Thinking Beyond Science

If you have lost a parent to death, while you are a child, you risk depression for the rest of your life. It may arise from having been introduced at a premature age about death.

Even at the fetal stage, your body learns about the natural world, metaphorically making lifelong diseasons. And if development involves some type of stressor, it can be very harmful. Eg pregnant women in famine. Eg dutch winter hunger of World War II : 16,000 people starved to death.

If you were a first trimester fetus during the famine, that programs you for greater risk of heart disease, obesity and unhealthy cholesterol profile however, if you are a third or second trimester fetus that programs you for a greater diabetes risk. From early childhood, you become highly efficient at storing nutrients.

Fetal Origins of Adult Diseases(FOAD) :

The excessive glucocorticoids exposure of a stressful fetus seems to contribute to the lifelong increase in the risk of metabolic syndrome(cluster of conditions that occur together, increasing your risk of heart disease, stroke and type 2 diabetes. These conditions include increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol).

Anxiety revolves around amygdala, and parental stress programs the amygdala into a lifelong profile that has anxiety written all over it. The amygdala winds up with more receptors for glucocorticoids and fewer receptors for a brain chemical that reduces anxiety called CRH(Corticotropin-releasing hormone).

FOADish tendencies can be carried across generations : If fetus is exposed to malnutrition, and it grows up to become pregnant again, even if mother is not living in malnutritive environment then also her body will keep some extra share of nutrients to her blood, so born baby will be mild malnutrition. 

Growth hormone is secreted by the pituitary gland, which in turn is regulated by the hypothalamus in the brain. The hypothalamus controls the release of growth hormone through the secretion of a stimulatory hormone and an inhibitory one, and it looks like stress dwarfism involves too much release of inhibitory hormone. Furthermore, the body becomes less responsive to what little growth hormone is secreted.

Once the growth period of a youth is complete, the hormones of growth mostly work at rebuilding and remodeling. Much of this takes place in bones. Bones are filled with blood vessels, with all sorts of cell types that are actively growing and dividing. Growth hormone, somatomedins(Somatomedins are a group of proteins produced predominantly by the liver when growth hormones act on target tissue. Somatomedins inhibit the release of growth hormones by acting directly on anterior pituitary and by stimulating the secretion of somatostatin from the hypothalamus.), parathyroid hormone(regulates the serum calcium concentration through its effects on bone, kidney, and intestine. PTH influences bone remodeling, which is an ongoing process in which bone tissue is alternately resorbed and rebuilt over time.), and Vitamin D stands out around supervising the calcium replacement process of bones.

Some of the bones serve as Federal Reserve for the body’s calcium, constantly giving and collecting loans of calcium to and from organs.

The hormones of stress wreck havoc with the trafficking calcium, biasing bone toward disintegration, rather than growth. Main culprits are Glucocorticoids. They inhibit the growth of new bones by disrupting the division of the bone precursor cells in the ends of the bones.

The primary job of the immune system is to defend the body against infectious agents such as viruses, bacteria, fungi and parasites. One of the challenges of the system is to differentiate between normal parts of the body and the cells that are the invaders. Somehow the immune system knows how every cell of the body looks and the mismatched cells are attacked.

Moreover, when your immune system encounters a novel invader, it can form an immunologic memory, to prepare for the next invasion. This is exploited when you are vaccinated with a mild version of the infectious agent.

Immune defense systems are brought by circulating cells called lymphocytes and monocytes(white blood cells).

T and B Lymphocytes – both originate in the bone marrow.

T Cells	B Cells
Mature in Thalymus	Mature in Bone Marrow
Types : T helper and T suppression	Produce antibodies
Bring cell mediated immunity	Bring antibody mediated immunity
AIDS knocks out the T system of the body.

In order to sound the immune alarms throughout the far flung system, blood borne chemical messengers that communicate between different cell types called cytokines have evolved.

Kinds of mistakes that immune system makes :

• Immune system misses an obvious invader.
• A normal part of our own body is mistaken for an infectious agent and is attacked.

Acquired Immunity :

• Dangerous Pathogen X : First, you acquire the ability to target pathogen X, with antibodies and cell immunity that specifically recognize that pathogen i.e. bullet with Pathogen X’s name on it.
• It takes some time to build up that immunity when you are first exposed to Pathogen X – this involves finding which antibody is the best to counter it and then make zillion copies of it.

Innate Immunity : Your saliva attacks any sort of microbe that may attack, instead of targeting specific targets.

Stress will suppress the formation of new lymphocytes and their release into circulation. Glucocorticoids cause lymphocytes to be yanked out of circulation and stuck back in storage in immune tissues. They can also kill them. The fewer social relationships a person has, the shorter his or life expectancy, and the worst impact of infectious disease will hit him.

Source : Why Zebras Don’t Get Ulcers by Robert M. Sapolsky

Goodreads : https://www.goodreads.com/book/show/327.Why_Zebras_Don_t_Get_Ulcers

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