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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:
https://brainly.in/question/123107
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Be found along with the diatoms and Radiolarla, in the uppermost
Answer:
b. They are produced by memory B cells
Explanation:
The rapid cell division in activated B cells is followed by the differentiation of daughter cells into the plasma cells. The plasma cells are the precursor for antibodies and memory B cells. The antibodies kill the antigens while memory B cells are long-lived cells.
Hence, antibodies are not produced by memory B cells but by plasma cells.
