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Physiology
Skeletal Muscle Fiber Anatomy - Test 4
| Question | Answer |
|---|---|
| What layer of connective tissue connects the two ends of the skeletal muscle fiber? | The endomysium layer. |
| A tendon attaches muscle to bone, what is the tendon made of? | Collagen and Elastin fibers that merge with the endomysium |
| Is a muscle fiber uninucleated? | No, it is multinucleated. |
| True or False, the skeletal muscle cell body is one of the largest cell bodies? | True |
| What is a myofibril? | series of sarcomeres running the length of the fiber. |
| How many T-Tubules are there per a sarcomere? | 2 |
| What mineral does the sarcoplasmic reticulum? | Ca++ |
| What is the thick fibers of the sarcomere called? | Myosin = Thick, Actin = Thin |
| Tropomysin complex is consists of Troponin and which type of fiber? | Actin |
| Tropomyosin is a THIN long fiber that covers and spans how many monomers? | 7 actin monomers |
| How many globular proteins? | 3 Globular Proteins - C, T, I as in aCTIn. |
| Which of the 3 globular proteins binds to actin? | I |
| Which of the 3 globular proteins binds to tropomyosin? | T |
| Which of the 3 globular proteins binds to calcium? | C |
| How many subunits is myosin composed of? | 6 protein subunits - 2 long thin units twisted together and 4 light chains |
| What type of fibers span the I band? | Only Actin |
| What protein structure supports the actin fibers? | The Z-Disc |
| True or False, the A Band changes length during muscle contraction? | False, the A Band does NOT change length |
| What are T-Tubules? | Invaginations of the sorcolemma |
| How does the action potential effect levels of Calcium in the sarcoplasm? | It increases it 1000X |
| How many Ca++ ions bind to Tropin C? | 4 |
| During muscle contraction the myosin head and ADP - P binds to what? | The Actin binding site |
| When the ADP and P group are released from the myosin head it causes the myosin head to flex from ____ degrees to _____ degrees? | 90 degrees to 45 degrees which in turns moves the actin fiber across the myosin. |
| How far does the actin move across the myosin in each flexion of the myosin head? | 10nm |
| What happens when ATP binds to the myosin head? | The myosin head releases the actin |
| What enzyme splits ATP into ADP - P causing the myosin head to return to its original 90 degree orientation? | MyosinATPase |
| What is the normal level of Ca++ ion concentrations in the sarcoplasm? | 0.00000007 molar |
| How many Ca++ ions is transported into the sarcoplasmic reticulum for every ATP burned? | 2 this is accomplished by Sarcoplasmic reticular Ca++ ATPase |