Parathyroid Hormone and Calcium Regulation Quiz

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Questions and Answers

Which gland synthesizes the thyroid hormones thyroxine (tetra-iodothyronine or T4) and triiodothyronine (T3)?

Parathyroid gland

Pituitary gland

Adrenal gland

Thyroid gland (correct)

What is the shape of the thyroid gland?

Circular

Oval

Butterfly-shaped (correct)

Rectangular

What is the function of the thyroid hormones?

Control blood sugar levels

Control blood pressure

Regulate body temperature

Control the basal metabolic rate (correct)

Which gland synthesizes the hormone calcitonin?

Thyroid gland Signup and view all the answers

What is the function of calcitonin?

Regulate calcium levels in the blood Signup and view all the answers

What is the blood supply of the thyroid gland?

Arterial blood supply Signup and view all the answers

Which hormone stimulates calcium reabsorption in the distal convoluted tubules of the renal cortex?

PTH Signup and view all the answers

What is the effect of hyperparathyroidism on blood calcium levels?

Increased blood calcium levels Signup and view all the answers

Which zone of the adrenal cortex synthesizes mineralocorticoids?

Zona Glomerulosa Signup and view all the answers

Which hormone affects carbohydrate metabolism and suppresses immune functions?

Cortisol Signup and view all the answers

Which layer of the adrenal cortex primarily secretes weak androgens?

Zona Reticularis Signup and view all the answers

What disorder causes degeneration of any layer of adrenal cortex and loss of glucocorticoids, mineralocorticoids, or androgens?

Addison disease Signup and view all the answers

Which cells in the thyroid gland secrete calcitonin?

Parafollicular cells Signup and view all the answers

Which hormone is secreted about 10 times the rate of T₃ and is much less potent than T₃?

Thyroxine (T₄) Signup and view all the answers

What is the major regulator of the anatomic and functional state of the thyroid follicle?

Thyroid-Stimulating Hormone (TSH) Signup and view all the answers

Which cells in the parathyroid gland are small, polygonal cells with round nuclei and a pale acidophilic staining cytoplasm?

Principal (chief) cells Signup and view all the answers

What is the function of parathyroid hormone (PTH) on osteoblasts?

Increases the number and activity of osteoclasts Signup and view all the answers

Where are the parathyroid glands located?

Embedded in the thyroid gland capsule Signup and view all the answers

Which type of cells make up the adrenal medulla?

Chromaffin cells Signup and view all the answers

Which type of neurons give rise to chromaffin cells in the adrenal medulla?

Preganglionic sympathetic neurons Signup and view all the answers

What is the primary hormone secreted by the adrenal medulla?

Epinephrine Signup and view all the answers

What are the main effects of epinephrine on the body?

Increases heart rate, dilates bronchioles, dilates arteries of cardiac and skeletal muscles Signup and view all the answers

What is the blood supply of the adrenal gland called?

Subcapsular arterial plexus Signup and view all the answers

Which arteries supply blood to the adrenal gland?

Superior, middle, and inferior suprarenal arteries Signup and view all the answers

What is the dual blood supply of the adrenal medulla?

Arterial blood from medullary arterioles and venous blood from cortical capillaries Signup and view all the answers

Study Notes

Thyroid Gland and Hormones

The thyroid gland synthesizes thyroid hormones: thyroxine (T4) and triiodothyronine (T3).
The thyroid gland is butterfly-shaped, consisting of two lobes connected by an isthmus.
Thyroid hormones regulate metabolism, energy levels, and overall growth and development.

Calcitonin and Its Function

Calcitonin is synthesized by parafollicular cells (C cells) in the thyroid gland.
It lowers blood calcium levels by inhibiting osteoclast activity, which prevents bone resorption.

Blood Supply of the Thyroid Gland

Blood supply is primarily provided by the superior and inferior thyroid arteries.
Rich vascular network ensures adequate delivery of hormones and nutrients.

Calcium Regulation

Parathyroid hormone (PTH) stimulates calcium reabsorption in the distal convoluted tubules of the renal cortex.
Hyperparathyroidism leads to elevated blood calcium levels (hypercalcemia).

Adrenal Cortex and Hormones

The zona glomerulosa of the adrenal cortex synthesizes mineralocorticoids, such as aldosterone.
Glucocorticoids, affecting carbohydrate metabolism and suppressing immune functions, are produced by the zona fasciculata.
The zona reticularis primarily secretes weak androgens, such as dehydroepiandrosterone (DHEA).

Adrenal Insufficiency

Adrenal crisis is caused by disorders like Addison's disease, leading to degeneration of adrenal cortex layers and loss of key hormones.

Parathyroid Gland

Chief cells are the small, polygonal cells in the parathyroid glands with round nuclei and pale staining cytoplasm.
PTH stimulates osteoblasts to promote bone mineralization and regulate calcium levels.

Location and Structure of Parathyroid Glands

Parathyroid glands are located on the posterior surface of the thyroid gland, typically four in number.

Adrenal Medulla Structure

Chromaffin cells, derived from neural crest cells, make up the adrenal medulla.
The primary hormone secreted by the adrenal medulla is epinephrine (adrenaline).

Effects of Epinephrine

Major effects include increased heart rate, enhanced blood flow to muscles, and rapid energy mobilization.

Blood Supply to Adrenal Gland

The blood supply of the adrenal gland is derived from the suprarenal arteries.
Dual blood supply includes both the adrenal medulla's rich vascularization and the surrounding adrenal cortex's blood supply.

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Description

Test your knowledge of the effects of parathyroid hormone (PTH) on blood calcium levels and its role in calcium reabsorption in the renal cortex and calcium absorption in the small intestines. Learn about age-related changes in the parathyroid gland.