Tag: organ

Posted in Psychology & Medicine

Viscera: Pancreas

Posted on by Jinavie

(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 pancreas is probably the most central organ in the human body. It is situated just under the liver and stomach, surrounded by the duodenum (first part of small intestine) and lies in front of the aorta. It is shaped like a fish and thus is divided into parts named the head, neck, body and tail. The head of the pancreas tucks into the loop of duodenum and drains its contents via the pancreatic duct, which joins with the common bile duct (from the liver and gallbladder).

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The function of the pancreas is divided into two functions: exocrine and endocrine.

An exocrine gland is an organ that excretes its products out of the body (including the intestines), such as the salivary or tear glands. The exocrine function of the pancreas is the production and secretion of digestive enzymes that break down proteins, fats and carbohydrates in the small intestine. Because of this, injury to the pancreas often causes a leak of this digestive juice, causing the body to self-digest the pancreas (leading to pancreatitis) and surrounding organs.

An endocrine gland is the opposite in that it secretes its contents into the bloodstream. These glands typically produce hormones, such as the thyroid, ovaries and adrenal glands. The pancreas’ endocrine function is related to an extremely common yet deadly disease: diabetes. Within the pancreas, there are millions of cells that cluster into groups called islets of Langerhans. There are various types of cells, but the most common are the alpha-islet cells that secrete glucagon and beta-islet cells that secrete insulin. Insulin acts to lower blood sugar (glucose) levels by promoting storage and use of glucose after a meal. Glucagon acts to increase blood glucose by promoting the breakdown of glucose storage units (glycogen) and the production of more glucose by the liver. Diabetes occurs when beta-islet cells fail to produce insulin because they are destroyed by the immune system (type 1 diabetes mellitus) or become desensitised by chronically elevated blood glucose levels (type 2 diabetes mellitus).

Another important disease concerning the pancreas is pancreatic cancer. Pancreatic cancer is notorious for its deadliness as it carries a 5-year mortality rate of over 95%. This is because it usually remains hidden – without any symptoms – until it as grown substantially and spread to other organs. However, this prognosis only applies to the most common type of pancreatic cancer involving exocrine cells (adenocarcinoma). There are far rarer cancers of the pancreas that involve the endocrine cells (e.g. insulinoma), which tend to have extremely good prognoses and are usually curable.

Steve Jobs (founder of Apple Inc.) had this kind of pancreatic cancer – an islet cell neuroendocrine tumour. Despite his excellent chance of cure with chemotherapy and surgery, he refused treatment for nine months and instead relied on alternative medicine for cure. However, his disease worsened and he finally resorted to having surgery. By this stage, his disease had spread to the liver due to the nine-month delay in treatment. Spreading of cancer is called metastasis and is often an indication that the cancer is no longer curable. Jobs went against his doctors’ advice and opted for a liver transplant in the hopes of curing his cancer. Organ transplant involves suppressing the patient’s immune system (which also keeps cancers in check) to prevent rejection of the donor organ, which is why oncologists advise against transplants in cancer patients. Jobs’ condition deteriorated quickly after his liver transplant and his decisions ultimately led to his demise.

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Posted in Psychology & Medicine

Viscera: Spleen

Posted on by Jinavie

(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 spleen is one of the lesser known organs of the human body. If you asked the lay person, they would not know what the spleen does, let alone where it is. The spleen is a solid organ that lies in the left upper corner of the abdomen, tucked under the left diaphragm (opposite to the liver which lies under the right diaphragm). Its functions are mainly related to blood, such as removing old red blood cells (sequestration), storing platelets in case there is an emergency bleeding, making antibodies and releasing lymphocytes (type of white blood cell) to help fight infection and in times of need, creating red blood cells. Red blood cells are usually made in bone marrow in adults, but if the bone marrow fails (e.g. leukaemia), the spleen and liver can step in to create vital blood components (extramedullary haematopoiesis).

