exammm 3

Question 1

What is true about most microorganisms we encounter every day in the way we contact them?

Answer 1

most microorganisms we encounter are harmless, and many are beneficial because they compete against opportunistic pathogens, help keep our digestive tract in good shape, and those that are sufficiently
similar to pathogenic microbes will help us develop specific immunity against those particular pathogens.

Question 2

What’s the difference indicated by “opportunistic” when we classify some microorganisms as pathogens but
classify others as “opportunistic” pathogens?

Answer 2

Unlike pathogens, “opportunistic” pathogens do not make us sick in normal circumstances. Theycause problems only when they get in a part of the body where they usually don’t live or when benign
microorganisms aren’t present to compete against the opportunistic pathogens. In contrast, pathogens make us sick (i.e., cause and extreme responses by the non-specific components of our immune system) pretty
much regardless of conditions.

Question 3

Most deaths in the United States prior to 1) the invention of antibiotics, 2) widespread methods to disinfect
water, 3) implementation of sanitary methods in health care were caused by microbial infections. Even today,
in parts of the world where people frequently encounter pathogens and have minimal access to antimicrobial
drugs, most deaths (most by far!) are caused by microbial infections. How do we reconcile these facts with
the popular notion that exposure to pathogens is good because it builds one’s immune system”?

Answer 3

Emphasizing the benefits of exposure without recognizing risks is potentially dangerous.
Emphasizing the risks without recognizing the benefits of exposure is potentially dangerous. A balanced
perspective is probably ideal: common sense hygiene without developing neurotic, compulsive behavior.

Question 4

hat is wrong with the notion that you’ll build up your immune system by exposing yourself to “a tad of Salmonella” or “only a touch of Anthrax” or “a just a smidge of Ebola” or, you know, “just wee bit of HIV”?

Answer 4

The problem is that exposure to even a little of those microorganisms (and other pathogens) usually causes sickness or (without proper treatment) death

Question 5

One of my friends grew up in a developing nation where she saw many people living in highly unsanitary conditions. She points to those people as evidence that exposure to pathogens builds the immune system.
There IS some merit to her argument. But what is the flaw in her argument?

Answer 5

Her conclusion focusses on the survivors and ignores the tens of thousands in her home country who die every year from infectious disease.

Question 6

What causes the symptoms of being sick (i.e., stuff like fever, inflammation, swelling, pain)?

Answer 6

Most of the suffering associated with “being sick” is caused by non-specific components of our immune system. Some microorganisms can produce toxins that cause cellular damage or tissue damage, but most of the damage that causes us to feel sick is caused by our immune system attacking the microorganisms. For
example, the aches, fever, and chills of an influenza infection are largely caused by interferons and other cytokines produced by our own cells as part of the defense response.

Question 7

What is wrong with the idea that “being a little dirty” will allow us to develop specific immunity to a pathogen (e.g., bacterium, virus, protist) we’ve not previously encountered without getting sick?

Answer 7

Several days are required for our specific immune system to build up in response to a new pathogen. During this time our nonspecific immune system engages in chemical warfare against the pathogen, which creates inflammation, pain, and other symptoms of “being sick” by killing many of our own cells.

Question 8

Do we retain life-long immunity once we develop specific immunity to a particular pathogen?

Answer 8

Not always. That’s why we must keep some of our immunizations “up to date.” Moreover, we aren’t able to develop immunity to some pathogens (e.g., Streptococcus, which causes strep throat), particularly pathogens that allow B cells to activate by cross-linking, and pathogens that produce toxins that are potent in miniscule concentrations (e.g., Clostridium and Bacillus), and pathogens (such as HIV) that kill Helper T cells

Question 9

nder what two conditions can “being a little dirty” be beneficial without the threat of getting sick? Follow each condition with a “because….” statement telling why “being a little dirty” is beneficial under the condition?
Hint 1: consider the fact that memory B cells and memory T cells don’t live forever. Hint 2: consider what happens if compliment proteins, macrophages, and dendritic cells are able to contain an
infection versus what happens if they can’t contain an infection

Answer 9

Exposing ourselves to pathogens (i.e., “being a little dirty”) can be beneficial…

1) if we’re exposing ourselves to pathogens we’ve already encountered because RE-exposure should cause us
to create a new batch of memory cells that respond to the (already known) pathogens.
2) if we know the amount of pathogen exposure is small enough for our macrophages, dendritic cells, and
compliment proteins to destroy all of the pathogens without “turning on” immune system components
that damage our own tissues, because the limited exposure sometimes allows us to create memory cells
(i.e., develop long term immunity) with minimal risk of getting sick or dying.
3) Otherwise, exposure to pathogens will likely make you sick, but that too can be beneficial, so to speak, if
you know you can keep the infection at bay (i.e., not die) during the several days required to develop
memory cells that convey long-term immunity…assuming memory cells can be developed in response to
the pathogens.

Question 10

Step 1: think about how many people were killed or crippled by infectious diseases such as smallpox,
diphtheria, measles, mumps, polio, tetanus, typhoid, rabies, etc. before vaccines.
Step 2: think about how many vaccinated people die or are crippled from these infectious diseases.
Step 3: we’re all entitled to our own opinions, but we’re not entitled to make up facts, so, given the facts
revealed in steps 1 and 2, how reasonable is it for people to claim vaccines do more harm than good? Explain

Answer 10

It’s probably unreasonable because history repeatedly shows vaccines usually protect people from targeted infections. In contrast, very few people are known to have been harmed by vaccines

Question 11

Which cellular components of the non-specific immune/defense system (also called “innate” immune system) did I emphasize in lecture

Answer 11

macrophages, dendritic cells, mast cells, neutrophils

Question 12

Which cellular components of the specific immune/defense system (also called “adaptive” immune system)
did I emphasize in lecture

Answer 12

B cells, T cells

Question 13

What part of our immune system produces antibodies?

