Reading notes for Chapter 23.


Describe the neuroendocrine system.  Give specific examples.

Why were Schally, Guillemin and Yalow awarded the Nobel prize in Medicine in Physiology or Medicine?

There are six different types of hormone actions in a cell.  List them, describe them and give and example of each.  (You may have to scavenge the chapter to find good examples.


Define paracrine, endocrine and autocrine.  Give a specific example of each type of hormone.

How are hormone levels regulated.  Give a specific example and discuss how it is regulated. Go back to chapter 7 on page 262, to read about lutinizing hormone and thyrotropin.  

Compare and contrast the anterior and posterior pituitary.

Liver
What does the liver do?  Discuss how the liver metabolizes sugars, amino acids and lipids.

Describe the alanine cycle in detail.  What does this cycle do during a fasting period?

Adipocytes
What is their function?  Go look at figure 21-40a to see a VLDL.  Where do VLDL's come from?  What are they?  How does fat get from the adipocyte to the tissues?  Describe the process that occurs from stored TAG (triacylglycerols) to free fatty acids at the muscle tissue.   Figures 17-1, 17-2 and 17-3 may be of interest.

Myocytes
What is slow-twitch and fast twitch muscle?  How are they different?  What is the effect of training?  What types of fuel does skeletal muscle use?  When do the myocytes typically use each type of fuel?  What role does lactate have in muscle energy metabolism.   What is the Cori cycle?

What is phosphocreatine?  

How does heart muscle differ from skeletal muscle?  What is the main fuel for cardiac myocytes?

Be sure you can compare and contrast the energy metabolism of skeletal muscle  and cardiac muscle.


The Brain

What is the major source of energy for the brain?  How is that energy source metabolized? What does the brain need energy for?  What does figure 23-21 show?  Also, figure 23-23 illustrates the importance of getting fuel to the brain.  Why can't fats be used as fuel for the brain?

Insulin says, "Store!"

What tissues are most responsive to insulin?  What cells in the pancreas produce insulin.  Describe the events that occur when blood glucose levels are elevated.  Be sure to use your own words.
What is a GLUT2 transporter?  (Page 395 has some information.)
Page 429- 432 has information about the insulin receptor and what happens when insulin binds to its receptor.

What does insulin do to the liver?
What does insulin do to extrahepatic tissues?  Give specific details.


Certain tumors cause an overproduction of insulin (hyperinsulinemia), how does excess insulin affect the metabolism of glucose, lipids and amino acids in the liver?  How can this condition lead to brain damage?

Glucagon says, "Spend!"

What causes glucagon to be released?  Where is it made?
What does glucagon do when it binds to a liver cell?
What does glucagon do when it binds to an adipocyte?  What is a perilipin (page 634)?


Fasting  (Which levels are higher, glucagon or insulin, during a fast?)
Figure 23-28 shows what happens in a liver cell during a prolonged fast.  What is exported by the liver?  Where do these exports go?

High levels of acetyl CoA prevent more pyruvate from being converted to Acetyl CoA. This sort of negative feedback forces carbons back towards gluconeogenesis as opposed to being committed to forming lipids or being totally oxidized.  The two fates of acetyl CoA are to be made into lipids or to be oxidized via the Citric Acid cycle.  Glucose can not be made from acetyl CoA.  

How does the body replenish glucose levels after all of the liver glycogen has been used?

Epinephrine
Where is it made and released from?  What tissues does it act on?  What does it do, and how does it do it.  See pages 435-441 for the details.
Muscle cells and Liver cells respond differently to epinephrine.  They both have an increase in glycogenolysis, however the end product is different in each tissue.  What are the end products?  What is the reason for this differences?


Cortisol
How does cortisol differ from epinephrine? Where is it made?  Why is it secreted?  How is its secretion controlled (page 890)?  What tissues does it act on?  Compare cortisol to insulin.

Diabetes
Give a description of type I and type II diabetes.  What is ketoacidosis?   What causes it?

Obesity
What is leptin?  Where is it made?  What is its target tissue?  What experiments were done to show the significance of leptin?  Look at figure 23-32 and then read the text to learn about the effects of leptin.  Figures 23-33 and 23-34 show even more of what this busy molecule does.
Do obese people have a shortage of leptin?

Adiponectin
This also comes from adipocytes.  When is it is released?  What triggers the secretion of adiponectin?  What does it do?  (Figure 23-36 has a summary.) Is there a relationship between adiponectin and insulin?

PPARs
What are they?    Where do they come from/go to?  What does Thiazolidine (a drug given to type II diabetics to decrease blood glucose levels) do to these PPARs?


Ghrelin  
This one comes from another organ.  Its receptors are in the pituitary and other tissues (what are they?)  What signal does it send?

What is PPY_3-30?
What does it do?

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Last updated on March 23 by Koni Stone.