Transcript Figure 5.10 Chemical Signaling Concepts Figure 5.10 Chemical Signaling Concepts.

Figure 5.10 Chemical Signaling Concepts
Figure 5.10 Chemical Signaling Concepts
Figure 45.3 Mechanisms of chemical signaling: a review
Concept 5.5 The Membrane Plays a Key Role in a Cell’s Response to Environmental Signals
Intercellular signaling is somewhat analogous to a lock and
key system. The lock won’t open unless the right key is
used, analogous to the cell needing to have the
appropriate receptor in order to respond to a signal.
Discuss in groups whether this statement is true or false.
Concept 5.5 The Membrane Plays a Key Role in a Cell’s Response to Environmental Signals
Intercellular signaling is somewhat analogous to a lock and
key system. The lock won’t open unless the right key is
used, analogous to the cell needing to have the
appropriate receptor in order to respond to a signal.
This statement is:
a. True
b. False
c. I don’t know.
Figure 5.11 Signal Transduction Concepts
Figure 5.11 Signal Transduction Concepts
Figure 11.5 Overview of cell signaling (Layer 1)
Figure 11.5 Overview of cell signaling (Layer 2)
Figure 11.5 Overview of cell signaling (Layer 3)
Figure 5.12 A Signal Binds to Its Receptor
Figure 5.12 A Signal Binds to Its Receptor
In-Text Art, Ch. 5, p. 92
Figure 5.13 A Protein Kinase Receptor
Figure 5.13 A Protein Kinase Receptor
Figure 11.8 The structure and function of a tyrosine-kinase receptor
Figure 5.14 A G Protein–Linked Receptor
Figure 5.14 A G Protein–Linked Receptor
Figure 11.7 The functioning of a G-protein-linked receptor
Figure 5.14 A G Protein–Linked Receptor (Part 1)
Figure 5.14 A G Protein–Linked Receptor (Part 2)
Figure 5.14 A G Protein–Linked Receptor (Part 3)
Figure 11.9 A ligand-gated ion-channel receptor
Figure 11.10 Steroid hormone interacting with an intracellular receptor
Figure 5.15 The Discovery of a Second Messenger
Figure 5.15 The Discovery of a Second Messenger
Figure 5.15 The Discovery of a Second Messenger (Part 1)
Figure 5.15 The Discovery of a Second Messenger (Part 2)
Figure 5.16 The Formation of Cyclic AMP
Figure 5.16 The Formation of Cyclic AMP (Part 1)
Figure 5.16 The Formation of Cyclic AMP (Part 2)
Figure 5.16 The Formation of Cyclic AMP (Part 3)
Figure 11.11 A phosphorylation cascade
Figure 11.18 The specificity of cell signaling
Figure 5.17 A Cascade of Reactions Leads to Altered Enzyme Activity
Figure 5.17 A Cascade of Reactions Leads to Altered Enzyme Activity
Figure 5.17 A Cascade of Reactions Leads to Altered Enzyme Activity (Part 1)
Figure 5.17 A Cascade of Reactions Leads to Altered Enzyme Activity (Part 2)
Figure 5.18 Signal Transduction Regulatory Mechanisms
Figure 5.18 Signal Transduction Regulatory Mechanisms (Part 1)
Figure 5.18 Signal Transduction Regulatory Mechanisms (Part 2)
Figure 5.18 Signal Transduction Regulatory Mechanisms (Part 3)
Figure 11.14 The maintenance of calcium ion concentrations in an animal cell
Figure 11.15 Calcium and inositol triphosphate in signaling pathways (Layer 1)
Figure 11.17 Nuclear response to a signal: the activation of a specific gene by a growth factor
Figure 5.19 Caffeine and the Cell Membrane
Figure 5.19 Caffeine and the Cell Membrane
Figure 5.19 Caffeine and the Cell Membrane (Part 1)
Figure 5.19 Caffeine and the Cell Membrane (Part 2)
Figure 30.5 Adrenergic Receptors
Figure 30.5 Adrenergic Receptors
Figure 30.5 Adrenergic Receptors (Part 1)
Figure 30.5 Adrenergic Receptors (Part 2)
Figure 30.5 Adrenergic Receptors (Part 2)
Concept 5.6 Signal Transduction Allows the Cell to Respond to Its Environment
Think about each of the following statements and discuss
whether they are true with respect to the signaling
cascade stimulated by epinephrine (the G protein–
mediated protein kinase pathway).
• In liver cells, each molecule of epinephrine results in
the liberation of one molecule of blood glucose.
• With respect to epinephrine, the same signal-receptor
binding event always produces the same cellular
response in muscles throughout the body.
