1. Thurs. 3/6
Collect: Lab Today: Test, INB check, Cell Communication POGIL Homework: Signal Transduction POGIL(print from my.ccsd.net), Print out notes for Ch. 40 for next class, Guided Reading-Ch. 40. Next class: Ch 40. Test Corrections must be done by Thurs. 3/13

2. Pg. 144 Ch 40 Guided Reading
Pg. 145 Ch 40 EK Paragraph 3D2 or 3D3

3. In: pg. 146 Watch video clip: Bozeman Cell Communication.
Complete Video Guide and tape in.

4. Cell Communication POGIL
Complete ONE copy in groups of 3-4 and turn in at end of period.

5. Pg. 147
Signal Transduction POGIL Print out the Signal Transduction POGIL from my.ccsd.net, complete and turn in next class. It will go on this page when returned.

6. Out Why is cellular communication is important for:
Unicellular organisms?
Multicellular organisms?

7. Mon. 3/10
Collect: Signal Transduction POGIL and Guided Reading-Ch 40 Today: Finish Cell Comm. POGIL, Notes-Ch 40 Homework: Endocrine diagrams and Guided Reading-Ch 37. Print Ch. 37 powerpoint for next class. Next class-Quiz-Ch 40 Test corrections by Thursday!!!

8. In: pg 148
What is the difference between and endocrine gland and exocrine gland? Give an example of each.

9. Pg. 149 Chp.40: Hormones & the Endocrine System

10. Why cells need to communicate:
Remember:
Why cells need to communicate:
Coordinate activities in multicellular organisms
Hormone actions
Cell recognition
To find mates (yeast cells)
Turn pathways on/off
apoptosis
Coordinate activities such as development and movement, hormones and neurotransmitters are chemical communications, cell recognition such as for antibodies, yeast exchange mating factors, pathways such as signal transduction pathway that are a series of steps by which a signal on the cell’s surface is converted to a specific cellular response, and apoptosis is a type of programmed cell death (think embryonic development of fingers and toes, the disappearance of a tadpole’s tail, etc.), just to name a few.

11. Evolutionary ties of cell communication
Cell-to-cell communication is everywhere in biological systems from Archaea and bacteria to multicellular organisms.
The basic chemical processes of communication are shared across evolutionary lines of descent.
Signal transduction is an excellent example

12. Signal Transduction Animation
Click on this link to access the animation:
At this point, we just want to introduce the concept of signal transduction. Preface this animation with a brief discussion of the “fight or flight” response. “Imagine observing a bear in its natural habitat…” is an appropriate introduction, then click on the animation link. Only explore the “overview” portion of the animation at this time.

13. Chemical Communication
Outside the body
Ex. Pheromones
Ex. Quorum sensing
Inside the body
Short Distance
Long Distance
Pheromones are chemicals that are produced by organisms to aid in communication by members of the same species, quorum sensing is used by organisms to react as a group usually in bacteria.

14. Pheromones
Members of the same animal species sometimes communicate with pheromones, chemicals that are released into the environment.
Pheromones serve many functions, including marking trails leading to food, defining territories, warning of predators, and attracting potential mates.
The video shows a gentleman laying down a PaperMate Ink trail on a plain white piece of paper. Next, he places a termite onto the paper and within seconds the termite follows the trail (with a bit of trial and error on the termite’s part). Students love this!

15. Quorum sensing
Quorum sensing in bacteria – single celled bacteria monitor their environment by producing, releasing and detecting hormone-like molecules called autoinducers.
This process, termed quorum sensing, allows bacteria to monitor the environment for other bacteria and to alter behavior on a population-wide scale in response to changes in the number and/or species present in a community. THERE IS NO NEED TO DESCRIBE THE DETAILS of the image shown.

16. Chemical Communication
Inside the body
Short Distance
Paracrine
Example Prostaglandin
Autocrine
Example Interleukin
Long Distance
Hormones
Example Insulin
This flow chart shows a simplified classification system for the cell communication occurring within the body. The dividing lines between hormones, paracrine and autocrine signals have blurred. In our study of hormones we will mostly focus on hormones as long distance communicators. Paracrine refers to a secreted molecule that acts on a neighboring cell, autocrine refers to a secreted molecule that acts on the cell that secreted it.

17. Direct Contact Communication
Ex. Plant cells communicate directly through openings called plasmodesmata.
Another example would be helper T cells bind with Killer T cells in the immune system.

18. Short Distance Communication
Paracrine signals diffuse to and affect nearby cells
Ex. Neurotransmitters
Ex. Prostaglandins
The next four slides outline the different “categories” of cell to cell communications involved in the endocrine system. Students should know an example for each one as well as the basics of how each type of communication works.
Paracrine chemical signals work in cells that are near the secreting cell. For example, neurotransmitters released by a presynaptic cell move across the synapse and impact the post synaptic cell.
In the immune system, prostaglandins promote fever and inflammation and intensify the sensation of pain.
Prostaglandins help regulate aggregation of platelets, an early step in formation of blood clots.

