Calcium is important in skeletal muscle contraction because it:
1. Detaches the myosin head from the actin filament.
2. Activates the myosin ATPase by binding to it.
3. Binds to troponin to remove the masking of active sites on actin for myosin.
4. Prevents the formation of bonds between the myosin cross bridges and the actin filament.

A motor unit consists of:
1. A motor neuron and all the muscle fibers innervated by it
2. All the motor neurons innervating one muscle fiber
3. All the muscle fibers in a fasciculus
4. All the muscle fibers in a skeletal muscle

Myasthenia gravis is an autoimmune disease in which antibodies are formed against:
1. Myelin sheath
2. Articular cartilage
3. Neuro-muscular junctions
4. Thyroid follicle

The first carpo-metacarpal joint is a/an:
1. Saddle joint             2. Ellipsoidal joint
3. Pivot joint               4. Fibrous joint

The central part of the thick myofilaments, not overlapped by thin filaments, is called the:
1. Z line         2. M line
3. I band        4. H zone

Vertebrochondral ribs attach to the seventh rib with the help of:

1. Elastic cartilage

2. Hyaline cartilage

3. Fibrous cartilage

4. White fibrous tissue

Myosin head cleaves ATP for:

1. Formation of cross bridges

2. Breaking of cross bridges

3. Both 1 and 2

4. Neither 1 nor 2

Vitamin D deficiency in an adult causes the condition known as _____.

1.rickets

2. osteoporosis

3. osteomalacia

4. giantism

The number of correct statements amongst the given statements is:

I. Cardiac muscles are striated and involuntary.

II. Myosin head is an active ATPase enzyme.

III. The neurotransmitter released at the neuromuscular junction is acetylcholine.

IV. White muscle fibers depend on anaerobic process for energy.

V. Functional unit of muscle contraction is the sarcomere.

  1.  2       

  2.  3

  3.  4       

  4.  5

In the given diagram of the human skull, the bones represented by the letters A, B, and C are respectively:

          1. Sphenoid, Ethmoid and Lacrimal

          2. Ethmoid, Sphenoid and Lacrimal

          3. Sphenoid, Lacrimal and Ethmoid

          4. Ethmoid, Lacrimal and Sphenoid