Every cell in the body goes through a life cycle. Cells grow and divide to replace cells that are lost because of normal wear and tear or injury. Different cells grow and die at different rates. Some cells, such as epithelial<span>epithelialA thin layer of epithelial cells that makes up the outer surfaces of the body (the skin) and lines hollow organs, glands and all passages of the respiratory, digestive, reproductive and urinary systems.</span> cells, reproduce quickly. Other cells, like nerve cells, grow slowly. Both normal cells and cancer cells go through a sequence of steps, or phases, when they form new cells. This is called the cell cycle.
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Water<span> issuing from a </span>hot spring<span> is heated geothermally, that is, with heat produced from the Earth's mantle. ... The rate of temperature increase with depth is known as the geothermal gradient. If </span>water<span> percolates deeply enough into the crust, it will be heated as it comes into contact with </span>hot<span> rocks.</span>
Answer:
Pupillary light reflex refers to the contraction that the pupils present when they light up. In cases of injury to the optic nerve, when the eye where the injured optic nerve is illuminated, since it cannot conduct the stimulus to the brain, neither pupil closes.
Explanation:
Pupillary light reflex refers to the reaction that causes the pupil to close with light thanks to the contraction of the sphincter of the pupil and to open in the dark thanks to the relaxation of that muscle by not receiving any stimulus. A light stimulus reaches the eye and in the retina it is transformed, through a chemical reaction, into an electrical stimulus that will be transmitted through the optic nerve and the visual pathways to the brain. The visual cells of the retina, rods and cones, also act as light receptors that control the pupil's motor activity. Thus, pupil-motor thresholds to light follow the same spectral sensitivity deviations as visual thresholds, which are a function of the state of light adaptation of the retina.
Bacterial cells pick up free pieces of DNA from the medium-pieces that were released from dead bacteria-in a process called<span>. transformation.</span>
