AP Biology

Homeostasis and Development

Signal Transduction Pathway

Kinases “turn on” processes (can amplify)

Phosphotases “turn off” processes

• Ligand• Hormone• Target tissue

Basic Hormone Pattern

Targeteffectors

Response

Simple endocrine pathway

Glycogenbreakdown,glucose releaseinto blood

Liver

Bloodvessel

Pancreassecretesglucagon ( )

Endocrinecell

Low bloodglucose

Receptorprotein

Stimulus

Pathway Example

3 parts of hormonal system

•Exocrine•Endocrine•Neurosecretory

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

Local Hormones

• Growth factors• Nitric Oxide (NO)• Prostaglandins• Cytokines

LE 45-7

Mammary glands,uterine muscles

Hypothalamus

Kidney tubules

OxytocinHORMONE

TARGET

ADH

Posteriorpituitary

Neurosecretorycells of thehypothalamus

Axon

Anteriorpituitary

CytokinesIL 1 – Macrophage to Helper TIL2 – Helper T to B or Cytotoxic T

Polar versus Non-polar HormoneSignal 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

• Most of the cells in the thyroid are called follicular cells, but there are others called parafollicular cells (or C cells) which produce another important hormone called calcitonin. The thyroid also has four teensy glands called the parathyroid glands, which are embedded in the back of the thyroid and produce the hormone creatively called parathyroid hormone. These two hormones, calcitonin and parathyroid hormone, work in tandem to keep your body's calcium level in check. We all know how important calcium is to prevent diseases like osteoporosis, but too much of a good thing isn't ideal either. That's where calcitonin comes in; it decreases how much calcium is in your blood, while parathyroid hormone works to beef those levels up.

• http://www.youtube.com/watch?v=-S_vQZDH9hY

• http://www.innerbody.com/image/endoov.html