Thyroid Gland - Introduction

Our body has a total of eleven organ systems

Of these eleven organ systems, two organ systems help in the cell to cell communication and various activities performed by our body

Those two organ systems include the nervous system and the endocrine system

While the nervous system consists of the brain, spinal cord and the nerves which control various activities of our body

The endocrine system consists of organs or glands which release chemicals called hormones

These hormones released by the endocrine glands control longterm activities like growth, metabolism, sexual development etc.

Our body has many different endocrine glands which release different hormones

Thyroid gland is one of the most important glands of the endocrine system

It is located at the base of the neck just below Adam’s apple

It is butterfly shaped and has 2 lobes (bilobed organ). The two lobes are interconnected with a tissue called isthmus

The thyroid gland is made up of 2 types of tissues; Follicles and stromal tissues

The follicular cells of the thyroid gland synthesize the hormone Thyroxine

This thyroxine (T${}_4$) is made from 2 components: Tyrosine (amino acid) and Iodine

The iodine for making thyroxine is obtained from the food and it is supplied to the follicular cells through the blood

Once the thyroxine is made by the follicular cells, it is released into the blood and is carried to various cells of the body

The thyroxine plays an important role in the metabolism of carbohydrates, lipids and proteins

The hormone increases the breakdown of carbohydrates and lipids (in the target cells) which can then release energy

This energy can then be used for our growth and development

Insufficient thyroxine release has effects on our body

In people who take food with no or little iodine, the thyroxine levels will be lower because, without iodine, thyroxine cannot be made

These people taking iodine-deficient food develop a condition called goiter

In people with goiter, the thyroid enlarges resulting in swollen necks

People with iodine-deficiency may also develop a condition called myxedema

Not just the adults, a child born to a mother who has severe iodine deficiency also develop a condition called cretinism

People with cretinism have poor growth and are often mentally challenged

Revision

The thyroid is a bilobed organ located in the neck

It is made up of stroma and follicular tissue

The follicular cells synthesize the hormone called thyroxine

Thyroxine plays an important role in carbohydrate, lipid and protein metabolism

Low levels of thyroxine production can lead to conditions like goitre and cretinism (in children born to mothers with iodine defeciency)

The END