The second question has the answer of A
Answer:
1. Acetylcholine binds to receptors on the motor end plate
2. Ligand-gated channels open leading to depolarization
3. End plate potential triggers an action potential
4. Transverse tubules convey action potentials into the interior of the muscle fiber
5. Calcium is released from the sarcoplasmic reticulum
6. Calcium ions bind to troponin, which then moves tropomyosin
Explanation:
Acetylcholine (ACh) is a signaling molecule (neurotransmitter) that binds to receptors on muscle cells. This binding triggers the opening of ligand-gated sodium channels, thereby ions enter into muscle cells, which causes the depolarization of the sarcolemma and thus promotes the release of Ca2+ ions from the sarcoplasmic reticulum. The myoneural junction, also known as the motor endplate, is the site of synaptic contact between a motor axon and a skeletal muscle fiber. The endplate potential is the voltage that produces the depolarization of muscle fibers when ACh molecules bind to their receptors in the cell membrane. This depolarization spreads in the sarcolemma through transverse tubules (T tubules) and thus generates an action potential. Finally, this action potential induces the release of Ca2+ in the sarcoplasmic reticulum, which activates troponin protein and induces muscle contraction.
Injury to cervical vertebra c 3-c 4 is particularly problematic because C) the phrenic nerve that serves the diaphragm receives its fibers from here.
- The top portion of the spinal cord, which is made up of the seven cervical vertebrae (C-1 to C-7) in the neck, is located in the cervical region of the spine.
- Cervical spinal cord injuries are often the most serious kind of spinal cord injury because they affect a bigger area of the body and are closer to the brain.
- Tetraplegia or quadriplegia, which means there is little to no feeling or movement below the shoulders or neck, will develop from a cervical injury.
- The cervical spine's middle segment is made up of the C3, C4, and C5 vertebrae. Injuries to the cervical vertebrae C3–C5 are frequently severe because they inflict more harm to the central nervous system.
learn more about cervical vertebra here: brainly.com/question/20840479
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The air that we breathe is mostly made up of nitrogen (78%). 21% is oxygen which is needed for animals and humans in respiration and 0.03% is carbon dioxide which is needed for plants to make energy in a process called photosynthesis. The bit that is left is made up of rare gases like helium and argon and methane.
