How the Vertebrate Nervous System is Organized

Many neurons play a role in the reflex. In order to simplify the diagram, only a few neurons are shown. Step 1: An artificial reflex is generated by tapping the tendon which is connected to the quadriceps muscle. Step 2: The sudden stretch in the quadriceps is detected by the sensors. Step 3: Sensory neurons then carry the message to the spinal cord. Step 4: Incited to action by the signals coming in from the sensory neurons, the motor neurons carry the signals to the quadriceps. As a result the quadriceps contract, extending the leg forward. Step 5: The sensory neurons communicate with interneurons in the spinal cord. Step 6: Inhibition of the motor neurons that lead to the hamstring muscle by the interneurons prevents the hamstring from contracting (hamstring offers resistance to the action of the quadriceps).

 

The spinal cord, enclosed inside the spinal column and running down the entire length of the back, carries signals back and forth from the brain to all the parts of the body. It is also involved in the regulation of our limbs and movement.

 

One function the spinal cord acts upon independently, without any input from the brain, is the regulation of the body's instinctive response to particular stimuli, a process known as réflex  action (reflexes).

The spinal cord is positioned dorsally and its neural network is arranged in a compartmental manner; they are within the spinal cord, and the spinal nerves and ganglia are on the outside of the spinal cord.

The functions of the cerebrospinal fluid are to nourish the brain, carry a supply of hormones to the brain, and carry waste away from the brain and drain it into the veins. It offers support, lubrication and protection for the connective tissues surrounding the brain and spinal cord of mammals.

Along with the cerebrospinal fluid, the brain is made of gray and white matter.

The gray matter is made of tightly packed dendrites, neurons and axons that are not insulated with myelin sheathing. On the other hand, the white matter comprises myelinated axons, which give it its white appearance.

cerebrospinal fluid

Abbreviated CSF. A clear bodily fluid in the form of a very pure saline solution with microglia that occupies the subarachnoid space in the brain (between the skull and the cerebral cortex), and which acts as a cushion or buffer for the cortex.

The central canal is the cerebrospinal fluid-filled space that runs longitudinally through the length of the entire spinal cord.

A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. Some people use the term "reflex" to mean a behavior that is mediated via the reflex arc; this does not apply to casual uses of the term 'reflex'.