Peripheral Hormones

Thyroid gland characteristics

Largest pure endocrine gland

Made up of follicles and areolar CT

Produces thyroid hormone (thyroxine - T4, TH - T4 + T3) and calcitonin

Thyroid hormone (function and what is needed for production)

Needs iodine for synthesis → iodine couplings produce T3 and T4 (what TH is), in peripheral tissues an iodine molecule is removed from T4 to make T3

Released when body is experiencing a higher metabolic demand (e.g. being cold)

Functions:

• acts on the cells

• Increases metabolism → increases heat

Hyperthyroidism (what it is, caused by, symptoms)

Excessive thyroxine production

Can be caused by a tumour of the thyroid gland

Symptoms:

• tachycardia

• Nervousness

• Weight loss / hunger

• Hot

• Hyperactivity

Grave’s disease (what it is and treatment)

Thyroid gland disease

Autoimmune disorder that causes hyperthyroidism

Treatment:

• medication

• Radiation

• Surgery

Simple goiter (what it is, symptoms, treatments)

Enlargement of thyroid → hypo- or hyperthyroidism

• can be caused by low iodine or tumour

Asymptomatic until large → leads to dyspnea and dysphagia

Treatment:

• iodine in diet

• Surgery to decrease dysphagia (trouble swallowing) and dyspnea (trouble breathing)

Calcitonin (where and when it’s released from and its effects)

Released from thyroid gland → when blood Ca2+ is high

Acts to decrease blood Ca2+:

• gut → decreased Ca2+ absorption

• Kidney → increased Ca2+ excretion

• Bones → increased Ca2+ absorption