Answer 13

B cells

Question 14

What is the primary function of mast cells?

Answer 14

mast cells release histamine, causing inflammation which allows other immune cells to have better
access to sites of infection and injury

Question 15

Which of the cell types identified in the previous four questions cause
inflammation, swelling, etc. associated with Type 1 allergic reactions.

Answer 15

mast cells

Question 16

We discussed four classes of antibodies (also called immunoglobulins): IgA, IgE, IgG, and IgM. Which class is associated with Type 1 allergic reactions?

Answer 16

IgE (which is the technical way to say “class E antibodies”)

Question 17

Why are IgE antibodies and mast cells associated with allergic reactions?

Answer 17

: B cells produce antibodies in response to molecules perceived as “foreign” to the body, including things that are harmful (such as molecules on the surface of bacteria and viruses) and things that are harmless (such as dust and pollen). If B cells produce an IgE antibody to a foreign molecule (rather than, for example,
an IgG antibody), the person will likely suffer what we call “allergies” in response to the molecule because IgE antibodies not only bind to the foreign molecule that triggered B cells to make them, they also bind to mast
cells. The consequence of IgE antibodies binding to mast cells is that future exposure to the foreign molecule causes any mast cells with IgE antibodies stuck to them to release floods of histamine, causing an allergic
reaction

Question 18

What part of our immune system (it’s a molecule) is released by our cells when they are invaded by a virus? This molecule—which is part of our immune system—causes fever, chills, and body aches

Answer 18

interferon

Question 19

The misery one experiences in response to contact with poison ivy is caused by our immune system reacting
to a harmless oil from the plant. Which part of our immune system is needlessly reacting to the oil?

Answer 19

T cells

Question 20

Why am I asking you to learn a tad of detail about the biochemistry underlying perception, muscle contractions, and thought?

Answer 20

When people realize that our physiological processes, including our consciousness, arise from chemical/molecular and electrical interactions among cells, they view themselves and humanity differently
than people who don’t have that understanding/realization/insight.

Question 21

What does the auditory illusion presented by Dr. Anil Seth teach us about consciousness in relation to the
brain?

Answer 21

Our conscious interpretation (ie., our mind’s “view”) of reality usually will be wrong if our brain hasn’t yet formed an internal model of the relevant topic.

Question 22

What does the hollow mask illusion presented in the notes and by Dr. David Eagleman teach us about consciousness in relation to the brain?

Answer 22

Our conscious interpretation (ie., our mind’s “view”) of reality often will be wrong if we experience something that contradicts a pattern our brain has learned.

Question 23

I presented three lines of evidence that consciousness is created by propagation of chemo-electrical interactions among networks of nerve cells in the brain. What were those three lines of evidence?

Answer 23

is found on page 3 (entry 3.a.) and page 11 of notes about brain-mind connection

Question 24

Excluding genetic evidence, explain four lines of evidence that neural activity is at least responsible for forming
our thoughts.

Answer 24

a. We have to “make sense” of what we “see” (or hear or smell, etc.). We “learn” what the environmental
signals mean. Did you know what they were when you were a baby seeing, hearing, or smelling them? No.
Why do you now? Because you learned. What does that mean? It probably means nerve cells your
brain formed new synapses and turned on genes (or turned off genes) responsible for particular molecules
in the membranes of the brain’s cells.
b. Injuries to the brain and brain lesions alter personality and behavior.
c. Alteration of neurotransmitter activity among nerve cells in the brain (e.g., through stress, drugs, etc.)
alters thoughts, decision making, reasoning, emotions, and behaviors.
d. Tomography allows us to see which groups of nerve cells are communicating when we experience various
emotions, make decisions, etc.

Question 25

Many studies consistently find evidence that people who possess a particular allele tend to be more aggressive and violent than people who don’t have the allele. Why would it be incorrect to argue that
inheritance of this allele condemns a person to being aggressive and violent?

Answer 25

…because aggression, like all/most of our behaviors, is controlled by multiple genes (not just this one) and is shaped in part by environmental factors such as training. Be able to reason through similar scenarios regarding inherited behavioral tendencies. For example, what
about ADHD, addiction?

Question 26

How are light, sound, pressure, temperature, and other environmental stimuli transformed into “information”
that travels via nerves? I recommend learning my answer so well that you can convert it into an annotated flow chart and into labeled pictures of the relevant structures.

Answer 26

a. Environmental stimulus is converted into a chemical signal, usually by changing the shape or form of a
molecule (usually a membrane protein) in the receptor cell.
b. This chemical signal is converted into an electrical signal because the molecular change causes membrane
proteins in the associated cell to change in a way that alters the amount of positively charged ions inside
versus outside the cell.
c. This electrical signal is converted into a chemical signal when it causes the release of a neurotransmitter
that binds to membrane molecules (usually proteins) in an associated nerve cell.
d. The binding causes a change in shape of the membrane molecules/proteins in the nerve cell, and this
chemical signal causes changes in this 2nd cell’s ion concentrations, creating a new electrical signal that
travels through the nerve cell ultimately resulting in the release of a neurotransmitter.
e. Steps c & d then repeat from one cell to the next until the signal causes a muscle to contract or a gland to
release a hormone…or perhaps for interacting signals to produce thought.

Question 27

Be able to identify the anatomical detail of a muscle: muscle bundles, muscle cell, myofibril, sarcomere, and the proteins actin and myosin.

Answer 27

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