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