Question

What is the thyroid hormones endocrine source?

What are the target organs and Actions of the Thyroid Hormone?

Answer 1

What are thyroid hormones ?

These are group of two hormones namely T3(triiodothyronine) and T4(thyroxine).

What is the thyroid hormones endocrine source?

The thyroid hormones are secreted by Thyroid gland. The thyroid gland is an endocrine gland which is located in the front of neck specifically below your Adam's apple, along the front of the windpipe. The thyroid gland secretes T3 and T4 directly into the blood stream and plays a vital role in many body functions.

What are the target organs and action of thyroid hormones ?

• Thyroid hormone targets majorly all the organs in the body.
• The action of thyroid hormones are -

1. Maintaining metablism of body.
2. Growth of bones along with help of growth hormone.
3. They increase heart rate, cardiac contractility and cardiac output
4. They help in normal functioning of the reproductive system.
5. Regulates muscle funtion
6. They promote vasodilatio that results in enhanced blood flow to many organs.
7. Regulates mental state(Low level of thyroid hormone gives feeling of mentally sluggish and high level induces anxiety and nervousness.)

Note -  

• The thyroid gland is regulated by TSH i.e. Thyroid stimulating hormone which is secreted by the anterior pituitary gland and TRH i.e. thyroid regulating hormone which is secreted by hypothalamus.
• Calcitonin is also secreted by the thyroid gland but T3 and T4 are considered to be the thyroid hormones