spinal cord

Examples of spinal cord in the following topics:

• The Central Nervous System (CNS)

  • The CNS includes the brain and spinal cord, which together comprise the body's main control center.
  • The CNS is comprised of the brain, brain stem, and spinal cord.
  • The spinal cord connects the brain and brain stem to all of the major nerves in the body.
  • Spinal nerves originate from the spinal cord and control the functions of the rest of the body.
  • This data is then sent back through the spinal cord to muscles and glands for motor output.

• Lower-Level Structures

  • The brain's lower-level structures consist of the brain stem, the spinal cord, and the cerebellum.
  • The medulla oblongata sits at the transition zone between the brain and the spinal cord.
  • It is the first region that formally belongs to the brain (rather than the spinal cord).
  • The spinal cord is a tail-like structure embedded in the vertebral canal of the spine.
  • The adult spinal cord is about 40 cm long and weighs approximately 30 g.

• Development of the Human Brain

  • The brain and the spinal cord make up the central nervous system, which alongside the peripheral nervous system is responsible for regulating all bodily functions.
  • In the embryos of vertebrates, the predecessor to the brain and spinal cord is the neural tube.
  • All sensory and motor information that travels between the forebrain and the spinal cord passes through the midbrain, making it a relay station for the central nervous system.

• Introduction to the Nervous System

  • The central nervous system includes the spinal cord and the brain.
  • The peripheral nervous system includes a large system of nerves that are linked to the brain and spinal cord.
  • The nervous system of the human body, including the brain and spinal cord (central nervous system) and all the nerves of the body (peripheral nervous system).

• Introducing the Neuron

  • They are activated by sensory input, and send projections to other elements of the nervous system, ultimately conveying sensory information to the brain or spinal cord.
  • Most sensory neurons are pseudounipolar, meaning they have an axon that branches into two extensions—one connected to dendrites that receive sensory information and another that transmits this information to the spinal cord.
  • Interneurons can save time and therefore prevent injury by sending messages to the spinal cord and back instead of all the way to the brain.

• The Peripheral Nervous System (PNS)

  • The CNS includes the brain, brain stem, and spinal cord, while the PNS includes all other sensory neurons, clusters of neurons called ganglia, and connector neurons that attach to the CNS and other neurons.
  • The human nervous system, including both the central nervous system (in red: brain, brain stem, and spinal cord) and the peripheral nervous system (in blue: all other neurons and receptors).

• Neural Networks

  • For example, motor neurons, which travel from the spinal cord to the muscle, can have axons up to a meter in length in humans.
  • In this conception, neural processing begins with stimuli that activate sensory neurons, producing signals that propagate through chains of connections in the spinal cord and brain, giving rise eventually to activation of motor neurons and thereby to muscle contraction or other overt responses.

• Stages of the Action Potential

  • Neural impulses from sensory receptors are sent to the brain and spinal cord for processing.
  • After the brain has processed the information, neural impulses are then conducted from the brain and spinal cord to muscles and glands, which is the resulting motor output.

• Stimulants

  • Stimulants increase the activity of the central nervous system (the brain and spinal cord), the sympathetic nervous system (part of the peripheral nervous system that controls the fight-or-flight response), or both.

• Prenatal Brain Development

  • During the germinal stage, the cells necessary for the placenta, umbilical cord, and amniotic fluid will differentiate to form the embryo.
  • The placenta is a structure connected to the uterus that provides nourishment and oxygen from the woman's body to the developing embryo through the umbilical cord.
  • The first part of the embryo to develop is the neural tube, which will become the spinal cord and brain.
  • During the germinal stage of prenatal development, the cells necessary for the placenta, umbilical cord, and amniotic fluid will differentiate to form the embryo.