As most of the functions of the spleen are not technically necessary to sustain life, it can be removed without significant consequences. The spleen is sometimes removed when a patient has severe thrombocytopaenia (lack of platelets) or when the spleen is damaged by trauma. Because it is a solid organ, trauma to it such as a kick to the stomach can cause it to rupture (i.e. break in to pieces). Splenic rupture can cause life-threatening haemorrhage (bleeding) and may not be evident in trauma cases. A person without a spleen needs regular check-ups and immunisations to help fight infections as they have a weakened immune system.

The role of the spleen was a mystery for thousands of years and thus various cultures tried to explain various medical phenomena using the spleen. The ancient Greeks thought the spleen produced black bile, which was associated with melancholy. The spleen was also associated to anger by the English and laughter by the Talmud.

Posted in Psychology & Medicine

Viscera: Heart

Posted on by Jinavie

(Learn more about the organs of the human bodies in other posts in the Viscera series here: https://jineralknowledge.com/tag/viscera/?order=asc)

Out of the numerous organs found in the human body, the heart is perhaps the most well-known. This is probably because since the dawn of time, man has put his hand on his chest and felt the rhythmic pounding of his heart – a reminder that he is alive. The function of the heart is to pump oxygenated blood from the lungs to the rest of the body via the circuit of blood vessels (vascular system).

The heart relies on electricity to pump blood in a rhythmic, autonomous way. Because of this property, a heart will beat on its own even if you took it out of the human body. Every muscle in the human body requires an electrical impulse for it to contract. This is also the case in the heart, but unlike the skeletal muscle in other parts of the body which receive their impulses from the brain and spinal cord, the heart has its own source of electricity.

The heart has a small group of pacemaker cells in the right atrium called the sinoatrial node, which always fires electrical impulses at a set rate and rhythm (sinus rhythm). The SA node will do this without any instruction from the brain. The impulse from the SA node spreads throughout the atria of the heart, causing the atrial muscles to contract simultaneously to squeeze blood into the ventricles. The impulses then reach the atrioventricular node, which filters the signals and sends a stream of electricity through a wiring system known as the Purkinje fibres. These fibres act like a high-speed internet cables running down the centre of the heart, sending rapid signals through out the ventricles to induce a strong, cooridnated contraction in both ventricles. This causes blood to be forcefully squeezed out through the two outlet vessels of the heart: the pulmonary artery (to the lungs) and the aorta (to the rest of the body).

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Although the SA node is completely autonomous, it can be controlled using hormones, nerve signals and medications. For example, adrenaline will speed up the rate the heart beats at while massaging the carotid arteries in the neck will slow the heart down.

One thing people wonder about is what the doctors listen to when they put a stethoscope to a patient’s chest. Everyone knows the heart makes a rhythmic “lub dub” sound as it beats away, but what information could that give away? A doctor can gain much information about the heart from a cardiac examination by taking the pulse and blood pressure, but listening to the heart (auscultation) may reveal a medical sign known as a murmur. A murmur is any added sound other than the normal “lub dub” sound of the heart. For example, a heart with aortic stenosis may give the sound “shhhhhhh” as if it was giving off static. This sound is produced when blood flow in the heart is turbulent and not smooth. This may be for a number of reasons but the most common reason is because the valves of the heart are not functioning properly. For example, the valve between the left atrium and left ventricle may be leaky (mitral regurgitation) or the valve at the start of the aorta may be stiff and narrowed (aortic stenosis).

By carefully listening to the sound the heart makes, an experienced doctor may pick up on such structural abnormalities even without the use of fancy medical imaging technologies.

Posted in History & Literature

Silence

Posted on by Jinavie

“Listen to the sound of silence.” ~ Buddhist saying

The anechoic chamber at Orfield Labs in Minneapolis is the quietest room in the world. It records a staggering sound level of -9.4 decibels (humans can only detect sound levels above 0dB), thanks to its special walls, floor and ceiling design that absorbs all sound instead of echoing it. The room is so quiet that the only sound you will hear inside is the sound of your own organs: the sound of air drifting in and out of your lungs, the blood being thumped out of your heart, the digested food gurgling in your stomach… Even your ears generate a tiny amount of noise from the tiny blood vessels in its walls. The absolute silence is so disturbing that the longest anyone has ever spent alone in the room is merely 45 minutes.

