Endocrinology - (ch4) Textbook

Question 1

Summarize the shared features of signaling systems.

Answer 1

In terms of endocrine vs nervous, they both communicate by sending signals out to the body. They both use hormones, and they both have receptors for these hormones.

Question 2

Compare and contrast the major chemical classes of signaling molecules.

Answer 2

The classes are:
1. Proteins
2. Biogenic Amines
3. Steroid Hormones
4. Eicosanoids

Question 3

Explain how chemical messengers communicate their signals to a target cell.

Question 4

Compare the general features of signal transduction via intracellular receptors, ligand-gated ion channels, receptor enzymes, and G protein–coupled receptors.

Question 5

Compare the different signal transduction pathways associated with G protein–coupled receptors.

Question 6

Outline some of the ways that endocrine systems are organized using selected examples.

Question 7

Outline some of the major patterns in the evolution of endocrine systems.

Question 8

Compare and contrast paracrine and endocrine communication in terms of the three main steps of indirect signaling.

Question 9

Compare and contrast hydrophilic and hydrophobic messengers in terms of the three main steps of indirect signaling.

Question 10

Are peptide messengers hydrophilic or hydrophobic?

Question 11

How does this property influence the mechanisms involved in each of the three main steps of indirect signaling?

Question 12

What is a preprohormone?

Question 13

What are the three main classes of steroid hormones in vertebrates?

Question 14

Why are steroids usually bound to carrier proteins when transported in the blood?

Question 15

Are amines hydrophilic or hydrophobic messengers? How does this affect their release, transport, and signaling?

Question 16

Outline the ways in which thyroid hormone release, transport, and signaling differ from that of other biogenic amines.

Question 17

What are eicosanoids?

Question 18

Name three gaseous signaling molecules, and one function that they share.

Question 19

Why do some cells respond to a chemical messenger while other cells ignore it?

Question 20

Compare and contrast receptor up-regulation and down-regulation. How do these phenomena help to maintain homeostasis?

Question 21

Some hydrophobic messengers alter the expression of only a few genes, while other messengers cause changes in the regulation of thousands of genes. Explain how this can be the case.

Question 22

Some responses to hydrophobic ligands are termed nongenomic responses. How do they differ from the typical responses to a hydrophobic ligand?

Question 23

What is the primary response of a cell when a ligand binds to a ligand-gated ion channel?

Question 24

Which would you predict to be faster, signaling via a ligand-gated ion channel or signaling via an intracellular receptor? Justify your answer

Question 25

What are the three main parts of a receptor-enzyme?

Question 26

How do receptor-enzymes amplify incoming signals?

Question 27

Outline the five main steps in G protein–coupled receptor signaling.

Question 28

What is a second messenger?

Question 29

Tell me abt Pineal gland
(Ch 4, “introduction to endocrine systems” - bottom chart).

Question 30

Tell me abt Hypothalamus(clusters of secretory neurons)

Question 31

Tell me abt Posterior pituitary (extensions of hypothalamic neurons)

Question 32

Tell me abt Anterior pituitary gland

Question 33

Tell me abt Thyroid gland

Question 34

Tell me abt Parathyroid gland

Question 35

Tell me abt Thymus gland

Question 36

Tell me abt Heart (individual cells in atrium)

Question 37

Tell me abt Liver (various cells)

Question 38

Tell me abt Stomach and small intestine (various cells)

Question 39

Tell me abt Pancreas

Question 40

Tell me abt Adrenal gland (cortex) in mammals; dispersed cells in other vertebrates

Question 41

Tell me abt Adrenal gland (medulla) in mammals; chromaffin cells in other vertebrates

Question 42

Tell me abt Corpuscles of Stannius (fish); various tissues in mammals

Question 43

Tell me abt Kidney (various cells)

Question 44

Tell me abt Testes (male)

Question 45

Tell me abt Ovaries (female)

Question 46

Tell me abt Placenta (pregnant female mammals only)

Question 47

What are antagonistic pairings? What are the advantages of this organization of control systems?

Question 48

Compare and contrast negative feedback and positive feedback. Which type of control allows maintenance of homeostasis?

Question 49

Provide an example of a hormone controlled by a third-order endocrine pathway, and outline each step in the regulatory cascade.

Question 50

What are the major differences between invertebrate and vertebrate endocrine systems?

