nervous system

• Neurons are the basic unit of the nervous system responsible for body regulation via the endocrine system
• Stimuli are internal or external changes that cause a response, which can be voluntary or involuntary
• Homeostasis is the body's ability to maintain internal equilibrium, sustained by the nervous and endocrine systems
• Neurons transmit impulses to and from different parts of the nervous system, carrying information as nerve impulses
• Nerve impulses are electrical signals that travel along nerve fibers in response to a stimulus
• Oligodendrocytes and Schwann cells are involved in myelin production, maintenance, and repair in the central and peripheral nervous systems
• Fiber tract consists of bundled nerve fibers along the spinal cord or brain
• Nerve impulses are chemical and electrical signals conducted along the neuron membrane and transmitted through synapses
• Neurotransmitters are chemical messengers facilitating information transfer across neurons
• core section of the neuron.

  ✓ contains genetic information, maintains the

  neuron's structure, and provides energy to drive

  activities

  Cell body
• shorter extensions of the cell body.

  ✓ threadlike structures that receive and carry

  information toward the cell body.

  Dendrites
• carries nerve impulses away from the cell body.

  ✓ neuron lacking a Nissl body

  Axon
• is composed

  of an axon and its myelin

  sheath.

  Nerve fiber
• are the main

  site of protein synthesis in

  the neuronal cytoplasm.

  Nissl bodies
• ✓ protects the axons and helps speed nerve

  transmissions.

  Myelin sheath
• ends of axons which transmit messages to the

  dendrites of other neurons.

  Axon terminals
• gaps between myelin sheath

  ✓ facilitate the rapid conduction of nerve impulses


  Nodes of Ranvier
• any of the cells in the peripheral

  nervous system that produce the myelin sheath.

  Schwann cells
• is the plasma

  membrane layer of the

  Schwann cells

  Neurilemma
• is the outermost layer of connective

  tissue of a peripheral nerve, surrounding the entire

  nerve and containing its supplying blood vessels

  Epineurium
• connective tissue

  forming a sheath around a

  single bundle of nerve fibers.

  Perineurium
• is the connective

  tissue layer surrounding a nerve

  fiber (neuron) including the

  neurolemma and the myelin

  sheath.

  Endoneurium
• receive initial stimuli from receptors.

  ✓ transmit impulses to the spinal cord

  or to the brain.

  Sensory neurons
• relay impulses or information from

  the sensory neurons to the motor

  neurons.

  Interneurons
• transmit impulses from the brain or

  the spinal cord to the effector cell or

  muscles or glands throughout the

  body.

  Motor neurons
• small gap at

  the end of a neuron that

  allows a signal to pass

  from one neuron to the

  next.

  Synapse
• carries signals from motor neurons

  to the body’s skeletal muscles.

  Acetylcholine
• plays an important role on how our

  body responds to stress

  Norepinephrine
• related to muscle activity

  Dopamine
• plays a key role in such body functions

  as mood regulation, consciousness, and emotions

  Serotonin
• regulates sleep and wake cycles

  Melatonin
• an automatic

  response to a change in

  the environment

  Reflex
• is a pathway that carry the nerve

  impulses for an automatic response

  Reflex arc
• does not involve the brain so you

  respond quickly

  Spinal reflex