19. Neurotransmitters and Neurohormones
Neuron
Synapse
Response
Synaptic signaling
Neurosecretory cell
Intercellular communication by secreted molecules.
Blood vessel
Response
Neuroendocrine signaling

20. Autocrine signals
These chemicals affect the same cells that release them.
Ex. Interleukin-1 produced by monocytes and can bind to receptors on the same monocyte.
Tumor cells reproduce uncontrollably because they self-stimulate cell division by making their own division signals.
Again…students need to become an expert on “an” example while have knowledge of various examples.

21. Long Distance Communication
Endocrine hormones via signal transduction pathway:
The word transduce means to convert. A signal transduction pathway “converts” the original signal molecule into a cellular response. This conversion requires several intermediate messenger molecules (sometimes called “second messengers”), so the signal is actually “converted” or transduced several times, as shown in the blue box above labeled Transduction. The concept of signal transduction pathways will be seen over and over again in AP Biology and is certain to be on the exam.

22. Hormones Endocrine glands produce hormones which are Chemical signals
Transported in tissue fluids
Detected only by target cells
Ask students to name some hormones. Testosterone and estrogen are sure to be in their list! Either of those make perfect “expert” examples.

23. Summary:
Allow students to correct their misconceptions before moving on. It would be great if they could leave class with a complete and ACCURATE concept map!

24. Communication Features
Secreting cell - releases the signal
Signal = chemical = ligand
Receptor - accepts and temporarily joins with the ligand forming receptor/ligand complex
Target cell – contains the receptor
A ligand is in a narrow sense, a signal triggering molecule, binding to a site on a target protein. The word “binding” refers to intermolecular forces (IMFs) rather than an actual chemical (covalent or ionic) bond. While actual chemical bonds can form, it is very rare. It is far more common for the “binding” to be more of an electrostatic attraction. You can demonstrate this for students using small pieces of torn paper and an ordinary comb. “Charge” the comb by combing it through someone’s hair (ions from the keratin protein of hair will adhere to the plastic comb). The comb will then attract the small pieces of paper. It is obvious that these attractions are not actual chemical bonds.
Historical note: In 1970, Dr. Martin Rodbell examined the effects of glucagon on a rat's liver cell membrane receptor. He noted that guanosine triphosphate disassociated glucagon from this receptor and stimulated the G-protein, which strongly influenced the cell's metabolism. Thus he deduced that the G-protein was a transducer that accepted glucagon molecules and affected the cell. For this he shared the 1994 Nobel Prize in Physiology or Medicine with Dr. Alfred G. Gilman. Dr. Gilman became Chairman of the Department of Pharmacology at the University of Texas Southwestern Medical Center in 1981 and then in 2006 he became Executive Vice President for Academic Affairs and Provost of the University of Texas Southwestern Medical Center in Dallas, TX. In short, he is a teacher as well as a Nobel Prize Winner! He has worked with the NMSI science staff on several teacher training projects including the development of a virtual microscope. He is a long standing supporter of LTF and of NMSI and an advocate of science education.

25. Apply the features
Insulin is secreted by beta cells of the pancreas. Once secreted, insulin travels around the body. When insulin docks with an integral protein on the membrane of a muscle cell, glucose can enter the cell.
What is the secreting cell, the target cell, ligand, and the receptor?
Insulin makes another excellent “expert” example. Students often know someone who is diabetic, so they may have a keen interest in learning more about diabetes.
Secreting cells are the pancreatic beta cells. Target cells (in this example) are muscle cells. The ligand is insulin. The receptor is an integral protein in the membrane of the muscle cell.

26. Endocrine System
The human endocrine system is composed of a collection of glands that secrete a variety of hormones.
These chemicals use long distance communication to control the daily functioning of the cells of the body, maintain homeostasis, respond to environmental stimuli, and growth & development.
The endocrine system is in contrast to the exocrine system, which secretes its chemicals using ducts. The word endocrine derives from the Greek words "endo" meaning inside, within, and "crinis" for secrete. The endocrine system is an information signal system like the nervous system, yet its effects and mechanism are classifiably different. By contrast, the endocrine system's effects are slow to initiate, and prolonged in their response, lasting from a few hours up to weeks.

