Sometimes when you’re lost and don’t know which direction to go, just follow the wind. It might not be the right direction but at least the breeze will keep you cool.
Tag: encyclopaedia
Brazil Nut Effect
Have you ever bought a bag of mixed nuts and noticed that Brazil nuts tend to be on the top of the pile? If you put nuts of various sizes in a bag and shake it, you will see that the larger nuts (such as Brazil nuts) will rise to the top slowly. This is strange as common sense dictates that heavier objects sink to the bottom. The strangest thing? No one knows exactly why this happens.
However, there are some persuasive theories. It has been suggested that the so-called Brazil nut effect is due to a phenomenon called granular convection. Convection is usually used to describe the movement of gases and liquids, where heated particles are more active and lighter, thus rising to the top. As the particles rise, they cool down and fall back to the bottom, creating a current. It seems to be that the same can be applied to solid particles, such as nuts. When the jar or bag of nuts is shaken, a vibrational force is applied. Nuts in the middle are pushed upwards by the vibration, with smaller particles filling the gap below. Once the nuts reach the top surface, the vibration pushes the nuts towards the side, where they are then pushed back to the bottom. However, larger nuts like Brazil nuts are too big to fit in this downward current so they stay on the top.
The Brazil nut effect is not exclusive to Brazil nuts. A similar phenomenon can be seen with any large particles surrounded by smaller particles, like pebbles in sand or coffee beans in ground coffee. The theory of granular convection has still not been fully understood, with various factors such as nut density and air pressure seeming to play a role.
Prostitution
They say that prostitution is the world’s oldest profession. The job sure lives up to its reputation – the first recorded incidence of paying money for sex is in 2400BC, where prostitution is recorded among a list of professions in ancient Sumer. Of course, there is no proof of it being literally the “oldest” profession, because the money (or any currency) to pay for sex must have come from somewhere else. Evidence of prostitution can be found in almost every other ancient civilisations, including the ancient Babylonians, Greeks, Romans, Egyptians, Jews, Aztecs, Korean, Chinese and Japanese. It is also heavily referenced in the Bible, suggesting that it was a widely spread profession.
As unnatural as the act of paying for sex may seem, prostitution has been recorded in animals as well. In 1998, a marine biologist named Fiona Hunter was studying the mating behaviour of Adélie penguins. She observed that the penguins would couple up and begin building a nest for their future offspring. The females would go out alone to look for pebbles at the beach. But then, she noticed that some female penguins would not head to the beach to collect the pebbles. Instead, they approached another male penguin (usually one that was single) and engage in courtship rituals to lure them into having sex. The female would then grab some pebbles and run off, while the male just let her go. Hunter concluded that this behaviour was indeed a material exchange for sexual pleasures.
Similar behaviour of offering food or grooming for sex has been observed in different primate species such as chimpanzees and crab-eating macaques. The most interesting study on this topic was that of training capuchin monkeys to use a currency. As soon as they learned that the silver discs could be used to purchase food, monkeys were seen “gifting” these silver discs to each other in exchange for sex. This kind of behaviour does not seem too unnatural if you consider that sex is a biological need (or at least a strong want), and sexual pleasure is, psychologically speaking, one of the strongest rewards.
Prostitution is generally deemed immoral and looked down upon, especially given the exploitation of women for their bodies and cheapening the act of making love. However, it should also be noted that throughout history, there are several cases of women using it as an opportunity to achieve something great. For example, Rahab was a harlot from Jericho in 1400BC. Back then, intelligent, independent women could not have much freedom as a married woman was treated as a slave to her husband. As a harlot, Rahab could live her own life and make her own decisions. When the city of Jericho was laid under siege by King Joshua, he sent in two spies to scout the area. Rahab hid these two men from the guards of the king of Jericho and showed them the secret passages of the city, ultimately allowing for Joshua to conquer the city with easy.
There is also the case of Theodora of Constantinople, who rose from being a harlot to an empress by seducing the Emperor Justinian, who made her a valued co-ruler of the empire. She then proceeded to use her power to crack down on the exploitation of women and protecting women’s rights.
Yawn
Yawning is a reflex that we usually associate with tiredness or boredom. When we feel quite sleepy or feel that it is bedtime, we will involuntarily take a deep breath in and stretch our muscles. It used to be believed that yawning is the brain’s response to lack of oxygen, which seems logical as we take a deep breath in during a yawn. However, studies have shown that yawning actually decreases the level of oxygen in the brain. The reason for yawning is still a mystery, but there are many theories suggesting that it cools the brain or to keep the muscles stretched and ready. It may even be a primitive reflex designed to display dominance and signal that they are not threatened by an incoming danger.
