Which of these represents the majority of muscle mass for women as well as men?

Question

Which of these represents the majority of muscle mass for women as well as men? Smooth muscle Skeletal muscle Cardiac muscle because it consists of both smooth and skeletal muscle What is the end result of the AP after is reaches the synaptic knob? Stimulates channel opening on the post-synaptic membrane Stimulates channel opening on the cell body Stimulates channel opening on the pre-synaptic membrane Which one of these represents the functional unit of skeletal muscle? Sarcomere Thin Thin filaments Thin filaments consist of how many different proteins? 3 2 1 During muscle contraction, where does the first AP terminate? Synaptic knob Synaptic cleft Post synaptic knob During muscle contraction, where does the second AP originate? Synaptic knob Within the muscle tissue Synaptic cleft True or false: A neurotransmitter (Acetylcholine) binds to receptors within the muscle tissue and generates AP that travel to the T-tubule. True False True or false: Rigor mortis s a result of an over abundance of ATP production. True False True or False: When a neuron is activated, all the muscle cells it supplies are stimulated to contract. True False Which of theses describes a delay in order to prevent muscle fatigue -the body alternates motor-unit activity. Asynchronous contraction Desynchronous contraction Motor end plate contraction

Explanation / Answer

1. b.Skeletal muscle ( reason : in human body skletal muscle makes around 70% of the total muscle composition)

3. a.Sarcomere (reason : A sarcomere is a reapting unitof myofribril composed of an array of overlapping thick and thin filament in between two adjacent z disc is the basic unit of striated muscular tissue.)

4. a. 3 (reason :Myofilaments makes up the myofibril, and are made up of three proteins: actin, troponin, and tropomyosin.)

5. b. (reason : The action potential of a neurone travels down a nerve cell, causing it to release the neurotransmitter into a small gap between the nerve cell and muscle cell junction or synapse called synaptic cleft)

6. b. (reason : An action potentia travels down a nerve cell, causing it to release neurotransmitter into a synaptic cleft between the nerve cell and muscle cell junction or synapse. The neurotransmitter crosses the synaptic cleft and binds toreceptor protein on the muscle-cell membrane and causes an action potential in the muscle cell)

7. a. True (reason : An action potentia travels down a nerve cell, causing it to release neurotransmitter into a synaptic cleft between the nerve cell and muscle cell junction or synapse. The neurotransmitter crosses the synaptic cleft and binds toreceptor protein on the muscle-cell membrane and causes an action potential in the muscle cell which rapidly spreads along the muscle cell and enters the cell through the T-tubule.)

8. b. False (reason :

Rigor mortis is the phenomena of the stiffening of muscles of the body several hours after death.

In the resting state, these cells build up the electric potential across their membrane by actively pumping out calcium ions. An action potentia travels down a nerve cell, causing it to release neurotransmitter into a synaptic cleft between the nerve cell and muscle cell junction or synapse. The neurotransmitter crosses the synaptic cleft and binds toreceptor protein on the muscle-cell membrane and causes an action potential in the muscle cell which rapidly spreads along the muscle cell and enters the cell through the T-tubule. The action potential opens gates in sarcoplasmic reticulum (of the muscle which store calcium) and Calcium ions flow into the cytoplasm, which is where the actin and myosin filaments are present.Calcium ions bind to troponin-tropomyosin molecules located in the grooves of the actin filaments. Generally tropomyosin covers the sites on actin where myosin can form crossbridges.Upon binding to Ca ions, troponin changes its shape to slide tropomyosin out of the groove and expose the actin-myosin binding sites. Myosin interacts with actin by cycling crossbridges. The muscle thusmakes force, shortens and contracts.

The muscles remain in the contracted state until ATP binds to myosin to release the myosin - actin filament conjugate. After death as breathing and circulation ceases muscle cells is deprived of oxygen thus cannot respire aerobically to efficiently produce ATP. Respiration continues anaerobically at first, but the muscle cells eventually become very low on ATP and the myosin and actin filaments cannot release from the contracted state, so calcium ions are not pumped out of the muscle cell, causing the muscles to remain contrated.)

9. a. True (reason : An action potentia travels down a nerve cell, causing it to release neurotransmitter into a synaptic cleft between the nerve cell and muscle cell junction or synapse. The neurotransmitter crosses the synaptic cleft and binds toreceptor protein on the muscle-cell membrane and causes an action potential in the muscle cell which rapidly spreads along the muscle cell and enters the cell through the T-tubule. The action potential opens gates in sarcoplasmic reticulum (of the muscle which store calcium) and Calcium ions flow into the cytoplasm, which is where the actin and myosin filaments are present.Calcium ions bind to troponin-tropomyosin molecules located in the grooves of the actin filaments. Generally tropomyosin covers the sites on actin where myosin can form crossbridges.Upon binding to Ca ions, troponin changes its shape to slide tropomyosin out of the groove and expose the actin-myosin binding sites. Myosin interacts with actin by cycling crossbridges. The muscle thusmakes force, shortens and contracts.)

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