ONLY actin
Z disc - acts as anchor, where actin attaches
M line - In H zone, keeps myosin together
H zone - NO actin overlapping when relaxed
Sarcomere is from z disc to z disc
What are the three sites of troponin, and what does each do?
TNT - interacts with tropomyosin
TNI - intermediate, talks to TNT when Ca2+ binds and tells it to shift to expose the binding site
TNC - binds Ca2+ which causes a conformational change
Say I really needed a katana (don't ask why), but I was in my room, motionless. What would need to happen in my body in order to go downstairs and ask Morgan to borrow it? In other words, what are the events of a muscular contraction?
When the Motor nerve initiates an action potential- it depolarizes the sarcolemma- this depolarization travels through the T-tubules and triggers the release of Ca from the adjacent cisternae of the sarcoplasmic reticulum into the sarcoplasm. The calcium binds to the TnC subunit of troponin- which causes a displacement of the tropomyosin and exposes the Myosin-binding sites on the F-actin. The myosin heads will interact with the actin fibers through these sites. A series of binding and unbinding events of the myosin heads to the F-actin causes the sliding of Myosin bundles over the actin fibers, causing contraction of the sarcomere. The pivot of the myosin head makes it lose ATP so the binding site is open, so more ATP binds which removes the myosin head and the cycle repeats
What is a dense body and what do they do?
Cy go jump in the snow or do a polar plunge
They are alpha actin aggregates, that allow for actin filaments to anchor and allows for a more efficient smooth muscle contraction
+400
Fill in each blank
word