GUT

The anus, saliva, stomach, oesophagus, small intestine, appendix and large intestine

Humans have two anal sphincters: an inner and an outer one. The outer sphincter is under our conscious control. The internal one is under the control of our unconscious mind: it makes sure everything is OK inside us. Between them are many sensor cells: they analyse the "tasters" allowed through by the inner sphincter and decide if they are solid or gaseous, analysing its composition and sending the information to the brain.

Suppressing our needs too long and too often cows the inner sphincter muscles causing constipation.

Childbirth can also sometimes cause tearing of the delicate nerve fibres ruining the connection between the two sphincters.

A muscle encircles the end of the large intestine when we are in a sitting position, creating a kink in the tube and making it harder for the gut's contents to be emptied. A crouching position eliminates this problem.

Saliva, is basically, filtered blood. Salivary glands sieve the blood, keeping back the red blood cells and hormones, calcium, some parts of our immune system are let through. Salivary glands also add calcium-containing compounds and natural painkillers to saliva.

-Opiorphine (stronger than morphine) is produced in small amounts in our saliva. This is because we have so many nerve endings in our mouths that even small sores would be very painful to us. Which is why sore throats feel better after eating: more saliva is produced. Can this perhaps also explain comfort eating when stressed?

-Bactericidal substances kill off some of the bacteria entering our mouths, but not all of it. Good bacteria helps even just by being there, and taking up space that could otherwise be used by bad bacteria.

-At night we produce less saliva, which is why we also wake up with bad breath, bacteria can multiply during that time.

The root of the tongue and our tonsils are made of immune tissue, that investigate any foreign substance they encounter and train the immune system to defend us.

Tonsils we can have removed because unlike the root of our tongue that has outer projections, they have inner crypts. Inside these crypts, too much foreign material can accumulate and lead to infection, tonsil stones and bad breath.

Tonsils should not be removed before the age of 7: when our immune system has "seen it all". They are very important in training our immune cells.

Why is the stomach crescent shaped?

The right-hand-side of the stomach is much shorter than the left side, so it curls up. In this way, liquid can flow against the shorter side, straight into the small intestine. Food will plop against the larger side of the stomach. So, it has two sides with different specialisations: one for fluids (short) and one for solids (long).

The oesophagus is also connected terminolaterally: to the side of the stomach. In this way, when we walk, talk, laugh, all of which cause us to clench our abdomen and put pressure on our stomach, the oesophagus has to deal with only a fraction of that pressure. Thesis why we can walk after a heavy meal without having to burp with every step.

We also have a small pouch of air on the top of our stomach, which we can see in X-rays. If we want to burp, it is easier to just swallow some air, making that gas bubble larger, and therefore closer to the opening of the oesophagus. Also, lying on your left side allows the gas bubble to escape.

The oesophagus is made out of spiralling muscle, like a phone chord. When you've eaten too much and have heartburn (the oesophagus isn't closed properly), stretching the oesophagus closes it better at either end. So sitting or standing up straight with your head looking upwards helps relieve heartburn.

Small intestine - surface area: folds - villli - microvilli - glycozcalyxes: sugar-based structures on the surface of microvilli.

The duodenal papilla (duodenal, duodenum - the first part of the small intestine and papilla, like the salivary papillae in our mouth - spurts juices) liver and pancreatic juices are delivered to the chyme through the duodenal papillae. They contain digestive enzymes and fat solvents.

Every individual villus has a blood vessel which absorbs molecules. All the small intestines blood vessels come together and go to the liver, for toxic screening.

- If we eat too much, this is where the first energy stores are created, you cannot have the extra sugar in your blood.

- Then the blood all goes to your heart, and the nutrients are pumped all through the body.

If you apply pressure to an inflamed appendix it hurts. If you apply pressure to the opposite side, it relives the pain. This is because you are pushing the fluid in the gut toward the inflamed appendix, cushioning it, which causes relief.

