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Locomotion and Movement (Human Physiology) - long answer expected questions for NEET-UG, AIPMT, MBBS entrance exams


Human Physiology - Locomotion and Movement

(NEET Syllabus): Origin Types of movement- ciliary, fiagellar, muscular; Skeletal muscle- contractile proteins and muscle contraction; Skeletal system and its functions (To be dealt with the relevant practical of Practical syllabus); Joints; Disorders of muscular and skeletal system-Myasthenia gravis, Tetany, Muscular dystrophy, Arthritis, Osteoporosis, Gout.
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Spinal Cord
Theoretical Questions - TQ 2 (Q. No.9 - 11)

Long Answer Type Questions

Question.9: Describe structure of actin and myosin proteins.
Question.10: Distinguish between
(a) Pronator and Supinator
(b) Abductor and Adductor
Question.11: Explain the Bones of Rib Cage.
Actin Proteins: Each actin filament is made up of the following components -
(a) F-actin: In each actin filament, two "F" (filamentous) actions helically wound to each other. Each "F" actin is a polymer of monomeric "G" (Globular) actins.
(b) Tropomyosin: Two filaments of another protein, tropomyosin also run close to the "F" actins throughout its length.
(c) Troponin: It is a complex protein which is distributed at regular intervals on the tropomyosin. In the resting state a subunit of troponin masks the active binding sites for myosin on the actin filaments.
Myosin: Each myosin (thick) filament is also a polymerised protein. Many monomeric proteins called Meromyosins constitute one thick filament. Each meromyosin has two important parts, a globular head with a short arm and a tail, the former being called the heavy meromyosin (HMM) and the latter, the light meromyosin (LMM). The HMM component, i.e.; the head and short arm projects outwards at regular distance and angle from each other from the surface of a polymerised myosin filament and is known as cross arm. The globular head is active ATPase enzyme and has binding sites for ATP and active sites for actin.

(a) Pronator and Supinator: The contraction of a pronator rotates the forearm to turn the palm downward or backward. Supinator is antagonist of pronator. A supinator contracts to rotate the forearm and thus to make palm face upward or forward.
(b) Abductor and Adductor: An abductor contracts to draw a bone away from the body midline. Muscle that brings the limb away from midline is called abductor. An adductor draws a bone towards the body midline. A muscle that brings the limb towards midline is called adductor. Abductor muscle is antagonist of adductor muscle.

Answer.11: There are 12 pairs of ribs. Each rib is a thin flat bone connected dorsally to the vertebral column and ventrally to the sternum. It has two articulation surfaces on its dorsal end and its hence, called bicephalic.
First seven pairs of ribs are called true ribs. Dorsally, they are attached to the thoracic vertebrae and ventrally connected to the sternum with the help of hyaline cartilage. The 8th,
9th and 10th pairs of ribs do not articulate directly with the sternum but join the seventh rib with the help of hyaline cartilage. These are called vertebral - chondral (false) ribs.

Last 2 pairs (11th and 12th) of ribs are not connected ventrally and are therefore, called floating ribs. Thoracic vertebrae, ribs and sternum together form the rib cage or thoracic cage.

 Human Physiology: Locomotion and Movement - Biology Objective Questions 

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