Simplified schema of basic nervous system function: signals are picked up by sensory receptors and sent to the spinal cord and brain, where processing occurs that results in signals sent back to the spinal cord and then out to motor neurons.

Major Parts of the System

The 3 major parts of the nervous system

1) Brain
2) Spinal Cord
3) Nerves
- Cranial Nerves
- Spinal Nerves

Reflex Arc

  • Receptor - A receptor is specialized cell or group of nerve endings or a specialized organ which responds to sensory stimuli .They receive the stimulus from the surrounding
  • Sensory neuron or afferent neuron - A neuron, whose cell body generally is found in a peripheral ganglion such as a dorsal root ganglion, which conducts impulses representing information about an (external or internal) environmental change inwards to the brain or spinal cord.
  • Control center - Those cells on the central nervous system, which receive sensory information from the environment, process that information, and, if appropriate, generate motor commands to effectors’ organs in response to the stimulus from the environment.
  • Inter-neuron - A nerve cell found entirely within the central nervous system that acts as a link between sensory neurons and motor neurons or between other internal linking neurons and integrating or communicating or transmitting information between different parts of the CNS.
  • Motor neuron - A neuron that conveys impulses outward from the central nervous system to a muscle, gland, or other effector tissue that regulates the activity of the effector.
  • Effector - A muscle, gland, or other organ capable of responding to a stimulus which has been evaluated by a control center, mediated by a nerve impulse or a hormonal signal.

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Alzheimer's Disease: A progressive disease that destroys memory and other important mental functions.Symptoms: mental decline, difficulty thinking and understanding, mental confusion, disorientation, delusion, inability to create new memories, inability to recognize common things, inability to do simple math, difficulty concentrating, making things up, confusion in the evening hours, or forgetfulness. Treatments Donepezil (Aricept), Galantamine (Razadyne), Memantine (Namenda), Rivastigmine through the skin or by mouth (Exelon)