chapter 16: the endocrine system

1. The release if which pituitary hormone would lead to an increased level of somatomedins in the blood?

Increased levels of GH would increase levels of somatomedins

Name the organs of the endocrine system

Hypothalamus, pituitary gland, thyroid gland, adrenal glands, pancreas (pancreatic islets), pineal gland, and parathyroid glands. Organs of other systems that have a secondary endocrine function are the heart, thymus, digestive system, kidneys, and gonads

1. What thyroid hormone aids in calcium regulation?

calcitonin

What kind of effect do hormones have if they produce different but complementary effects?

integrative effects

1. Define regulatory hormone

A hormone secreted by the hypothalamus that controls endocrine cells in the anterior lobe of the pituitary gland

Define diabetes mellitus

Endocrine disorder characterized by elevated blood glucose levels high enough to overwhelm the reabsorption capabilities of the kidneys

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

Stimulate conversion of glycogen to glucose in the liver, which in turn reduces the amount of glycogen stored in the liver

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

The amount of ADH released would increase in response to increased blood osmotic pressure resulting from a rise in solute concentration

1. Name the hormone and enzyme secreted by the kidneys

· The kidneys secrete the hormone erythropoietin (EPO) and the enzyme renin. EPO increases red blood cell production. Upon its release into the blood stream, renin functions as an enzyme that activates the renin-angiotensin-aldosterone system. Together, these responses ultimately cause blood pressure and blood volume to increase

1. Describe the two types of diabetes mellitus

· Type 1- inadequate insulin production by the pancreatic beta cells · Type 2- insulin resistance, failure of the body to use insulin properly

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

steroid hormones

1. List the three phases of the stress response

Alarm phase, resistance phase, and the exhaustion phase

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

Aldosteronism

Which of the four hormonal effects are involved in a negative feedback loop?

Antagonistic effects

Name the two lobes of the pituitary gland

Anterior lobe and posterior lobe

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

Blood vessels of the hypophyseal portal system link the hypothalamus and anterior lobe of the pituitary gland. Unusually permeable 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

Describe the locations of the parathyroid glands

Imbedded in the posterior surfaces of the lacteal lobes of the thyroid gland

Define endocrine system

Includes organs whose primary function is the production of hormones or paracrine, which are chemical secretions that are transported by the extracellular fluid or bloodstream to target cells in other sites within the body

1. What effects would increased circulating levels of glucocorticoids have on the pituitary secretion of ACTH?

Increased glucocorticoids inhibit the release of CRH vy the hypothalamus. The lack of CRH reduces secretion of ACTH from the pituitary gland, so ACTH levels would decrease

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

Increased secretion of PTH

The secretion of which hormone lowers blood glucose concentration?

Insulin secretion lowers blood glucose concentration

Describe the resistance phase

Long-term metabolic adjustments including mobilization of remaining energy reserves (lipids and amino acids), conservation of glucose, elevation of blood glucose concentration, and conservation of salts and water coupled with loss of K+ and H+

1. List three functions suggested for melatonin in humans

Maintain circadian rhythms, affect the timing of sexual maturation, and protect against damage by free radicals

Identify three common causes of hormone hyposecretion

Metabolic factors, physical damage, and congenital disorders

Name the hormones secreted by the heart

Natriuretic peptides, which ultimately cause blood pressure and blood volume to decrease

Explain how parathyroid hormone increases blood calcium level

PTH increases blood calcium levels by increasing calcium release from bones, increasing reabsorption of calcium in the blood by the kidneys, which increases the absorption of calcium from the digestive tract

What effect would increased cortisol levels have on blood glucose level?

