Module 1

• The part of the neuron that transmits impulses away from the cell body.

  Axon
• The branchlike structure of the neuron that extends from the cell body to receive an impulse.

  Dendrite
• An organism in its early stages of development, especially before it has reached a distinctively recognizable form.

  Embryo
• An organ that produces chemical secretions released directly into the bloodstream.

  Endocrine Gland
• Also called ovum (plural: ova); the female gamete.

  Egg Cell
• A process that occurs when the sperm and egg combine to produce an embryo.

  Fertilization
• The ability or tendency of an organism to maintain internal equilibrium by regulating its processes.

  Homeostasis
• A chemical substance produced in the body that controls and regulates the activity of certain cells or organs.

  Hormone
• An electrochemical gradient moving along a neuron.

  Impulse
• The basic unit of the nervous system, also called nerve cell, that transmits messages to and from the central nervous system.

  Neuron
• The ejaculated fluid containing sperm cells and secretions from the seminal vesicle, prostate gland, and bulbourethral gland.

  Semen
• Shorter term for spermatozoon (plural: spermatozoa); the male gamete.

  Sperm
• Any factor in the environment that influences the behavior of an organism.

  Stimulus
• The space between neurons where electrochemical signals pass.

  Synapse