1. Messages in the Body: Hormones and Drugs
Katie Hancock
Mayo Medical School, Year 1
Hazen c/o 2007
Open polleverywhere.com, tell students to take out their cell phones
Open video links and pause them so they’re ready to go.

2. Where We’re Going… Nervous System Endocrine System
Agonists and Antagonists
How Drugs Work
Endocrine System
Hormones and the Menstrual Cycle
Hormones and Sleep

3. Nervous System  Electrical Endocrine System  Chemical
Nervous System – faster, by nerves cells & impulses, uses neurotransmitters that travel across a synapse
Endocrine system – slower, by endocrine glands, uses hormones that travel through circulation

4. Agonists & Antagonists
Agonists help neurotransmitters (NTs)
By mimicking NT effects
By blocking NT reuptake
Antagonists hinder NTs
By blocking NT release
By occupying the NT receptor site
Ok, so what happens when the message gets all the way to the axon? Basically these little things (red dots here) called neurotransmitters are pushed out of the axon terminals, cross the synaptic cleft and bind to the dendrite of the next neuron, and the message continues. (Remember – axons announce, dendrites detect…it makes sense now!) *Check if there are any questions at this point* Now, what would happen if in addition to these little red dots you had some little blue ones that connected here and did the same thing? Would that increase or decrease the messages? (increase). Anything that helps the neurotransmitter is called an agonist. BUT what if a little green dot came in that also fits in the receptor, but it doesn’t do the same thing red does? It just sits there and blocks red from doing it’s job. Then what happens to the message (decrease). So anything that stops the neurotransmitter from doing its job is an antagonist. These 2 concepts are important to understand drugs – so before we move on, are there any questions?

5. Drugs: How They Work Caffeine Alcohol Marijuana Nicotine Cocaine
Heroin

6. How Caffeine Works
Link to video embedded in image. (Show 0-2:15, or the whole thing, depending on time)
Polleverywhere.com: Agonist or Antagonist? Antagonist to Adenosine
Sources:
Caffeine blocks the neurotransmitter adenosine in the brain (to trick your brain into thinking you’re awake).

7. How Alcohol Works
Ethanol, which is the alcohol in beverages, enhances the activity of GABA. GABA, in general, is an inhibitory neurotransmitter that has a sedative effect. So ethanol helps GABA inhibit signals. By enhancing the inhibitor GABA, what are you doing to the strength of the signal? (decreasing it) This decrease in signals is the reason alcohol generally slows your body down. This is why it’s called a depressant – it depressed the nervous system.
Alcohol affects important parts of your brain like the frontal cortex which is important for decision making and moral judgments, and it also affects the hippocampus which is important for memory. Some of this damage can be irreversible. There’s a reason the legal drinking age is 21; our brains continue to develop until age 20-25, and alcohol has the potential to screw it up before it’s done developing, not to mention astronomically increases your risks of getting into an alcohol-related car crash. So next time you go out, maybe have a sprite instead  (Seriously, it’s worth it).
Polleverywhere.com: Agonist or Antagonist? Agonist to GABA (which means it helps GABA inhibit signals)
Sources:
Ethanol enhances the neurotransmitter GABA in the brain, essentially slowing stuff down.

8. How Marijuana Works
Link to video embedded in image. Show 0-3:30.
Polleverywhere.com: Agonist or Antagonist? Agonist to Anandimide (sort of tricky – it’s a partial agonist because it has a similar effect but doesn’t do it’s job quite as well as Anandimide)
Sources:
THC binds to the receptor for the neurotransmitter amandimide and works kind of like amandimide, but not quite as well.

9. How Nicotine Works
Disclaimer: I’m not actually a doctor. But I can confidently tell you that smoking is bad for you. How it works is the nicotine binds to the alpha-4-beta-2 nicotinic acetylcholine receptor (click to show biology meme) in the brain, where acetylcholine normally binds. (That’s up here at the top of the blue neuron). Nicotine causes the channel to open – just like acetylcholine normally would – so sodium to flow in and the nerve can fire (remember how we saw that happening with the demonstration earlier?). So the nerve fires toward the reward center of your brain, where it releases dopamine out of the end of its axon terminals. This dopamine produces short-lived feelings of well-being, improved mood, and increased attention. It is this reward response, paired with the fact that nicotine’s half life is only 2 hours (which means it gets broken down pretty fast and you crave more to replace it), which make it so addictive.
Polleverywhere.com: Agonist or Antagonist? Agonist to Acetylcholine (and indirectly, to dopamine)
Sources:
Nicotine binds to ion channels in the brain that are normally bound by acetylcholine. As a result, nerve firing increases, and more dopamine is released in the brain’s reward center.

