Dictionary > Urination


The process of voiding urine from the body to the outside
Urination is the process whereby urine is released from the body to the outside. In humans and other animals, the urinary system is responsible for the production of urine and its eventual excretion. The urinary system is comprised of kidneys, ureters, urinary bladder, and urethra. The initial process of urine production is filtration. The by-products and other compounds are filtered out. This is then followed by reabsorption wherein the nephron removes water and solutes from the pre-urine and then returns them to the circulating blood. From the kidneys, the urine passes through the ureter and stored in the urinary bladder. When it has to be excreted from the body, the urine passes through the urethra to the outside of the body. Thus, urination involves the urinary bladder and the urethra. Urination is typically a voluntary control. However, certain conditions, e.g. old age and neurological injury, make the process more of a reflex than voluntary. The inability to hold urine is called urinary incontinence whereas the inability to initiate urination is referred to as urinary retention.
Apart from the purpose of excreting metabolic wastes, urination is also used by certain animals to mark territories.

  • micturition
  • voiding
  • uresis

See also:

  • urine
  • kidney
  • Related form(s):

    • urinate (verb, to pass urine; micturate)

    You will also like...

    green plant cells
    Plant Cells vs. Animal Cells

    Plant cells have plastids essential in photosynthesis. They also have an additional layer called cell wall on their cell..

    human brain structure
    The Conscious & Unconscious Nervous System

    This tutorial elaborates on how the nervous system works, particularly at the tissue level of the brain. There are three..

    running freshwater community
    Running Water Freshwater Community Factors

    This tutorial noted some of the physical and chemical factors that provide the framework of a running water community in..

    Principles of Hormonal Control Systems
    Principles of Hormonal Control Systems

    Hormones are essential in the regulation of the activity of the various biological systems of the human body. The ineffi..

    Protein (illustration)
    Protein Variety

    The sequence of amino acids determines the type of protein. Protein is synthesized according to the sequence of nucleoti..

    An artist depiction of a Precambrian multicellular life form.
    The Evolution of Cell Organelles

    The nucleus containing the genetic material, DNA, and the mitochondria, well-identified as the "powerhouse of the cell",..