[Biology Class Notes] on Thymus Pdf for Exam

Thymus Gland Location

The thymus is a soft, bilobed structure and is encased between the chest, the breastbone or sternum and between the lungs. To be precise, the thymus lies encapsulated in the superior mediastinum and the anterior region of the inferior mediastinum, next to the pericardium of the heart. Also, this is almost anterior to the heart vessels, and somewhat deep inside the sternum.

The phrenic nerves, which connect and supply to the diaphragm, lie parallel to the left and right side of the thymus. The two different lobes of the thymus are connected in the middle with the help of the isthmus.

While the thymus is functional in infants, it is redundant in adult humans. As a child slowly approaches puberty, the thymus starts to shrink and eventually, replaced by fat. Surprisingly, in adults, the thymus weighs only about 5 grams.

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Read on to find out more about thymus function.

Thymus Gland Function

As mentioned above, the thymus is the site of development of progenitor cells, which are the precursors of mature T-cells (cells derived from the thymus). Our body employs these T-cells to help locate and destroy cells that are infected, cancerous or prone to disease. These mature T-cells also provide a safe space to other organs of the immune system to gain nourishment and grow.

Furthermore, the T-cells help fend off foreign disease-causing pathogens such as deadly viruses and bacteria. Thus, the thymus helps to regulate the immune system and prevent autoimmunity in the body.

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Rack Your Brains: Now that you know how the thymus works, it’s time to find out how to test thymus function. Consult your teacher, mentor or a school senior and conduct experiments to know how it works.

Pop Quiz 1

1. Which of these are cells produced by the thymus?

1. A-cells

2. B-cells

3. C-cells

4. T-cells

Thymus Gland Hormones

The thymus releases a hormone called thymosin which helps kickstart the production of T-cells. Throughout childhood, lymphocytes, a type of white blood cells are known to pass through the thymus, wherein they are ultimately changed into T-cells.

As T-cells attain maturity, they move towards the lymph nodes, which are clusters of immune cells distributed all over the body. However, regardless of where they are located, these T-cells can sometimes develop into cancerous tumours, and the condition is known as Hodgkin disease. These cells are called non-Hodgkin lymphomas.

Thus the most significant thymus function is its role in protecting the body from all sorts of diseases and ensuring its long-term health. The dysfunction of the gland can cause major diseases, for instance, red cell aplasia, myasthenia gravis and hypogammaglobulinemia.

This was all about thymus definition and function. For more on the endocrine system and its various glands, sign up for live demo classes and watch them for free on our app.