The lymphatic pharyngeal ring is also known as Waldeyer’s pharyngeal ring. It extends in the area of the mouth, pharynx, and nasal cavity and is part of the lymphatic system.
What is the lymphatic pharyngeal ring?
The lymphatic pharyngeal ring is a collection of so-called lymphoepithelial tissue in the nasopharynx. Lymphoepithelial organs, unlike lymphoreticular organs, have epithelium. In addition to the Waldeyer pharyngeal ring, the thymus is also one of the lymphoepithelial tissues. Basically, the term ring is not to be taken literally, since strictly speaking it is not a ring, but various tissue islands localized in the oral cavity, nose and pharynx. These tissue islands are also called tonsils or, in medical terminology, tonsils. The main purpose of the lymphatic pharyngeal ring is to defend against bacteria, viruses and fungi that enter the body through the oral and nasal cavities. The lymphatic pharyngeal ring was first described by the German anatomist and physician Heinrich Wilhelm Waldeyer and later titled Waldeyer’s pharyngeal ring in his honor.
Anatomy and structure
The lymphatic pharyngeal ring consists of several structures. The tonsil pharyngealis (pharyngeal tonsil) is located at the roof of the pharynx. It receives sensory supply from the tonsillar branches of the glossopharyngeal nerve. The accumulation of lymphoid tissue at the opening of the eustachian tube is attributed to the tonsilla tubaria (tubal tonsil). The tonsil palatina, on the other hand, is located between the anterior and posterior palatal arches. It is arranged in pairs and is also called the palatine tonsil. The palatine tonsils are located in the so-called palatal bay and consist of lymphoid tissue up to two centimeters thick, which is covered by a multilayered and unkeratinized squamous epithelium. On the surface of the palatine tonsils are two depressions, the so-called crypts. The crypts provide the characteristic fissured appearance of the tonsils. The lymphoepithelial tissue in the mucosa at the base of the tongue belongs to the tonsil lingualis. The lingual tonsil is also covered by multilayer squamous epithelium and has crypts. The excretory ducts of some salivary glands open into the crypts of the lingual tonsil.
Function and Tasks
Basically, the lymphatic pharyngeal ring serves as a defense against viruses, fungi, and bacteria. It forms the first defense barrier of the upper respiratory tract. The pharyngeal tonsil serves primarily to trap pathogens that enter through the nose. The tubal tonsil protects the middle ear from bacteria, viruses and fungi that might enter the middle ear from the nasal cavity via the Eustachian tube. The palatine tonsils perform a special task. Bacterially colonized food debris accumulates in the crypts of the palatine tonsils. Leukocytes and exfoliated tissue also find their way into the grooves. The entire mixture of leukocytes, food debris and tissue remnants is also called detritus. The detritus that accumulates in the crypts represents a contact between the outside world and the body’s immune system. The white blood cells learn about different types of bacteria through the crypts of the tonsils and are able to deal with the pathogens for the first time. The detritus from the crypts is regularly emptied, so that the blood cells regularly come into contact with new pathogens. The lingual tonsil also serves as a defense against pathogens that enter the body through the mouth and nose. Because it is constantly flushed by the salivary glands, it is less susceptible to inflammation.
Diseases
Tonsillitis is an inflammatory disease of the tonsils. Usually, only the painful inflammation of the palatine tonsils is called tonsillitis. The palatine tonsil is the tonsil of the lymphatic pharyngeal ring that becomes inflamed most frequently. The disease is contagious and is transmitted by droplet infection. Depending on the temporal course, a distinction can be made between acute and chronic tonsillitis. If only one side of the tonsil is affected, unilateral inflammation is present. If inflammation occurs on both sides, it is accordingly bilateral tonsillitis. With regard to the clinical aspects, an additional distinction can be made between catharral, follicular and lacunar angina. The cause of tonsillitis is usually bacteria. Only in rare cases is the inflammation caused by viruses.Typical pathogens of tonsillitis are beta-hemolytic group A streptococci. Pneumococci, staphylococci, Neisseria gonorrhoaea and Haemophilus influenzae can also cause inflammation of the lymphatic throat ring. The most common causative agent of viral tonsillitis is Epstein-Barr virus. Leading symptoms of tonsillitis are difficulty swallowing due to constriction of the pharynx, bad breath, and slurred speech. Ulceration of the mucosa and swelling of the mandibular lymph nodes are possible. In addition, there are often accompanying symptoms such as headache, fever, and fatigue. In angina catarrhalis, the palatine tonsils are exclusively swollen and red. In angina follicularis, fibrinous plaques also develop. These turn out to be even larger in angina lacunaris. The infectious disease scarlet fever is also accompanied by tonsillitis. Typical here is the accompanying rash, the so-called scarlet fever exanthema. If chronic tonsillitis is present, detritus accumulates on the tonsils, causing constant irritation of the mucous membranes and lymphatic tissue. A special form of tonsillitis is angina plaut vincenti. This relatively rare form of tonsillitis is caused by spirochetes and fusobacteria and is manifested by unilateral, moderate swallowing difficulties. The general condition is only slightly affected and patients do not have fever. In contrast to the rather mild complaints, the local findings are very striking. Severe necrosis and ulceration with a foul-smelling greasy coating develop.
