Chemical Regulating Systems Hormones: cell to cell communication molecules Made in gland(s) or cells Transported by blood Distant target tissue.

Chemical Regulating Systems

Hormones: cell to cell communication molecules Made in gland(s) or cells

Transported by blood

Distant target tissue receptors

Activates physiological response

Pheromones: organism to organism communication

Mechanisms of cell-to-cell signaling via hormones

Anatomy Summary: Hormones

Figure 7-2 (1 of 4)

Figure 7-2 (2 of 4)

Anatomy Summary: Hormones

Anatomy Summary: Hormones

Figure 7-2 (3 of 4)

Figure 7-2 (4 of 4)

Anatomy Summary: Hormones

Hormones: Function

Control of Rates of enzymatic reactions

Transport of ions or molecules across cell membranes

Gene expression and protein synthesis

Exert effects at very low concentrations

Bind to target cell receptors

Half-life indicates length of activity

Enzyme-linked immunosorbent assay (ELISA)

Hormone dose response curve

Hormones: Classification

Peptide or protein hormones

Steroid hormones

Amine hormones

Peptide Hormone Synthesis, Packaging, and Release

Figure 7-3, step 1

ECFCytoplasm Plasma

Capillaryendothelium

Messenger RNA on the ribosomes binds amino acids into a peptide chain called a preprohormone.The chain is directed into the ER lumen by a signal sequence of amino acids.

mRNA

Ribosome

Endoplasmic reticulum (ER)

Preprohormone

1

1

Peptide Hormone Synthesis, Packaging, and Release

Figure 7-3, steps 1–2

ECFCytoplasm Plasma

Capillaryendothelium

Messenger RNA on the ribosomes binds amino acids into a peptide chain called a preprohormone.The chain is directed into the ER lumen by a signal sequence of amino acids.

Enzymes in the ER chop off the signal sequence, creating an inactiveprohormone.

mRNA

Ribosome

Prohormone

Signalsequence

Endoplasmic reticulum (ER)

Preprohormone

1 2

1

2

Peptide Hormone Synthesis, Packaging, and Release

Figure 7-3, steps 1–3

Golgi complex

ECFCytoplasm Plasma

Capillaryendothelium

Messenger RNA on the ribosomes binds amino acids into a peptide chain called a preprohormone.The chain is directed into the ER lumen by a signal sequence of amino acids.

Enzymes in the ER chop off the signal sequence, creating an inactiveprohormone.

The prohormone passes from theER through the Golgi complex.

mRNA

Ribosome

Prohormone

Signalsequence

Transportvesicle

Endoplasmic reticulum (ER)

Preprohormone

1 2 3

1

2

3

Peptide Hormone Synthesis, Packaging, and Release

Figure 7-3, steps 1–4

4

Active hormone

Golgi complex

Secretoryvesicle

ECFCytoplasm Plasma

Peptidefragment

Capillaryendothelium

Messenger RNA on the ribosomes binds amino acids into a peptide chain called a preprohormone.The chain is directed into the ER lumen by a signal sequence of amino acids.

Enzymes in the ER chop off the signal sequence, creating an inactiveprohormone.

The prohormone passes from theER through the Golgi complex.

Secretory vesicles containing enzymes and prohormone bud off the Golgi. The enzymes chop the prohormone into one or more active peptides plus additional peptide fragments.

mRNA

Ribosome

Prohormone

Signalsequence

Transportvesicle

Endoplasmic reticulum (ER)

Preprohormone

1 2 3

1

2

3

4

Peptide Hormone Synthesis, Packaging, and Release

Figure 7-3, steps 1–5

4 5

Active hormone

Golgi complex

Secretoryvesicle

ECFCytoplasm Plasma

Peptidefragment

Releasesignal

Capillaryendothelium

Messenger RNA on the ribosomes binds amino acids into a peptide chain called a preprohormone.The chain is directed into the ER lumen by a signal sequence of amino acids.

The secretory vesicle releases its contents by exocytosis into the extracellular space.

Enzymes in the ER chop off the signal sequence, creating an inactiveprohormone.

The prohormone passes from theER through the Golgi complex.

Secretory vesicles containing enzymes and prohormone bud off the Golgi. The enzymes chop the prohormone into one or more active peptides plus additional peptide fragments.

mRNA

Ribosome

Prohormone

Signalsequence

Transportvesicle

Endoplasmic reticulum (ER)

Preprohormone

1 2 3

1

2

3

4

5

Peptide Hormone Synthesis, Packaging, and Release

Figure 7-3, steps 1–6

4 5

To target

Active hormone

Golgi complex

Secretoryvesicle

ECFCytoplasm Plasma

Peptidefragment

Releasesignal

Capillaryendothelium

Messenger RNA on the ribosomes binds amino acids into a peptide chain called a preprohormone.The chain is directed into the ER lumen by a signal sequence of amino acids.

The secretory vesicle releases its contents by exocytosis into the extracellular space.

The hormone moves into the circulation for transport to its target.

Enzymes in the ER chop off the signal sequence, creating an inactiveprohormone.

The prohormone passes from theER through the Golgi complex.

Secretory vesicles containing enzymes and prohormone bud off the Golgi. The enzymes chop the prohormone into one or more active peptides plus additional peptide fragments.

mRNA

Ribosome

Prohormone

Signalsequence

Transportvesicle

Endoplasmic reticulum (ER)

Preprohormone

1 2 3 6

1

2

3

4

5

6

Activation of a G-protein coupled receptor (GPCR)

Peptide Hormone-Receptor Complex

Membrane receptors and signal transduction for peptide hormones

Figure 7-5

Steroid Hormones: Features

Cholesterol-derived Lipophilic and can enter target cell

Cytoplasmic or nuclear receptors (mostly)

Activate DNA for protein synthesis

Slower acting, longer half-life

Examples Cortisol, estrogen, and testosterone

Steroid Hormones: Structure

Steroid hormones are derived from cholesterol

Figure 7-6

Steroid Hormones: Action

Figure 7-7, step 1

Most hydrophobic steroids are bound to plasma protein carriers. Only unbound hormones can diffuse into the target cell.

