Short Answer Type
Long Answer Type
Match The FollowingMatch Column I with Column II :
| A. Smooth muscle | (i) Myoglobin |
| B. Tropomyosin | (ii) Thin filament |
| C. Red Muscles | (iii) Sutures |
| D. Red Muscles | (iv) Involuntary |
Long Answer TypeDescribe the important steps in muscle contraction.
The important steps muscle contraction:
1. Muscle contraction is initiated by a signal sent by the central nervous system (CNS) via a motor neuron and reach the neuromuscular junction. As a result, neurotransmitter (Acetyl choline) which generates an action potential in the sarcolemma.
2. This spreads through the muscle fibre and causes the release of calcium ions into the sarcoplasm.
3. Increase in Calcium level leads to the binding of calcium with a subunit of troponin on actin filaments and thereby remove the masking of active sites for myosin. Utilising the energy from ATP hydrolysis, the myosin head now binds to the exposed active sites on actin to form a cross bridge.
4. The actin filaments are pulled. As a result, the H-zone reduces. It is at this stage that the contraction of the muscle occurs.
5. After muscle contraction, the myosin head pulls the actin filament and releases ADP along with inorganic phosphate. ATP molecules bind and detach myosin and the cross bridges are broken and decreases the calcium ions contraction. As a result, masking the actin filaments and leading to muscle relaxation.
Multiple Choice QuestionsLack of relaxation between successive stimuli in sustained muscle contraction is known as
fatigue
tetanus
tonus
tonus
Which type of tissue correctly matches with its location?
| Tissue | Location |
| Areolar tissue | Tendons |
| Tissue | Location |
| ATransitional epithelium | Teip of nose |
| Tissue | Location |
| Cuboidal epithelium | Tlining of stomach |
| Tissue | Location |
| Cuboidal epithelium | Tlining of stomach |
The H -zone in the skeletal muscle fibre is due to
the absence of myofibrils in the central portion of A-band
the central gap between myosin filaments in the A-band
the central gap between actin filaments extending through myosin filaments in the A-band
the central gap between actin filaments extending through myosin filaments in the A-band
Select the correct statement with respect to locomotion in humans
A decreased level of progesterone cause osteoporosis in old people
Accumulation of uric acid crystals in joints causes their inflammation.
The vertebral column has 10 thoracic
The vertebral column has 10 thoracic
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