Calcium is important in skeletal muscle contraction because it
Binds to troponin to remove the masking of active sites on actin for myosin.
Activates the myosin ATPase by binding to it.
Prevents the formation of bonds between the myosin cross bridges and the actin filament.
Detaches the myosin head from the actin filament.
A.
Binds to troponin to remove the masking of active sites on actin for myosin.
The signal for contraction increase Ca++ level many folds in the sarcoplasm.
Ca++ now binds with sub-unit of troponin (troponin 'C') which is masking the active site on actin filament and displaces the sub-unit of troponin.
Once the active site is exposed, head of the myosin attaches and initiate contraction by sliding the actin over myosin.
Match the items given in Column I with those in Column II and select the correct option given below:
| Column i | Column ii | ||
| a | Tidal volume | i | 2500 – 3000 mL |
| b | Inspiratory Reserve volume | ii | 1100 – 1200 mL |
| c | Expiratory Reserve volume | iii | 500 – 550 mL |
| d | Residual volume | iv | 1000 – 1100 mL |
| a | b | c | d |
| iii | ii | i | iv |
| a | b | c | d |
| iii | i | iv | ii |
| a | b | c | d |
| iv | iii | ii | i |
| a | b | c | d |
| i | iv | ii | iii |
Match the items given in Column I with those in Column II and select the correct option given below:
| Column I | Column II | ||
| a | Fibrinogen | i | Osmotic balance |
| b | Globulin | ii | Blood clotting |
| c | Albumin | iii | Defence mechanism |
| a | b | c |
| iii | ii | i |
| a | b | c |
| i | ii | iii |
| a | b | c |
| ii | iii | i |
| a | b | c |
| i | ii | iii |
Which of the following gastric cells indirectly help in erythropoiesis?
Chief cells
Mucous cells
Parietal cells
Goblet cells
Which of the following is an occupational respiratory disorder?
Anthracis
Silicosis
Emphysema
Botulism
Match the items given in Column I with those in Column II and select the correct option given below:
| column i | column ii | ||
| a | Tricuspid valve | i | Between left atrium and left ventricle |
| b | Bicuspid valve | ii | Between right ventricle and pulmonary artery |
| c | Semilunar valve | iii | Between right atrium and right ventricle |
| a | b | c |
| iii | i | ii |
| a | b | c |
| i | iii | ii |
| a | b | c |
| ii | i | iii |
| a | b | c |
| i | ii | iii |
The transparent lens in the human eye is held in its place by
ligaments attached to the ciliary body
ligaments attached to the iris
smooth muscles attached to the ciliary body
smooth muscles attached to the iris
Which of the following hormones can play a significant role in osteoporosis?
Aldosterone and Prolactin
Progesterone and Aldosterone
Parathyroid hormone and Prolactin
Estrogen and Parathyroid hormone
Which of the following structures or regions is incorrectly paired with its functions?
Medulla oblongata : Controls respiration and cardiovascular reflexes
Limbic system: consists of fibre tracts that interconnect different regions of brain; controls movement.
Corpus callosum: band of fibres connecting system: left and right cerebral hemispheres.
Hypothalamus: production of releasing hormones and regulation of temperature,the hunger and thirst.
