Hormones Secreted By Thymus Gland

INTRODUCTION OF THYMUS GLAND

“The thymus get its name from its silhouette. It is shaped much like a thyme leaf, a common  cooking herb. It has two separate lobes divided by a central medulla and a peripheral cortex”

·         The thymus gland is both an endocrine gland & lymphatic organs.

·         The thymus secretes a large number of hormones.

·         It is composed of two lobes & is located in front of the heart & behind the sternum.

·         Thymus is specialized organ in the immune system.

·         After puberty, it decreases in size and is slowly replaced by fat.

·         The thymus reached its maximum weight ( about 1 ounce ) during puberty.

             The thymus gland will not function throughout a full lifetime, but it has a big responsibility when it’s active- helping the body protect itself against autoimmunity, which occurs when the immune system turns against itself.

               Therefore, the thymus plays a vital role in the lymphatic system ( your body’s defense network ) and endocrine system.

                The thymus is special in that, unlike most organs, it is at its largest in children. Once you reach puberty, the thymus starts to slowly shrink and become replaced by fat. By age 75, the thymus is little more than fatty tissue. Fortunately, the thymus produces all of your T cells by the time you reach puberty.

HORMONES SECRETED BY GLAND

·         Thymosin

·         Thymopoietin

THYMOSIN HORMONES

INTRODUCTION:

Thymosin is a hormone secreted by the thymus (an endocrine gland in the human body .

Thymosin stimulates the development of T cells. Throughout your childhood years, white blood cells called lymphocytes pass through the thymus, where they are transformed into T cells.

Thymosin α1 stimulates the development of precursor T cells in the thymus to mature T cells. Thymosin β4 is the principal G-actin sequestering molecule in mammalian cells, playing an important role in the organization of the cytoskeleton.

STRUCTURE

PHYSIOLOGICAL ROLE OF THYMOSIN

The roles of the hormone thymosin include activating the immune system by activating the T-cells ( T-killer Cells, T-Helper Cells and T-Memory  Cells ) which are types of lymphocytes in the blood.

THYMUS

THYMOPOIETIN HORMONE

INTRODUCTION:

Thymopoietin , a polypeptide hormone secreted by the thymus; it induces the proliferation of lymphocyte precursors and their differentiation into T-lymphocytes.

STRUCTURE

PHYSIOLOGICAL ROLE OF THYMOPOIETIN

Thymopoietin is a polypeptide hormone secreted by the thymus that affect the rate at which your skin ages. Simply put, thymopoietin affect the body’s capacity to maintain youthful function in everything from skin cells to brain cells.

DISORDERS OF THYMUS GLAND

·         Myasthenia gravis

·         Pure red cell aplasia

·         Hypogammaglobulinemia

MYASTHENIA GRAVIS

INTRODUCTION;

Myasthenia gravis is an uncommon condition that causes certain muscles to become weak. With treatment, most people can lead a normal life.

Myasthenia gravis literally means ‘grave muscle weakness’.

The condition can affect any muscles that you can control voluntarily. Muscles that you cannot control voluntarily, such as the heart muscles, are not affected.

        Myasthenia gravis most commonly affects the muscles that control eye and eyelid movement, facial expression, chewing, swallowing and talking, and the muscles in the arms and legs. Less often, the muscles involved in breathing may be affected.

  The muscle weakness is usually made worse by physical activity and improved by rest

CAUSE: 

Myasthenia gravis is an autoimmune disease, which means that your immune system attacks your own body tissues. In the case of myasthenia gravis, your immune system produces antibodies that block or damage your muscle receptor cells. This blocks themessages that pass from the nerve endings to the muscles, so your muscles do not contract well and become weak.

        The reason why some people’s  immune systems make antibodies against muscle receptor cells is not fully understood.

SYMPTOMS: 

·         Trouble talking

·         Problems walking up stairs or lifting objects.

·         Facial paralysis

·         Difficulty breathing due to muscle weakness

·         Difficulty swallowing or chewing

·         Fatigue

·         hoarsevoice

·         drooping of eyelids etc.

AFFECTED PEOPLE BY MYASTHENIA GRAVIS:

Myasthenia gravis affects about 20 per 100,000 people worldwide. The prevalence has been increasing in recent decades, which likely results from earlier diagnosis and better treatments leading to longer lifespans for affected individuals.

PURE RED CELL APLASIA

INTRODUCTION:

Pure red cell aplasia ( PRCA ) or erythroblastopeniarefers to a type of anemia affecting the precursors to red blood cells. In PRCA, the bone marrow ceases to produce red blood cells.

CAUSES;

Acquired pure red cell aplasia is thought to be an autoimmune disorder possibly caused either by a tumor of the thymus gland, certain drugs or a viral infection is one of a group or bone marrow failure syndromes.

SYMPTOMS:

symptoms may include fatigue, lethargy, and/or abnormal paleness of the skin (pallor) due to the anemia the caused by the disorder

AFFECTED POPULATION BY ( PRCA ):

Acquired pure red cell aplasia is a rare disorder affecting males and females in equal numbers.

HYPOGAMMAGLOBULINEMIA

INTRODUCTION;

Hypogammaglobulinemia is a problem with the immune system in which not enough gamma globulins are produced in the blood ( thus hypo- + gamma + globulin + -emia ). This results in a lower antibody count, which impairs the immune system, increasing risk of infection.

CAUSES:

Hypogammaglobulinemia may result from a variety of primary genetic immune system defects, such as common variable immunodeficiency, or it may be caused by secondary effects such as medication, blood cancer or poor nutrition, or loss of gamma globulins in urine as in nonselective glomerular proteinuria.

SYMPTOMS:

·         Coughing

·         Sore throat

·         Fever

·         Ear pain

·         Congestion

·         Sinus pain

·         Diarrhea

·         Nausea and vomiting

AFFECTED POPULATION BY

HYPOGAMMAGLOBULINEMIA:

CVID is the second most common cause of hypogammaglobulinemia  and affects both sexes equally. The incidence is about 1 in 50,000 people. In most patients there is a reduced amount of the immunoglobulinsIgG, IgA and IgM in the blood. It is an immune deficiency disorder that can be acquired or inherited.