endocrinology intro

Question 2

What are the two major parts of the pituitary gland?

Answer 2

Anterior (adenohypophysis) and posterior (neurohypophysis)

Question 3

Where are posterior pituitary hormones synthesized?

Answer 3

In the hypothalamic supraoptic and paraventricular nuclei

Question 4

How are posterior pituitary hormones transported?

Answer 4

Via axons through the pituitary stalk

Question 5

What connects the hypothalamus to the anterior pituitary?

Answer 5

Hypothalamo-hypophyseal portal system

Question 6

What do anterior pituitary hormones target?

Answer 6

Troph cells that secrete additional hormones

Question 7

What are somatotrophs?

Answer 7

Anterior pituitary cells that secrete growth hormone (GH)

Question 8

What hormone stimulates IGF-1 production in the liver?

Answer 8

Growth hormone (GH)

Question 9

What is the role of IGF-1?

Answer 9

Mediates the growth-promoting effects of GH

Question 10

What structure is key for linear growth in bones?

Answer 10

Epiphyseal growth plate

Question 11

Why does linear growth stop after puberty?

Answer 11

Epiphyseal growth plates close

Question 12

What is pituitary dwarfism caused by?

Answer 12

Deficient GH secretion

Question 13

What causes gigantism?

Answer 13

Excess GH before growth plate closure

Question 14

What causes acromegaly?

Answer 14

Excess GH after growth plate closure

Question 15

What are signs of acromegaly?

Answer 15

Enlarged hands, feet, nose, lips, ears

Question 16

What regulates GH secretion?

Answer 16

GHRH and somatostatin from the hypothalamus

Question 17

What happens to GH secretion if the pituitary stalk is severed?

Answer 17

It decreases

Question 18

When does GH secretion peak?

Answer 18

At night during deep sleep

Question 19

What type of receptor is the GH receptor?

Answer 19

Tyrosine kinase-associated receptor

Question 20

What kinase is activated by GH receptor binding?

Answer 20

JAK2

Question 21

What transcription factor is activated by GH signaling?

Answer 21

STATs (Signal Transducers and Activators of Transcription)

Question 22

What are the indirect effects of GH?

Answer 22

Stimulation of IGF-1 production

Question 23

What are the acute metabolic effects of GH?

Answer 23

Lipolysis, reduced glucose uptake, protein synthesis

Question 24

What is the role of IGFBPs?

Answer 24

Bind IGFs to prolong their half-life and regulate availability

Question 25

What hormone plays a major role in fetal growth?

Answer 25

IGF-1

Question 26

How are IGF-1 and insulin structurally related?

Answer 26

Both share sequence similarity and receptor pathways

Question 27

What other hormones influence growth?

Answer 27

Thyroid hormone, sex steroids, cortisol, insulin

Question 28

What happens in GH receptor knockout mice?

Answer 28

Impaired growth due to lack of GH action

Question 29

What is leptin?

Answer 29

A hormone that regulates appetite and energy expenditure

Question 30

What causes leptin deficiency?

Answer 30

Mutations in the leptin gene (e.g. Ob/Ob mice)

Question 31

What does leptin therapy do in leptin-deficient individuals?

Answer 31

Reduces appetite and body weight

Question 33

What is the classic definition of a hormone?

Answer 33

A substance produced in one tissue and carried in the blood to act on another.

Question 34

What are the four types of endocrine signaling?

Answer 34

Endocrine, paracrine, autocrine, and intracrine.

Question 35

What is intracrine signaling?

Answer 35

Hormones act within the cell that produces them.

Question 36

What connects the hypothalamus and anterior pituitary?

Answer 36

Hypothalamo-hypophyseal portal system.

Question 37

What are the seven classic endocrine glands?

Answer 37

Pituitary, thyroid, parathyroids, adrenal, pancreas, ovaries, testes.

Question 38

What hormone does the pineal gland produce?

Answer 38

Melatonin.

Question 39

What is the main endocrine function of the thymus?

Answer 39

Produces thymopoietin.

Question 40

Name a peptide hormone.

Answer 40

Insulin.

Question 41

Name an amine hormone.

Answer 41

Thyroid hormone or dopamine.

Question 42

Name a steroid hormone.

Answer 42

Cortisol or testosterone.

Question 43

What are hormone-binding proteins?

Answer 43

Carriers that transport hormones in the blood.

Question 44

What are the advantages of hormone-binding proteins?

Answer 44

Reservoirs, extend half-life, restrict free hormone, guide delivery.

Question 45

Which hormones circulate mostly unbound?

Answer 45

Catecholamines and most peptides.

Question 46

What are the steps in hormone signaling?

Answer 46

Synthesis, storage, secretion, transport, recognition, response, degradation.

Question 47

What are non-glandular endocrine tissues?

Answer 47

Tissues like CNS, GI tract, liver, kidney, heart, bone, muscle, adipose.

Question 48

What hormone is produced by skeletal muscle?

Answer 48

Irisin or IL-6.

Question 49

What are exosomes and how are they related to hormones?

Answer 49

Small vesicles that may carry hormone-like miRNAs.

Question 50

What is paraneoplastic syndrome?

Answer 50

Hormonal symptoms caused by tumors secreting hormones.

Question 51

Which cancer secretes ACTH and causes Cushing syndrome?

Answer 51

Small-cell lung cancer.

Question 52

What hormone causes hypercalcemia in breast cancer?

Answer 52

PTHrP.

Question 53

What is feedback control in endocrinology?

Answer 53

Mechanism by which hormones regulate their own levels.

Question 54

What is the difference between positive and negative feedback?

Answer 54

Positive amplifies output; negative inhibits it.

Question 55

What is a G protein-coupled receptor (GPCR)?

Answer 55

A cell surface receptor that activates intracellular G proteins.

Question 56

What does Gαs activation do?

Answer 56

Increases cAMP and activates PKA.

Question 57

What does Gαi activation do?

Answer 57

Inhibits adenylyl cyclase and decreases cAMP.

Question 58

What does Gαq activation do?

Answer 58

Activates PLC to generate IP3 and DAG.

Question 59

What does IP3 do?

Answer 59

Releases Ca²⁺ from the ER.

Question 60

What does DAG do?

Answer 60

Activates protein kinase C (PKC).

Question 61

What is the function of guanylyl cyclase receptors?

Answer 61

Generate cGMP, which activates PKG and causes vasodilation.

Question 62

What is the mechanism of receptor tyrosine kinases (RTKs)?

Answer 62

Ligand binding leads to autophosphorylation and signaling.

Question 63

What is JAK-STAT signaling?

Answer 63

Ligand binding activates JAKs which phosphorylate STATs for gene regulation.