Endocrine

Question 1

Q1: List the hormones (along with type of chromophil cell) produced by the anterior pituitary gland.

Answer 1

Somatropes (growth hormone, GH), acidophils
Lactotropes (prolactin & vasoactive inhibitory peptide, PRL & VIP), acidophils
Corticotropes (adrenocorticotropic hormone & proopiomelanocortin, ACTH & POMC), basophils
Gonadotropes (follicle-stimulating & luteinizing hormones, FSH & LH), basophils
Thyrotopes (thyroid-stimulating hormone, TSH), basophils

Question 2

Q2: Clinical correlation: what is Sheehan syndrome?

Answer 2

During pregnancy the pituitary enlarges & requires increased blood supply. If a hemorrhage associated with the pregnancy/delivery occurs, the pituitary can become infarcted. Sheehan syndrome has lack of milk production, loss of pubic & axillary hair, & fatigue. (Atlas p 213)

Question 3

Q3: Why does the follicular epithelium have a varied appearance?

Answer 3

Follicular epithelium ranges from squamous to cuboidal to low columnar depending on its activity level. Higher epithelium associated with increased activity.

Question 4

Q4: What do the parafollicular cells secrete and what is their critical function?

Answer 4

Parafollicular cells (C cells) secrete calcitonin which regulates calcium metabolism: lowers serum calcium levels by suppressing the action of osteoclasts & promotes calcium deposition in bones by increasing the rate of osteoid calcification. This response is rapid.

Question 5

Q5: Which cell of the parathyroid gland has a secretory product and what is its function?

Answer 5

Chief cells (principal cells) synthesis & store PTH (parathyroid hormone) which increases calcium & decreases phosphate blood levels simultaneously. Oxyphil cells do not have a secretory role.

Question 6

Q6: Which portion of the adrenal gland is responsible for “flight or fight”?

Answer 6

Chromaffin cells (medulla) secrete catecholamines and the cells of the zona fasciculate secrete glucocorticoids which induce the conversion of norepinephrine to epinephrine.

Question 7

Q7: Clinical correlation: what is Cushing Syndrome and which portion of the adrenal gland is responsible for this syndrome?

Answer 7

• Cushing’s syndrome describes the signs and symptoms associated with prolonged exposure to inappropriately high levels of the hormone cortisol. This can be caused by taking glucocorticoid drugs, or diseases that result in excess cortisol, adrenocorticotropic hormone (ACTH), or CRH levels. • osteoporosis
• diabetes mellitus
• hypertension
• menstrual disorders such as amenorrhea in women and decreased fertility in men
• Hirsutism
• baldness
• hypercholesterolemia
C - Central obesity, Cervical fat pads, Collagen fiber weakness, Comedones (acne)
U - Urinary free cortisol and glucose increase
S - Striae, Suppressed immunity
H - Hypercortisolism, Hypertension, Hyperglycemia, Hypercholesterolemia, Hirsutism, Hypernatremia, Hypokalemia
I - Iatrogenic (Increased administration of corticosteroids)
N - Noniatrogenic (Neoplasms)
G - Glucose intolerance, Growth retardation

Question 8

Q8: What fixation and stain can be used to differentiate between the 3 cell types, and what does each of the different cell types produce?

Answer 8

Zenker-formol fixation followed by Mallory-Azan staining identifies pancreatic cell types. (lecture slide 47) Immunohistochemical stains can demonstrate that cells secrete more than one hormone.

Question 9

Q9: What are physiological and radiological correlations of the pineal gland?

Answer 9

Pinealocytes secrete melatonin that may help establish circadian rhythms. It may also have antigonadotropic effects that delay the onset of sexual maturity.
The central location of the pineal gland within the brain and the radiopacity of brain sand provide a useful landmark for radiologists.

Question 10

Q10: What is indicated by the blue and green arrows?

Answer 10

Pinealocyte and capillary.

Question 11

tumor of anterior pituitary causes?

Answer 11

cushing’s syndrome. Anterior pituitary. Adenomas are specific to the anterior pituitary may cause Cushing’s syndrome. Excess ACTH leads to excess corticosteroids released from the adrenal cortex (Cushing’s syndrome). Alternatively, LH- and FSH-producing adenomas may occur, but these tend to cause hypogonadism. Prolactinomas are the most common form of pituitary adenoma resulting in infertility, galactorrhea (spontaneous flow of milk from the breast, unassociated with childbirth or nursing) , and amenorrhea (absence of a menstrual period in a woman of reproductive age).

2: The thyroid secretes T3 and T4.
3: Diabetes insipidus is caused by absence of vasopressin, leading to excretion of dilute urine.
4: Overproduction of PTH leads to osteoporotic changes, but PTH is not regulated by the anterior pituitary.
5: Somatotropic tumors produce GH and cause giantism.

Question 12

tumor of adrenal medulla causes?

Answer 12

Excess norepinephrine

Response Feedback:
Correct answer: 5. Excess norepinephrine leads to paroxysms. A pheochromocytoma is a common tumor of the adrenal medulla, and is characterized by excess norepinephrine, leading to paroxysms. Symptoms include headache, sweating, palpitations, and anxiety. Hypertension and hyperglycemia are common.

1: Vasoconstriction of arterioles occurs in conjunction with the increased blood pressure.
2: Epinephrine has anti-insulin effects, thus leading to hyperglycemia.
3: Hirsutism,excessive hairiness, is not associated with adrenal medulla tumors.
4. Pheochromocytoma is associated with an increased metabolic rate.