Endocrine System Review

Flashcards about the endocrine system, pituitary gland, hormones, and adrenal glands.

Name two endocrine glands mentioned.

Pineal gland and Hypothalamus

What are the two types of hormones based on solubility?

Hydrophilic and Hydrophobic

What is the paracrine effect?

Hormones that affect a place far from the releasing location

What are tissues and organs affected by hormones called?

Target tissues or target organs

How do cells respond even if the hormone is present in the blood at a low density?

They contain receptors for the hormones.

What are the three chemical classes hormones are divided into?

Steroids, Small peptides/polypeptides/proteins, and Amino acids/arachidonic acid analogs

What are steroids derived from?

Cholesterol

What secretes small peptides, polypeptides, and proteins?

Hypothalamus, pituitary gland, thyroid gland, parathyroid gland, pancreatic cells, and the dispersed enteroendocrine cells of the gastrointestinal and respiratory systems

What are examples of amino acid and arachidonic acid analogs?

Norepinephrine, epinephrine, and phenylalanine/tyrosine derivatives

What does the hypothalamus produce?

ADH, oxytocin, and regulatory hormones

What produces melatonin?

Pineal gland

What does the pituitary gland produce?

ACTH, TSH, GH, PRL, FSH, LH, and MSH (anterior lobe); Release of oxytocin and ADH (posterior lobe)

What does the thyroid gland produce?

Thyroxine (T4), Triiodothyronine (T3), and Calcitonin (CT)

What does the parathyroid glands produce?

Parathyroid hormone (PTH)

What is the structural organization of endocrine organs?

Cells form cords or clusters while the thyroid gland cells form a follicle structure

Where is the pituitary gland located?

In the sella tursica, a saddle-shaped depression of the sphenoid bone at the base of the brain

What are the two functional components of the pituitary gland?

Anterior lobe (adenohypophysis) and posterior lobe (neurohypophysis)

What are the three types of cells found in the pars distalis of the adenohypophysis?

Acidophils, basophils, and chromophobes

What hormones do acidophils secrete?

Growth hormone (GH) and Prolactin

What hormones do basophils secrete?

ACTH, FSH, LH, and TSH

What do somatotrophs produce?

Growth hormone (somatotropin, GH)

What inhibits the release of GH from somatotrophs?

Somatostatin

What does growth hormone stimulate the liver to synthesize?

Insulin-like growth factor 1 (IGF-1)

What do lactotrophs produce?

Prolactin (PRL)

What does ACTH stimulate the release of?

Glucocorticoids and gonadocorticoids from the adrenal cortex

What does thyroid stimulating hormone (TSH) stimulate?

Growth of the follicular cells of the thyroid and the production/release of thyroid hormones

What regulates the secretion of FSH and LH?

Gonadotropin-releasing hormone (GnRH)

What is the function of Pars Tuberalis?

FSH-LH, vascularized region that contains the veins of the Hypothalamo-Hypophyseal System

What hormones are related to the neurohypophysis?

ADH (antidiuretic hormone, vasopressin) and oxytocin

What is the function of ADH?

Facilitates water absorption in the kidneys

What is the function of oxytocin?

Contraction of uterine muscles and myoepithelial cells of the breast

What cells produce Melatonin?

Pinealocytes, the main secretory cells of the pineal gland

What is the function of the thyroid gland?

Located in the anterior region of the neck and consists of two large lateral lobes connected by the isthmus

What are Follicular cells?

Responsible for the production of thyroid hormones, T3 and T4.

What are Parafollicular cells?

Responsible for the synthesis and secretion of calcitonin (thyrocalcitonin), which lowers blood calcium levels

What is one role of T3 and T4?

Regulate cell and tissue basal metabolism and heat production

How many parathyroid glands are there?

Typically 4 small glands located behind the thyroid gland

What is the function of chief cells?

Secrete parathyroid hormone (PTH), which regulates calcium levels in the blood

How does PTH affect osteoclast activity?

Raises blood calcium levels by enhancing osteoclast activity

What is the major function of the adrenal gland?

Consist of 2 zones : Cortex (80-90%), the part where steroid secretion occurs and Medulla (10-20%), the part with catecholamine secretion

What does the zona glomerulosa synthesize?

Mineralocorticoids, mainly aldosterone, which provides electrolyte and water balance

What is the Renin-Angiotensin-Aldosterone System?

Aldosterone secretion is controlled by renin-angiotensin and ACTH. In response to falling sodium levels and blood pressure, the release of aldosterone is increased. The absorption of sodium and water from the distal tubules in the kidney is enhanced.

What does zona fasciculata produce?

Glucocorticoids (cortisol), effective in carbohydrate metabolism

What does the zona reticularis produce?

Dehydroepiandrosterone, a weak androgen

What cells are in the adrenal medulla?

Chromaffin cells, which secrete catecholamines like epinephrine and norepinephrine

What is Cushing's syndrome?

Adrenal cortex tumors cause excessive production of glucocorticoids or aldosterones. Cushing's syndrome is usually due to pituitary adenoma resulting in excessive production of ACTH.

What is Addison's disease?

Adrenal glands not produce sufficient steroid hormones