Endocrine Flashcards
The secretion of too little hormone is known as __________.
Hyposecretion
The secretion of too much hormone is known as __________.
Hypersecretion
This occurs when the receptors on target cells are under-responsive to a hormone.
Hyporesponsiveness
This occurs when the receptors on target cells are over-responsive to a hormone.
Hyperresponsiveness
What is a primary disorder?
the disorder is located primarily in the end-organ. (Ex: primary hypothyroidism is underproduction of thyroid hormone, which happens because of problems in the thyroid itself.)
What is a secondary disorder?
The source of the disorder is somewhere besides the end-organ, usually the hypothalamus or the pituitary. (Ex: Secondary Hypercortisolism happens because of a pituitary tumor that makes too much ACTH, causing the adrenal gland to make too much cortisol.)
Secretion of CRH in the hypothalamus stimulates the secretion of _______ in the anterior pituitary
ACTH
Secretion of TRH in the hypothalamus stimulates the secretion of _______ in the anterior pituitary
TSH
Secretion of GHRH in the hypothalamus stimulates the secretion of _______ in the anterior pituitary
GH
Secretion of SS in the hypothalamus inhibits the secretion of _______ in the anterior pituitary
GH
What are the 2 forms of thyroid hormones?
T3 (3 iodide groups)
T4 (4 iodide groups)
Draw the hypothalamus-pituitary-thyroid (target gland axis) feedback loop
Neural inputs –>
TRH secretion in the hypothalamus –>
Increase in plasma TRH –>
TSH secretion in the anterior pituitary –>
Increase in serum TSH –>
T3/T4 secretion by the thyroid gland –>
Increase in plasma T3/T4
T3/T4 ________ feeds back to the _______ and the_______
Negatively
Hypothalamus
Anterior Pituitary
T4 is converted ___ in a response to an _______ level in T3
T3
Increased
What are the THREE actions of thyroid hormones?
- Metabolic Actions (Speeds metabolic processes)
- Permissive Actions (Magnifies the effect of other hormones)
- Growth/Development (Acts in conjunction with GH)
- You are on your gynecology rotation and have scrubbed in on your first surgery—an oophorectomy being performed on an ovarian mass. The ovary is removed and sent to pathology for a frozen section—a quick pathological look to see if the mass is cancerous or not. The pathologist calls your OR and informs you, excitedly, that the patient has an ovarian tumor called a struma ovarii—a tumor which secretes active thyroid hormone (T3 and T4) whether it is stimulated or not.
a. is this patient hyperthyroid, euthyroid, or hypothyroid?
b. Is her condition primary, or secondary?
c. Will the following labs be low, normal or elevated?
i. TSH
ii. FT4
iii. T3
iv. TRH
A. Hyperthyroid
B. Secondary
C.
i. TSH is LOW
ii. T4 is HIGH
iii. T3 is HIGH
iv. TRH is LOW
- President John F. Kennedy is one of the most famous people to have Addison’s Disease (primary adrenal insufficiency). How would you expect this disease to affect his:
a. Serum Cortisol?
b. Serum ACTH?
c. Serum Potassium? (Hint: Aldosterone production can also be affected by Addison’s disease)
d. Serum Sodium?
(REMEMBER: In normal renal function the kidneys “absorb” K+ and excrete Na+)
A. Low
B. High
C. Elevated
D. Decreased
- A 23 year old female patient has been found to have a large pituitary tumor; your PA preceptor thinks this may be an ACTH- secreting tumor, so she wants you to look for lab evidence that would support this idea.
a. If this is an ACTH- secreting tumor, what condition would you expect this patient to have? (specify hyper or hypo, primary or secondary)
b. What would likely be true of this patient’s levels of:
i. ACTH?
ii. Cortisol?
iii. Glucose?
A. Secondary hypercortisolemia
B.
i. HIGH
ii. HIGH
iii. HIGH
Richard Keil is an american actor with acromegaly. This is a hard disease to diagnose. It is most common with GH-producing pituitary tumors.
a. What change in his IGF-1 levels would you expect to see compared to the norm?
b. What is the typical GH response when a patient is given a glucose load? How would Richard Kiel’s response be different? .
A. Elevated (high)
B. Usually, GH decreases after a large glucose load (1-2 hours later). Richard Kiel’s will remain high.
- A 15 year old boy has come to see you for mental status changes and recurrent bone injury including two bones which have broken with only minimal exertion. You find out that he has abnormal serum calcium levels and osteoporosis.
a. What feedback loop is likely to be affected for him? Is he hypo- or hyper secretory of the active hormone?
b. What gland in this boy’s body might have a tumor growing within it?
c. Are his serum calcium levels low, or high?
A. the PTH loop with calcium. He is probably hyperparathyroid.
B. His parathyroid glands.
C. High. PTH causes serum calcium levels to go up—by stimulating the bowel to absorb Ca++ better, the bone to release Ca++ , and the kidney to decrease the amount of calcium that is excreted int o the urine (in other words, to save calcium). So oddly enough, this boy will have elevated serum calcium but also may have significant osteoporosis.
What is the permissive function of cortisol?
The action of epinephrine and norepinephrine on muscles and blood vessels.
How does cortisol work as a maintainer of glucose?
Ensures that there are adequate cellular concentrations of the enzymes required to produce glucose between meals.
How does cortisol work as a decreaser of inflammation?
It mediates events that are associated with the inflammatory response, such as capillary permeability and production of prostaglandins.
If you give a dose of cortisol (corticosteroids) what would happen to glucose? Inflammation?
Glucose would increase and inflammation would decrease