Cellmembrane

Interstitialfluid

Nucleus

Bloodvessel

Proteincarrier

1

1

Steroid Hormones: Action

Figure 7-7, steps 1–2

Most hydrophobic steroids are bound to plasma protein carriers. Only unbound hormones can diffuse into the target cell.

Steroid hormone receptors are typically in the cytoplasm or nucleus.

Cellmembrane

Interstitialfluid

Cytoplasmicreceptor

Nucleus

Nuclear receptor

Steroidhormone

Bloodvessel

Proteincarrier2

1

1

2

Steroid Hormones: Action

Figure 7-7, steps 1–2a

Most hydrophobic steroids are bound to plasma protein carriers. Only unbound hormones can diffuse into the target cell.

Some steroid hormones also bind to mem-brane receptors that use second messenger systems to create rapid cellular responses.

Steroid hormone receptors are typically in the cytoplasm or nucleus.

Cellmembrane

Interstitialfluid

Cytoplasmicreceptor

Nucleus

Nuclear receptor

Rapid responses

Steroidhormone

Bloodvessel

Proteincarrier

Cell surface receptor

2

1

2a

1

2

2a

Steroid Hormones: Action

Figure 7-7, steps 1–3

Most hydrophobic steroids are bound to plasma protein carriers. Only unbound hormones can diffuse into the target cell.

Some steroid hormones also bind to mem-brane receptors that use second messenger systems to create rapid cellular responses.

Steroid hormone receptors are typically in the cytoplasm or nucleus.

The receptor-hormone complex binds to DNA and activates or represses one or more genes.

Cellmembrane

Interstitialfluid

Cytoplasmicreceptor

Nucleus

Nuclear receptor

DNA

Rapid responses

Steroidhormone

Bloodvessel

Proteincarrier

Cell surface receptor

2

3

1

2a

1

2

2a

3

Steroid Hormones: Action

Figure 7-7, steps 1–4

Most hydrophobic steroids are bound to plasma protein carriers. Only unbound hormones can diffuse into the target cell.

Some steroid hormones also bind to mem-brane receptors that use second messenger systems to create rapid cellular responses.

Steroid hormone receptors are typically in the cytoplasm or nucleus.

The receptor-hormone complex binds to DNA and activates or represses one or more genes.

Activated genes create new mRNA that moves into the cytoplasm.

Cellmembrane

Interstitialfluid

Cytoplasmicreceptor

Nucleus

Nuclear receptor

DNA

Rapid responses

Transcriptionproduces mRNA

Steroidhormone

Bloodvessel

Proteincarrier

Cell surface receptor

2

3

1

4

2a

1

2

2a

3

4

Steroid Hormones: Action

Figure 7-7, steps 1–5

Most hydrophobic steroids are bound to plasma protein carriers. Only unbound hormones can diffuse into the target cell.

Translation produces new proteins for cell processes.

Some steroid hormones also bind to mem-brane receptors that use second messenger systems to create rapid cellular responses.

Steroid hormone receptors are typically in the cytoplasm or nucleus.

The receptor-hormone complex binds to DNA and activates or represses one or more genes.

Activated genes create new mRNA that moves into the cytoplasm.

Cellmembrane

Interstitialfluid

Cytoplasmicreceptor

Endoplasmicreticulum

Nucleus

Nuclear receptor

DNA

Translation

Rapid responses

Transcriptionproduces mRNA

Steroidhormone

Bloodvessel

Proteincarrier

Newproteins

Cell surface receptor

2

3

1

4 5

2a

1

2

2a

3

45

Amine Hormones: Examples

Thyroid hormones

Catecholamines Epinephrine

Norepinephrine

Dopamine

Amine Hormones: Structure

Tyrosine-derived amine hormones

Figure 7-8

Endocrine Reflex Pathways

Hormones may have multiple stimuli for their release

Figure 7-9

Figure 7-10

Simple Endocrine Reflex: Parathyroid Hormone

Neurohormones: Major Groups

Adrenal medulla Catecholamines

Hypothalamus Anterior pituitary

Posterior pituitary

The Pituitary Gland Anatomy

Figure 7-11

The Pituitary Gland: Two Fused

Posterior pituitary Vasopressin

Oxytocin

Figure 7-12 (1 of 4)

Hypothalamic-Hypophyseal Portal System

The Pituitary Gland: Two Fused

Hormones of the hypothalamic-anterior pituitary pathway

Figure 7-13

Endocrine Control

Three levels Hypothalamic stimulation—from CNS

Pituitary stimulation—from hypothalamic trophic hormones

Endocrine gland stimulation—from pituitary trophic hormones

Negative Feedback Controls

Long-loop feedback

Short-loop feedback

Figure 7-14

Control Pathway for Cortisol Secretion

Figure 7-15

Figure 7-16

The Hypothalamic-Hypophyseal Portal System

Example of Synergism

Figure 7-18

Figure 7-19

Endocrine Pathologies

Exogenous medication Replaces and

exceeds normal

Cause atrophy of gland

Excess cortisol

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Endocrine Pathologies

Hypersecretion: excess hormone Tumors or cancer

Grave’s disease—thyroxin

Hyposecretion: deficient hormone Goiter—thyroxin

Diabetes—insulin

Pathologies: Due to Receptors

Downregulation Hyperinsulinemia

Transduction abnormalities Testicular feminization syndrome

Pseudohypothyroidism

Abnormalities of control mechanisms