The appendix is part of the tonsillar immune tissue. It monitors the foreign microbes in the gut, leaving only the good germs alive - so a healthy appendix is a storehouse of the best, helpful bacteria.

For example, after a heavy bout of diarrhoea, many of the typical gut bacteria have been flushed out, leaving space for new, potentially harming bacteria to settle. This is when the appendix spreads out its good bacterial reserves.

The large intestine takes its time with all the things that the small intestine couldn't digest for around 16hours. It's bacteria also provide us with nutrients from these leftovers.

- Calcium can only be properly absorbed here.

- Vitamin K, Vitamin B12, thiamine, Vitamin B2.

- In the final metre of the large intestine, water levels are finely tuned, and therefore salt levels too.

All the blood from the large intestine also first goes to the liver for detoxification, except for the last few centimetres, which is because usually nothing important is absorbed from there - this is how medical suppositories work so fast, they can go straight to the heart and the rest of the body.

Fat digestion and transportation, allergies, lactose intolerance, fructose intolerance

Fats are not transported in our blood, they are transported in our lymphatic system, which accompanies every single blood vessel and even every capillary. Lymphatic system vessels are transparent and have no muscles of their own, lymph transportation is usually done via gravity.

It is the muscles in our legs that squeeze lymph back up with every step, so no accumulation will occur.

Fat passes into its main duct from the small intestine, and goes straight to the heart. Fat detoxification happens as the fat droplets slowly happen to pass through the liver from the body - but as the liver contains a lot of blood at any given time, the fat droplets will end up there sooner or later. But, before that happens, all the undetoxified blood is in our body.

Cold-pressed virgin olive oil is good against:

- Arteriosclerosis, cellular stress, Alzheimer's disease, eye diseases, inflammatory diseases, cancer

- It also blocks an enzyme in fatty tissue, that creates fat out of spare carbohydrates

- Olive oil is damaged by heat, so it is not suggested to be used in cooking.

- It also tends to capture free radicals fro the air. The free radicals can latch onto anything, causing inflammation of blood vessels, skin ageing, nerve disease. So olive oil should be kept in a well-closed container in the fridge.

- It also contains oleocanthal, a fat that works in a similar way to aspirin but in smaller doses. So regular use of olive oil can help those who suffer from inflammatory disease, regular headaches or menstrual pain.

What is an allergy?

If we fail to break down a protein, then it will not make it into our bloodstream. But, it may find itself in our lymphatic system, embedded in fat droplets. The immune cells can detect it there, and attack the piece of peanut for example, as a foreign body. The next time they see the peanut, they re more ready and can attack it more aggressively.

- This is why most allergies come from foods that are both fatty, and rich in protein such as milk, eggs, peanuts.

- We aren't allergy to greasy bacon: we are made up of meat ourselves and have few problems digesting it.

If the gut is too porous, substances can get to where they shouldn't be, and cause an immune reaction. Stress or a heavy bout of alcohol drinking can cause the gut to become porous, after which it is good to avoid gluten for some days.

Lactose Intolerance

It is more of a deficiency. Lactose needs to be broken down into ints constituent sugars for it to be absorbed into the body. The enzyme for this doesn't come from the paella, it should be made by the cells of the villi themselves, which must in turn digest the lactose when they come into contact with it. Sometimes they can't produce this enzyme, so lactose doesn't get broken down or absorbed.

This lactose travels on, into the large intestine. There, it becomes food for the many bacteria, resulting in fatulence and many other symptoms, due to overfed large intestinal microbes.

Fructose Intolerance

Occurs in people that have fewer fructose-processing enzymes. Fructose may therefore accumulate int heir cells, interfering with other processes. It also can appear later in life when the gut has a reduced ability to absorb fruit sugars so the majority of their fructose ends up in the large intestine.

Fructose intolerance can affect your mood.

