Difference Between CNS and PNS | Difference Between | CNS vs PNS
The nervous system has two different major parts. PNS contains the nerves, which leave the brain and the spinal cord and travel to certain areas of the body. Here are some key similarities and differences when comparing the CNS The sympathetic nervous system (part of the autonomic nervous system) and the. Scientists categorize the nervous system into two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord, while the PNS includes all other nervous system tissue. All sensory receptors, sensory neurons and.
Let's break the central nervous system and the peripheral nervous system into more parts. Central Nervous System The central nervous system is divided into two parts: The average adult human brain weighs 1. The brain contains about 86 billion nerve cells neurons and trillions of "support cells" called glia. The spinal cord is about 43 cm long in adult women and 45 cm long in adult men and weighs about grams. The vertebral column, the collection of bones back bone that houses the spinal cord, is about 70 cm long.
Therefore, the spinal cord is much shorter than the vertebral column.
THE CNS AND PNS: THE MAIN DIVISIONS OF THE NERVOUS SYSTEM
For brain weights of other animals, see brain facts and figures. A stegosaurus dinosaur weighed approximately 1, kg but had a brain that weighed only approximately 70 grams 0.
Therefore, the brain was only 0. In contrast, an adult human weighs approximately 70 kg and has a brain that weighs approximately 1. This makes the brain to body ratio of the human times greater than that of the stegosaurus.
Peripheral Nervous System The peripheral nervous system is divided into two major parts: Somatic Nervous System The somatic nervous system consists of peripheral nerve fibers that send sensory information to the central nervous system AND motor nerve fibers that project to skeletal muscle.
The picture on the left shows the somatic motor system. The cell body is located in either the brain or spinal cord and projects directly to a skeletal muscle.
Firstly the environment in the spinal cord is different from that in the extremities. Secondly the tissues differ in their genetic reaction.
To understand the aftermath of different environments, you need to know what they are composed of. The devil is in the details Together the spinal cord and the brain form the central nervous system CNS. It is connected to the peripheral nervous system PNS which includes the nerves in our extremities.
Difference Between CNS and PNS
But, there are big differences between the two. And, there are more cell types in the nervous system than just neurons.
Without glia, growing neuronal processes rarely find their target. And, if they do, they will fail to form a functioning contact synapse.
The difference between centre and periphery
The glue is the true The differences in healing abilities of CNS and PNS injuries become clearer when we focus on the regional differences, which, to a large extent, depend on glial cells. In the CNS there are three main types of glial cells: But in the PNS, there are neither astrocytes nor microglia and so-called Schwann cells do the isolation.
What does that mean for an injured neuron?Types of Nervous system(CNS,.PNS,ANS)Explained
The basic problem An injury to nervous tissue always leads to the same basic problem. A given signal originating from the cell body can't reach its destination any more: If the process of a neuron is severed, the part without the cell body will degrade.
Neuroscience For Kids - Explore the nervous system
If the process of a neuron is not severed but loses its insolation because oligodendrocytes in the CNS or Schwann cells in the PNS are damaged and die then the signal will stop and attempts to regenerate the isolation sheet will start.
The situation in the PNS Sending out new processes and re-establishing the right contacts works relatively well in the PNS, for example after a deep cut into or through a finger. This is because regenerating neurons receive considerable support.
Scavenger cells from the immune system hurry to remove the debris of the old isolation material, while they excrete molecules, which encourage Schwann cells to participate.
The latter rejuvenate to a state without isolation abilities, but are capable of secreting so-called growth factors. These have the same effect on a newly built neuronal processes as fertilizer to a plant.
Now the regenerating neuron is building new processes, extending along the old path towards their old contact sites and able to re-establish these contacts. After that, the scavenger cells change back into the resting state, stopping further growth. The Schwann cells will build a new isolation sheet on the processes that were not cut, but that lost their isolation sheet, but will also do so on the newly formed processes.