AP Bio- Communication 2: Hormonal Control

Hormonal Control

Big Questions

Things Like This Don't Just Happen.

Coordination is Required!

Make Sure You Can:

Any Questions?

Compare the uses of cell signaling in different lineages of organisms.

Identify common features in all cell signaling mechanisms.

Compare different modes of cell signaling in animal systems

Diagram the processes by which signal transduction occurs in multicellular animals, including steroid and lipid hormone signaling pathways

Diagram the regulatory effects of various hormones in animals and plants, at the cellular and system-wide levels of organization.

Why is communication between cells necessary?

How is cellular communication used in multicellular life?

How do mechanisms of cellular communication demonstrate a shared evolutionary history among organisms?

Theory

How Cells Communicate

Applications

Molecules are Required!

The 3 Phases of Signal Reception

Why Cells Communicate (Multicellular Version)

Note:

Metamorphosis in Arthropods

This is a review of "Cellular Communication"

The Immune System demonstrates Local Signaling

"ligands"

Three major hormones are responsible for the total breakdown and reorganization of juvenile arthropods into adult forms (and its ensuing awesomeness).

Two Kinds of Hormone Molecules

Different Reception

Different Chemistry

Distance Signals

Released by cells, received by neighbors

Local Signals

• The Systems that send distance signals are the nervous and endocrine systems.
• These are the major regulatory systems in animals.
• There is a good deal of interplay between all signaling systems

An Epinephrine ("Adrenaline") Receptor

What kind of hormone is epinephrine?

Epinephrine is a polar amine ligand

Different Responses

Epinephrine signal transduction is mediated by G-Protein linked receptors.

G-Proteins are very common signal relay proteins for membrane receptor ligands.

"G-Protein" means it is associated with GTP

AMP is high when ATP is low

Pheromones!

Nervous Systems (Not Now!)

Lipid Hormones Tend To Have Longer Term Effects than Peptides

Signaling Molecules produced by one organism that are recieved by another organism

Generally speaking, nervous and endocrine systems have complementary purposes.

Nervous system: quick, fast, regulation. More on that later.

Endocrine system: long term, regular regulation.

Both systems interact

Estrogen is responsible for long term changes in sexual cycles (menstruation, puberty).

Estrogen activates long term responses by changing protein expression in cells.

{Vitellogenin is a precursor to nutritive egg yolk proteins present in all egg producing female animals}

Cells Amplify A Message

The ligand isn't important.

The Response is!

Advanced

Considerations

The Role of the "Second Messenger"

Internal signalling molecules released due to external ("first") signals

Things Get Complicated Quickly

Plants

Mammals

Have Hormones, Too!

The Endocrine System

A Tour Of Select Glands

Leaf Abscision is Complex!

Auxin & Apical Dominance

Auxin Production at the Apical Bud determines the direction of plant growth

Modes of Endocrine Function

Endocrine glands respond from nervous system cues, or from hormones made by other endocrine glands.

The Brain is the ultimate seat of control of endocrine and nervous systems

Abscision (loss of leaves),

involves interactions between many hormones, including ethylene, gibberelin, and absisic acid

An example of negative feedback

An example of positive feedback

A typical neuroendocrine signaling pathway

The pituitary gland is typically referred to as the "master gland"

It makes control hormones for many other glands throughout the body.

Input from the hypothalamus is crucial.

The pituitary has two distinct lobes that make distinct hormones.

All pituitary hormones are peptidyl.

The Master Gland & The Thermostat

Pituitary Hormones

Some Major Plant Responses

The thyroid makes two hormones (T3 and T4) which are involved in regulating metabolism.

Iodine is necessary for proper thyroid function

The parathyroids produce parathyroid hormone (PTH), which is involved in regulating calcium levels in the blood.

Calcium is an important second messenger in many cellular processes.

Brain-Thyroid feedback loop

A "goiter" due to insufficient iodine in the diet

Blood-Calcium regulation feedback loop

Gibberellin and lots of things

Gibberellin treatment leads to "bolting" in growing plants & accelerated fruit ripening

Here They All Are!

Don't Forget Me!

Intake of water in germinating seeds leads to gibberelin production and the breakdown of stored starch to power cotyledon growth

The Adrenal glands are involved in producing stress hormones:

• Adrenal Medulla: Epinephrine and Norepinephrine-Short-Term ("fight or flight") Response
• Adrenal Cortex: Corticoids- Long-Term Response

Absisic Acid Prevents Growth

Ethylene is Awesome!

Increased ethylene is associated with the "triple response" in young plants, a reaction to encountering an overhead blockage during growth

Decreasing [ABA] leads to germination

Ethylene is a gas!

It triggers growth

& Fruit Ripening

The regulation of the menstrual cycle is the responsibility of four major hormones

Gametes & Sexiness!

Ethylene response mutants

precocious!

Pituitary Hormones:

• FSH- Follicle stimulating hormone.
• LH- Leutenizing hormone

Trigger development and release of a mature ovum (inside a follicle).

Ovarian Hormones:

• Estrogen
• Progesterone

Are involved in the development and maintenance of the uterine lining (the endometrium)

This is a very important thing that you need to understand.

A bunch of very cool feedback loops.

The human menstural cycle is 28 days, EXACTLY & ALWAYS!!!

:)

The gonads (ovaries and testes) produce the sex hormones which control:

• Gamete production
• Development of secondary sex characteristics (what are the primary ones?)

Leads To

We're not going to spend a lot of time here.

Note: Same hormones involved here as in female gamete production, with ONE major difference.