Stimulation of a muscle fiber by a motor neuron occurs at:
1. the neuromuscular junction
2. the transverse tubules
3. the myofibril
4. the sarcoplasmic reticulum
In a healthy person, the red muscle fibres appear red due to stored
1. Carboxyhemoglobin
2. Carbaminohemoglobin
3. Myoglobin
4. Erythropoietin
Which of the following property cannot be attributed to white fibers?
1. Fewer mitochondria
2. Anaerobic process for energy
3. Sarcoplasmic reticulum is high
4. More quantity of myoglobin
If production of pyruvic acid by anaerobic metabolism in a muscle is faster than it can be utilized, the surplus is converted to:
1. lactic acid
2. adenosine diphosphate
3. carboxylic acid
4. creatine phosphokinase
Red muscle fibres differs from white muscle fibres in having
1. More sarcoplasmic reticulum
2. Less myoglobin content
3. More number of mitochondria
4. High lactic acid due to anaerobic oxidation
Hypocalcemia may lead to:-
1. Kidney stones
2. Cholelithiasis
3. Stronger muscle contractions
4. Tetany
Arrange the following events involved in muscular contraction
(i) Action potential enters muscle fibre through T-tubules
(ii) Ca2+ binds with troponin-C
(iii) Actomyosin cross bridge formation
(iv) Sliding of thin myofilament along the thick myofilament
(v) Exposure of active sites on actin filaments
(vi) Release of Ca2+ from sarcoplasmic reticulum
1.
2.
3.
4.
Identify the incorrectly matched pair:
Disease | Cause | |
1. | Myasthenia gravis | Antibodies against neuromuscular junction |
2. | Tetany | Hypocalcemia |
3. | Osteoporosis | Hypoparathyroidism |
4. | Gout | Accumulation of uric acid crystals |
What is true about the white muscle fibers?
1. Myoglobin content is high
2. They have a large number of mitochondria
3. They depend on anaerobic process for energy
4. They are adapted for slow sustained activities
Match each item in Column I with one item in Column II and choose your answer from the codes given below:
Column I | Column II | ||
I. | Influx of sodium | 1. | Original establishment of RMP |
II. | Efflux of potassium | 2. | Repolarization |
III. | Na+/K+ pump | 3. | Depolarization |
IV. | Ca++ | 4. | Plateau in cardiac muscles |
Codes :
I | II | III | IV | |
1. | 3 | 2 | 4 | 1 |
2. | 2 | 1 | 4 | 3 |
3. | 2 | 1 | 3 | 4 |
4. | 3 | 2 | 1 | 4 |