Intro to Endocrine System

Question 1

What are the three general classes of hormones?

Answer 1

Proteins/peptides, amines, steroids

Question 2

Protein hormones are _ soluble

Answer 2

Water

Question 3

Steroid hormones are _ soluble

Answer 3

Lipid

Question 4

Where are protein hormones and steroid hormones stored?

Answer 4

Protein hormones stored in secretory vesicles

Steroid hormones not stored

Question 5

What are steroid hormones synthesized from?

Answer 5

Cholesterol— via the addition or removal of side chains

secreted and made in Adrenal cortex, gonads, corpus luteum, and placenta

Question 6

What are amine hormones derived from?

Answer 6

Tyrosine

Question 7

What are protein/peptide hormones first synthesized as and where are they modified?

Answer 7

Preprohormones, modified in ER to become prohormone, and then modified again in golgi to become hormone

Then released by an increase in intracellular Ca or increased cAMP/PKA activation

Question 8

What are the two groups of amine hormones?

Answer 8

Catecholamines- synthesized in cytosol and secretory granules
Thyroid hormones- synthesized by thyroid gland and stored as thyroglobulin in follicles

Question 9

What is the correlation between binding proteins, half life, and clearance rate?

Answer 9

Increased % binding protein = increased half life and decreased clearance rate

Thyroid Hormones longest HL, followed by Steroids, Then Protein hormones

Question 10

What are the two regulatory mechanisms of hormone secretion?

Answer 10

Neural mechanism - neuronal input to an endocrine cell

Feedback mechanism - negative/positive, more common than neural mechanism

Question 11

What is long-loop feedback?

Answer 11

Hormone released from 3rd tier endocrine gland feeds back to the 1st (hypothalamus) or 2nd (pituitary) tier

Question 12

What is short-loop feedback?

Answer 12

Hormone secreted from 2nd tier feeds back to 1st tier

Question 13

What is ultra short-loop feedback?

Answer 13

Gland inhibits its own secretion

Question 14

How can hormone receptor responsiveness be changed?

Answer 14

Changing number of receptors of changing affinity or receptors for hormone

Question 15

What types of hormones use adenylyl cyclase as a primary effector?

Answer 15

ACTH, LH, FSH, TSH, glucagon, etc

Question 16

What are the 2nd messengers for the adenylyl cyclase mechanism?

Answer 16

cAMP -> PKA

Question 17

What types of hormones use phospholipase C as a primary effector?

Answer 17

GnRH, TRH, oxytocin, etc

Question 18

What are the 2nd messengers for the phospholipase C mechanism?

Answer 18

PIP2 -> IP3, DAG -> Ca2+

Question 19

What types of hormones use the steroid hormone mechanism?

Answer 19

Glucocorticoids, estrogen, aldosterone, etc

Question 20

What types of hormones use the tyrosine kinase mechanism?

Answer 20

Insulin, IGF-1, GH, prolactin

Question 21

What are the two categories of tyrosine kinases?

Answer 21

Receptor tyrosine kinases (intrinsic tyrosine kinase activity) and tyrosine kinase-associated receptors (non-covalent association to proteins w/ kinase activity)

Question 22

What types of hormones use the guanylate cyclase mechanism (cGMP)?

Answer 22

ANP, NO

Question 23

What are a couple major hypothalamic neural inputs mentioned?

Answer 23

Suprachiasmatic nucleus SCN: circadian rhythm

Pineal gland: melatonin release (day-night info)- feeds back to the SCN