muscularis mucosae

(noun)

Also called the lamina muscularis mucosae, this is the thin layer of smooth muscle found in most parts of the gastrointestinal tract. It is located outside the lamina propria mucosae and separates it from the submucosa.

Related Terms

Examples of muscularis mucosae in the following topics:

  • Muscularis

    • From the inside out they are called the mucosa, submucosa, muscularis externa, and serosa.
    • It should not be confused with a thin layer of muscle known as the muscularis mucosa, which lies within the submucosa, a layer of tissue adjacent to the muscularis externa.
    • The muscularis mucosa is made up of smooth muscle, and is most prominent in the stomach.
    • The thickness of muscularis externa varies in each part of the tract.
    • The muscularis mucosa is adjacent to the submucosa, and should not be confused with the muscularis externa.

  • Submucosa

    • From the inside out they are called: mucosa, submucosa, muscularis, and serosa .
    • The submucosa lies under the mucosa and consists of fibrous connective tissue, separating the mucosa from the next layer, the muscularis externa.
    • The submucosa consists of a dense irregular layer of connective tissue with large blood vessels, lymphatics, and nerves branching into the mucosa and muscularis externa.
    • It contains Meissner's plexus, an enteric nervous plexus, situated on the inner surface of the muscularis externa.
    • Tiny parasympathetic ganglia are scattered around forming the submucosal plexus (or "Meissner's plexus") where preganglionic parasympathetic neurons synapse with postganglionic nerve fibers that supply the muscularis mucosae.

  • Mucosa

    • From the inside out they are called: mucosa, submucosa, muscularis, and serosa.
    • The mucosa is the innermost layer, and functions in absorption and secretion.
    • The muscularis mucosae is a thin layer of smooth muscle and its function is still under debate.
    • The mucosae (singular: mucosa) are highly specialized in each organ of the gastrointestinal tract in order to deal with different digestive tract conditions.
    • Describe the structure and function of the mucosa of the GI tract

  • Microscopic Anatomy of the Stomach

    • From the inside to the outside, the first main layer is the mucosa.
    • This consists of an epithelium, the lamina propria underneath, and a thin bit of smooth muscle called the muscularis mucosae.
    • The submucosa lies under this and consists of fibrous connective tissue that separate the mucosa from the next layer, the muscularis externa.
    • The muscularis in the stomach differs from that of other GI organs in that it has three layers of muscle instead of two.
    • The muscularis externa is made up of three layers of smooth muscle.

  • Histology of the Small Intestine

    • The small intestine wall has four layers: the outermost serosa, muscularis, submucosa, and innermost mucosa.
    • Serous fluid is a lubricating fluid that reduces friction from the movement of the muscularis.
    • The muscularis is a region of muscle adjacent to the submucosa membrane.
    • The intestinal villi are part of the mucosa.
    • This image shows the layers of the duodenum: the serosa, muscularis, submucosa, and mucosa.

  • Anatomy of the Gallbladder

    • There are several different layers of the gallbladder: the mucosa (epithelium and lamina propria), the muscularis, the perimuscular, and the serosa.
    • The lamina propria is a thin layer of loose connective tissue, which together with the epithelium, forms the mucosa.
    • The muscularis is a layer of smooth muscular tissue that helps the gallbladder contract and squirt its bile into the bile duct.
    • The perimuscular (meaning around the muscle) is a fibrous connective tissue layer that surrounds the muscularis.

  • Histology of the Large Intestine

    • The longitudinal layer of the muscularis is reduced to three strap-like structures known as the taeniae coli—bands of longitudinal muscle fibers, each about 1/5 in wide.
    • The enterocytes in the mucosa contain digestive enzymes that digest specific food while they are being absorbed through the epithelium.

  • Anatomy of the Large Intestine

    • The large intestine is much wider, and the longitudinal layers of the muscularis are reduced to three, strap-like structures known as the taeniae coli.
    • It contains the least lymphoid tissue, and it is a part of mucosa-associated lymphoid tissue, which gives it an important role in immunity.

  • Enteric Nervous System

    • The myenteric (Auerbach's) plexus, located between the inner and outer layers of the muscularis externa.
    • The mucosa and epithelial tissue associated with the submucosal plexus have sensory nerve endings that feed signals to both layers of the enteric plexus.

  • Skin and Mucosae (Surface Barriers)

    • In mammals, the skin and mucosae constitute complex protective barriers that guard against infection and injury.
    • In humans, the outer covering of the body consists of the skin and mucosae, which together make up the barrier immune system.
    • The mucous membranes (or mucosae; singular mucosa) are linings of mostly endodermal origin, covered in various types of epithelium, that are involved in absorption and secretion.
    • The mucosae are highly specialized in each organ to deal with different conditions.
    • Describe how the skin and mucosae serve as a protective barrier which guards against infection and injury