Option A. Increases and decreases of the heart rate result from changes in the activity of the <u>medulla oblongata</u>
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What is medulla oblongata ?
- Medulla oblongata, also called medulla, the lowest part of the brain and the lowest portion of the brainstem.
- The medulla oblongata is connected by the pons to the midbrain and is continuous posteriorly with the spinal cord, with which it merges at the opening (foramen magnum) at the base of the skull.
- The medulla oblongata plays a critical role in transmitting signals between the spinal cord and the higher parts of the brain and in controlling autonomic activities, such as heartbeat and respiration
- The medulla is divided into two main parts: the ventral medulla (the frontal portion) and the dorsal medulla (the rear portion; also known as the tegmentum).
- The ventral medulla contains a pair of triangular structures called pyramids, within which lie the pyramidal tracts.
- The pyramidal tracts are made up of the corticospinal tract (running from the cerebral cortex to the spinal cord) and the corticobulbar tract (running from the motor cortex of the frontal lobe to the cranial nerves in the brainstem)
To know more about medulla oblongata, refer:
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Answer: synthesize a pre-rRNA 45S (35S in yeast), which matures and will form the major RNA sections of the ribosome. RNA polymerase II synthesizes precursors of mRNAs and most snRNA and microRNAs. RNA polymerase III synthesizes tRNAs, rRNA 5S and other small RNAs found in the nucleus and cytosol.
Explanation:
If your car is changing speed by accelerating or decelerating, or changing directions by turning or hitting a bump, your body can sense these accelerations. You might be pressed against the back of your seat while speeding up or against the car door as you turn for example. If you are cruising at a constant speed, with no changes in speed or direction, you wouldn't be able to feel it. You would need to use your other senses. You could see the scenery going by through the windows, with closer objects moving by more quickly than objects in the distance. You could also hear sounds like the wind rushing by and the hum of the tires rolling on the highway.