- Sugar helps the body absorb many other nutrients too. The amino acid tryptophan latches onto fructose during digestion. So if we have too much fructose, most of it will not be absorbed, so we will lose a lot of tryptophan with it too. But tryptophan is needed to produce serotonin. So too much fructose can lead to symptoms of depression.

- Furthermore, fructose is not absorbed by all our body cells like glucose, it is only processed in the liver, where it is converted into triglycerides. Also, unlike fructose, it doesn't stimulate the release of leptin, which signals station, so we end up eating more.

How much fructose is too much?

You should consume less than 50g of fructose a day, which translates to about 5 pears or 8 bananas or six apples. More than that can lead to an upset gut, fatulence and depressive disorders.

Cigarette smoking stimulates areas of the brain which are stimulated by eating. But it therefore causes gastric acid production for no reason, and causes the sphincter between the oesophagus and stomach to relax, causing heartburn. Stopping smoking relieves heartburn.

Vomiting, motion-sickness, constipation, laxatives, the three day rule, nerves and the gut

Pregnancy hormones relax the womb muscles, but also the sphincter of the oesophagus, causing heartburn. Some hormonal contraception also causes the same effect.

Gastritis is the inflammation of the lining of the stomach.

Reflux is especially dangerous when bile from the small intestine reaches the oesophagus through the stomach. This can confuse the oesophageal cells into thinking that they are intestinal cells, making them change into them. These cells often mutate, and no longer grow and replicate in a controlled way, causing oesophageal cancer.

A lot of saliva is produced before vomiting so it can protect our teeth from the corrosive effects of stomach acids. Animals that cannot vomit do not eat in the same way as us. They have to nibble at their food, testing its suitability. Furthermore, their livers have more toxin breaking substances.

The more solid and undigested the contents of the vomit are, the more likely they came from the stomach.

Sudden vomiting in a violent surge with almost no warming is probably a gastrointestinal virus. Sensors count how many pathogens they encounter: if they are beyond a certain threshold they cause emergency vomiting.

Food or alcohol poisoning can also cause vomiting in surges, but with more warming beforehand = nausea.

Motion Sickness

Occurs when the information the body is getting from its eyes is at odds with that from the ears: the body pulls its emergency breaks and vomits.

CFR (corticotropin releasing factor) is a hormone produced to tan our skin, prevents the immune system from overreacting but is also a stress hormone in upsetting situations. The gastrointestinal cells also secrete it in times of stress or danger. So when gastrointestinal cells register large amounts of CFR, irresponsive of its source, the brain gets intense feelings of emotion stress, strain, anxiety, our body reacts with diarrhoea, vomiting, nausea.

When the brain is stressed, the vomiting is done to save the energy digestion would need and use it for the problem at hand.

When the gut is stressed, the vomiting is done either because the food is toxic, or because the gut isn't in a position to complete the digestion.

Ginger contains substances that block the vomit centre in the brain.

Constipation is defined as having a bowel movement less than three times per week, having particularly hard stool form a quarter of the time.

It results from a disconnection between the nerves and the muscles of the gut. The nerves put the breaks on bowel movement when, for example, you're travelling. How to minimise constipation:

1. Dietary fibre, the best are plums. Or buying dietary fibre from the store, about 30g/day should be consumed.

2. Consuming sufficient fluids. Especially during flights, the dry air draws out even more water than usual from the body. So you should drink more water than normally.

3. Try to complete the bowel movements you usually would at the same times. The gut is a creature of habit. The longer you leave the faeces in the gut, the more water is extracted from them, making them even harder.

4. Probiotics and Prebiotics can breathe new life into a tired gut.

Types of laxatives

Osmotic laxatives: are sugars or salts or short molecular chains that use osmotic water regulation. They make their way to the large intestine, and there, when part of the bowel contents, they draw in water because of the added concentration, making bowel movements easier. If, however, you take too much, you end up having diarrhoea.

