Vídeo Aula 153 | Sistema Endócrino | Anatomia Humana | Glândula Tireóide: Anatomia e Hormônios

Summary

In this video lesson, Rogério provides an in-depth and engaging explanation of the thyroid gland, focusing on its anatomy, function, and role in metabolism. He covers essential topics such as the thyroid's structure, vascularization, and hormone production. Key aspects like the thyroid's relationship with the trachea and cricoid cartilage, the importance of iodine and tyrosine in hormone synthesis, and the impact of thyroid hormones on metabolic rate are explored. Additionally, Rogério touches on thyroid-related diseases like goiter and hypothyroidism, while providing practical insights into how the thyroid regulates bodily functions.

Takeaways

• 😀 The thyroid gland is located in the anterior part of the neck and is shaped like a butterfly, with left and right lobes connected by the isthmus.
• 😀 The name 'thyroid' comes from the Greek word 'thyreos,' meaning shield, reflecting the gland's resemblance to a shield.
• 😀 The thyroid is surrounded by important structures such as the trachea and cricoid cartilage, which play a role in its position and function.
• 😀 The thyroid gland is composed of two main lobes (left and right) and a central part called the isthmus. A pyramidal lobe is also present in about 40% of people.
• 😀 The thyroid's posterior part houses the parathyroid glands, which regulate calcium metabolism through the hormone parathyroid hormone (PTH).
• 😀 The thyroid requires iodine and tyrosine to produce its hormones (T3 and T4), which are essential for regulating metabolism.
• 😀 The thyroid is uniquely capable of storing iodine, which it uses to produce hormones. Iodine can be sourced from iodized salt and seafood.
• 😀 The thyroid receives blood supply from the inferior thyroid artery (branch of the subclavian artery) and the superior thyroid artery (branch of the common carotid artery).
• 😀 T3 (triiodothyronine) and T4 (thyroxine) are the two main thyroid hormones, with T3 being more potent but produced in smaller quantities compared to T4.
• 😀 Thyroid hormones are lipophilic, meaning they can pass through cell membranes and bind to intracellular receptors in various cells to regulate basal metabolic rate.
• 😀 Diseases like goiter (bósio) can occur due to iodine deficiency, leading to thyroid swelling. Goiter was common when salt was not iodized.

Q & A

What is the thyroid gland and where is it located?

The thyroid gland is an endocrine gland located in the neck, anterior to the trachea. It is shaped like a butterfly and is divided into two lobes, left and right, connected by a central portion called the isthmus.

Why is the thyroid gland named 'tireoide'?

The term 'tireoide' comes from the Greek words 'thyreos' meaning shield and 'eidos' meaning resembling. The thyroid gland was named for its resemblance to a shield, a characteristic noted by early anatomists.

What is the relationship between the thyroid gland and the thyroid cartilage?

The thyroid gland is located below the thyroid cartilage, which forms part of the larynx (voice box). The thyroid cartilage is often referred to as the 'Adam's apple' or 'Gogó' and is found above the thyroid gland.

What are the lobes and variations in the thyroid gland's structure?

The thyroid gland has two main lobes, the left and right lobes, which are connected by an isthmus. In about 40% of individuals, a pyramidal lobe can also be present, located above the isthmus, as a variation.

What are the parathyroid glands and where are they located?

The parathyroid glands are small glands located on the posterior side of the thyroid gland. Typically, there are four parathyroid glands: two superior and two inferior, which are involved in regulating calcium metabolism.

What are the primary substances needed by the thyroid gland to produce hormones?

The thyroid gland primarily requires iodine and tyrosine to produce thyroid hormones. These substances enter the gland through the bloodstream, with iodine being particularly important for hormone synthesis.

How is the blood supply to the thyroid gland structured?

The thyroid gland receives blood supply from two main arteries: the inferior thyroid artery, a branch of the subclavian artery, and the superior thyroid artery, a branch of the external carotid artery. These vessels ensure the gland receives the necessary nutrients for hormone production.

What are the thyroid hormones and how are they named?

The thyroid hormones are T3 (triiodothyronine) and T4 (thyroxine). T3 contains three iodine molecules, while T4 contains four. These hormones regulate metabolism by influencing the rate at which cells use energy.

What is a goiter, and how is it related to thyroid function?

A goiter is an abnormal enlargement of the thyroid gland, often caused by iodine deficiency or thyroid disorders like hypothyroidism or hyperthyroidism. It results in a visible swelling in the neck, sometimes called a 'papo' or 'papuda.'

How do thyroid hormones affect the body's metabolism?

Thyroid hormones, particularly T3 and T4, regulate the body's basal metabolic rate by controlling the utilization of oxygen and glucose. They influence cellular energy production, including processes like glycolysis and the Krebs cycle.