AP Biology

Endocrine Systems

Signal Transduction Pathway

Kinases “turn on” processesPhosphotases “turn off” processes

Basic Hormone Pattern

Targeteffectors

Response

Simple endocrine pathway

Glycogenbreakdown,glucose releaseinto blood

Liver

Bloodvessel

Pancreassecretesglucagon ( )

Endocrinecell

Low bloodglucose

Receptorprotein

Stimulus

Pathway Example

Remember the “hands” on cell membranes? (In GREEN)

LE 45-7

Mammary glands,uterine muscles

Hypothalamus

Kidney tubules

OxytocinHORMONE

TARGET

ADH

Posteriorpituitary

Neurosecretorycells of thehypothalamus

Axon

Anteriorpituitary

CytokinesIL 1 – Macrophage to Helper T

IL2 – Helper T to B or Cytotoxic T

Polar versus Non-polar Hormone

Signal Reception

SECRETORYCELL

Hormonemolecule

Signal receptor

VIABLOOD

VIABLOOD

TARGETCELL TARGET

CELLSignaltransductionpathway

OR

Cytoplasmicresponse

DNA

NUCLEUS

Nuclearresponse

Receptor in plasma membrane Receptor in cell nucleus

DNA

NUCLEUS

mRNA

Synthesis ofspecific proteins

Signaltransductionand response

Signalreceptor

Hormonemolecule

SECRETORYCELL

Examples of Negative Feedback Loops

Hypothalamus

TRH

Anteriorpituitary

TSH

Thyroid

T3 T4

Positive Feedback Loop

Tropic Hormones of the

PosteriorPituitary

Mammary glands,uterine muscles

Hypothalamus

Kidney tubules

OxytocinHORMONE

TARGET

ADH

Posteriorpituitary

Neurosecretorycells of thehypothalamus

Axon

Anteriorpituitary

Tropic Hormones of the Anterior Pituitary

Neurosecretory cells of the hypothalamus

Endocrine cells of theanterior pituitary

Portal vessels

Pituitary hormones(blue dots)

Pain receptorsin the brain

Endorphin Growth hormone

BonesLiver

MSH

Melanocytes

Prolactin

Mammaryglands

ACTH

Adrenalcortex

TSH

ThyroidTestes orovaries

FSH and LH

TARGET

HORMONE

Hypothalamicreleasinghormones(red dots)

Tropic Effects OnlyFSH, follicle-stimulating hormoneLH, luteinizing hormoneTSH, thyroid-stimulating hormoneACTH, adrenocorticotropic hormone

Nontropic Effects OnlyProlactinMSH, melanocyte-stimulating hormoneEndorphin

Nontropic and Tropic EffectsGrowth hormone