Lactulose is the most common laxative sugar. It acts by 1. raising the stool concentration and therefore drawing in water and 2. feeding the gut flora that can produce substances that can act as stool softeners. But too much can cause gases: cramps and fatulence. Lactulose is made by high-temperature milk.

Sorbitol: occurs naturally in some fruit: plums, pears and apples. It isn't absorbed into the bloodstream, so it is used as a sweetener which is why some cough drops have a laxative warning.

Short molecular chain laxatives are best tolerated by the body: unlike salts, they don't disrupt the body's electrolyte balance, and unlike sugars, they don't feed gut bacteria and produce gas. So they can be used over longer periods of time with little side effects.

Osmotic laxatives make faeces moister and increase their mass. The more there is, the more motivated the gut will be to move = the basic principle of the peristaltic reflex.

Faecal lubricants make defecation easier and less painful, but fat-based lubricants cause many fat-soluble vitamins to get dissolved in them and then they are simply defecated.

Hydragogues latch onto gut receptors and signal them to stop extracting fluid from the food passing through and to just let it out. Often use damages the normal activity of these nerves, so hydragogues shouldn't be used more often than once every 2-3 days.

The 3-day rule

Must be remembered when using laxatives. The gut has three parts, and usually we just empty the third and last part. But laxatives usually cause full emptying of the gut, so when no more defection happens again because the first two parts need to be filled, laxatives are used again and the problem repeats itself. You should wait three days after laxative use, its normal.

Theory:

The only reason for having a brain is movement: pulling faces, talking, running, walking, influencing the world around us even by moving. But if you're a tree and you can't chose to move or not, you don't need a brain. Like the sea squirt that no longer needs its brain once it has found a place to permanently settle down.

The gut also has an unimaginable number of nerves, comparable only with the brain, and that command many signalling substances, nerve insulating materials and ways of connecting.

The regions of our brain that signals from the gut can get to: insult, limbic system, prefrontal cortex, amygdala, hippocampus, anterior cingulate; affecting self awareness, emotion, morality, fear, memory, motivation.

The vagus nerve: the most important route from gut to the brain. Runs through the diaphragm, between the lungs and the heart, up along the oesophagus, through the next to the brain.

The brain depends on sensory organs to get a picture of what is going on: it is very isolated itself by a thick skull and very well filtered blood. The gut is right in the thick of it, with such a large surface area and so many nerves, it is the largest sensory organ.

Forced-swimming test, irritable bowel syndrome, gut flora and behaviour, neuroplasticity, immune system and the gut, birth and bacteria

The forced-swimming test

Puts rats in water containers too deep for them to reach the bottom with their paws and measures the length of time that they keep swimming until they give up. Used in studies that try to observe the effectiveness of antidepressants for example. When given a cocktail of good gut bacteria, the rats swim significantly longer than without, but when the vagus nerve is severed, they didn't swim longer anymore.

The thalamus is the brain's bouncer, it filters the sensory information and decides what will be sent to the conscious brain. For example, if you will be able to recognise curtains that have been changed is decided there. When the gut is unhealthy, feelings of unease also pass onto the brain.

People with Irritable Bowel Syndrome have a higher incidence of anxiety or depressive disorders.

This may be caused by micro-inflammations, bad gut flora or undetected food intolerances.

Stress can damage the gut, because it reduces the blood supply to the gut, producing less mucus there via signals passed through the sympathetic nervous system. This weakens the gut walls, which sends distress signals to the brain.

Glut flora can also affect behaviour in mice. Timid and exploratory strains of mice were put on antibiotics to wipe out their gut flora, and then there were fed each other's gut bacteria. They showed behavioural characteristics atypical of their own strain, and similar to those from which their gut bacteria originated from.

Stress when eating, such as being told to finish all your food when you are young, activates nerves that inhibit the digestive process, which means we extract less energy from our food, we take longer to digest it, and put the gut under strain.

