Mhine

* The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body
  * The nervous system has 2 subsystems: The central and peripheral nervous system.
  * The central nervous system of vertebrates contains the brain, spinal cord, and retina.
  * The peripheral nervous system consists of sensory neurons, clusters of neurons called ganglia, and nerves connecting them to each other and to the central nervous system.
  * Neurons send signals to other cells as electrochemical waves travelling along thin fibers called axons, which cause chemicals called neurotransmitters to be released at junctions called synapses.
  * Sensory neurons are activated by physical stimuli impinging on them, and send signals that inform the central nervous system of the state of the body and the external environment.
  * Motor neurons, situated either in the central nervous system or in peripheral ganglia, connect the nervous system to muscles or other effector organs.
  * Central neurons, which in vertebrates greatly outnumber the other types, make all of their input and output connections with other neurons.
  * Along with neurons, the nervous system contains other specialized cells called glial cells (or simply glia), which provide structural and metabolic support.
 
  * The brain is made of three main parts: the forebrain, midbrain, and hindbrain.

  * The forebrain consists of the cerebrum, thalamus, and hypothalamus (part of the limbic system).

  * The midbrain consists of the tectum and tegmentum.

  * The hindbrain is made of the cerebellum, pons and medulla. Often the midbrain, pons, and medulla are referred to together as the brainstem.
  * The cerebrum or cortex is the largest part of the human brain, associated with higher brain function such as thought and action.
  * The cerebral cortex is divided into four...