Question

2. The trapezius muscle is a large muscle located in the posterior superior thoracic region. The actions of the trapezius are to 1. Superior: Elevate scapula, extend and laterally flex neck 2. Middle: Retract Scapula 3. Inferior: Depress Scapula a. What neuromuscular principal makes it possible for one muscle to have so many actions, including antagonist/agonist actions present in the same muscle? b. Give two neuromuscular processes by which force of contraction may be increased c. Describe a way that muscle tension is regulated

Answer 1

Answer- a og The mixed actions like agonist / Antagonist refer to a system mechanism which under some conditions behave as an ~ Agonist [substance (neurotransmitter) that fully activates the receptor on which it bind ] and some other condition behave as an can blocks the activity). Neurotransmission Mechanism involved in multiple action is u Reuptake inhibition Antagonist .. · Blocks neurotransmitters • often binds directly from re-entering the to receptor in pre - Synaptic axonasi Synaptic cleft, and blocking terminal. Nts (neurotransmitters).

Answer-b! Neuromuscular process which may increase Muscle contraction — firstly we'll see the pathway of Muscle contraction - An action potential arrives at Nit's Neuromuscular junction Ach is released, bind to receptor, - and opens sodium ion channels. Action potential generated in Sarcolemma, Action potential reaches to T- tub ile. caat increases Interaction of Thick & Thin filament CATP de pendent process) Muscle contraction occur. Muscle contraction increases by ) Increment of respective Action potential 2) cat ↑ (increment).

Answer-c Regulation of Muscle Tension Muscle Tension → Force generated by the contraction of the muscle; tension generated. contraction involved Isotonic Isometric sollici contraction or contraction na In order to contract;> Muscle fibers are inne rrated by Motor units. Motor unit Actual number of muscle fibre innervated by motor neuron). • Smaller Motor Unit - arrangement where Single motor neuron supplies a muscle fiber in muscle • Larger Motor Unit - arrangement of multiple motor neurons in motor unit These wide range of Motor units are involved in Regulation of contraction. Smaller unit Larger unit Activation results → Activation resuts Small degree of Targer degree of contractile strength contractile Strength 1 →