Neuroplasticity and depression

After the age of 25, nerves start to fire mostly in well-rehearsed patterns. it is harder to learn and change. Thought patterns such as "I am worthless" have taken firm root. If antidepressants increase neuroplasticity, they may work by loosening negative thought patterns.

The side effects on the gut of antidepressants such as prozac are diarrhoea, constipation and nausea, they are caused because the same neural receptors in the gut are also being affected.

95% of the serotonin we produce is manufactured in gut cells, where it enables nerves to stimulate muscle movement, and is a signalling molecule. So affecting gut serotonin can affect the brain too and vice versa.

Where the "self" originates

1) The insula receives information about feelings from the entire body. Each piece of information is like a pixel, all pixels form a picture of a cold, hungry, us sitting on a table for example.

2) The purpose of our brain is to create movement. The insula's map is used to plan meaning for movement

3) The brain is an organ of the body. The insula creates an image of the body, also containing the brain. That must therefore include the areas for social empathy, morality and logic, our perceptions of the environment, and our memories from the past.

Our gut's microbiome can weigh up to 2kg.

80% of our immune system is located in our gut - that is because there are so many bacteria there.

The bacteria are located on the mucous membrane of the gut - preventing them from getting too close to the cells of the gut wall.

Here, immune cells can get acquainted with many previously-unsown species where they don't pose a danger to the body. So when they later encounter them elsewhere, they can react very quickly.

So the immune system in the gut must:

1) suppress its defensive instincts

2) still weed out the bad bacteria

Sometimes there are communication breakdowns, and the immune cells are wrongly trained to distinguish between bacterial cells and body cells, and may attack the body, as in the cases of scarlet fever, type I diabetes.

Usually immune cells are trained in the gut before they are allowed to enter the bloodstream.

They encounter many different pathogens there: if the cells cannot clearly distinguish between a foreign body and our own cells, and nee dot stop and prod, they will never graduate into our bloodstream.

Some cells like red blood cells have markers on their surface very similar to bacteria.

Immune cells are trained to recognise the specific markers of their won body's cells and not to attack them: these are the blood group markers. However, if another blood group's blood is transfused, with these other protein markers, it will be attacked as though it is bacteria. The immune system will make clumps of these red blood cells.

Babies can theoretically receive any blood group transfusion, because their immune cells are not trained yet, however they are given their mother's blood group, in case immune cells from her body are in theirs.

Colonisation resistance: Harmless bacteria occupying spaces that could otherwise we taken up by harmful species.

10% of our cells are human, microbial cells compose 90% of us by number.

In the uterus, we are sterile.

The vagina has the first bacteria we come into contact with. The vagina itself is covered in acidic mucous produced by the bacteria there. This limits the types of bacteria that can survive in that environment, and as they coat the emerging baby, the bacteria that can come into contact with the baby to is selected. These helpful microbe and some that come from the skin of the mother and the hospital are those which will start to train the immune system immediately.

It takes about three years for the gut flora to stabilise. This depends on our environment, what we touch, lick and play with.

Breastmilk also provides many gut flora members. It also contains antibodies to help the child's immune system.

Children born with a C-section have a higher chance of developing allergies and intolerances because of the random gut flora they get to have. Poor nutrition, too much antibiotics, excessive cleanness, too much exposure to bad bacteria can cause a bad start to gut bacteria and hence the immune system too.

Babies contain more active genes for digesting milk.

Guts of obese people more carbohydrate breakdown genes.

Older people have fewer bacteria to deal with stress.

Every microbe contains genes for protein and carbohydrate breakdown and vitamin production.