10. How Cocaine Works Original ingredient in Coca-Cola
Stimulates the central nervous system
Link to video imbedded in image on right. Show whole video (0-1:42)
Polleverywhere.com: Agonist or Antagonist? Agonist to Dopamine
Sources:
Cocaine blocks the reuptake of dopamine, so there is more dopamine around to do it’s thing.

11. How Heroin Works
Ask how many people have heard of opioids. Ask if anyone can name some, and ask what their purpose is (Answers: morphine, pain relief). Heroin acts by hijacking the normal pain relief system in the brain.
To understand heroin, we’ll start on the left side. These pink circles are neurotransmitters called GABA. Remember GABA? It inhibits stuff. In this case, when GABA binds to it’s receptor, it INHIBITS dopamine release. Dopamine is used as the reward chemical in the brain, so basically this GABA system is keeping the reward system in check. But if you look over at the right side, you’ll see how heroin interferes with this normal process. Heroin is converted into morphine, binds to one of these purple opioid receptors in the brain, and INHIBITS the release of GABA. So what’s going to happen if you don’t have GABA (get an answer from the class, giving them hints if needed). Remember, more GABA leads to less dopamine, so LESS GABA leads to more dopamine…which means more reward, more pain relief, and more relaxation. Unfortunately, Heroin is much less controllable than natural opioids in the body, so it can relax the body so much that you stop breathing completely…and for good.
This is serious stuff. I lost my cousin to this last year, he was 24. It’s extremely addictive because it works on the reward system of the brain (as is the case of many other drugs). Please, if you or someone you know is experimenting with this drug (or any of these illegal drugs for that matter), please find help. Or contact me and I will connect you with help. I’ll put up my up at the end, so feel free to contact me any way you want, directly or anonymously.
But on to some more lighter trivia…
Polleverywhere.com: Agonist or Antagonist? Agonist to opioids (and more indirectly to dopamine)
Sources:
Heroin inhibits the release of GABA, so GABA can’t keep dopamine in check (so again, there’s more dopamine to do its thing).

12. Sources:
Science.memebase.com

13. The Endocrine System
Ok, so we’ve covered the nervous system (which is our body’s electrical system) and how some drugs work on that system. Now we’ll move on to the endocrine system (which is our body’s chemical system) and explain a few hormones that are involved. These (click to show picture) are all the endocrine glands in our body. I’m just going to go straight down this list and want you guys to shout out anything you know about that gland. You can shout what hormone is releases, what it helps do in your body, what diseases it’s related to…anything you know about it…or you can shout “nothing” if you’ve never heard of it (which is a perfectly acceptable answer!)
Some sample responses to fill in whatever blanks the students don’t know:
Pineal – sleep, melatonin (produced in the dark)
Hypothalamus – regulation (hunger, thirst, temperature, sex drive), controls pituitary, GnRH, oxytocin
Pituitary – “the master gland” (kind of ironic since the hypothalamus controls it), releases FLAT PG – FSH, LH, ACTH (note “tropic” means having an affinity for), TSH, Prolactin, GH
Thyroid – thyroxine, metabolism, calcitonin (Calcitonin tones down calcium levels)
Parathyroids – 4 of them, on thyroid, calcium control, parathyroid hormone (Parathyroid Picks up calcium levels)
Thymus – immune system, where T cells mature, degenerates as we age
Adrenals – sit on top of kidneys (also called “suprarenals”), cortex and medulla, epinephrine and norepinephrine, mineral corticoids (aldosterone), glucocorticoids (cortisol), and androgens such as the precursor to testosterone (salt, sugar, and sex!)
Pancreas – insulin, glucagon, and somatostatin (also secretes bicarb into the gut), controls glucose, related to diabetes
Testes – testosterone, sperm production, secondary sex characteristics
Ovary – egg storage and development, estrogen and progesterone (which we’re about to talk about on the next slide), and produce secondary sex characteristics
The way a lot of these glands work is by feedback. It can either be positive feedback, which is the way the hormone oxytocin is released in childbirth (where contractions cause more oxytocin to be released and oxytocin causes more contractions to occur). Fun fact – oxytocin is called the cuddle chemical because that’s what it makes people want to do  Anyway, there is also negative feedback where an increase in something (like a hormone) goes back to the system that’s producing it and sort of switches it off or dials it down. We’ll see an example of that in just a moment.
Sources:

