What is medulla?

Medulla refers to various structures in different biological contexts:

1. Medulla Oblongata: In humans and other vertebrates, the medulla oblongata is a part of the brainstem located at the base of the skull. It is responsible for controlling several essential bodily functions, including breathing, heart rate, blood pressure, and reflexes like swallowing and vomiting.

2. Bone Marrow Medulla: The bone marrow is composed of two types of tissue: red marrow and yellow marrow. The red marrow is responsible for producing blood cells, while the yellow marrow stores fat. The medulla in this context refers to the red bone marrow.

3. Medullary Ray: In botany, medullary rays are bands of parenchyma cells that extend radially from the pith to the bark of a stem or root. They help in the transport of water and nutrients between different parts of the plant.

4. Medullary Pyramid: In the adrenal gland, the medulla is the inner portion composed of chromaffin cells. These cells produce and release hormones like adrenaline and noradrenaline, which play a role in the body's response to stress.

5. Adrenal Medulla: The adrenal medulla is the central part of the adrenal gland located above the kidneys. It is responsible for producing and secreting hormones such as adrenaline (epinephrine) and noradrenaline (norepinephrine) in response to stress or danger, contributing to the body's "fight or flight" response.

6. Spinal Cord Medulla: The medulla spinalis, commonly referred to as the spinal cord, is a cylindrical bundle of nervous tissue that runs from the brainstem through the vertebral column. It serves as a communication pathway between the brain and the rest of the body, transmitting nerve signals and controlling various reflexes.