1. Ch. 40 Warm-Up
What type of behavior in animals might be triggered by cold temperatures?
What type of behaviors might be triggered in hot temperatures?
List 2 examples of negative feedback. List 2 examples of positive feedback.
What is the main type of chemical messenger in the endocrine system? The nervous system?

2. Ch. 45 Warm-Up Compare peptide hormones to steroids.
Explain how insulin and glucagon work to regulate blood sugar levels.
Which glands and hormones respond when your body is under stress?

3. Chapter 45 Hormones and the Endocrine System
A hormone called ecdysteroid regulates the timing of metamorphosis in this anise swallowtail butterfly.

4. You must know: Two ways hormones affect target organs.
The secretion, target, action, and regulation of at least 3 hormones.
An illustration of both positive and negative feedback in the regulation of homeostasis by hormones.

5. Hormones Why are hormones needed?
chemical messages from one body part to cells in other parts of body
communication needed to coordinate whole body
maintaining homeostasis
energy production
growth
development
maturation
reproduction
growth hormones

6. Endocrine System Endocrine system releases hormones
glands which secrete chemical signals into blood
chemicals cause changes in other parts of body
slow, long-lasting response
growth hormones
sex hormones
response hormones
metabolism hormones
and more….
Hormones coordinate slower but longer–acting responses to stimuli such as stress, dehydration, and low blood glucose levels. Hormones also regulate long–term developmental processes by informing different parts of the body how fast to grow or when to develop the characteristics that distinguish male from female or juvenile from adult. Hormone–secreting organs, called endocrine glands, are referred to as ductless glands because they secrete their chemical messengers directly into extracellular fluid. From there, the chemicals diffuse into the circulation.

7. Types of Intercellular Signaling

8. Endocrine System = Hormone-secreting cells + Tissues
Endocrine glands: ductless, secrete hormones directly into body fluids
Hormones: chemical signals that cause a response in target cells (receptor proteins for specific hormones)
Affects 1 tissue, a few, or most tissues in body
Or affect other endocrine glands (tropic hormones)
Regulation by Positive & Negative Feedback

9. Pheromones Hormones Local Regulators
Chemical signal from 1 individual to another individual
Chemical signal from endocrine gland through blood to target cell
Chemical signal from one cell to an adjacent cell
Eg. ant trail; sex phermones
Eg. peptide, steroid hormones
Eg. cytokines, growth factors, nitric oxide (NO)

11. Glands Pineal Pituitary Thyroid Adrenal Pancreas Ovary Testes
melatonin
Pituitary
many hormones: master gland
Thyroid
thyroxine
Adrenal
adrenaline
Pancreas
insulin, glucagon
Ovary
estrogen
Testes
testosterone

12. Discovery Video: Endocrine System

13. Types of Hormones Peptide Steroid Water-soluble
Bind to receptors on plasma membrane & triggers signal transduction pathway
Affects protein activity already present in cell
Rapid response
Short-lived
Eg. oxytocin, insulin, epinephrine
Lipid-soluble
Enters cell & binds to intracellular receptors
Causes change in gene expression (protein synthesis)
Slower response
Longer life
Eg. androgens (testosterone), estrogen, progesterone, cortisol

15. Maintaining homeostasis
hormone 1
gland
lowers body condition
high
specific body condition
low
raises body condition
gland
hormone 2

16. specific body condition
Negative Feedback
Response to changed body condition
every time body is high or low from normal level a signal tells the body to make changes that will bring body back to normal level
once body is back to normal level, signal is turned off
hormone 1
gland
lowers body condition
high
specific body condition

17. Controlling Body Temperature
Nervous System Control
Controlling Body Temperature
nerve signals
brain
sweat
dilates surface blood vessels
high
body temperature
low
constricts surface blood vessels
shiver
brain
nerve signals

18. Regulation of Blood Sugar
Endocrine System Control
Regulation of Blood Sugar
insulin
body cells take up sugar from blood
liver stores sugar
reduces appetite
pancreas
liver
high
blood sugar level
(90mg/100ml)
low
liver releases sugar
triggers hunger
pancreas
liver
glucagon

19. Negative feedback systems:
Thyroid hormones
Blood Ca2+ levels
Blood glucose levels
Positive feedback system:
Oxytocin (birthing process; release of milk/suckling)

20. Epinephrine: one hormone  many effects
Liver cells break down glycogen and release glucose
Blood vessels to skeletal muscles dilate
Blood vessels to intestines constrict

21. Master Glands
Hypothalamus
Pituitary Gland

22. Master Glands Hypothalamus Pituitary Gland
Receives info from nerves and brain
Initiates endocrine signals
Hypothalamus
Posterior pituitary gland:
Oxytocin: contract uterine muscles, eject milk in nursing
Antidiuretic Hormone (ADH): promote H2O retention by kidneys
Pituitary Gland
Anterior pituitary gland:
Follicle-stimulating hormone (FSH): development of ovarian follicles (eggs); promote sperm production
Luteinizing hormone (LH): trigger ovulation; stimulate testosterone production in testes

25. BIOFLIX: HOMEOSTASIS – BLOOD SUGAR

26. Control of Blood Glucose
High blood glucose
Liver breaks down glycogen and releases glucose into blood
Insulin released from pancreas
Body cells take up glucose
Liver stores glucose as glycogen
Glucagon released from pancreas
Blood glucose drops

27. Diabetes Mellitus Type I diabetes (10%):deficiency of insulin
Insulin-dependent
Autoimmune disorder  beta cells of pancreas destroyed
Type II diabetes (90%): failure of target cells to respond to insulin
Non-insulin dependent
Insulin produced  cells don’t respond (defect in insulin receptor or response pathway)
Risk factors: obesity, lack of exercise