Chapter 18

Thyroid-stimulating hormone (Function, target organ, hypothalamic releasing factor, and Negative feedback system)

Function: Stimulate thyroid gland to release thyroid hormone Target Organ: Thyroid gland Hypothalamic releasing factor: TRH Negative feedback system: Thyroid hormones rise the rates of TRH and TSH production decreases

Explain diabetes insepidus

Generally develops because the neurohypophysis is no longer releases adequate amounts of ADH. (Urinate too much --> rapid dehydration)

Explain the function of the "stress hormone" CORTISOL

Glucocorticoids speed up the rates of glucose synthesis & glycogen formation especially in the liver.

What is the basic function of the thyroid hormone

Increase metabolism

Where are the 2 places target cell hormone receptors located?

Plasma membrane & inside the cell

Explain the function of Aldosterone and what triggers the adrenal cortex to secrete aldosterone

Stimulates the conservation of sodium ions & the elimination of potassium ions Aldosterone secretion occurs in response to a drop in blood sodium content, blood volume or BP or rise in potassium concentration

Which of the 2 thyroid hormones is primarily responsible for the observed effects of the thyroid hormone?

T3

identify the hormones of the thyroid gland

T4 and T3, and calcitonin

What hormone plays a key role in both the synthesis and the release of thyroid hormones

TSH

Identify the two regions of the adrenal gland, AND cite which regions secrete the hormones epinephrine, aldosterone, and cortisol

Two regions of the adrenal gland are the cortex & the medulla Cortex: secretes mineralocorticoids, glucocorticoids & androgens and Aldosterone Medulla: epinephrine & norepinephrine

Identify the first 2 types of cells in the pancreatic islets, the hormones produced by each and the function of each hormone

Alpha cells- glucagon- mobilize energy reserves Beta cells- insulin- affects cellular metabolism

Explain the steps the steroid hormone testosterone would take to stimulate the production of enzymes and structural proteins in skeletal muscle fibers, causing an increase in muscle size and strength

1) steroid hormones diffuse through the membrane lipids 2) Bind to receptors in the cytoplasm or nucleus 3) Hormone receptor complex then binds to DNA 4) Activation of gene 5) Protein synthesis

If a person were dehydrated, how would the amount of ADH released by the neurohypophysis change?

Amount of ADH would increase because the blood concentration is increased

List 3 mechanisms of hypothalamic control over endocrine function

1) Secretes regulatory hormones to control the anterior pituitary glad 2) makes ADH & Oxytocin for the posterior pituitary gladn 3) Controls sympathetic output to the adrenal medullae

Briefly list the 3 ways PTH can increase Ca concentration

1) mobilizes ca from bone by affecting osteoblast & osteoclast activity 2) enhances the reabsorption of ca by the kidneys, reducing urinary losses 3) help digestive tract absorption

The neurohypophysis contains the axons of hypothalamic neurons. What 2 hormones do these neurons produce and deliver to the neurohypophysis?

ADH- anti-diuretic OXT- Oxytocin

Identify the two lobes of the pituitary gland

Anterior lobe- adenohypophysis Posterior lobe- neurohypophysis

What hormones is produced by the C-CELLS OF THE THYROID GLAND and what is this hormones function?

Calcitonin- lowers levels in the blood

What is the primary function of ADH?

Decrease water loss from the kidneys

What conditions in the body can cause release of ADH?

Dehydration

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

Elevation of blood glucose

What element (ion) must combine with the globular protein THYROGLOBULIN in the thyroid gland to make THYROID HORMONE

IODIDE (IODINE)

Explain how PTH and CALCITONIN maintain the homeostatic regulation of calcium ion concentrations

If homeostasis is disturbed decreasing ca levels in blood the parathyroid gland secrete PTH increasing ca. If homeostasis is disturbed increasing ca levels in blood the thyroid gland produces calcitonin decreasing ca.

Identify the hormone secreted by the 4 parathyroid glands

PTH

What is the function of growth hormone (GH)

Stimulates cell growth & protein synthesis

What must a target cell have to be affected by a hormone?

an appropriate receptor

What signs and symptoms would you expect to see in an individual whose diet lacks iodine?

decreased metabolic rate decreased body temp poor responses to physiological stress increase in size of the thyroid gland

What are the 2 functions of the parathyroid cells

increase ca levels and monitors ca levels

Define hormone

the release of chemical messengers into the bloodstream to other tissues