What masks the active sites for myosin head present on the actin myofilaments?
1. Light meromyosin
2. Heavy meromyosin
3. G – actin
4. Troponin
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
The muscle can directly use which of the following as a source of energy?
1. Creatine phosphate
2. Glucose
3. ATP
4. Fatty acids
With respect to the red muscle fiber, the white muscle fiber has higher:
1. Density of capillary network
2. Number of mitochondria
3. Amount of sarcoplasmic reticulum
4. Glycogen reserve
Myasthenia gravis is an autoimmune disease in which antibodies are formed against:
1. Myelin sheath
2. Articular cartilage
3. Acetylcholine receptor
4. Thyroid follicle
A glenoid cavity is seen in:
1. | Scapula | 2. | Coxa |
3. | Humerus | 4. | Clavicle |
The first carpometacarpal joint is a/an:
1. Saddle joint
2. Ellipsoidal joint
3. Pivot joint
4. Fibrous joint
In the resting stage, the axonal membrane:
1. is more permeable to sodium than to potassium ions
2. is more permeable to potassium than to sodium ions
3. is equally permeable to both sodium and potassium ions
4. is impermeable to both sodium and potassium ions
The depression on the coxa where the head of the femur articulates is the
1. acetabulum.
2. auricular surface.
3. iliac fossa.
4. ischial tuberosity.
The ability of a muscle fiber action potential to cause an increase in cytosolic calcium concentration is dependent upon
1. The conduction of action potentials down T-tubules which are in intimate contact with the sarcoplasmic reticulum.
2. The presence of the voltage sensitive protein called the ryanodine receptor in the T-tubule membrane
3. The calcium channel protein called the dihydropyridine receptor which is located in the sarcoplasmic reticulum membrane
4. Ca++-ATPase pumps in the sarcoplasmic reticulum
When a skeletal muscle shortens during contraction which of these statements is false?
1. The l-band shortens
2. The A-band shortens
3. The H-zone becomes narrow
4. The sarcomeres shorten
Which of the following is not a feature of red muscle fibres?
1. They have plenty of mitochondria.
2. They have a high content of Myoglobin.
3. They have a high amount of Sarcoplasmic reticulum.
4. They are called aerobic muscles.
During resting stage the binding site of actin for myosin remains masked by
1. Troponin 2. Gactin
3. Tropomyosin 4. Meromyosin
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
The muscle can directly use which of the following as a source of energy?
1. Creatine phosphate
2. Glucose
3. ATP
4. Fatty acids
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
A glenoid cavity is seen in:
1. Scapula 2. Coxa
3. Humerus 4. Clavicle
The first carpo-metacarpal joint is a/an:
1. Saddle joint 2. Ellipsoidal joint
3. Pivot joint 4. Fibrous joint
Osteoporosis in a post-menopausal woman is most directly due to the deficiency of:
1. Progesterone 2. Estrogen
3. LH 4. FSH
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
The human ribs are termed as bicephalic because they have:
1. Two articulation surfaces on its dorsal end
2. Two articulation surfaces on its ventral end
3. One articulation surface on its dorsal and one on its ventral side
4. No articulation surfaces
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