Tag: zoology

The spinal cord begins at the occipital bone and extends down to space between the first and second lumbar vertebrae. The terminal portion of the spinal cord is called the conus medularis. It is tapperd and located near the lumbar vertebrae.

A unipolar neuron is a type of neuron in which only one protoplasmic process (neurite) extends from the cell body. A pseudounipolar neuron is a kind of sensory neuron in the peripheral nervous system. This neuron contains an axon, that has split into two branches; one branch runs to the periphery and the other to the spinal cord.

The spinal cord is a thick cord of the nervous tissue that forms the central nervous system along with the brain. It extends from the brain down through the spine and is protected within the bony vertebral column which is made of bones called the vertebrae. It ends at the second lumbar vertebrae. It is divided into the regions according to the vertebral column as cervical, thoracic and lumbar. The bunch of nerve fibres at the end of the spinal cord is called the cauda equina. It forms a horse tail-like structure. The nerves from this region supply to the pelvic region and lower limbs.

The cavity or system of cavities in the interior of the vertebrate central nervous system comprising the central canal of the spinal cord and the ventricles of the brain is called as neurocoel. 

A dorsal root ganglion (or spinal ganglion) (also known as a posterior root ganglion), is a cluster of nerve cell bodies (a ganglion) in a posterior root of a spinal nerve.
The cell bodies of peripheral neurons are often found grouped into clusters called ganglia. On the basis of the type of nerve cell bodies found in ganglia, they may be classified as either sensory or motor. Sensory ganglia are oval swellings located on the dorsal roots of spinal nerves and on the roots of certain cranial nerves.

The fourth ventricle present between the brainstem and the cerebellum is called the metacoel. It continues to the spinal cord in the form of the central canal to form the cavity of the spinal cord filled with the cerebrospinal fluid. The central canal is also called the neurocoel.

Oxygen is very important for the microorganism to break down and degrade the organic matter which is present in the sewage or the activated sludge. If the oxygen availability of the activated sludge floc is reduced then the degradation rate will slow down.