muscle -type of muscle - Largest to smallest

 which of the following correctly lists the structure of a muscle from largest to smallest? 

1. Fasciculus ,muscle fiber , actin , myofibril 
2. muscle fiber , fasciculus , myofibril, actin 
3. sarcomere, fasciculus , myofibril, myosin
4. muscle fiber, myofibril , sarcomere, actin

Be able to define and put the following structures of a skeletal muscle in order from largest to smallest (and vice versa): MYOFILAMENTS (ACTIN AND MYOSIN), WHOLE MUSCLE, SARCOMERE, FASCICLES, MYOFIBRIL, and MUSCLE FIBER. 

Muscle Contraction Flowchart

1. Nerve impulse arrives at neuromuscular junction
   ⬇
   Neurotransmitter acetylcholine (ACh) is released → triggers muscle fiber action potential.

2. Action potential travels along sarcolemma & down T-tubules
   ⬇
   This stimulates the sarcoplasmic reticulum (SR).

3. SR releases calcium ions (Ca²⁺)
   ⬇
   Calcium binds to troponin.

4. Troponin shifts tropomyosin
   ⬇
   Binding sites on actin are exposed.

5. Myosin cross-bridges attach to actin
   ⬇
   Cross-bridge cycle begins.

6. Power stroke

   • Myosin head pulls actin toward the center of sarcomere.

   • ADP + Pi released.

7. ATP binds to myosin
   ⬇
   Cross-bridge detaches.

8. ATP hydrolyzed → ADP + Pi
   ⬇
   Myosin head re-cocks and cycle repeats (if calcium is still present).

9. When calcium is pumped back into SR
   ⬇
   Troponin–tropomyosin complex covers actin sites → contraction ends.

Give this one a try later!

Skipped

Correct answer

myofilament, sarcomere, myofibril, muscle fiber, fascicle, whole muscle (smallest to largest)

bundle of muscle fiber is called fascicle 

bundle of muscle fiber is called fascicle 

bundle of muscle fiber is called fascicle 

bundle of muscle fiber is called fascicle

bundle of muscle fiber is called fascicle

bundle of muscle fiber is called fascicle 

bundle of muscle fiber is called fascicle 

bundle of muscle fascicle is called whole muscle 

bundle of muscle fascicle is called whole muscle 

bundle of muscle fascicle is called whole muscle 

bundle of muscle fascicle is called whole muscle 

filament of myofibrils constructed from protein principally from actin and myosin is called myofilament

filament of myofibrils constructed from protein principally from actin and myosin is called myofilament

filament of myofibril constructed from protein principally from  actin and myosin is called myofilament. 

filament of myofibril constructed from protein principally from actin and myosin is called myofilament .

Sarcomere 

A structural unit of myofibril in striated muscle, consisting of a dark band and the near half of each adjacent pale band is called sarcomere . 

A structural unit of myofibril in striated muscle, consisting of a dark band and the nearer half of each adjacent pale band. .

• Be able to define and put the following structures of a skeletal muscle in order from largest to smallest (and vice versa): MYOFILAMENTS (ACTIN AND MYOSIN), WHOLE MUSCLE, SARCOMERE, FASCICLES, MYOFIBRIL, and MUSCLE FIBER.

  myofilament, sarcomere, myofibril, muscle fiber, fascicle, whole muscle (smallest to largest)
• Myofilaments

  filaments of myofibrils, constructed from proteins, principally myosin or actin
• Sarcomere

  a structural unit of a myofibril in striated muscle, consisting of a dark band and the nearer half of each adjacent pale band.
• Myofibril

  tightly packed filament bundles found within skeletal muscle fibers
• muscle fiber

  muscle cell
• Fascicle

  bundle of muscle fibers
• whole muscle

  bundle of fascicles

Excellent!

Sarcoplasmic Reticulum

Myosin

Sarcomere

Sarcolemma