• The signaling cascade set off by epinephrine involves
the activation of some enzymes as well as the
inactivation of others.
Concept 5.6 Signal Transduction Allows the Cell to Respond to Its Environment
Which of the following statements are true with respect to
the signaling cascade stimulated by epinephrine (the G
protein–mediated protein kinase pathway).
a. In liver cells, each molecule of epinephrine results in
the liberation of one molecule of blood glucose.
b. With respect to epinephrine, the same signal-receptor
binding event always produces the same cellular
response in muscles throughout the body.
c. The signaling cascade set off by epinephrine involves
the activation of some enzymes as well as the
inactivation of others.
d. Both a and b
e. All of the above
Chapter 30 Opener
Figure 30.1 Three Classes of Hormones
Figure 30.1 Three Classes of Hormones (Part 1)
Figure 30.1 Three Classes of Hormones (Part 2)
Figure 30.1 Three Classes of Hormones (Part 3)
Figure 30.2 A Diffusible Substance Triggers Molting
Figure 30.2 A Diffusible Substance Triggers Molting
Figure 30.2 A Diffusible Substance Triggers Molting (Part 1)
Figure 30.2 A Diffusible Substance Triggers Molting (Part 2)
Figure 30.3 Hormonal Control of Metamorphosis
Figure 30.3 Hormonal Control of Metamorphosis
Concept 30.1 Hormones Are Chemical Messengers
What is a hormone?
Read the descriptions below and then discuss with a classmate:
• Ghrelin is a large peptide that is secreted by certain stomach
cells into the bloodstream. High levels of ghrelin affect hunger
and feeding networks in the brain, often increasing feeding.
• Trypsin is a peptide secreted by gut cells into the interior of the
small intestine. It helps degrade proteins in food.
• Acetylcholine is a small molecule released by neurons into
interstitial fluid. It usually does not enter the bloodstream. It is
used to communicate messages from one neuron to a
neighboring neuron, or from a neuron to a nearby muscle cell.
Are any of these molecules hormones? Why or why not?
Concept 30.1 Hormones Are Chemical Messengers
Which of the following are hormones?
a. Ghrelin
b. Trypsin
c. Acetylcholine
d. Both a and c
e. All of the above
Concept 30.1 Hormones Are Chemical Messengers
Why isn't there an insulin pill?
Some hormones can be administered to patients through the gut (i.e., in pills)
or through the skin. For example, the hormone progesterone, which is often
prescribed for birth control, can be easily delivered in pill form, in adhesive
skin patches, in small rods that implanted in the skin, or even via
progesterone-releasing rings placed in the vagina.
One of the most common hormone disorders is diabetes, which is often caused
by a deficiency in the blood-sugar hormone insulin. People with this form of
diabetes (Type I diabetes) must inject themselves with insulin several times
daily. Delivery of insulin via a pill, skin patch, or implantable rod would
clearly be more convenient and less painful, yet most patients do injections.
Discuss in small groups:
• Why can’t insulin be delivered via the gut or the skin, like progesterone?
• Once you think you have figured out the answer, list at least one other
hormone that you think can be delivered in a pill or via the skin, and one
other hormone that can’t. Explain your reasoning.
Concept 30.1 Hormones Are Chemical Messengers
Insulin cannot be delivered effectively in a pill or a skin
patch because it is
a. a steroid.
b. a hormone.
c. a peptide.
d. a neurotransmitter.
e. not soluble in water.
Figure 30.4 The Fight-or-Flight Response
Figure 30.4 The Fight-or-Flight Response
Figure 30.5 Adrenergic Receptors
Figure 30.5 Adrenergic Receptors
Figure 30.5 Adrenergic Receptors (Part 1)
Figure 30.5 Adrenergic Receptors (Part 2)
Concept 30.2 Hormones Act by Binding to Receptors
Would you drink bGH milk?
In the United States, many dairy cattle are given injections of growth
hormone (GH). Among GH’s many other roles, GH promotes milk
production in lactating mammals. Thus, cattle injected with GH
produce more milk.
In addition to its role in milk production, GH has many other effects in
mammals. In children, it causes elongation of the long bones,
causing growth. In adults, it stimulates muscle growth, and also
causes thickening of the bones of the face.
Injection of dairy cattle with GH is not permitted in most industrialized
nations, including Canada, Australia, New Zealand, and the EU. The
USA is the only major industrialized nation to permit this practice.
In small groups, first poll each other on the following question:
Would you (or do you) drink milk from bGH-treated cows?
Concept 30.2 Hormones Act by Binding to Receptors
Poll #1
Would you drink a glass of milk from a bGH-treated cow?
