The Endocrine System

Nervous System vs. Endocrine SystemNervous System

Endocrine System

Speed of Action?

How Long do the Effects Last?What is Used as a “Signal”?

How Far Does the Signal Travel?

Hormones

• Hormones are _______________ produced and secreted by endocrine organs into the ___________.

• 2 Classes of Hormones:– 1. _____________ Hydrophilic or Hydrophobic?

– 2. _____________ Hydrophilic or Hydrophobic?

Bloodstream

Target Cell

Endocrine Organ Protein

Hormone

Receptors

cAMP

Figure 9.1b, step 1

CytoplasmNonsteroidhormone (firstmessenger)

Receptorprotein

Plasmamembraneof target cell

Figure 9.1b, step 2

CytoplasmNonsteroidhormone (firstmessenger)

Enzyme

Receptorprotein

Plasmamembraneof target cell

Figure 9.1b, step 3

CytoplasmNonsteroidhormone (firstmessenger)

Enzyme

Receptorprotein

Secondmessenger

Plasmamembraneof target cell

ATP

cAMP

Figure 9.1b, step 4

CytoplasmNonsteroidhormone (firstmessenger)

Enzyme

Receptorprotein

Secondmessenger

Effect on cellular function,such as glycogenbreakdown Plasma

membraneof target cell

ATP

cAMP

Endocrine Organ Bloodstream Steroid

Hormone

Figure 9.1a, step 1

NucleusCytoplasmSteroidhormone

Plasmamembraneof targetcell

Figure 9.1a, step 2

NucleusCytoplasmSteroidhormone

Plasmamembraneof targetcell

Figure 9.1a, step 3

NucleusCytoplasmSteroidhormone Receptor

protein

Hormone-receptorcomplex

Plasmamembraneof targetcell

Figure 9.1a, step 4

NucleusCytoplasmSteroidhormone Receptor

protein

Hormone-receptorcomplex

DNA

Plasmamembraneof targetcell

Figure 9.1a, step 5

NucleusCytoplasmSteroidhormone Receptor

protein

Hormone-receptorcomplex

DNA

mRNA

Plasmamembraneof targetcell

Figure 9.1a, step 6

NucleusCytoplasmSteroidhormone Receptor

protein

Hormone-receptorcomplex

DNA

mRNANewprotein

Plasmamembraneof targetcell

Hormones Work by Negative Feedback

How Do Endocrine Glands Get Stimulated?

Neural StimulationHormonal

Stimulation Humoral Stimulation