Endocrine system study guide

Define diabetes mellitus

Diabetes mellitus is a condition characterized by elevated blood glucose levels resulting form inadequate insulin production or diminished sensitivity to insulin by cells.

Define the prefixes of hyper- and hypo- in the context of endocrine disorders.

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Describe the resistance phase

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During which phase of the general adaption syndrome is there a collapse of vital systems?

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Explain the action of renin in the bloodstream.

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Identify several hormones necessary for normal growth and development.

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Identify three common causes of hormone hyposercretion

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List three phases of the stress response

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What condition is characterized by increased body weight due to Na+ and water retention and a low blood K+ concentration?

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Describe the structural classification of hormones.

1) amino acids derivatives(thyroid hormones, catecholamines, and tryptophan derivatives); 2) peptide hormones(glycoproteins or short polypeptide chains), which are chains of amino acids that are synthesized as prohormones; 3) Lipid derivatives (eicosanoids and steroid hormones), which contain carbon rings and side chains that are built from fatty acids or cholesterol.

Define hormone receptor.

A hormone receptor is a protein molecule, located either on the plasma membrane or inside the cell, that binds with a specific hormone.

Differentiate between a first messenger and a second messenger.

A first messenger is a hormone whose binding to a protein receptor in the plasma membrane gives rise to a second messenger in the cytoplasm. The second messenger changes the rate of various metabolic reactions by acting as an enzyme activator, an enzyme inhibitor, or a cofactor.

Define regulatory hormone.

A regulatory hormone is a special hormone, secreted by the hypothalamus, that controls endocrine cells in the anterior lobe of the pituitary gland.

Identify the types of cells in the pancreatic islets and the hormones produced by each.

Alpha cells(glucagon), beta cells(insulin), delta cells (GH-IH) and F cells (pancreatic polypeptide PP)

Why does a person with diabetes mellitus urinate frequently?

An individual with type1 or type 2 diabetes has such high blood glucose levels that the kidneys cannot reabsorb all the glucose; some glucose is lost in the urine. Because the urine contains high concentrations of glucose, less water can be reclaimed by osmosis, so the volume of urine production increases, and the individual needs to urinate more often.

What thyroid hormone aids in the regulation of calcium?

Calcitonin aids in calcium regulation.

Decreased blood calcium levels would result in increased secretion of which hormone?

Decreased blood calcium levels result in increased secretion of parathyroid hormone (PTH).

What effects would elevated circulating levels of glucocorticoids have on the pituitary secretion of ACTH?

Elevated circulating levels of glucocorticoids inhibit the release of CRH by the hypothalamus. The lack of CRH reduces the secretion of ACTH form the pituitary gland, so ACTH levels would decrease. This is an example of negative feedback.

What effect would elevated cortisol levels have on blood glucose levels?

Elevated cortisol levels would result in elevated blood glucose levels, because cortisol reduces the use of glucose by cells while increasing both the available glucose and the conversion of amino acids to carbohydrates.

Which type of hormone diffuses across the plasma membrane and binds to receptors in the cytoplasm?

Hormones that diffuse across the plasma membrane and bind to receptors in the cytoplasm are steroid hormones.

In a dehydrated person, how would the amount of ADH released by the posterior pituitary change?

In a dehydrated individual, the amount of ADH released by the posterior pituitary increases in response to increased blood osmotic pressure resulting from a rise in solute concentration.

List three functions of melatonin.

In humans, melatonin may affect the timing of sexual maturation, protect against damage by free radicals, and set circadian rhythms.

What is the effect of increased glucagon levels on the amount of glycogen stored in the liver?

Increased levels of glucagon stimulate the conversion of glycogen to glucose in the live, which would in turn reduce the amount of glycogen stored in the liver.

Increased amounts of light would inhibit the production of which hormone?

Melatonin secretion is influenced by light--dark cycles. Increased amounts of light would inhibit the production ( and release ) of melatonin from the pineal gland, which receives neural input concerning the presence of light or darkness form visual pathway collaterals.

Why do signs and symptoms of decreased thyroxine concentrations not appear until about a week after a thyroidectomy?

Most of the body's reserves of thyroid hormone, thyroxine, are bound to transport proteins in the bloodstream called thyroid-binding globulins. Because these compounds represent such a larger reservoir of thyroxine, it takes several days after the removal of the thyroid gland for blood levels to thyroxine to decline.