14. Menstrual Hormones
In general, I want you to focus on these three boxes (hypothalamus, pituitary, and ovaries). The hypothalamus produces this hormones called gonadotropin releasing hormones. Who remembers what tropin means? (affinity) So what do you think gonadotropin means? (affinity for the gonads) So GnRH is going to stimulate the pituitary to release these hormones to the gonads, or ovaries. The 2 hormones it releases are LH and FSH. These cause the ovaries to release estrogen, which feeds back to the hypothalamus in the brain in a couple different ways. We’ll take a more detailed look on the next slide.
Sources:

15. Menstrual Hormones
Now for the scarier picture (but don’t worry, we’ll take it one piece at a time).
GnRH from hypothalamus  FSH and LH from pituitary  Follicle grows
Follicle releases E  expansion of endometrium, positive feedback to hypothalamus to send more LH
LH surge triggers ovulation
Before ovulation we had a follicle, that was the follicular phase. Now we have a corpus luteum, and we’re in the luteal phase.
Corpus luteum secretes E + P  builds up uterine lining (via P) and sends negative feedback to hypothalamus and pituitary (saying we got it, we’re good, stop sending more)
Sources:

16. Hormones and Sleep Stages of sleep = N1, N2, N3, REM
N2 helps form muscle memories
Growth hormone is secreted in N3
REM is critical for memory solidification
 Athletics
 Health
 Academics

17. Hormones and Sleep
Melatonin is a hormone that is produced in the dark and induces sleep.
In adolescence, both melatonin and growth hormone peak later.
Melatonin peak is delayed by 40 min between 9th-10th grade
Adolescents go to bed later across cultures, across time, and in both genders

18. More Sleep = Better Health
Obesity:
Sleep-deprived individuals have lower leptin, higher ghrelin, higher visfatin, fluctuating seratonin, and decreased metabolic function.
Those who sleep less than 8hrs are at 3x greater risk for obesity than those who sleep more than 10hrs.
They’re also much more prone to viral infections and colds (viral = 50% if <6hrs, cold = 3x if <7hrs)

19. More Sleep = Better Health
Mental Health:
Adolescents who sleep less than 5hrs are at 71% higher risk for depression and 48% higher risk of suicidal thoughts than those who get 8hrs.
Sleep deprivation leads to more irritability, frustration, anger, anxiety, and substance abuse.
Substance abuse most notably includes caffeine, alcohol, and tobacco. Note that this second bullet point describes our picture of a typical teenager…however, as Dr. William Dement of Stanford notes, the reason teenagers typically act out in these ways is because of sleep deprivation!

20. More Sleep = Safer Teens
1 week on 6hrs/night = same cognitive function as someone who is legally drunk
1 drink on 6hrs of sleep = 6 drinks on 8hrs
Those under 25 years old are responsible for more than half of fall-asleep car crashes
Mostly in the morning on the way to school

21. More Sleep = Better Grades
HS Students who get A’s and B’s sleep 10-33min longer and go to bed 10-50min earlier than those who get C’s, D’s, and F’s.
REM solidifies memories, and most REM occurs between 6-8 hours of sleep.
When students get 6hrs of sleep, they are missing out on the most important memory-solidifying hours of sleep. I really mean it when I say sleeping is studying, and I live by that philosophy in med school  The recommended amount of sleep for adolescents is 9.25 hours.

22. Questions?
Feel free to contact me!

23. Just for the AP Bio class – I know these first 2 pics are how you feel right now, but really soon you’ll be feeling like this third pic  Hang in there.