Different types of gut bacteria; yoghurt; diet, gut, weight and bacteria; inflammation and weight gain; salmonellae in eggs and chicken meat; Helicobacter Pylori; Toxoplasmata Gondii

Bacterioides

- Best known family of gut bacteria, they love to feed on meat products

- Often they are the dominant population in the gut

- Carbohydrate breakdown experts, they have many genes for that purpose

- They can extract a lot of energy from food

- They produce a lot of biotin = vitamin B7 and vitamin H

Prevotella

- The opposite of bacteroides: there are more present in the vegetarian gut

- They have a long flagellum and travel to find useful proteins

- Produce sulphur compounds as a byproduct

- Other bacteria, desulphovironales take up the suphur

- They produce vitamin B1, which is required by our nerves to insulate them in fat. B1 deficiency causes muscle tremors and forgetfulness. Low levels of deficiency cause irritability, frequent headaches, concentration problems, high levels of deficiency cause beriberi: muscle atrophy and inability to walk in their sufferers.

Ruminococcus

- Feeds on plant cell walls

- Produces haem, needed for blood

Cows keep their bacteria in the beginning of their digestive tract. In this way they can:

1) Break down complex carbohydrates for them

2) They are themselves a rich source of protein: when they die they fall down the digestive tract and become themselves a source of food

In humans bacteria are too far down to provide any food, so they are passed out indigested.

Rodents have them as far down their digestive tract as us, so they don't digest bacteria. This is why they eat their own faeces: to not waste the bacterial protein that was excreted.

Yoghurt is pre-bacterially digested milk. The lactose is broken down and transformed into lactic acid: making ti both sweeter and sourer than milk. Lactic acid can either be dextrorotatory (left turning) or levorotatory (right turning). It is better to buy milk with dextrorotatory lactic acid for the human digestive system.

Diet, gut bacteria, weight

Fat mice fed the same diet as skinner mice secreted less indigestible calories: their gut bacteria fed them more.

Bacteria are capable of producing different fatty acids out of indigestible carbohydrates.

Vegetable-loving bacteria tend to produce fatty acids that feed the gut and the liver, and are therefore essential.

Other bacteria produce fatty acids that feed the rest of the body: so if you eat a banana vs a chocolate with the same amount of calories, the banana is less likely to make you fat since it will only feed the liver and gut as oppose to the whole body (very simplified summary considering only one aspect of digestion)

Obese people have less diversity in their gut flora: mainly groups of carbohydrate-loving bacteria prevail.

Inflammation causes weight gain

Metabolism problems: obesity, diabetes, high blood lipid levels usually come with increased levels of infection markers in the blood too.

A sub-clinical infection: the markers are there but they are not high enough to be detected or treated

Usually, the bacteria are located on the mucous membrane, and are not in contact with the gut bacteria. But when there are too many bacteria, or when the host eats an overly-fatty diet, too many bacteria walk into the bloodstream - this causes the body to slip into infection mode.

Bacterial signalling substances can also latch onto other organs, they can lock onto the liver or fatty tissue, and encourage the deposition of more fat.

They can also hinder thyroid function, thyroid hormone production, and slow the rate of fat burning.

Sub-clinical infection causes weight gain, hormonal imbalances, too much oestrogen production, too little vitamin D.

Bacteria can affect their host's appetite

We chose our food based on what we feel like eating at any given moment, and we stop eating when we feel satiated.

Bacteria can influence both of these conditions.

Bacteria needs to send signals to the brain to do this:

It produces Tyrosine and Tryptophan, amino acids needed for dopamine and serotonin production. So, in theory, the bacteria reward us when we send them food. It makes us feel good, and crave more food to bring about the same pleasure.

How does salmonellae get to eggs?

Salmonellae is a common gut dweller of African lizards. Cheap chicken feed comes from Africa, sometimes lizards or tortoises have excreted it in the feed, and when the feed gets eaten, it multiplies in the chickens and gets excreted by them too.

Chickens have one hole for both faeces and for eggs, so the shells get salmonella which gets transferred to the egg itself if the egg or the hands touch the outside of the shell.

How does salmonellae get into chicken meat?

After being slaughtered and beheaded, chickens are put into large baths, where one batch of infected chickens can infect them all.

