Option (d) The grey matter in the centre of the spinal cord is shaped like a butterfly and consist of cell bodies of interneurons and motor neurones as well as neurogila cell and myelinated axon . Projection of the grey matter are called horns...

The butterfly-like structure surrounding the central human spinal cord is called the gray matter. The gray matter is an essential component of the central nervous system and plays a crucial role in transmitting and processing information.

The gray matter is composed of nerve cell bodies, dendrites, and unmyelinated axons. It gets its name from its grayish appearance, which is due to the presence of cell bodies and dendrites that lack the white fatty substance called myelin. The gray matter is located in the central regions of the spinal cord and forms an H-shaped structure.

The gray matter is divided into two regions: the dorsal (posterior) gray matter and the ventral (anterior) gray matter.

Dorsal Gray Matter:
1. Located at the back or posterior side of the spinal cord.
2. It contains interneurons, which connect sensory and motor neurons.
3. Processes sensory information from the peripheral nervous system and relays it to the brain.

Ventral Gray Matter:
1. Located at the front or anterior side of the spinal cord.
2. Contains motor neurons, which transmit signals from the brain to the muscles and organs.
3. Controls voluntary movements and reflexes.

The gray matter is further divided into different regions or nuclei, each responsible for specific functions. These nuclei include the posterior horn, anterior horn, and lateral horn.

- Posterior Horn:
1. Located in the posterior region of the gray matter.
2. Receives sensory information from the peripheral nervous system.
3. Processes and relays this information to higher brain centers.

- Anterior Horn:
1. Located in the anterior region of the gray matter.
2. Contains motor neurons that send signals to the muscles and organs.
3. Controls voluntary movements.

- Lateral Horn:
1. Located on the lateral sides of the gray matter.
2. Contains autonomic motor neurons that regulate involuntary functions such as heart rate, digestion, and respiration.

In summary, the gray matter is the butterfly-like structure surrounding the central spinal cord. It is composed of nerve cell bodies, dendrites, and unmyelinated axons. The gray matter is responsible for processing and transmitting sensory information and controlling voluntary and involuntary movements.