Result in elevated blood glucose levels, because cortisol reduces the use of glucose by cells while increasing both the available glucose (by promoting glycogen breakdown) and the conversion of amino acids to carbohydrates

1. Name the regions and zones of an adrenal gland from superficial to deep

The regions are the Adrenal capsule, adrenal cortex, and adrenal medullae. The zones are the zona glomerulosa, zona fasciculata, and zona reticularis

1. Name the hormones of the thyroid gland

Thyroxine (T4), or tetraiodothyronine; triiodothyronine (T3); and. Calcitonin

1. What is the common goal of the nervous and endocrine systems?

To preserve homeostasis by coordinating and regulating the activities of other cells, tissues, organs, and organ systems

1. Define synergistic effect

Two hormones have an additive effect so that the net result is greater than the effect each would produce alone

1. 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 A second messenger changes the rate of various metabolic reactions by acting as an enzyme activator, an enzyme inhibitor, or a cofactor

Define hormone receptor

· A protein molecule located either on the plasma membrane (extracellular receptor) or inside the cell (intracellular receptor) that binds with a specific hormone

Cite the hormones secreted by each region of an adrenal gland

· Adrenal cortex - secretes mineralocorticoids, primarily aldosterone; glucocorticoids, mainly cortisol (or hydrocortisone) and corticosterone; and androgens Adrenal medullae- secretes epinephrine and norepinephrine

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) Pancreatic polypeptide cells (pancreatic polypeptide hormone)

Describe the structural classification of hormones

· Amino acid derivatives (thyroid hormones, catecholamines, and tryptophan derivatives · Peptide hormones (glycoproteins or short polypeptide chains) · Lipid derivatives (eicosanoids and steroid hormones), which contain carbon rings and side chains that are built from fatty acids or cholesterol

1. List the hypothalamic releasing hormones

· Corticotropin-releasing hormone (CRH). Thyrotropin-releasing hormone (TRH), growth hormone-releasing hormone (GH0RH), prolactin =-releasing hormone (PRH), and gonadotropin-releasing hormone (GnRH)

1. Identify some clinical problems associated with diabetes mellitus

· Diabetic retinopathy, blockages in heart circulation and increased risk for heart attack, diabetic nephropathy, diabetic neuropathy, and decreased blood flow to the distal limbs

1. During which phase of the general adaptation syndrome is there a collapse of vital systems?

· During the exhaustion phase

Identify several hormones necessary for normal growth and development

· GH, thyroid hormones, insulin, PTH, calcitriol, and reproductive hormones

1. Identify the nine pituitary hormones and their target tissues

· Hormones produced/released by anterior lobe: Thyroid stimulating hormone (TSH) which targets the thyroid gland, adrenocorticotropic hormone (ACTH) targets the adrenal cortex, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) target the testis in males and ovaries in females, growth hormone (GH) targets liver cells, prolactin (PRL) targets mammary glands in females, melanocyte-stimulating hormone (MSH) targets melanocytes in the skin. · Hormones released by the posterior lobe: oxytocin (OXT) targets the uterus and mammary glands and antidiuretic hormone (ADH) targets the kidneys

Define the prefixes hyper- and hypo- in the context if endocrine disorders

· Hyper refers to excessive hormone production · Hypo refers to inadequate hormone production

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

· Melatonin secretion is influenced by day/night patterns. Increased amount of light would inhibit the production and release of melatonin from the pineal gland

Why do signs and symptoms of decreased thyroxine concentration not appear until about a week after a thyroidectomy (surgical removal of the thyroid gland)

· Most of the body's reserves of hormone (T4) are bound to transport proteins in the bloodstream including thyroid-binding globulins, transthyretin, or albumin (a plasma protein). Because these compounds represent such a large reserve of thyroxine, it takes several days after removal of the thyroid gland for blood levels pf thyroxine to decline

Identify the hormone secreting cells of the pineal gland

· Pinealocytes

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

· Secretion if antidiuretic hormone (ADH) and oxytocin (OXT) · Secretion of regulatory hormones that control activity of the anterior love if the pituitary gland Neural (sympathetic) control over the endocrine cells of the adrenal medullae