Thyroid Gland section 2

quiz 4

Thyroid Gland Properties

The Thyroid gland is the largest endocrine gland u

Ductless

Produces and secretes its products or hormones directly into the blood 

Thyroxine - a hormone that stimulates the metabolic rate u Influences heart rate, body temperature, mood, alertness

Controlled by the pituitary gland u Not visible clinically

Can be palpated during H/N exam and should be movable during swallowing

Thyroid Gland Properties

Located in the anterior and lateral regions of the neck

Inferior and lateral to the thyroid cartilage, at the junction between the larynx and the trachea

The gland consists of two lateral lobes connected anteriorly by the isthmu

Thyroid Gland Histology

The thyroid gland is covered by a connective tissue capsule

The septa divide the gland into larger lobes and smaller lobules

Each follicle consists of a layer of simple cuboidal epithelium enclosing a cavity that is usually filled with colloid - produces thyroxine

Parathyroid Glands

Typically consist of four to eight small endocrine glands, two on each side, close to the thyroid gland

Not visible or palpable during an extraoral examination of the patient

The parathyroid glands may alter the physiology of the thyroid gland because of their involvement in a disease proces

Thyroid Gland Development

The thyroid gland is the first endocrine gland to appear in embryonic development and develops from endoderm invaded by mesenchyme

Develops approx. 24th day of prenatal development

Forms from a median downgrowth at the base of the tongue, connected by a thyroglossal duct

Opening of the thyroglossal duct is the foramen cecum

Choice of imaging is ultrasound not radiographs

Clinical applications: Goiter

Gland may become enlarged and visible during extraoral exam

Enlarged thyroid is called a goiter

May be firm and tender when palpated

May contain hard masses

Clinical Consideration: Tumorous Thyroid Growth

Diseased gland may lose its mobility and not move up when the patient swallows; indicative of a tumorous growth

Only 4-5% of thyroid nodules are cancerous