Endocrine Physiology Flashcards
Covers: Hypothalamic pituitary interaction, Hormonal regulation of calcium, Pituitary gland function, Thyroid gland function, and Adrenal gland function lectures
What portion of the brain regulates hormonal activity in the body by receiving information from the body through the blood and controlling the secretion of hormones?
(Hypothalamus)
Is the secretion of hormones through the posterior pituitary gland a direct or indirect mechanism?
(Direct)
Is the secretion of hormones through the anterior pituitary gland a direct or indirect mechanism?
(Indirect)
What are the similarities and differences between neurotransmitters and neurohormones?
(Both are released by neurons; neurotransmitters → act locally on neighboring neurons/cells (e.g. ACh) while neurohormones travel in the blood to affect cells at a distant site (e.g. ADH))
Do ‘classic mechanism’ endocrine hormones, which are released by endocrine organs/glands/tissue/cells, affect local cells or distant cells?
(Distant)
Do ‘extended definition’ endocrine hormones affect local cells or distant cells?
(Local)
What is the neural part of the central neuroendocrine system?
(Hypothalamus)
What is the endocrine part of the central neuroendocrine system?
(Pituitary)
Hypophysis is an additional term for what structure?
(Pituitary)
What is the term for hormones that target other endocrine tissues and cause the production or secretion of another hormone?
(Tropic hormones)
What is the term for a hormone that promotes cellular growth differentiation or survival?
(Trophic hormones; trophic does not just refer to hormones though but I referenced a hormone to make answering the question easier)
What is usually the goal of endocrine negative feedback loops?
(Homeostasis)
What is the term for the extension of the endocrine tissue of the pituitary gland into the pituitary stalk?
(Pars tuberalis)
What is the term for the extension of neural tissue of the hypothalamus into the pituitary stalk that houses the hypothalamohypophyseal tract?
(Infundibulum)
What are the two other terms for neurohypophysis?
(Posterior lobe of the pituitary gland or the pars nervosa)
What are the two other terms for the pars distalis?
(Anterior lobe of the pituitary gland or the adenohypophysis)
What is the term for the blood supply to the hypothalamus and pituitary that is important for their communication?
(Hypophyseal portal system)
Which lobe of the pituitary gland forms its own hormones in response to hormones released by the hypothalamus?
(Anterior pituitary)
Which lobe of the pituitary gland stores hormones that were released by the hypothalamus and then releases those hormones as needed?
(Posterior pituitary)
What are the two hormones related to the posterior pituitary?
(Oxytocin and ADH/vasopressin)
What value would you look at on your chem to tell you how much extracellular calcium there is in your patient?
(tCA2+/total calcium)
What value would you look at on your chem to tell you how much intracellular calcium there is in your patient?
(None, cannot measure intracellular calcium)
What does an ionized calcium test tell you?
(How much calcium is in its active form within plasma)
Will hypoproteinemia lead to a decreased or increased tCA2+ value?
(Decreased, 40% of extracellular calcium is bound to albumin so if you have decreased protein, less albumin, and therefore less extracellular calcium)
What are the two hormones that play pivotal roles in the maintenance of calcium and phosphorus values WNL?
(Parathyroid hormone/PTH and calcitriol/vitamin D)
What hormone is required for the synthesis of vitamin D in the kidneys?
(PTH)
What effect does vitamin D have on the GI tract and what is the resultant effect on the patient’s serum?
(Stimulates calcium and phosphorus absorption → increased serum calcium and phosphorus)
What effect does PTH have on the bone and what is the resultant effect on the patient’s serum?
(Stimulates calcium and phosphorus release → increased serum calcium and phosphorus)
What effect does PTH have on the kidney and what is the resultant effect on the patient’s serum?
(Stimulates calcium reabsorption → increased serum calcium; inhibits phosphorus reabsorption → decreased serum phosphorus)
Decreased serum calcium will stimulate or inhibit (choose one) PTH?
(Stimulate)
Decreased serum calcium will stimulate or inhibit (choose one) vitamin D?
(Stimulate)
Increased serum calcium will stimulate or inhibit (choose one) PTH?
(Inhibit)
Increased serum calcium will stimulate or inhibit (choose one) vitamin D?
