HUMAN ORGANS

Human Organs

Human Organs

I. Introduction

Lingual thyroid is a rare embryological anomaly and originates from failure of the thyroid gland to descend from the foramen caecum to its normal eutopic pre-laryngeal site. The ectopic gland located at the base of the tongue is often asymptomatic but may cause local symptoms such as dysphagia, dysphonia with stomatolalia, upper airway obstruction and haemorrhage, often with hypothyroidism. This case reports a 47-year-old female, who complained of a weight gain of 10 lbs every lear for the last 3 years. The sensation of dysphagia and dyspnoea caused by ectopic lingual thyroid. Treatment was performed with a partial endoscopic removal and an external cervical approach, followed by substitutive hormone treatment, respectively.

II. What is the chosen organ or organ system?

Lingual thyroid is a rare developmental anomaly originating from aberrant embryogenesis during the passage of the thyroid gland through the neck. Embryonic development begins about 24 days after fertilization in the floor of the primitive hypopharynx from median endodermal thickening, then the primitive gland descends closely related to the hyoid bone and laryngeal cartilages. The thyroglossal duct is a narrow tube connecting the developing thyroid gland to the tongue and it usually involutes at the sixth or eighth week. The foramen caecum is the opening of the thyroglossal duct in the tongue. The thyroid gland then descends to meet the lateral ultimo-branchial bodies; the fusion of these elements leads to the formation of the functional and mature thyroid gland by the third foetal month.

III. What is its' role in the normal functioning of the human organism? What is its' contribution to maintenance of homeostasis?

A standard micro-laryngoscopic surgical procedure was performed using a bivalve Weerda-type laryngoscope and a Zeiss microscope. The prominent part of the lingual thyroid was removed trans-orally, using cold instruments and monopolar coagulation in order to achieve a sufficient airway space. Due to diffuse bleeding, oropharyngeal packing was left in situ and naso-tracheal intubation was maintained for the first 24 hours. The packing was removed on the first day after surgery and the post-operative course was uneventful. The histo-pathological examination revealed ectopic thyroid tissue. By the fifth post-operative day, soft oral feeding was commenced and the patient was discharged. (Kumar 2001 Pp. 304)

IV. What are the anatomical, physiological, chemical and cellular mechanisms behind the structure(s) or performance parameter? (in other words) How chemistry is important to the function, as well as what is the basic structure and functions?

Ectopic thyroid is a rare embryological aberration which can occur in any moment of the migration of the thyroid resulting in lingual (at tongue base), sublingual (below the tongue), prelaryngeal (in front of the larynx), and substernal (in the mediastinum) ectopy. Dual ectopic thyroid has been described, even with the thyroid gland in a normal location.

It occurs more frequently in females, with a female to male ratio 4:1; ectopic thyroid is seen at any age but more commonly during childhood, adolescence and around menopause. This probably occurs when demands for thyroid hormones increase, causing the ...