(Assume you are very thirsty and it is the only drink
available.)
a. Yes
b. No
c. I’m not sure.
Concept 30.2 Hormones Act by Binding to Receptors
Here is some more information about growth hormone:
GH is a large protein, and its amino acid sequence differs slightly from
species to species. It turns out that bovine growth hormone (bGH)
differs by one amino acid from human growth hormone (hGH).
Because of this difference, bGH cannot bind to the hGH receptor.
In small groups, discuss the following questions:
• If a cow is injected with bGH, will bGH be able to move from the
cow’s blood into the cow’s milk?
• Suppose you swallow some pure bGH. Will all the bGH that you
swallowed enter your bloodstream? Why or why not?
• Suppose you are given an injection of pure bGH directly into your
bloodstream. What effect, if any, will it have on you?
Once you have discussed the above questions, poll your group again.
How many people in your group would drink a glass of milk from a
bGH-treated cow?
Concept 30.2 Hormones Act by Binding to Receptors
Suppose you are given an injection of pure bGH directly
into the bloodstream. What effect, if any, will it have on
you?
a. Elongation of the long bones
b. Thickening of the facial bones
c. Muscle growth
d. Both b and c
e. None of the above
Concept 30.2 Hormones Act by Binding to Receptors
Poll #2
Would you drink a glass of milk from a bGH-treated cow?
(Assume you are very thirsty and it is the only drink
available.)
a. Yes
b. No
c. I’m not sure.
Concept 30.2 Hormones Act by Binding to Receptors
Now consider the following complications:
• Milk from bGH-treated cows is now known to be slightly different
in composition, in several small ways, from milk from non-bGHtreated cows. In particular, bGH milk contains higher-than-usual
levels of another hormone called insulin-like growth factor 1 (IGF1). When IGF-1 is ingested, a very small fraction of it does cross
the gut walls and enter the human bloodstream, and it can bind to
the human IGF-1 receptor.
• IGF-1 in small doses over short time frames appears to have little
effect on human health, but little is known about its potential
effects if ingested regularly for many years.
For the third (and last) time, poll your group again on the same
question:
Would you drink a glass of milk from a bGH-treated cow?
Concept 30.2 Hormones Act by Binding to Receptors
Poll #3 (final poll)
Would you drink a glass of milk from a bGH-treated cow?
(Assume you are very thirsty and it is the only drink
available.)
a. Yes
b. No
c. I’m not sure.
Figure 30.6 The Human Endocrine System
Figure 30.7 The Posterior Pituitary
Figure 30.7 The Posterior Pituitary
Figure 30.7 The Posterior Pituitary (Part 1)
Figure 30.7 The Posterior Pituitary (Part 2)
Figure 30.8 The Anterior Pituitary
Figure 30.8 The Anterior Pituitary
Apply the concept p. 613
The pituitary gland links the nervous and endocrine systems
Once released from the adrenal gland into the bloodstream,
cortisol diffuses from blood plasma into saliva, enabling the
collection of measurable amounts of hormone from saliva
samples. The table gives cortisol concentrations in saliva
samples taken from two female Asian elephants over a 6 day
period during which the animals were introduced to each
other at a Berlin zoo. Given that (a) baseline salivary cortisol
in elephants is 4-5 nanomoles per liter and (b) elephant 1
received an immunization shot on day 1, graph the data in the
table and answer the following questions:
Question:
1. Do the data indicate that the elephants experienced an
adrenal stress response on meeting each other?
2. What physiological effects would elevated cortisol levels
cause in the elephants?
3. Do these data indicate communication between the nervous
and endocrine systems? Explain your answer.
Apply the Concept, Ch. 30, p. 613
Figure 30.9 Multiple Feedback Loops Control Hormone Secretion
Concept 30.3 The Pituitary Gland Links the Nervous and Endocrine Systems
Name that pituitary hormone!
Working in pairs, one person quiz the other on one of the following questions.
The person asking the question can consult notes and give small hints, but
the person answering the question cannot look at any notes!
1. Name the pituitary hormone that triggers ovulation.
2. Name any hormone from the posterior pituitary.
3. Name a pituitary hormone that stimulates the adrenal gland to produce
yet another hormone.
4. Name a pituitary hormone that controls skin pigmentation.
5. Name a pituitary hormone besides GH that stimulates milk production
6. What does “FSH” stand for?
7. What does “ADH” stand for?
8. Where exactly is oxytocin made? (Be as precise as possible!)
9. Name a class of hormone that affects pain.
10. Name a hormone from the anterior pituitary that has not been named
yet.