27. Endocrine System
The endocrine system produces more than 30 different chemicals used by your body to and promote normal body function.
This system contains 9 primary glands as well as endocrine cells found within major organs.
The endocrine system is a ductless system that employs the circulatory system when delivering chemical signals over long distances.
The nervous system sends information very quickly, and responses are generally short lived. Hormones are substances (chemical mediators) released from endocrine tissue into the bloodstream where they travel to target tissue and generate a response. Hormones regulate various human functions, including metabolism, growth and development, tissue function, sleep, and mood. The field of study dealing with the endocrine system and its disorders is endocrinology, a branch of internal medicine.
Features of endocrine glands are, in general, their ductless nature, their vascularity, and usually the presence of intracellular vacuoles or granules storing their hormones. In contrast, exocrine glands, such as salivary glands, sweat glands, and glands within the gastrointestinal tract, tend to be much less vascular and have ducts or a hollow lumen (interior).

28. While it is not necessary to memorize every cell type or gland found within the system, it will be helpful to recognize the endocrine glands and the function of the hormones produced by select glands to use as examples of how both short and long distance chemical communication occurs.
In addition to the specialized endocrine organs mentioned above, many other organs that are part of other body systems, such as the kidney, liver, heart and gonads, have secondary endocrine functions. For example the kidney secretes endocrine hormones such as erythropoietin and renin.

29. The Endocrine System works with the Nervous System
Two systems coordinate communication throughout the body: the endocrine system and the nervous system.
The endocrine system secretes hormones that communicate regulatory info throughout body.
The nervous system uses neurons to transmit signals; these signals can regulate the release of hormones.
The endocrine system is made of a series of glands that produce chemicals called hormones. A number of glands that signal each other in sequence are usually referred to as an axis, for example, the hypothalamic-pituitary-adrenal axis.

30. Table 45.1a
Major Human Endocrine Glands and Some of Their Hormones. Have students “pick a favorite” from either this slide or the next so they can use it as an example in their free-response writing.

31. Table 45.1b
Major Human Endocrine Glands and Some of Their Hormones

32. Negative feedback Figure 45.17 Example Pathway Stimulus Cold
Sensory neuron
Hypothalamus 
Hypothalamus secretes thyrotropin-releasing hormone (TRH).
Neurosecretory cell
Releasing hormone
Blood vessel 
Anterior pituitary secretes thyroid-stimulating hormone (TSH, also known as thyrotropin).
Anterior pituitary
Tropic hormone
Negative feedback
How accurate were you?
Thyroid gland secretes thyroid hormone (T3 and T4).
Endocrine cell
Hormone
Target cells
Body tissues
Increased cellular metabolism
Response

33. The Process of Communication: Signal-Transduction Pathway
Three stages of the Signal-Transduction Pathway
1. reception
2. transduction
3. response
Most cell communication involves three basic steps, reception, transduction and response. Today, we will see this signal transduction pathway being initiated by hormones. We will look at specific examples of how communication is completed using this pathway.

34. Typical Signal Transduction Pathway
The diagram shows a typical signal transduction pathway. In our example today, we will consider a ligand or signal molecule to be a hormone produced by one of the endocrine glands we discussed earlier.
The word transduce means to convert. A signal transduction pathway “converts” the original signal molecule into a cellular response. This conversion requires several intermediate messenger molecules (sometimes called “second messengers”), so the signal is actually “converted” or transduced several times, as shown in the blue box above labeled Transduction. The concept of signal transduction pathways will be seen over and over again in AP Biology and is certain to be on the exam.

35. Ligand = Chemical Messenger
Three major classes of molecules function as hormones in vertebrates (ligands)
Polypeptides (proteins and peptides)
Amines derived from amino acids
Steroid hormones
The hormones we consider today fall into three main categories. Polypeptides, amines and steroid hormones. The chemical make up of each is different so it is not surprising that these ligands impact cells very differently.

36. Cellular Response Pathways
Water- and lipid-soluble hormones differ in their paths through a body
Water-soluble hormones are secreted by exocytosis, travel freely in the bloodstream, and bind to cell-surface receptors
Lipid-soluble hormones diffuse across cell membranes, travel in the bloodstream bound to transport proteins, and diffuse through the membrane of target cells
Protein/peptide hormones are released by exocytosis, steroid hormones are able to leave their secretory cells by way of diffusion. Once in the blood stream, both travel to their target cells.. Upon arrival at the target cell, these two types of hormones have different methods of communicating with the target cells.

37. Type of Receptor: Ex- G-protein linked (Water soluble = polypeptides & amines, can’t pass cell membrane)
G protein linked receptors are located in the membrane of the cell. When activated, the G-protein linked receptor sets off a chain of events inside the cell.