The secretion of which hormone lowers blood glucose concentrations?

The secretion of insulin lowers blood glucose concentrations.

Name the organs of the endocrine system.

Organs of the endocrine system are the hypothalamus, pituitary gland, thyroid gland, adrenal gland, pancreas, pineal gland, and parathyroid gland. Organs of other systems that have endocrine functions are the heart, thymus, digestive tract, kidneys, and gonads.

Explain how the parathyroid hormones raises the blood calcium levels.

Parathyroid hormone (PTH) raises blood calcium deposition in bones, by increasing reabsorption of calcium form the blood by the kidneys, and by increasing the production of calcitriol by the kidneys.

Identify the hormone-secreting cells of the pineal gland.

Pinealocytes

If a blood sample contained elevated levels of somatomedins, which pituitary hormone would expect to be elevated?

Somatomedins mediate the action of growth hormone. Elevated levels of growth hormone typically accompany elevated levels of somatomedins.

Name and describe the characteristics and functions of the blood vessels that link the hypothalamus with the anterior lobe of the pituitary gland.

The blood vessels of the hypophyseal portal system link the hypothalamus and anterior lobe. Fenestrated capillary beds in each structure are connected by portal vessels. This arrangement ensures that hypothalamic regulatory hormones reach the "downstream" endocrine cells of the anterior lobe directly, before mixing with, and being diluted by, the general circulation.

Define endocrine system.

The endocrine system includes organs whose primary function is the production of hormones or paracrine factors, which are chemical secretions that are transported via the extracellular fluid or bloodstream to target cells in other sites within the body.

* Name the peptide secreted by the heart and a hormone released by the kidneys.

The heart secretes natriuretic peptide and the kidneys release erythropoietin.

Name the hormones of the thyroid gland.

The hormones of the thyroid gland are Thyroxine (T4), T3, and calcitonin.

Identify the nine pituitary hormones and their target tissues.

The hormones produced and released by the anterior lobe are 1. Thyroid-stimulating hormone (TSH), which targets the thyroid gland. 2. Adrenocorticotropic hormone (ACTH), which targets the adrenal gland. 3. Follicle-stimulating hormone (FSH) 4. Luteinizing hormone (LH), which target the testes in males and the ovaries in females. 5. Growth hormone (GH), which targets lever cells ( which respond by synthesizing somatomedins). 6. Prolactin (PRL), which targets mammary glands in females 7. Melanocyte-stimulating hormone (MSH), which targets melanocytes in the skin. Hormone released in the posterior lobe are 8. Oxytocin (OXT), which target the mammary gland. 9. Anti-diuretic hormone (ADH), which targets the kidneys.

List the hypothalamic releasing hormones.

The hypothalamic releasing hormones are 1. corticotrophin-releasing hormone (CRH) 2. thyrotropin-releasing hormone (TRH) 3. growth hormone-releasing hormone (GH-RH) 4. prolactin-releasing hormone (PRF) 5. gonadotropin-releasing hormone (GnRH)

Describe the locations of the parathyroid glands.

The parathyroid glands are embedded in the posterior surfaces of the lateral lobes of the thyroid gland.

Identify the three mechanisms by which the hypothalamus integrates neural and endocrine function.

The three mechanisms of hypothalamic integration of neural and endocrine functions are (1) secretion of antidiuretic hormone and oxytocin (2) secretion of regulatory hormones that control activity of the anterior love of the pituitary gland, and (3)neural (sympathetic) control over the endocrine cells of the adrenal medulla

List three zones of the adrenal cortex

The three zones of the adrenal cortex are the zona glomerulosa, zona fasciulata, and zona reticularis.

Name the two lobes of the pituitary gland.

The two lobes of the pituitary gland are the anterior lobe and posterior lobe.

Identify the two regions of an adrenal gland, and cite the hormones secreted by each.

The two regions of an adrenal gland are the cortex and the medulla. The cortex secretes mineralocorticoids, primarily aldosterone; glucocorticoids, mainly cortisol and corticosterone; and androgens. The medulla secrets epinephrine and norepinephrine.

Identify and describe the two types of diabetes mellitus

The two types of DM. are type 1, characterized by inadequate insulin production by the pancreatic beta cells, and type 2, characterized by insulin resistance.