Lecture 22: Endocrine System - Thyroid and Parathyroid Glands Flashcards
What does thyroid dysfunction (hypothyroidism/hyperthyroidism) cause?
Cretinism, myxedema, Graves’ disease, and other pathologies
What does parathyroid dysfunction (hyperparathyroidism/hypoparathyroidism) cause?
Overexcitement of muscle and nervous systems, bone demineralization, high calcium levels, duodenal ulcers, kidney stones, and behavioral disorders.
Thyroid gland functions
Regulation of intensity and rate of metabolic/chemical reactions
What are the right and left lobes of the thyroid gland connected by?
The isthmus
What is the thyroid gland mostly made of?
Follicles that are made of two types of cells that they produce: thyroxine/tetraiodothyronine/T4 and triiodothyronine T3
What do the parafollicular cells (C cells) make?
Calcitonin
What does the thyroid need eaten?
Iodine, since its chemistry is iodine based. If it doesn’t get enough, the thyroid swells, causing Benign goiter.
What are nodules
Cancerous thyroid tumors that are caused by people having their face irradiated.
Where are hormones stored in the thyroid?
In the follicles and will last three months.
Amino acids and iodine are synthesized into what?
Thyroglobulin; they are stored in the follicles as colloid.
What do thyroid hormones manage?
Oxygen uptake; gross basal metabolic rate; body temperature regulation; protein synthesis; lipid and cholesterol breakdown; body growth rate and NS development; effects of catecholamines.
What are the effects of catecholamines in hyperthyroid patients?
High blood pressure, nervousness, sweating, and fast heart rate.
Process of iodine in follicular cells
- Follicular cells search them out and attract them
- Taken in through capillaries and are trapped in the endoplasmic reticulum
- Follicles synthesize thyroglobulin
- Small transport veins (vesicles) take iodine deeper into the follicles
- There it is combined with thyroglobulin to make amino acid tyrosine
What is cretinism
Hypothyroidism during fetal development. It causes mental retardation, physical deformities, and dwarfism
What is myxedema
Hypothyroidism during adult life; causes edema, slow heart rate, low blood pressure, lethargy, sensitivity to cold, low body temperature, muscle weakness, hair loss, and obesity
What is myxedema madness?
Psychotic episodes that are caused by myxedema
What does hyperthyroidism cause?
Increased heart rate and blood pressure; high body temperature and sweating, nervousness, diarrhea, heat intolerance, and weight loss
What is Graves’ disease?
Autoimmune disorder; antibodies are not controlled and imitate TSH effects. Results in goiter, thyroid enlargement, and exophthalmos.
What do the four parathyroid glands do?
Regulates calcium and potassium levels in the blood. The chief cells (principal cells) produce parathormone (PTH) and oxyphil cells.
Define “parathyroid”
“beside the thyroid”
Name the four parathyroid glands
- left inferior
- right inferior
- left superior
- right superior
Effects of PTH
Raise levels of phosphorus and serum calcium; increases osteoclasts (bone cells) for reabsorption of calcium, calcium urinary reabsorption in the kidneys, phosphorus excretion in the kidneys.
What does potassium cause the kidneys to do?
Form calcitriol (hormone made from vitamin D) that increases calcium absorption from the GI tract.
What does calcitonin from the thyroid gland do?
Is involved in forcing calcium back into bones because of the negative feedback system
What causes hyperparathyroidism?
PTH is increased in production, normally because of a parathyroid adenoma. Calcium from the kidneys, stomach, and bones is reabsorbed into the blood. It causes kidney stones, osteoporosis, duodenal ulcers, and psychosis
What is parathyroid adenoma
A benign tumor in one or more of the parathyroid glands.
Results of hypoparathyroidism
Elevated nerve and muscle excitement, low serum calcium levels, and when extreme, convulsions and death
What is exophthalmos?
Bulging eyeballs because of fat deposited behind the eye