An interesting thing about yawning is that it is extremely contagious. It is thought that yawn contagiousness serves a social purpose. Our brains contain certain types of neurons called mirror neurons, that are responsible for copying an action that we see (hence the proverb “monkey see, monkey do”). It has been suggested that by copying the yawn of another member in the group, a sense of camaraderie is established, acting as a social lubricant (much like mirroring to build rapport). The contagiousness is surprisingly strong, even working when you see a video of a person yawning or even reading about yawning. It spreads to animals as well, such as other primates (e.g. monkeys, apes) and dogs. Interestingly, autistic children are less likely to yawn when someone nearby yawns, suggesting that there is indeed a social element to yawning.
Good
Good food.
Good wine.
Good coffee.
Good dessert.
Good song.
Good show.
Good laugh.
Good company.
The simpler your demands, the easier life can fulfil them and give you happiness.
Viscera: Brain
(Learn more about the organs of the human bodies in other posts in the Viscera series here: https://jineralknowledge.com/tag/viscera/?order=asc)
(NB: I have written MANY ARK posts about the brain and all the delightful ways it screws up. Some of them are probably the most interesting posts on my blog. Please click the hyperlinks to check out the various related articles! 😀 Alternatively, here’s a convenient list: https://jineralknowledge.com/tag/brain/?order=asc)
Among the many organs of the human body, no organ comes close to the magnificent complexity that is the brain. The brain acts as the command centre of the body. It receives massive amounts of information through the various senses, processes it and sends out electrical signals to control how the body operates. Not only does it control “basic” functions such as movement of muscles, controlling organ functions and regulating homeostasis, it is also responsible for the so-called “higher functions” such as consciousness, emotions and cognition. It is the true seat of the mind and soul.
The brain is the only major visceral organ not located in the trunk (body). It is enclosed in the cranium of the skull, which acts as a protective casing. Because it is a closed box, even a small increase in volume (such as due to a bleed or a tumour) can cause extreme pressures to build, causing severe problems. The entire brain and spinal cord are bathed in a fluid called cerebrospinal fluid (CSF), all enclosed by a sheath made of three layers (dura, arachnoid and pia maters). The brain sends out nerves to the rest of the body, which act as electrical wiring transmitting signals. These include the cranial nerves and the spinal cord, which leaves the bottom of the skull down the spine. The spinal cord branches off into many nerves that supply every nook and cranny of the body. The brain itself is made up of two large hemispheres, which are connected by a bridge called the corpus callosum. Despite popular belief, the actions of the two hemispheres are much more complicated than “analytical vs. creative”. The brain also encompasses the cerebellum (the small stripey structure at the back), which controls coordination and speech articulation, and the brainstem, which is involved in autonomic control of life-sustaining functions such as breathing, and also the source of the cranial nerves.
In the last century, scientists have learned that specific parts of the brain play a specific role. This thought started with the field of phrenology, where small areas of the brain were mapped to a certain mental faculty, such as love, wit or destructiveness. Although this turned out to be complete hokum, the idea stayed and we now know the actual functions of each part of the brain. The brain is broadly divided into four lobes: frontal, parietal, temporal and occipital. The frontal lobe is the domain of thought, personality, motor function and other higher functions. The parietal lobe is related to spatial awareness and sensory functions (such as touch). The temporal lobe is linked to hearing, comprehension of language and storing new memories. The occipital lobe is primarily associated with vision. The brain can then be subdivided into more focussed areas, such as Broca’s area that governs speech and Wernicke’s area that governs listening. It should be noted that the four lobes only describe areas on the surface of the brain (cerebral cortex) where the higher functions belong. The inside of the brain is just as complicated and has many different parts, such as the hypothalamus that is involved in homeostasis, and the hippocampus that converts short-term memories into long-term memories.
How does a lump of cells weighing around 1.5kg produce such wondrous abilities such as philosophical thought, deduction, emotions and calculation? The truth is that we still do not know how the brain functions exactly. However, we know that the brain is composed of a large number of neurons (nerve cells) – about 100 billion of them. These neurons connect to one another via a synapse, which is a gap between two nerve cells where neurotransmitters travel to and fro (allowing electrical impulses to jump from one neuron to another). Using these connections, neurons form an unbelievably intricate and complex network of electrical activity. Because one neuron can connect to many more others, the number of synapses is estimated to be around 100~1000 trillion – significantly more powerful compared to any computer in the world. The number of synapses directly correlates to intelligence and it seems intellectual activities such as reading a book increases the number of synapses in the brain. We have yet to understand exactly how the brain uses this incredible computational power to produce cognition and self-awareness.
