Chapter 2: Glands, Gooseflesh, and Hormones

The brain sends messages to your body through the nerves that branch from your brain down your spine and out to the periphery of your body.

• The voluntary nervous system: you decide to move  a muscle and it happens – conscious
• The autonomic nervous system: The  set of nerve projections to places like sweat glands carry messages that are relatively involuntary

One half of the autonomic nervous system is activated in response to stress, one half is suppressed

• Sympathetic NS*: kicks into action during emergencies, or what you think are emergencies (fight or flight) – epinephrine and norepinephrine are secreted
• Parasympathetic NS: mediates calm, vegetative activities – promotes growth and energy storage

There is another way, besides the sympathetic system, that can mobilize activity in response to a stressor: the secretion  of hormones

• When the sympathetic nerve endings in your heart secrete norepinephrine, which causes the heart muscle to work differently, norepinephrine is playing a neurotransmitter role. If a neuron secrets a messenger that percolates into the bloodstream, that messenger is a hormone.
• All sorts of glands secrete hormones; the secretion of some  of them is turned on during stress, and the secretion of others is turned off.

The hypothalamus contains a huge array of releasing and inhibiting hormones which instruct the pituitary, which in turn regulates the secretions of the peripheral glands

• The brain can trigger the release of pituitary hormone X through the action of a single releasing hormone
• Sometimes it can halt the release of pituitary hormone Y by releasing a single inhibiting hormone
• In some cases, a pituitary hormone is controlled by the coordination of both a releasing and an inhibiting hormone from the brain (dual control)

As the  master gland,  the brain can experience or think of something stressful and activate components of the stress-response hormonally

• The hormones epinephrine, norepinephrine and glucocorticoids are important for stress-response.
• Glucocorticoids: steroid hormones secreted by the adrenal gland. They often act in ways similar to epinephrine. While epinephrine acts within seconds; glucocorticoids back this activity up over the course of minutes or hours.

Glucocorticoid secretion:

• A stressor is sensed or anticipated in the brain, triggering the release of CRH (corticotropin releasing hormone) in the hypothalamus.
• These  hormones enter the private circulatory system linking the hypothalamus and the anterior pituitary, causing the release of ACTH (corticotropin) by the anterior pituitary.
• ACTH enters the general circulation and triggers the release of glucocorticoids by the adrenal gland.

Other hormones:

Chapter 4: Liquidating your assets

In cases of crisis (e.g. running away from a lion), your cardiovascular system kicks into high gear and is delivering oxygen and energy to your exercising muscles.

Where does the extra energy come from?

• By digestion, complex food matter is broken down into smaller building blocks (e.g.: amino acids, glucose) . These building blocks can be burned by the body to provide the energy to do constructions and operate new structures
• In immediate physical emergency, your body stops storing energy (digesting). The activation in your sympathetic nervous system is turned up, and the parasympathetic is turned down, along with the insulin secretion.
• With the onset of the emergency, you secrete glucocorticoids, which block the transport of nutrients into fat cells
• Stored nutrients are converted into a simpler form. Then, amino acids are converted into glucose, as it is a better source of energy. This glucose is now readily available for energy during the disaster.
• Not being able to mobilize during crisis is a characteristic of Addison’s disease, where people cannot secrete adequate amounts of glucocorticoids, or in Shy-Drager syndrome, where it is epinephrine and norepinephrine that are inadequate

Why do we get sick?

• Every time you store energy away from the circulation and then return it, you lose some of the potential energy. It takes energy to shuttle nutrients in and out of the bloodstream to power the enzymes that glue them together. As a consequence, you tire more easily
• Your muscles may waste away. If you are stressed chronically, your muscles never get the chance to rebuild
• Having lots of fat and glucose perpetually circulating in your blood stream increases your chances of it glomming on to some damaged blood vessel and worsening atherosclerosis.
• If you are stressed too often, the metabolic features of the stress-response can increase your risk of cardiovascular disease.

Juvenile diabetes

• Also called type 1 or insulin dependent diabetes
• Because a person with type 1 diabetes can no longer secrete adequate amounts of insulin, there is little ability to promote the uptake of glucose into target cells. Cells starve, there’s not enough energy and organs don’t function right
• The hormones of the stress-response cause even more glucose and fatty acids to be mobilized into the bloodstream, which, for a juvenile diabetic, increases the likelihood of pathologies of glucose and fatty acids gumming up in the wrong places
• Stress promotes insulin resistance, which creates an imbalance within the body
• Stress,  including psychological stress, can wreak havoc with metabolic control in    a juvenile diabetic
• There are higher rates of major stressors

Chapter 8: Immunity, Stress, and Disease

Psychoneuroimmunologist: someone who studies the fact that what goes on in your head can affect how well your immune system functions

There is a strong link between the nervous system and the immune system

• Example: Give an animal a drug that suppresses the immune system, along with a conditioned stimulus (e.g.: artificially flavored drink). A few days later, present the conditioned stimulus by itself—and the immune function goes down

The immune system

• Its primary function is to defend the body against infectious agents such as viruses, bacteria, fungi, and parasites
• Immune defense is carried out by white blood cells called lymphocytes and monocytes
• Lymphocytes: consists of T cells and B cells
• T cells: originates in the bone marrow but migrates to mature in the thymus. Has several functions (T helper and T suppressor cells, cytotoxic killer cells, and so on)
• B cells: originates and matures in the bone marrow. Produces antibodies
• If the immune system confuses sorting self and non-self, several problems might occur.
• If your immune system decides that something is foreign and dangerous, even though its not, it may result in allergies. E.g.: peanut, pollen etc.
• When the immune system attacks a normal part of the body a variety of autoimmune diseases may follow (e.g.: multiple sclerosis
• Acquired immunity:

1. Acquire the ability to target new pathogen specifically, with antibodies and cell-mediated immunity.
2. Finding which antibody has the best fit and generating many copies of it
3. Finally, repeated exposure to the new pathogen will boost the targeted defenses even more

• Innate immunity: the second any sort of pathogen hits your system, this nonspecific immune response swings into action

How does stress inhibit immune functioning?

