Answer:
Sensory neurons
Explanation:
Sensory neurons receive impulses and carry them from the sense organs to the spinal cord or brain.
The standard operating procedure or SOP is a
written safety and health measures for hazardous tasks. It is a detailed
instructions or step-by-step directions for conducting a specific procedure especially when dealing with
chemicals that may cause injury. Moreover, because of these SOP’s accident and
untoward circumstances in the workplace can be avoided.
The correct order is:
- Action potential arrives at the axon terminal.
- Calcium ions enter the axon terminal.
- Synaptic vesicles fuse to membrane of axon terminal.
- Acetylcholine is released into the synaptic cleft.
- Acetylcholine binds to its receptors on the junctional folds.
- Junctional folds become depolarized.
- Action potential is initiated on the sarcolemma.
Action potential travels through the membrane of the presynaptic cell causing the channels permeable to calcium ions to open. Ca2+ flow through the presynaptic membrane and increase the Ca concentration in the cell which will activate proteins attached to vesicles that contain a neurotransmitter (e.g. acetylcholine). Vesicles fuse with the membrane of the presynaptic cell, thereby release their contents into the synaptic cleft-space between the membranes of the pre- and postsynaptic cells. Neurotransmitter binds to its receptors on the postsynaptic membrane and its binding causes depolarization of the target cell (muscle cell).
Answer:
The light from Alpha Centauri system takes 4.37 light-years and Sirius star system takes 8.6 light-years to reach the Earth.
Explanation:
Light from millions of stars in more distant galaxies takes a long time to reach the Earth. Light travels at a speed of 300,000 kilometers per second. The time taken for light from these stars to reach the Earth is the distance to the star divided by the speed of the light. The distance traveled by light in one year is known as a light year and the distance to the stars that are farther away is expressed in light years.
The Sun is the closest star to the Earth and the sunlight takes about 8.3 minutes to reach on Earth. Apart from the Sun, the other stars closest to Sun include Alpha Centauri system and the Sirius star systems.
The Alpha Centauri system includes the stars Alpha Centauri A, Alpha Centauri B and Proxima Centauri. This system is 4.37 light-years away from the Earth. The third star, Proxima Centauri is 4.24 light-years away from the Earth i.e., the light from it takes 4.24 years to reach the Earth.
The Sirius star systems include Sirius A (Dog Star) and Sirius B. It is about 8.6 light years from Earth and so the light about 8.6 years to reach the Earth.