(Video of neuronal activities in a zebrafish brain)
Because the brain uses electrical impulses for most of its functions, a common abnormality that is seen with the brain is when the electrical activity becomes disorganised and out of control – a seizure. This abnormal electrical activity may be due to a focal problem such as a tumour, or a generalised misfiring of neurons or altered regulation of electrical activity. When a seizure happens, the disorganised activity results in the brain not being able to function normally. For example, the most common consequence is a fit (tonic-clonic seizure) where every muscle spasms out of control, because the muscles are overloaded with chaotic signals. Focal seizures can cause fascinating symptoms depending on the location, such as temporal lobe seizures causing religious visions (hallucination). This also disrupts consciousness, which is why most epilepsy patients do not remember the event.
Viscera: Large Intestine
(Learn more about the organs of the human bodies in other posts in the Viscera series here: https://jineralknowledge.com/tag/viscera/?order=asc)
The final destination of food travelling through the digestive tract is the large intestine, or colon. It is the site where digested food is transformed into faeces, ready for excretion. The large intestine is much shorter than the small intestine – roughly 1.5m in length. Unlike the small intestine which is relatively free and mobile, the colon is fixed to the abdominal wall. It starts in the lower-right corner of the abdomen in a pouch called the caecum (connected to the small bowel). This is where the appendix is located. The colon then ascends the right-side of the abdomen (ascending colon) all the way to the diaphragm, does a 90-degree turn to the left (transverse colon) until it hits the spleen, then goes downwards to the lower-left corner (descending colon). Here, the colon bends into an S-shape towards the centre (sigmoid colon) until it ends as the rectum, which opens out to the anus. The colon essentially frames the contents of the abdomen.
The colon’s main function is the absorption of water and salts from the food that has been processed by the small bowel. As it sucks out the water in this liquid, it becomes more and more solidified. The brown colour of normal stool comes from bile and bilirubin (from the breakdown of red blood cells) secreted by the liver into the duodenum. For this reason, biliary obstruction (e.g. due to gallstones) causes pale stool and dark urine (overflow). Stool also contains undigested material like fibre, giving it bulk. Because it is at the end of the digestive tract, stool can be used to diagnose many diseases, such as an infection in the gut (bacterial, viral or parasitic).
The colon is a common site for cancer to occur in. Because there is room to grow, colon cancers are often found late when they have already spread and is incurable. The key symptoms of colon cancer are bloody stool (although this can be due to many reasons such as haemorrhoids), worsening constipation, anaemia (from blood loss causing iron deficiency), change in bowel habit and general symptoms of cancer (e.g. weight loss, fatigue).
(Appearance of colon cancer on colonoscopy)
Viscera: Small Intestine
(Learn more about the organs of the human bodies in other posts in the Viscera series here: https://jineralknowledge.com/tag/viscera/?order=asc)
Abdominal organs are often grouped into the colloquial term gut. “Gut” also refers to a specific organ – the small intestine (or small bowel). It is an important part of the gastrointestinal (digestive) tract, connecting the stomach to the colon and involved in digesting and absorbing nutrients. The small intestine is extremely long, roughly 7m in an adult. It fits in the abdomen by folding and packing neatly, lying under the liver, stomach and pancreas while being framed by the large intestine. The small intestine is not freely hanging so you cannot just pull it out like a rope. It is connected to the body by a fan-like membrane called the mesentery, which provides blood supply to the gut. The mesentery is attached along one side of the gut the entire way through.
The small bowel is composed of three parts: the duodenum, jejunum and ileum. Although people think digestion mainly happens in the stomach, it is actually primarily performed in the duodenum. The duodenum not only receives liquefied food from the stomach, but is also the place where the pancreas and liver drain digestive juices such as pancreatic enzymes and bile. The enzymes breakdown large molecules like fat, protein and carbohydrates into smaller building blocks, while bile acts like detergent to allow fat to mix better with water (emulsification).
The digested food then travels down the GI tract through a process called peristalsis, where the gut squeezes behind the bolus of food to push it forward, much like squeezing toothpaste out of the tube. The broken down products are mainly absorbed in the second part of the bowel (jejunum) via the walls. The small bowel wall looks like a carpet due to microscopic finger-like projections called villi. Villi allow for a much greater surface area for enhanced absorption. In coeliac disease, these villi are flattened by an autoimmune process and the patient cannot absorb as much nutrients (including vitamins).
