What is Thyroid?

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What is Thyroid?

What is Thyroid? Whole Body Checkup Blood Test At Home In Delhi NCR, Whole Body Checkup, whole body checkup package, blood sample collection from home

What is Thyroid?

Thyroid is a small butterfly-shaped gland which is a located just below the adam’s apple around the trachea or windpipe.

Isthmus is thin tissue which joins the thyroid lobes on each side. Thyroid actually uses iodine to produce various vital hormones, thyroxine or T4  is a crucial hormone produced by the thyroid gland.

After the delivery via the body’s bloodstream T4 is converted into triiodothyronine (T3) which is one of the most active hormone.


Working of the thyroid gland.


All the functions of the thyroid gland are systematically regulated by the feedback mechanism operated by our brain.

When the thyroid levels are low the brain’s hypothalamus produces a hormone known as thyrotropin releasing hormone (TRH) that causes the pituitary to gland to release thyroid stimulating hormone (TSH) .

TSH stimulates the thyroid gland to release more of T4 thus completing the last element of the feedback system.


There are mainly 2 types of thyroid disorders:



  • Hypothyroidism

  • Hyperthyroidism



Hypothyroidism (Underactive thyroid)


Hypothyroidism also known as “Underactive thyroid” is a condition where your thyroid gland doesn’t make enough thyroid hormones which is necessary to regulate the feedback system of the body.


Symptoms of  hypothyroidism


  1. Excessive fatigue
  2. Dry skin.
  3. Unexplained increase in weight.
  4. Depressed mood
  5. Impaired memory.
  6. Pain stiffness & swelling in joints.
  7. Elevated blood cholesterol level.
  8. Puffy face & neck
  9. Thinning of hair & excessive hair fall.
  10. Hoarseness in voice.


What are the causes of hypothyroidism?


  • Hashimoto’s thyroiditis:



One of the major cause of hypothyroidism is Hashimoto’s thyroiditis which is a condition where our immune system turns against our body’s thyroid gland and tissues this can occur because of some ultraviolet radiation exposure, viral infection or through genes,

However there is not much scientific evidence on the cause of Hashimoto’s thyroiditis and the exact cause of Hashimoto’s thyroiditis is still under the hood even after an extensive amount of research in the medical sector.

Top thyroid expert Mary Shomon says “Every woman between the age of 18-30 years must ensure an yearly thyroid checkup even if they have no history of thyroid disorders in the family”


  • Radiation therapy:


Many neck cancer patients are given radiation therapy to get rid of the tumour.

But radiation therapy near the neck area may damage the cells in the thyroid gland this can make it difficult for our body to produce the thyroid hormones.


  • Certain medications:


It has been observed that the overdose of various medicines which are prescribed to treat heart diseases may affect your thyroid gland in the long term this includes lithium and interleukin-2.


  • Too little iodine!


This is one of the most major symptom of hypothyroidism as iodine is mainly responsible for the production of thyroid hormones in your body deficiency of iodine is the most common reason for hypothyroidism.

As the thyroid gland uses iodine to produce the T4 thyroid hormone, lack of T4 means inadequate production of the thyroid hormone in your body.

Hyperthyroidism (overactive thyroid):


Hyperthyroidism is the exact opposite of hypothyroidism as under hyperthyroidism the thyroid gland starts producing too much of thyroid hormones causing a disruption in the hypothalamus feedback mechanism.

What are the causes of Hyperthyroidism?


Hyperfunctioning thyroid nodules:


Sometimes a lump or two in the thyroid nodule starts growing rapidly which leads to the secretion of excessive thyroid hormones responsible for various complications in our body.


Excessive iodine:


If low amount of iodine leads to inadequate production of the T4 hormones, high amount of iodine obviously leads to the production of more of the T4 hormone which again disrupts the feedback mechanism of the body.




It has been observed that certain medicines & dietary supplements which contain significantly high amount of  tetraiodothyronine can be the reason for high TSH (Thyroid stimulating hormone) levels.


Symptoms of hyperthyroidism:


  1. Sudden change in appetite.
  2. Increase in sweating.
  3. Problems with fertility.
  4. Vision Changes.
  5. Fluctuation in blood sugar level.
  6. Unexplained weight loss
  7. Depressed mood.
  8. Sudden change in voice.
  9. Increase in intolerance to heat.
  10. Decrease in emotional stability.


Normal TSH levels:


TSH levels for Children


  • Birth to four days : 1‑39 mIU/L
  • 2‑20 weeks: 1.7‑9.1 mIU/L
  • 21 weeks to 18 years: 0.7‑64 mIU/L


TSH levels for Adults


  • 19‑54 years: 0.4‑4.2 mIU/L
  • 55‑87 years: 0.5‑8.9 mIU/L


TSH levels during Pregnancy


  • First trimester: 0.3‑4.5 mIU/L
  • Second trimester: 0.3‑4.6 mIU/L
  • Third trimester: 0.8‑5.2 mIU/L

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