Michels - High Yield for Exam One

Question 1

What is a hormone?

Answer 1

A hormone is a chemical substance that is classified as a peptide, steroid, or amine. Hormones are secreted into the circulation in small amounts and delivered to target tissues, where they produce physiologic responses. Hormones are synthesized and secreted by endocrine cells usually found in endocrine glands

Question 2

Lipid versus water soluble hormones?

Answer 2

Know the differences

Question 3

Lipid soluble hormones (details):

Answer 3

I.e. = steroids, thyroid hormones
Receptors: inside the cell (usually in nucleus)
Action: Production of specific new proteins
Storage? No, synthesized as needed (exception here is thyroid hormones)
Plasma transport: Attached to carrier proteins (exception here is adrenal androgens)
t1/2: Long (hours/days, depends on protein carrier)

Question 4

Water soluble hormones (details):

Answer 4

I.e. = Peptides / proteins
Receptors: outer surface of cell membrane
Action: Second messengers (i.e. cAMP)… modify action of intracellular enzymes
Storage? Yes, in vesicles (sometimes prohormones)
Plasma transport: No, dissolved (free, unbound)
t1/2: Short (mins, depends on MW)

Question 5

Sampling of hormones is difficult because…

Answer 5

There is/are variation/patterns of hormone release throughout the 24-hr day (i.e. sleep-wake cycle and cortisol / GH)

Question 6

Measuring hormone levels in blood and urine (details):

Answer 6

Plasma analysis:
Reflective only of time of sampling
Pulsatile secretion, diurnal variation, cyclic variation, age, sleep entrainment, hormone antagonism, hormone and metabolite interaction, and protein binding can all cause variation in hormone levels

Urine analysis:
Restricted to the measurement of catecholamines and steroid hormones
Can reflect an integrated sample

Question 7

In general, what happens if there is endocrine dysfunction?

Answer 7

Either the loss or gain of hormone production… in general.

Question 8

What encases the pituitary gland?

Answer 8

The pituitary gland is encased in the sphenoid bone in the sella turcica

Question 9

Pituitary adenomas can cause…

Answer 9

Pituitary tumors will expand upward and can press on the optic chiasm and other regions of the brain → causes dizziness and vision problems

Question 10

What is one of the most severe complications of people with acromegaly?

Answer 10

Organ enlargement, specifically cardiomegaly (can cause electric problems and heart failure)

Question 11

What is the most valid and useful assessment of thyroid function?

Answer 11

Serum TSH level (normal = 0.5 - 5.0 microUnits/mL)

Question 12

Triad of Grave’s Dz

Answer 12

1) Hyperthyroidism- hyperfunctional, diffuse enlargement of the thyroid gland, TSH ↓ but T3, T4 and thyroid size ↑
2) Infiltrative ophthalmopathy with exophthalmos
3) Localized, infiltrative dermopathy (pretibial myxedema)

Question 13

Are circulating levels of lipids also linked to glucose metabolism?

Answer 13

YES… “We are interested in not only carb intake but also fat intake”

Question 14

Insulin receptor signaling causes increases in translocation of which glucose transporters?

Answer 14

Glut4 and Glut12 to the cell membrane

Question 15

What are the four changes that glucagon-like intestinal peptide GLP-1 induces?

Answer 15

1) inhibits gastric emptying
2) *promotes insulin release
3) inhibits glucagon release
4) suppresses appetite

Question 16

What “degrades” GLP-1?

Answer 16

DPP-IV

Question 17

Double peak on CGM monitoring graph?

Answer 17

First peak is due to carbs

Second peak is from fats

Question 18

What is the percentage for family hx in DMII?

Answer 18

50% (contrasted against 10-20% for type one)

Question 19

What are the 3 causes for obesity-induced insulin resistance?

Answer 19

Decreased GLUT-4 uptake of glucose in response to insulin release (just mm. and adipocytes??????) LIPOTOXICITY

Decreased ability of insulin to repress hepatic glucose production LIPOTOXICITY AND INFLAMMATION

Inability of insulin to repress hormone-sensitive lipase (HSL) or increase lipoprotein lipase (LPL) in adipose tissue DYSLIPIDEMIA

Question 20

Describe type 2 diabetes in one sentence:

Answer 20

Reactive hyperinsulinemia followed by relative hypoinsulinemia

Question 21

Does type 2 diabetes causes an increase or decrease in incretin levels (in response to glucose)?

Answer 21

A decrease

Question 22

What causes the rebound effect in diabetics (bounce back on CGM after a period of hypoglycemia)?

Answer 22

Endogenous glucagon

Question 23

GH has what kind of an effect on insulin?

Answer 23

It is an antagonist… causes hyperglycemia sometimes seen after growing kids fall asleep

Question 24

What is the key test in the differential diagnosis of hypercalcemia?

Answer 24

Serum PTH assay

Question 25

PTH-dependent hypercalcemic disorders:

Answer 25

Primary hyperparathyroidism (increased PTH)

Hypercalcemia of malignancy (PrTH)

Question 26

PTH independent disorders for hypercalcemia:

Answer 26

Thiazide diuretics (can be a cause for hyperCa)
Milk-alkali syndrome*
Immobilization
Acute renal failure (diff. b/w acute vs chronic)
Granulomatous disease*
Vitamin D intoxication*

Question 27

DDx for Hypocalcemia:

Answer 27

Vitamin D Deficiency
Hypoparathyroidism* 
Pseudohypoparathyroidism
Genetic disorder causing resistance to PTH
Hypomagnesemia
Chronic Renal Failure (causes deficiency/decreased 1,25)***
Liver Failure
Acute Pancreatitis
Hypoproteinemia (albumin)