Search results
Results From The WOW.Com Content Network
The tonsils are a set of lymphoid organs facing into the aerodigestive tract, which is known as Waldeyer's tonsillar ring and consists of the adenoid tonsil (or pharyngeal tonsil), two tubal tonsils, two palatine tonsils, and the lingual tonsils. These organs play an important role in the immune system.
The adenoids, also known as the pharyngeal tonsils, are lymphoid tissue structures located in the posterior wall of the nasopharynx. Waldeyer's tonsillar ring is an annular arrangement of lymphoid tissue in both the nasopharynx and oropharynx. The nasopharynx is lined by respiratory epithelium that is pseudostratified, columnar, and ciliated.
The lymphatic system drains the head and neck of excess interstitial fluid via lymph vessels or capillaries, equally into the right lymphatic duct and the thoracic duct. Lymph nodes line the cervical spine and neck regions as well as along the face and jaw. The tonsils also are lymphatic tissue and help mediate the ingestion of pathogens.
The tonsillar fossa (or tonsillar sinus) is a space delineated by the triangular fold (plica triangularis) of the palatoglossal and palatopharyngeal arches within the lateral wall of the oral cavity. [1] In many cases, however, this sinus is obliterated by its walls becoming adherent to the palatine tonsils.
Explanation of the levels in the human body; defines the column labels in the next table. Level Definition Organ systems: A biological system consisting of a group of organs that work together to perform one or more functions. Organ sub-systems A biological system consisting of a group of organs that work together to perform just one function.
In biology, a motor unit is made up of a motor neuron and all of the skeletal muscle fibers innervated by the neuron's axon terminals, including the neuromuscular junctions between the neuron and the fibres. [1] Groups of motor units often work together as a motor pool to coordinate the contractions of a single muscle.
The torus tubarius (or torus of the auditory tube) is an elevation of the mucous membrane of the nasal part of the pharynx formed by the underlying base of the cartilaginous portion of the Eustachian tube (auditory tube).
The pyramidal motor system, also called the pyramidal tract or the corticospinal tract, start in the motor center of the cerebral cortex. [4] There are upper and lower motor neurons in the corticospinal tract. The motor impulses originate in the giant pyramidal cells or Betz cells of the motor area; i.e., precentral gyrus of cerebral cortex ...