The Thyroid GlandCelina Brown

The Thyroid Gland• One of the largest endocrine

glands

• The thyroid gland is located low in the front of the neck

• The gland is shaped like a butterfly and wraps around the windpipe or trachea.

• Controls how quickly the body uses energy, makes proteins, and controls the body’s sensitivity to hormones

Thyroxine• Tyrosine-based hormones produced by

the thyroid gland • Iodine is necessary for production• Effects of thyroxine in the body:

Increases cardiac output Increases heart rate Increases ventilation rate Increases basal metabolic rate Potentiates brain

development Thickens endometrium in

females Increase metabolism of

proteins and carbohydrates 

Thyroxine Regulation

Iodine Deficiencies• Thyroxine is heavily composed of iodine• If there is not enough iodine in the body, there will

be a resulting decrease in thyroxine• The body does not make iodine, so it’s an

essential part of your diet. • Iodine deficiency can lead to hypothyroidism,

mental disorders in infants whose mothers were iodine deficient, and goiters

Goiters• A goiter is the swelling of the neck resulting from

enlargement of the thyroid gland• The thyroid swells when it is not functioning

properly• This is mostly due to an iodine deficiency

Hyperplasia of thyroid to compensate for decreased efficiency

3 Classes of Goiters

Class OneGoiter cannot be

seen, but it can be felt.

Class ThreeGoiter is very large and causes pain. Pressure in the

neck can result in compression

marks.

Class TwoGoiter is both easily felt and

seen.

Hypothyroidism• Hypothyroidism is a condition

characterized by abnormally low thyroid hormone production.

• This is, once again, associated with an iodine deficiency, or simply a malfunctioning thyroid gland (most commonly Hashimoto’s Disease)

• Since the thyroid gland is responsible for producing hormones that influence growth, development, and many cellular and metabolic processes, insufficient thyroid hormone has many consequences on the body

HypothyroidismSymptoms

Delay in growth (in children and teens)

Poor memory and concentration

Fatigue Muscle weakness

Feeling cold Increased blood cholesterol

Shortness of breath Depression

Weight gain with poor appetite Slowed heart rate

Treatments

Hormone Replacement: Standard treatment for hypothyroidism involves daily use of the synthetic thyroid hormone levothyroxine (Levothroid, Synthroid, others). This oral medication restores adequate hormone levels, reversing the signs and symptoms of hypothyroidism.

Hyperthyroidism• Often referred to as an overactive thyroid, is a

condition in which the thyroid gland produces and secretes excessive amounts of thyroid hormones

• Can be cause by: Graves' disease. Toxic thyroid adenoma Toxic multinodular goiter

HyperthyroidismSymptoms

Increased appetite Tremors

Increased heart rate Nervousness

Sudden weight loss Sweating

Increased sensitivity to heat Enlarged thyroid gland

Digestive fluctuations Difficulty sleeping

Treatments

Radioactive Iodine Taken orally, it shrinks the thyroid, reducing it’s hormone producing activity.

Anti-thyroid medications. Drugs that prevent the thyroid from producing excess amounts of hormones

Beta blockers. Won’t reduce thyroid levels, but will reduce raped heart rate and prevent palpitations.

Surgery (thyroidectomy). A rare treatment for those who can’t tolerate drugs or radioactive iodine therapy.

Question Time!

7) Name one way hypothyroidism might be prevented.

2) Is the thyroid gland an example of a negative or positive feedback system? How do you know?

3) Describe the shape and location of the thyroid.

4) Describe the difference between hypothyroidism and hyperthyroidism.

5) List three symptoms of hypothyroidism.

6) List two methods of treating hyperthyroidism.

1) Is the thyroid an endocrine of exocrine gland? How do you know?