October 2, 2013

Sr Inter Zoology - Muscles - Very Short Answer Questions

1. What is a motor unit with reference to muscle and nerve?
A: Amotor neuron and the set of muscle fibres innervated by all the teledendrites constitute a motor unit.

2. What is triad system?
A: The T - tubule along with terminal cisternae of sarcoplasmic reticulum on either side together form the triad system of a muscle.

3. Write differences between Actin and Myosin.
A: a) Actin is one of the proteins that form a thin filament of myofibril besides troponin
and tropomyosin.
b) Myosin is the protein that forms the thick filaments of a myofibril.

4. Distinguish between red muscle fibres and white muscle fibres.
A: a) The sarcoplasm of red muscle fibre contains myoglobin (a red pigment) that store much Oxygen.
b) The sarcoplasm of white muscle fibre contains very little amount or no myoglobin.

5. Name two cranial sutures and their locations.
A: a) Coronal suture - Frontal and Parietal.
b) Lamboid suture - Parietal and Occiput.

6. Name the Keystone bone of the cranium. Where it is located?
A: a) Sphenoid is called the Keystone bone of cranium.
a) It is present in the middle of base of skull and articulates with all other cranial

7. Human skull is called dicondylic skull why?
A: Due to presence of two exoccipital condyles (one on each side of foramen

8. Name the ear ossicles and their evolutionary origin in man.
A: a) Malleus - Modified articular.
b) Incus - Modified quadrate.
c) Stapes - Modified hyomandibular.
9. Name the type of joint between
a) Atlas and axis.
b) Carpal and metacarpal of human thumb.
c) Atlanto - axial joint.
d) Femur and acetabulum.
e) Cranial bones.
f) Inter tarsal joint.
A: a) Pivot joint.
b) Saddle joint.
c) Pivot joint joint.
d) Ball and socket joint.
e) Sutures.
f) Gliding joint.

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