38. Intracellular Receptor
Type of Receptor:
Intracellular Receptor
(Lipid Soluble = Steroid Hormones, can pass cell membrane)
Some receptors are located inside the cell and are described as intracellular receptors. The receptor for testosterone, for example is found inside the cell.
Testosterone is a steroid hormone. Challenge students to explain why steroid hormones have intracellular receptors, while protein hormones have extracellular receptors. (Steroids are lipids and therefore easily diffuse through the membrane and into the cell. Proteins will not diffuse through the membrane due to both charge and size, so they must bind with receptors on the cell’s surface.)

39. Water- soluble hormone Lipid- soluble hormone
SECRETORY CELL
Water- soluble hormone
Lipid- soluble hormone
VIA BLOOD
Transport protein
Signal receptor
TARGET CELL OR
Signal receptor
Receptor location varies with hormone type.
Cytoplasmic response
Gene regulation
Cytoplasmic response
Gene regulation
NUCLEUS
(a)
(b)

40. Relay molecules in a signal transduction pathway
Recap
EXTRACELLULAR FLUID
CYTOPLASM
Plasma membrane 1
Reception 2
Transduction 3
Response
Receptor
Activation of cellular response
Relay molecules in a signal transduction pathway
Overview of cell signaling.
Signaling molecule

41. Multiple Effects of Hormones
The same hormone may have different effects on target cells that have
Different receptors for the hormone
Different signal transduction pathways
The same hormone can cause different reactions depending upon the cell it has targeted.

42. Multiple Effects of Hormones
The hormone epinephrine has multiple effects in mediating the body’s response to short-term stress
Epinephrine binds to receptors on the plasma membrane of liver cells
This triggers the release of messenger molecules that activate enzymes and result in the release of glucose into the bloodstream
For example, epinephrine can be stimulatory is some parts of the body and stimulatory in others.

43. Epinephrine inhibits the glycogen synthesizing work of a liver cell while promoting the breakdown of glycogen

44. Same receptors but different intracellular proteins (not shown)
Different receptors
Different cellular responses
Different cellular responses
Epinephrine
Epinephrine
Epinephrine
 receptor
 receptor
 receptor
Glycogen deposits
One hormone, different effects.
Vessel dilates.
Vessel constricts.
Glycogen breaks down and glucose is released from cell.
(a) Liver cell
(b)
Skeletal muscle blood vessel
Intestinal blood vessel
(c)

45. Insulin and Glucagon: Control of Blood Glucose
Hormones work in pairs to maintain homeostasis.
Insulin (decreases blood glucose) and glucagon (increases blood glucose) are antagonistic hormones that help maintain glucose homeostasis.
The pancreas has clusters of endocrine cells called pancreatic islets with alpha cells that produce glucagon and beta cells that produce insulin.

46. Body cells take up more glucose.
Figure 45.13
Insulin
Body cells take up more glucose.
Beta cells of pancreas release insulin into the blood.
Liver takes up glucose and stores it as glycogen.
STIMULUS: Blood glucose level rises (for instance, after eating a carbohydrate-rich meal).
Blood glucose level declines.
Homeostasis: Blood glucose level (70–110 mg/100mL)
STIMULUS: Blood glucose level falls (for instance, after skipping a meal).
Describe the actions that occur when blood glucose levels decline and when they rise. Glucagon and insulin are paired hormones that work together to maintain blood glucose levels between 70 and 110 mg/100mL
Blood glucose level rises.
Liver breaks down glycogen and releases glucose into the blood.
Alpha cells of pancreas release glucagon into the blood.
Glucagon

47. Out of Balance: Diabetes Mellitus
Diabetes mellitus is perhaps the best-known endocrine disorder.
It is caused by a deficiency of insulin or a decreased response to insulin in target tissues.
It is marked by elevated blood glucose levels.
Ask students to explain how a lack of insulin leads to elevated levels of glucose in the blood. Then ask them to suggest reasons this increased level of glucose is harmful to the person with diabetes.

48. Out of Balance: Diabetes Mellitus
Type 1 diabetes mellitus (insulin-dependent) is an autoimmune disorder in which the immune system destroys pancreatic beta cells.
Type 2 diabetes mellitus (non-insulin-dependent) involves insulin deficiency or reduced response of target cells due to change in insulin receptors.
Type 1 has in the past been referred to as Juvenile Diabetes. Just as a point of interest, the incidence varies from 8 to 17 per 100,000 in Northern Europe and the U.S. with a high of about 35 per 100,000 in Scandinavia to a low of 1 per 100,000 in Japan and China.

49. Insulin & Glucose Regulation
Scroll across the bottom of the slide to activate the animation controls and press PLAY

50. Pg. 150 Diagram and label fig. 40.12 AND 40.15.
Pg. 151 Create a similar diagram for the stress response. One loop will be short term stress and the other loop will be long term stress.

51. Out
Insulin and glucagon are antagonistic hormones. What does this mean? Use a specific example.