Anatomy of Thymus Gland
- Location: A soft, bilobed organ with encapsulation, the thymus gland. It is located near the pericardium in the superior mediastinum and the anterior region of the inferior mediastinum. The thymus is located deep in the sternum and anterior to the large heart arteries. It reaches the fourth costal cartilage from the level of the inferior poles thyroid gland above. Parallel to the gland on its left and right side are the phrenic nerves (which go on to supply the diaphragm) (which go on to supply the diaphragm). An isthmus connects the thymus’ two separate lobes in the middle.
- Blood supply: The internal thoracic artery, as well as the superior and inferior thyroid arteries, supplies blood to the thymus. Drainage is to the superior, middle, and inferior thyroid veins, as well as the left innominate vein. There are many thymic arteries that can enter the organ’s content and follow the path of the interlobular septae. The blood thymus barrier is made up of the arteries, which organise themselves into a series of intricate arcades in the cortex of the thymus, along with the reticular endothelial cells and white blood cells (lymphocytes and macrophages). Proteins cannot pass through the non-fenestrated endothelium and thick basal lamina of thymic capillaries. After that, blood enters the medullary veins.
- Lymphatics: There are no afferent lymphatics in the thymus. The thymic lymph nodes, which include the internal mammary-parasternal, tracheobronchial-hilar, and mediastinal-brachiocephalic, are close to the gland where the lymph drains.
- Nerve supply: The sympathetic nervous system and vagus nerves, which reach deeply into the thymus via postganglionic noradrenergic fibres, provide the thymus with its meagre nerve supply.
What is Thymus Gland?
A gland in an animal is a collection of cells that produce compounds, such as hormones, for release into the bloodstream (endocrine gland), into cavities inside the body, or onto the animal’s surface (exocrine gland). Each gland is created by the ingrowth of epithelial tissue. This ingrowth may initially have a tubular form, but glands can also begin as a solid column of cells that later develops into a tubular structure.
The column of cells may divide or release offshoots as growth progress, in which case a compound gland is created. Many glands have a finite number of branches, whereas others (such as the pancreas and salivary glands) repeatedly expand and divide to eventually form a very massive structure. Normally, the branches don’t join together, but the liver is one exception since a reticulated compound gland develops there. The terminal portion of each branch in compound glands is made up of the more common or secretory epithelium, and the connecting segments, which ducts, are lined with a less altered type of epithelial cell.