Parthasarathi - Physiology

Question 1

What are the 2 major systems for endocrine control?

Answer 1

• Endocrine glands
• Nervous system

Question 2

What is a hormone?

Answer 2

• Chemical substance released in small quantities from endocrine glands (ductless glands) that travels through the circulatory system to elicit a typical physiological response in target cells and target tissues
• Includes “neurohormones”
• Does NOT include chemicals like carbon dioxide (or intracellular messengers like cyclic AMP)

Question 3

What are the 4 types of EC chemical signaling?

Answer 3

• SYNAPTIC: across synaptic cleft, local, specificity depends on anatomic location and receptors
• PARA/AUTOCRINE: diffusion in interstitial fluid, locally diffuse, specificity depends on receptors
• ENDOCRINE: circulating body fluids, general, and specificity depends on receptors
• NEUROENDO: circulating body fluids, general, and specificity depends on receptors

Question 4

What are the major endocrine glands?

Answer 4

Question 5

What are the 3 general categories of hormones?

Answer 5

• Steroids and steroid-like hormones
• AA derivatives: catecholamines and thyroid hormones
• Peptides and proteins:

Question 6

Name the steroid(-like) hormones.

Answer 6

• ANDROGENS: testosterone, dihydrotestosterone, DHEA
• ESTROGENS: estradiol-17B, estrone, estriol
• PROGESTAGENS: progesterone
• MINERALOCORTICOIDS: aldosterone, deoxy-corticosterone
• GLUCOCORTICOIDS: cortisol, corticosterone
• STEROID LIKE: Vitamin D

Question 7

Why is this important?

Answer 7

• Appropriate combination of enzymes required for conversion of cholesterol to the appropriate hormone (in each zone of the adrenal glands, for example)

Question 8

What are the AA derivative hormones?

Answer 8

• CATECHOLAMINES: norepinephrine, epinephrine, and dopamine (DA; PIH)
• THYROID HORMONES (from Tyrosine): thyroxine (T4), tri-iodothyronine (T3)
• MELATONIN