• Stress suppresses the formation of new lymphocytes and their release into circulation, and shorten the time preexisting lymphocytes stay in the circulation
• Stress also inhibits the manufacturing of new antibodies in response to an infectious agent, and disrupt communication among lymphocytes.
• Stress inhibits the innate immune response, suppressing inflammation
• Sympathetic nervous system hormones, beta-endorphin, and CRH* within the brain play a role in suppressing immunity during stress
• Immune suppression also occurs via glucocorticoids, by causing the thymus gland to shrink

Can stress enhance the immune system?

• During the first few minutes after the onset of a stressor, your immune system is enhanced in many ways. This is seen particularly in innate immunity.
• Both physical and psychological stressors appear to cause

Chapter 15: Personality, Temperament, and Their Stress-Related Consequences

People differ in their ways of modulating stress-responses with psychological variables:

• Style, temperament and personality determine whether you regularly perceive opportunities for control   or safety signals, whether you interpret ambiguous circumstances as implying good news or bad, whether you typically seek out social support etc.

Primates are strongly individualistic and there are astonishing differences in their personalities, temperaments,  and coping styles.

• The lessons learned from some of these animals can be highly relevant to humans
• Baboons:
  • If a male could tell the difference between a threatening and a neutral interaction with a rival, his glucocorticoid levels were twice as low as those who couldn’t tell the difference
  • If the situation is really threatening, those who actively do something about it have less stress than those passively waiting for the enemy’s next move
  • The baboon who can’t tell the difference between winning and losing has much higher glucocorticoid levels
  • Males  with a cluster of low-glucocorticoid traits remain high ranking significantly longer
  • The baboons which are capable of developing friendships have lower cortisol levels

Psychiatric disorders and abnormal stress-responses:

• Half of depressives have resting glucocorticoid levels that are dramatically higher than in other people
• Depressives often don’t even attempt to mount a coping response when facing a stressor
• People prone toward anxiety  overestimate risks and the likelihood of a bad outcome

• The amygdala is overactivated in people with anxiety, therefore ambiguous stimuli are more likely to be seen as threatening.

Type A and cardiovascular diseases

• A trait of type A personality, hostility, is a predictor of heart disease
• The expression of anger is a powerful stimulant of the cardiovascular system
• Hostile people might lack social support
• The hostility component in Type-A can be reduced by therapy and this can lower the risk for further heart disease

Repressive personality and stress

• These people describe themselves as quite happy, they are not depressed nor anxious
• Repressive individuals are planners, who live structured, rule-bound lives
• They desire social approval and don’t like ambiguity – everything has to be black or white, never or always etc.
• They have a peculiar lack of emotional expression
• They have overactive stress responses
• EEG studies show that repressors have unusually high activity in the frontal cortex, which is involved in inhibiting impulsive emotion and cognition

Resources: Sapolsky,

Chapter 18: Managing stress

Consider the physiological studies of people carrying out dangerous, stressful tasks (e.g. parachuting). The studies show the same pattern: most people have stress-responses but a subset is physiologically unflustered.

Questions of this chapter: Who makes up that subset that can cope? How do they do it? And how can we?

Successful aging

• Old rats secrete too much glucocorticoids- they have elevated levels during basal, non-stressful situations and difficulty shutting off secretion at the end of stress. This could arise from damage to the hippocampus, the part of  the brain that helps inhibit glucocorticoid secretion.
• The glucocorticoids could hasten the death of hippocampal neurons.
• The tendency of glucocorticoids to damage the hippocampus increases the over secretion of glucocorticoids, which in turn leads to more hippocampal damage, more glucocorticoids, spiraling downward.
• If a rat is handled during the first few weeks of its life, it secretes less glucocorticoids as an adult. Therefore, it will have less problems with hippocampal degeneration in  old age.
• Despite the mathematical impossibility, the average aged person feels herself to be better off than the average aged person.
• Being needed and respected in old age is related to successful aging.

Coping with illness and learned helplessness

• A study concerning the parents of children with cancer showed that some parents secreted immense quantities of glucocorticoids and others average amounts. The parents with lower levels of glucocorticoids were able to:

1. Displace their worries onto something less threatening.
2. Deny that relapse and death were likely and instead focus on the seemingly healthy moments.
3. Use religious rationalization to explain the illness (e.g.: God is testing us)

•  Feeling helpless when faced with an uncontrollable stressor, and globalizing that stressor enhances feelings of giving up on life.

Stress management lessons from baboons

• Males with low glucocorticoid personalities were likely to remain high-ranking significantly (3x) longer.
• Older baboons get harassed by younger ones. Those old baboons who don’t have a strong social network may even transfer to another group because of it, which is a stressful and hazardous journey. Those who have strong social connections stay and feel less stressed, despite the harassment.

Applying principles of dealing with psychological stress

• We can change the way we cope, both physiologically and psychologically.
• By exercising you lower your blood pressure and resting heart rate and increase ling capacity etc.
• Among type-A people, psychotherapy is useful for changing behavior. It also lowers cholesterol profiles, risk of heart attack, and risk of dying, independent of changes in