The Thyroid is a gland that is present in the endocrine system. It is present in the neck and is divided into sections. These sections consist of follicles.
Epithelia surround the whole section. While the Hormones get built in the follicles. It is the source of thyroxine T4 and triiodothyronine T3. The Thymus is an organ responsible for the immune system.
It is present in the lymphatic system. The size is the largest when the person is just born. It starts shrinking when the person starts growing and ageing. The older you are smaller the thymus. The thymus is divided into two lobules. An organ that resides in the endocrine system. It is responsible for the secretion of two types of hormones which are responsible for metabolism in the body. It is present in the neck.
It is differentiated into two lobes. These lobes have follicles that are covered by epithelia. Hormones are built in the follicles. These hormones are solely responsible for controlling metabolism in the body. These hormones get formed with the help of iodine within the follicles. The anterior pituitary gland and the hypothalamus control the action of hormone secretion in the body.
It is in the follicles that hormones are made. The thyroid produces two different hormones that are involved in controlling metabolism in the body. The hormones that are made are thyroxine T 4 and triiodothyronine T 3. They are formed from iodine molecules within each of the follicles of the thyroid. The control of hormonal secretion from the thyroid is by actions of the anterior pituitary gland and the hypothalamus. These regions are both found in the brain with the activity controlled by a negative feedback loop.
When there are too few thyroid hormones in the blood the hypothalamus is triggered. This then stimulates the release of thyrotropin-releasing hormone which triggers the anterior pituitary to secrete thyroid-stimulating hormone that stimulates the thyroid to, in turn, make and release the two thyroid hormones into the bloodstream.
In general, there are two problems that can occur with the thyroid gland, either there are too few thyroid hormones being made or there are too many thyroid hormones being made for whatever reason. In the case of too few hormones an underactive thyroid , a person may have a sluggish metabolism and tend to gain weight; their hair may also become dry and brittle. A person who has an overactive thyroid, by comparison, often loses weight and has a rapid heart rate. The thymus is a triangular-shaped organ of the lymphatic system that is involved in the immune system response.
The thymus is at its greatest size when a person is a fetus or baby and it slowly decreases in size as the person ages and when a person is very old this organ is greatly reduced in size. There is an outer capsule region and inner medulla region making up the thymus and the entire structure is divided into two parts which are called lobules.
The thymus has cells known as reticulocytes as well as lymphocytes. The function of the thymus is to protect the individual from pathogenic organisms such as viruses, particularly the developing fetus and newborn child. It is the site where white blood cells made in the bone marrow develop further into T-cells. There are several types of T cells which play various roles in cell-mediated immunity.
The production of immune system cells and maturation of cells in the thymus is controlled by a system which involves the hypothalamus of the brain and the pituitary gland. When a cell-mediated immune response is required, the brain can instruct the pituitary to send a signal to the thymus to produce more T cells. Disorders of the thymus include the condition myasthenia gravis and hypogammaglobulinemia. Myasthenia gravis is when there is an enlarged thymus that produces antibody chemicals that attack the receptors of muscle cells.
The thyroid is an endocrine gland that produces hormones to regulate the metabolic rate in the body. The thymus is an organ of the lymphatic system where white blood cells develop further into T cells.
The thyroid gland consists of two lobes, each comprised of follicles surrounded by epithelia. The thymus consists of an outer capsule and inner medulla section and is made up of two lobules. The thyroid does not change in size as you age unless there is a problem. The thymus does change in size and actually becomes smaller as you age. The hormones thyroxine and triiodothyronine are secreted by the thyroid gland. The fully-matured T cells migrate to the lymph nodes. This suggests that thymus is involved in both immune function and endocrine function in the body.
Thyroid is a large, ductless gland , which is located in the neck and secretes hormones to regulate the growth and development by regulating the rate of metabolism in the body. It is a butterfly-shaped gland, which lies just below the larynx. The two lobes of the thyroid gland are located on either side of the throat.
They are connected by a strip of thyroid tissue called the isthmus. The structure and the location of the thyroid gland are shown in figure 2.
The thyroid gland produces, stores, and secretes hormones known as thyroxine T4 and triiodothyronine T3. The secretion of the thyroid hormones is regulated by the hypothalamus and the pituitary gland in the brain. Thyroid stimulating hormone TSH and the thyroid releasing hormone TRH are the two hormones which regulate the production and the secretion of thyroid hormones. The T4 and T3 hormones travel to each cell of the body to regulate metabolism. They regulate breathing, heart rate, body weight, muscle strength, body temperature, cholesterol level etc.
The function and the regulation of the thyroid are shown in figure 3. Thymus: Thymus is a lymphoid organ, which is located behind the sternum between the lungs of vertebrates and produces T cells for the immune system. Thyroid: Thyroid is a large, ductless gland, which is located in the neck and secretes hormones to regulate the growth and development by regulating the rate of metabolism in the body.
Thymus: Thymus is located in the upper chest. Thymus: The size of the thymus becomes smaller compared to the size of the body. The minimal size of the thymus is at the puberty. Thyroid: The size of the thyroid keeps on increasing with age.
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