The bacteria are then frozen with the chickens.

Usually the salmonellae gets transferred to other things during the thawing process of the chicken on the sink or other surfaces, and this is the main way it can infect humans.

10minutes of cooking at 75degrees celsius is enough to kill almost all salmonellae, so rarely is the method of cooking that which is the problem.

Helicobacter Pylori poets itself from the acids stomach with these mechanisms:

1) Byproducts of its metabolism are very alkaline so they neutralise any acid in their immediate vicinity

2) It burrows itself beneath the mucous membrane that protects the stomach from digesting itself.

There it injects substances into the cells which are eventually fatal to the stomach cells. So if the HP does not have the injecting gene, they cause less damage to the host.

3) By getting under the mucous membrane, HP damages it, so our stomach acids end up digesting parts of our stomach too - ulcers.

Sulphurophane blocked the enzyme that HP uses to neutralise gastric acid.

If too many stomach cells are destroyed, too many new ones are made to try and replace them, this can cause cancer.

They can also produce a neurotoxin, which in turn causes trembling hands, facial paralysis, motor problems.

Interestingly, people who have HP also have lower risk of dying of lung cancer, about a half chance.

HP also provides protection against childhood asthma. The theory for this is that the bacterium teaches the immune system to "stay cool":

It causes large numbers of T-cells to be produced when it latches onto our stomach cells.

T-cells calm down the immune response, so they also are less aggressive towards pollen and other allergens.

Toxoplasmata Gondii

Tiny, one celled organisms with very complex genetic information.

They reproduce in the guts of cats, which are their definitive hosts - which means that they are only able to reproduce there.

A cat can only get toxoplasmata once in it's lifetime, and it is a danger only during that initial time of infection: this is because when the toxoplasmata are found in the cats faeces, they mature in the litter for about two days, and then are ready to infect a host. They can stay in a human or other mammal for up to five years trying to find a definite host.

First symptoms are mild-flu-like.

But more importantly, it alters behaviour:

Infected rats have a decreased aversion to cat urine, an evolutionary adaptation to increase the parasite's reproductive success by getting the rodent to the cat. It happens through epigenetic remodelling of neurons which govern associated behaviours.

In people: the risk of being involved in a car accident is higher amount toxoplasmata carriers, especially in the early stages of infection.

Infected human men like cat urine smell more, and infected human women like it less.

How does it work?

When infected, the immune system activates the IDO enzyme to protect us from these parasites.

IDO breaks down a substance that the invaders like to eat, forcing them into a dormant state.

But IDO is also a substance needed to produce serotonin.

So less serotonin affects our mood negatively.

Also, the serotonin precursors that are now unused can dock onto brain receptors, causing lethargy. These are the same receptors for painkillers: causing indifference and sedation.

The amygdala is the part of the brain associated with fear:

Fibres run straight from the eyes to the amygdala, so even if the visual cortex is damaged and you cannot process visual information consciously, you can still get scared from a spider in your field of vision = blindsight.

If the amygdala gets damaged, a person may become fearless.

Toxoplasmata hibernate in muscles and in the brain: in the amygdala, the olfactory centre, the prefrontal cortex:

1) the rat can become more fearless

2) The rate does not dislike cat urine smell

3) it an weaken mechanisms that suppress self-destructive behaviour and decision-making

Toxoplasmata posses genes that influence the production of dopamine in the brain too.

Dopamine is over-abundant in schizophrenics.

The proportion of toxoplasmata carriers is twice as high in schizophrenics as in the the non-schizophrenic population..

Toxoplasmata is especially dangerous to pregnant women, who shouldn't touch or dispose of cat litter, and whose cat litter should be changed daily by someone else:

1) wash fresh fruits and vegetables well before eating

2) shovel cat litter daily

3) cook chicken well

4) stay away from kittens who have a higher risk of carrying toxoplasmata