(Inhibit)
What effect does calcitonin have on bones and what is the resultant effect on the patient’s serum?
(Inhibits calcium release → decreased serum calcium)
Increased serum calcium will stimulate or inhibit (choose one) calcitonin?
(Stimulate)
The blood capillary system that is contained within the pituitary stalk connects what two structures? Be specific.
(Hypothalamus and anterior pituitary)
The large neurons contained within the pituitary stalk connect what two structures? Be specific.
(Hypothalamus and posterior pituitary)
What is a releasing hormone?
(A hormone that is released by the hypothalamus that acts on the anterior pituitary gland)
What is a stimulating hormone and from what structure are they secreted?
(Anterior pituitary secrete stimulating hormones which affect distant endocrine glands to secrete other hormones)
What is a functional hormone and from what structures are they secreted?
(Both posterior and anterior pituitary glands secrete functional hormones which affect distant organ tissue to perform a specific function that is not related to the production of additional hormones)
What is the function of deiodinases found in peripheral tissues?
(Deiodination of T4 which turns it into T3 which is the more bioactive/effective thyroid hormone)
Do thyroid hormones increase or decrease (choose one) the heart rate?
(Increase)
Do thyroid hormones increase or decrease (choose one) the contractility of the heart?
(Increase)
Do thyroid hormones increase or decrease (choose one) renal blood flow?
(Increase)
Do thyroid hormones increase or decrease (choose one) GFR?
(Increase)
Do thyroid hormones increase or decrease (choose one) blood pressure?
(Increase)
Do thyroid hormones increase or decrease (choose one) systemic vascular resistance?
(Decrease)
What structure secretes thyroid-releasing hormone?
(The hypothalamus)
What structure secretes thyroid-stimulating hormone?
(Anterior pituitary gland)
What changes do you expect to see in T4, fT4, and TSH in a hyperthyroid cat?
(T4 and fT4 will be increased while TSH will be decreased)
What changes do you expect to see in T4, fT4, and TSH in a hypothyroid dog?
(T4 and fT4 will be decreased while TSH will be increased)
(T/F) The zona glomerulosa of the medulla of the adrenal gland secretes mineralocorticoids i.e. aldosterone.
(F, the zona glomerulosa of the CORTEX of the adrenal gland secretes aldosterone)
What does the zona fasciculata of the cortex of the adrenal gland secrete and give an example?
(Glucocorticoids i.e. cortisol)
What does the medulla of the adrenal gland secrete and give two examples?
(Catecholamines i.e. nor/epinephrine)
Does aldosterone actively or passively promote water uptake?
(Passively → aldosterone actively promotes sodium reabsorption and water follows passively)
Does aldosterone stimulate potassium and hydrogen reabsorption or secretion (choose one)?
(Secretion → decreases serum K+ and H+)
Is cortisol an insulin agonist or antagonist?
(Antagonist → it is a diabetogenic hormone)
What is the primary stimulus for cortisol production in the adrenal gland?
(Adrenocorticotropic hormone/ACTH)
What is the primary stimulus for aldosterone production in the adrenal gland?
(Serum potassium levels → increased potassium will increase aldosterone production, and decreased potassium will decrease aldosterone production)
What is the secondary stimulus for aldosterone production in the adrenal gland?
(Angiotensin II → increased angiotensin II will increase aldosterone production, and decreased angiotensin II will decrease aldosterone production)
Does an increased or decreased (choose one) extracellular fluid volume increase renin and angiotensin II production (which then increases aldosterone production)?
(Decreased ECF/hypovolemia → increases RAAS to stimulate sodium reabsorption and then water follows to increase volume)
What are the locations of alpha (1 and 2), beta 1, and beta 2 receptors in the body?
(Alpha 1/2 is in peripheral blood vessels, beta 1 is in the heart, and beta 2 is in the airways primarily)
Which of the catecholamines (nor/epinephrine) has a greater affinity for alpha receptors?
(Norepinephrine)
Which of the catecholamines (nor/epinephrine) has a greater affinity for beta receptors?
(Neither, epinephrine has equal affinity while norepinephrine has a greater affinity for alpha receptors)