Question 51

How have gene duplications played a role in the evolution of the vertebrate endocrine system? Support your answer with at least two examples.

Question 52

LO 1 What are the main types of indirect signaling, and what is the primary feature that distinguishes them?

Question 53

LO 1 What are the three major steps involved in indirect chemical signaling?

Question 54

LO 2 If the newspaper article in Question #3 were about a peptide hormone, how would your predictions change?

Question 55

LO 2 You read an article in the newspaper about the discovery of a new steroid hormone. What can you predict about how it is synthesized and/or stored by the signaling cell, how it is transported through the blood, and how it acts on the target cell?

Question 56

LO 3 From the perspective of the target cell, is there a fundamental difference between a paracrine signal and an endocrine signal? Why or why not?

Question 57

LO 3 What are the three main domains of a transmembrane receptor, and what are their functions?

Question 58

LO 4 Compare and contrast the signal transduction cascades initiated by intracellular receptors and G protein–coupled receptors.

Question 59

LO 4 Compare and contrast the functions of intracellular and transmembrane steroid receptors.

Question 60

LO 5 Compare and contrast the function of heterotrimeric G proteins and a small soluble G protein such as Ras.

Question 61

LO 5 What is the difference between signaling through and ?

Question 62

LO 6 Which classes of chemical messenger are utilized for endocrine communication? Give one example of a hormone from each class.

Question 63

LO 6 Compare and contrast positive and negative feedback. Provide an example from the endocrine system of vertebrates for each type of feedback.

Question 64

LO 7 Are the endocrine systems of vertebrates and invertebrates homologous? Justify your answer.

Question 65

LO 7 Compare and contrast the insulin/glucagon system for blood glucose regulation in vertebrates with the function and regulation of crustacean hyperglycemic hormone (CHH).

Question 66

Epinephrine and glucagon both act to increase blood glucose, but they act on a different subset of tissues. What characteristics are likely to determine whether a particular tissue responds to epinephrine, glucagon, or to both hormones?

Question 67

People who do not regularly drink coffee often feel much greater effects when they ingest modest doses of caffeine than do heavy coffee drinkers. Explain at a molecular level why this might be so.

Question 68

The anticancer drug tamoxifen binds to the estrogen receptor. Tamoxifen inhibits the growth of breast tissue but promotes growth of uterine tissues, thus reducing the risk of breast cancer but potentially increasing the risk of uterine cancer. Explain how the same chemical messenger could have opposite effects in two different tissues.

Question 69

What are the advantages of a multistep signal transduction pathway in cell-to-cell communication?

Question 70

Epinephrine binds to a G protein–coupled receptor that signals via . Acetylcholine binds to a G protein–coupled receptor that signals via . You construct a recombinant receptor with the extracellular domain of the acetylcholine receptor and the intracellular domain of the epinephrine receptor, and transfect it into cultured cells. Your preliminary experiments indicate that the receptor is processed correctly, and inserted into the plasma membrane. If you applied acetylcholine to your transfected cells, what would you expect to happen to intracellular cAMP levels? What would happen if you applied epinephrine? Explain your answers.

Question 71

Why are peptide messengers released by exocytosis? Why are steroid hormones not released in this way?
Why do selective serotonin reuptake inhibitors (SSRIs) affect the response of a target cell to serotonin?

Question 72

How does increasing the amount of a receptor on a target cell affect the and of the ligand-receptor interaction? What would be the effect of this change on the response of a target cell to the ligand?

Question 73

Thinking about the evolution of endocrine systems, what evolutionary patterns result in the phenomenon of “endocrine disruption” observed when male fish living in sewage outfalls are feminized by artificial human contraceptives and hormone replacement therapies in the effluent?

Question 74

What are the major parts of any control system (mechanical or biological)? Choose an example of a biological control system and show how it fits the general description of control systems that you provided.

Question 75

In insects, the Malpighian tubules are involved in the maintenance of ion and water balance. When a peptide hormone called diuretic hormone is applied to Malpighian tubules isolated from the blood-sucking insect Rhodnius prolixus, the tubule epithelium begins to secrete fluid at a rate of approximately 5 nL/min. The biogenic amine serotonin has similar effects, causing secretion at a rate of approximately 4 nL/min. When both chemical messengers are applied together, however, fluid secretion occurs at a rate of approximately 45 nL/min. Is this an example of additivity, synergism, or antagonism? Justify your answer.