Chapter 18: Endocrine System

Question 0

Functions of Neuroendocrine System …?

Answer 0

Communication, Integration, and Control

Question 1

What are the Endocrine and Nervous System functions?

Answer 1

Achieve and maintain homeostasis

Question 2

Hormone Molecules….?

Answer 2

Secreted by the endocrine system.

Travels through blood to specific Target cells contained in Target tissues/organs.

Question 3

Hormones…?

Answer 3

Can be carried to almost every point in the body.
Regulate most cells.
Effects work slowly and last longer than neurotransmitters.

Question 4

Endocrine Glands…?

Answer 4

“Ductless Glands”
Made of glandular epithelium, cells manufacture and secrete hormones.
Glands are widely scattered throughout the body.
Few of the endocrine glands are made of Neurosecretory tissues.

Question 5

Tropic Hormones…?

Answer 5

Target other endocrine glands.

Stimulate their growth and secretion.

Question 6

What are the types of chemical structures in endocrine glands?

Answer 6

Steroid Hormone and Nonsteroid Hormone

Question 7

Steroid Hormone…?

Answer 7

Synthesized from cholesterol.
Lipid soluble, easily pass through phospholipid P.M. of target cells.

Ex: cortisol, aldosterone, estrogen, progesterone, and testosterone

Question 8

Nonsteroid Hormone…?

Answer 8

Synthesized mainly from amino acids.
Three different forms:
-Protein Hormones: long, folded chains (insulin, parathyroid hormone)
-Glycoprotein Hormones: protein hormones w/carbohydrate groups attached to amino acid chain (hCG)
-Peptide Hormones: smaller than protein hormones, short amino acid chains (oxytocin, antidiuretic hormone)

Question 9

Amino Acid Derivative Hormones…?

Answer 9

Each derived from single amino acid molecule.

• Amine Hormones: synthesized by modifying single molecule if tyrosine or tryptophan, produced by neurosecretory cells and neurons (epinephrine, norepinephrine)
• Amino Acid Derivatives: synthesized by adding iodine to tyrosine, produced by Thyroid Gland

Question 10

What is “Lock and Key”?

Answer 10

The binding to target cell’s specific receptors (by a hormone’s signal).

Different Hormone receptor interactions produce different regulatory changes w/in a target cell through chemical reactions ( protein synthesis, activate enzymes, open channels)

Question 11

Synergism..?

Answer 11

Combo of hormones acting together have a greater effect on target cells than sum of the effects each would have alone.

Question 12

Permissiveness….?

Answer 12

Small amount of one hormone allows second one to have its full effect on a target cell.

Question 13

Antagonism…?

Answer 13

One hormone produces opposite effect of another hormone, used to fine tune activity of target cells w/great accuracy.

Question 14

Most hormones have…?

Answer 14

Primary effects that directly regulate target cells, many secondary effects influence or modulate other regulatory mechanisms in target cells.

Question 15

What happens to excess hormone molecules?

Answer 15

The unused hormones are quickly excreted by the kidneys or broken down by metabolic processes.

*Endocrine glands produce more hormone molecules than are needed, because of feedback loop.

Question 16

Hormone-Receptor Complex…?

Answer 16

After a steroid hormone molecule has diffused into the nucleus it binds to mobile receptor molecules to form a mobile-receptor model (a aka)

Question 17

mRNA…?

Answer 17

The mobile-receptor complex activates a certain gene sequence to begin transcription of mRNA.
The formed mRNA molecules move into cytoskeleton, associate w/ribosomes, begin synthesizing protein molecules which produce effects of the hormone.

Question 18

Fixed Membrane Receptor Model…?

Answer 18

Is the second messenger mechanism.

Nonsteroid hormone molecule acts as a “1st messenger”