mucus

(noun)

A slippery secretion from the lining of the mucous membranes.

Related Terms

Examples of mucus in the following topics:

  • Epithelial Membranes

    • These mucus membranes are involved in absorption and secretion.  
    • The term "mucous membrane" refers to where they are found in the body; not every mucous membrane secretes mucus.
    • Submucosal glands consist of exocrine glands that secrete mucus.
    • These glands excrete mucus to facilitate the movement of particles along the body's various tubes, such as the throat and intestines.
    • The submucosal glands are a companion to unicellular goblet cells, which also produce mucus, and are found lining the same tubes.

  • Mammalian Systems and Protective Mechanisms

    • The trachea is lined with mucus-producing goblet cells and ciliated epithelia that propel foreign particles trapped in the mucus toward the pharynx.
    • The forced exhalation helps expel mucus when we cough.
    • The lungs produce mucus that traps particulates.
    • The bronchi and bronchioles contain cilia that help move mucus and other particles out of the lungs.
    • Mucus glands secrete mucus into the airways, keeping them moist and flexible.

  • Physical and Chemical Barriers

    • These include tears in the eyes; mucous membranes that provide partial protection despite having to allow absorption and secretion; mucus secretions that trap and rinse away pathogens; and cilia (singular cilium) in the nasal passages and respiratory tract that push the mucus with the pathogens out of the body .
    • Furthermore, tears and mucus secretions contain microbicidal factors that prevent many infections from entering via these routes.
    • Despite these barriers, pathogens may enter the body through skin abrasions or punctures, or by collecting on mucosal surfaces in large numbers that overcome the mucus or cilia.

  • Trachea

    • It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus.
    • This mucus and cilia of the trachea form the mucociliary escalator, which lines the cells of the trachea with mucus to trap inhaled foreign particles.
    • A cross section of the trachea, showing the hyaline cartilage, mucus glands, and ciliated epithelium.

  • Hormonal Methods

    • Progesterone only contraceptives can also prevent ovulation, but rely significantly on secondary mechanisms such as the thickening of cervical mucus.
    • A secondary mechanism of action of all progesterone containing contraceptives is inhibition of sperm penetration through the cervix into the upper genital tract (uterus and fallopian tubes) by decreasing the amount of and increasing the viscosity of the cervical mucus.
    • These contraceptives inconsistently inhibit ovulation in approximately 50% of cycles and rely mainly on their progestogenic effect of thickening the cervical mucus, thereby reducing sperm viability and penetration.
    • The same cervical mucus changes occur as with low dose progesterone.
    • The same cervical mucus changes occur as with very low dose and intermediate dose progesterone.

  • Squid-Aliivibrio Symbiosis

    • To do this, the squid secretes a special mucus whenever its cells detect peptidoglycan (which is found in the cell walls of bacteria).
    • The mucus collects near the opening of the light organ which traps passing bacteria.
    • For instance, A. fischeri is able to survive in the mucus better than other species.

  • Nose and Paranasal Sinuses

    • The macroscopic nasal hairs prevent large particles from reaching the lungs, while the cilia and mucus trap pathogens and dust to take them to the pharynx, where they can be destroyed by digestion. 
    • Sneezing occurs from irritation of the nasal mucus, which expels foreign particles, but can also spread microbial and viral infections between humans.
    • The most important function is the sinuses' role in draining mucus from the nasal cavity to the nasopharynx, which helps regulate pressure inside the nasal cavity.

  • Microscopic Anatomy of the Stomach

    • The layers of the stomach produce mucus to protect itself, enyzmes to break down the food for digestion, and muscles to churn the food.
    • Near the top of the pits, closest to the contents of the stomach, there are mucus-producing cells called goblet cells that help protect the stomach from self-digestion.

  • Mucosa

    • The mucosa contains specialized goblet cells that secrete sticky mucus throughout the GI tract.
    • Food, mucus, and digestive juices pass through the lumen, and the mucosa comes in direct contact with digested food (chyme).

  • Cystic Fibrosis

    • This protein is required to regulate the components of sweat, digestive juices, and mucus.
    • The hallmark symptoms of cystic fibrosis are salty tasting skin, poor growth and poor weight gain despite a normal food intake, accumulation of thick, sticky mucus, frequent chest infections and coughing or shortness of breath.
    • Lung disease develops in CF as a result of clogging of the airways due to mucus build-up, decreased mucociliary clearance, and resulting inflammation.
    • Many of these symptoms occur when bacteria that normally inhabit the thick mucus grow out of control and cause pneumonia.