Concept 30.3 The Pituitary Gland Links the Nervous and Endocrine Systems
Diagramming the hypothalamic–pituitary hormones
Working in small groups:
• Make a diagram of the glands and
hormones that are involved in
controlling the release of cortisol from
the adrenal cortex.
• Then make a similar diagram of the
glands and hormones involved in
controlling thyroxine from the thyroid
gland.
Use the diagram at right as a guide.
At the bottom of the diagram, list the effects
of cortisol and thyroxine on target cells
elsewhere in the body.
What are the similarities in both of your
diagrams?
Concept 30.3 The Pituitary Gland Links the Nervous and Endocrine Systems
How do your diagrams indicate how the nervous and
endocrine systems communicate?
a. Nerves can affect the rate of hormone release.
b. Hormones can affect nerves.
c. Both a and b are true; hormones and nerves interact.
d. Nerves and hormones operate independently of each
other and do not communicate.
e. I’m not sure.
Concept 30.3 The Pituitary Gland Links the Nervous and Endocrine Systems
What happens if negative feedback stops working?
Referring again to your diagram, notice the negative feedback loops.
Occasionally, the pituitary gland develops a tumor that causes release
of very high levels of pituitary hormones. A certain type of pituitary
tumor can cause release of very high levels of ACTH, no matter how
much cortisol is circulating. Essentially, the pituitary “ignores” the
circulating cortisol, and escapes from negative feedback control.
Discuss the following questions with a classmate:
• Would cortisol levels go up, go down, or remain unchanged?
• Would CRH levels go up, go down, or remain unchanged?
• What would be the likely symptoms?
In-Text Art, Ch. 30, p. 614
Figure 30.10 Goiter
Figure 30.11 Hormonal Regulation of Calcium
Figure 45.9 Hormonal control of calcium homeostasis in mammals
Apply the concept p. 616
Hormones regulate mammalian physiological systems
The time courses of action for different hormones vary widely.
Some hormones are released rapidly, establish their effects
almost immediately, and then are cleared from the
bloodstream within minutes. Others are released slowly and
remain in the blood for many hourse or even days.
One way of characterizing the time course of a hormone is to
measure its half-life in the blood: the length of time it takes for
the blood level of a given hormone to fall from its maximum
level following its release (or injection) halfway back to
baseline values. The table gives blood of thryoxine (T4)
following a 600-ug injection.
Plot these data.
Questions:
1. Before assessing your graph, consider what you know about
the functioning of T4. Would you expect this hormone to have
a short or long half-life? Why?
2. Use the data in the table to estimate the actual half-life of
600ug of T4 in the bloodstream. (Time 0 is the baseline)
3. If you were trying to correct a hormonal deficit by
administering hormone therapy and needed to maintain a
relatively constant hormone level in the blood (i.e. minimizing
peaks and troughs), how would your dosing differ for
hormones with different half-lives?
Apply the Concept, Ch. 30, p. 616
Figure 30.12 The Adrenal Is a Gland within a Gland
Figure 30.12 The Adrenal Is a Gland within a Gland
Figure 45.10 Glucose homeostasis maintained by insulin and glucagon
Figure 45.14 Stress and the adrenal gland
Figure 44.24 Hormonal control of the kidney by negative feedback circuits
Figure 46.14 Hormonal control of the testes
Figure 46.19 Hormonal induction of labor
Figure 46.15 The reproductive cycle of the human female
Figure 30.13 Sex Steroids Direct the Development of Human Sex Organs
Figure 30.13 Sex Steroids Direct the Development of Human Sex Organs
Figure 30.13 Sex Steroids Direct the Development of Human Sex Organs (Part 1)
Figure 30.13 Sex Steroids Direct the Development of Human Sex Organs (Part 2)
Concept 30.4 Hormones Regulate Mammalian Physiological Systems
Sexual differentiation: What happens if MIS can’t bind to its
receptor?
Consider an embryo with an XY genotype that has a mutation in the
gene for the MIS receptor. In this embryo, MIS (Müllerian-inhibiting
substance) cannot bind to its receptor.
Discuss in pairs or small groups:
• Will any testosterone (T) be produced?
• Will the female internal reproductive ducts develop?
• Will the male internal reproductive ducts develop?
• Will the external genitalia become female-type or male-type?
Describe the inner and outer anatomy of the resulting adult.
Concept 30.4 Hormones Regulate Mammalian Physiological Systems
If MIS cannot bind to the MIS receptor of an XY male
embryo, the resulting adult will have
a. a complete internal female reproductive tract.
b. a complete internal male reproductive tract.
c. Both a and b
d. None of the above
e. I’m not sure.
Figure 30.14 Real People, Real Lives