By the time the food reaches the ileum, most of the nutrients have been absorbed. The ileum finishes the job by absorbing some extra things like vitamin B12 and bile salts, then sends the food through the ileocoecal valve, which is the door between the small and large intestine.
The small bowel is used by various cultures for culinary purposes. Other than simply eating the bowel itself after cooking, it is often used to pack different meats or other food inside, such as sausages or soondae (Korean sausages, filled with chop sui noodles).
Viscera: Stomach
(Learn more about the organs of the human bodies in other posts in the Viscera series here: https://jineralknowledge.com/tag/viscera/?order=asc)
The stomach is an organ that is well-known, so much so that the abdomen is often colloquially referred to as “the stomach”. It is an important organ that is part of the digestive tract, responsible for breaking down food that comes in through the mouth then the oesophagus. The stomach lies centrally and just below the sternum, surrounded by the liver on the right, spleen on the left and pancreas below.
Food is broken down primarily by the mouth via chewing. Once you swallow, the food is squeezed through the oesophagus until it is dumped into the stomach. The stomach produces a very strong acid (hydrochloric acid, pH 1~2), which dissolves the chewed food. It enhances this process by contracting its powerful wall muscles to churn and mix the food. Once it is nicely dissolved into a thick liquid, it releases it into the duodenum (the first part of the small intestine).
If the stomach uses strong acid to breakdown food, which is organic matter, how come it does not digest itself? This is because the lining of the stomach is coated with a substance called mucin which protects the stomach wall from being corroded by acid. However, the stomach is not perfectly safe from the acid it produces. If the stomach becomes inflamed, the production of mucin and self-repair process of the stomach is limited and acid begins dissolving the stomach lining. This causes peptic ulcers to form, which is essentially a hole in the lining of the stomach, causing severe abdominal pain and occasionally bleeding. Peptic ulcers are commonly caused by an infection by a bacteria called Helicobacter pylori. It may also be caused by severe stress and anger or medications such as NSAIDs (non-steroidal anti-inflammatory drugs, e.g. ibuprofen, diclofenac/Voltaren).
Viscera: Thyroid
(Learn more about the organs of the human bodies in other posts in the Viscera series here: https://jineralknowledge.com/tag/viscera/?order=asc)
There lies a small, butterfly-shaped organ called the thyroid gland in your neck, just in front of your windpipe above the clavicles. The thyroid may not seem important given its small size, but it has the important function of controlling the body’s rate of metabolism. Metabolism is a group of chemical reactions your body relies on to function as a lifeform. Chemicals such as glucose are processed by various enzymes – biological catalysts that encourage chemical reactions – and converted in to fuel (such as ATP) that cells can use for numerous bodily functions. The thyroid produces the thyroid hormones, thyroxine and triiodothyronine, to fine-tune the rate at which these reactions occur.
To see the function of the thyroid gland, we can look at two types of diseases: hyperthyroidism and hypothyroidism.
In hyperthyroidism, the thyroid is overactive and produces too much thyroxine. This causes the body’s metabolic rate to speed up, causing increased heart rate, weight loss, sweating, tremors and sensitivity to heat. Depending on the cause, the eyes may be affected as well, causing them to protrude forwards, giving a rather scary appearance. This disease may happen for various reasons, but the most common cause is Grave’s disease, where antibodies lock on to receptors in the thyroid to stimulate thyroxine production, much like a stuck key on a keyboard.
Hypothyroidism is the direct opposite syndrome caused by an underactive thyroid. This causes a reduction in metabolic rate, leading to weight gain, tiredness (due to lack of energy), slow heart rate and cold intolerance. It can also be caused by an autoimmune disorder (called Hashimoto’s thyroiditis), or more commonly due to iodine deficiency, as the thyroid uses up iodine to produce thyroid hormones.
Both diseases may cause the thyroid to grow to an abnormal size, which is called goitre (seen as a large neck lump). The treatment is usually adjusting the total level of thyroid hormone produced by removing parts of or all of the thyroid, or replacing thyroid hormone if needed via medication.
Because the thyroid uses iodine to make hormones, thyroid diseases such as thyroid cancer can be treated using an interesting method. If you inject radioactive iodine into the patient, it will make its way to the thyroid gland, which actively collects the iodine from the blood. Overactive thyroid tissue (such as in Grave’s or thyroid cancer) take up iodine at a faster rate. The iodine then delivers a focussed dose of radiation to the thyroid, leaving the other tissues in the body unharmed. This method is used for both first-line treatment of hyperthyroidism and to clean-up remaining cancer cells after thyroid surgery.