The disturbing power of silence is also demonstrated in the infamous musical piece 4’33” (4 minutes 33 seconds) by John Cage. When it was first premiered in 1952, the audience watched in anticipation as the pianist David Tudor entered the stage. Tudor calmly approached the piano and sat down with a graceful demeanour. Then, he closed the piano lid. For 4 minutes and 33 seconds, the pianist did not play a single note. His only actions were opening and closing the lid to mark the end of one movement and the start of the next one. After the 4 minutes and 33 seconds, he stood up, bowed to the (stunned) audience and exited.

The audience was confused, bewildered and angry. How dare they be mocked with such an outrageous performance? By definition, silence is the absence of music, meaning that the audience were not given the musical performance they expected. However, the audience simply did not understand the “sound of silence”. Outside of the anechoic chamber mentioned above, there is no such thing as absolute silence on Earth. For example, that concert room would have been filled with the noise of the unsettled audience shifting in their seats, the raindrops pattering on the roof and the sound of the footsteps of those who walked out in rage.

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Posted in Science & Nature

Cattle Mutilation

Posted on by Jinavie

For decades, there have been case reports by farmers who found mysteriously dead cattle with strange, surgically precise wounds. Strangely, these corpses were split open and most of their soft organs (e.g. eyes, tongues, intestine, genitals) had been removed. Even stranger, the corpses were completely drained of blood.

The mysterious, mutilated cattle corpses set off a diverse range of conspiracies of what could have caused such a bizarre phenomena. The most popular theories included: alien experimentation (explaining the surgical precision and lack of blood and organs), sacrifice by cults, vampires and the El Chupacabra (a mythological vampiric beast).

Cattle mutilation became so well-known that during the 70’s, it was properly investigated by the FBI. Of course, no evidence was found of aliens and vampires. As with most supernatural phenomena, cattle mutilation could be logically explained by science.

It was found that the cattle had simply died of natural causes, with no foul play involved (other than the occasional psychopaths attacking cattle). But how could natural death cause the surgical wounds, the missing organs and lack of blood? The answer is obvious when one thinks of what happens to animals after they die.

Scavengers such as foxes and buzzards often feast on decomposing corpses, cleanly removing the soft organs before they rot away (organs are the first to spoil). As scavengers usually bite into the corpses, this does not explain the clean wounds. This phenomena is due to insects also feasting on the corpse – a key part in putrefaction. Insects prefer softer tissue such as organs and ragged wounds, so after the insects are finished, wounds often look extremely clean. Also, putrefaction of tissue leads to massive gas production, causing bloating. Once this reaches a peak, the cattle corpse bursts like a balloon, causing clean tears in the abdomen. Lastly, the flies that were involved in cleaning away organs lay eggs, which hatch into maggots. Maggots immediately eat away the dead flesh and organs, even sucking up the blood that pooled at the bottom of the corpse. All of these factors combined results in what appears to be a mysterious alien bovine autopsy.

Although this may sound crazier than Chupacabras, the theory was actually tested in 1979 by a sheriff who kept receiving complaints about cattle mutilation. He took a dead cow, left it on a field and filmed it for 48 hours. The video clearly showed each step described above, proving that cattle mutilation was simply Mother Nature’s cruel, vicious way of returning a corpse back to the soil.

Posted in Psychology & Medicine

Scrubs

Posted on by Jinavie

Scrubs is the uniform that surgeons, anaesthetists, emergency department doctors and nurses wear for the freedom and mobility required in activities such as surgery and CPR. Also, since it is owned and washed by the hospital instead of being privately owned, it is more hygienic and helps prevents infections. A noticeable trait of scrubs (and also surgical gowns) is that almost every hospital uses a shade of blue or green instead of white. Why is this?

The reason being, looking at a surgical scene for a long period of time can cause eye fatigue and afterimages due to the redness of blood and organs. Afterimage is a phenomenon that occurs when the retina becomes insensitive to a strong colour and instead making the complementary colour stand out more. Ergo, a surgeon looking at blood and organs for too long will see afterimages of a blue shade, which may cause accidents to happen as it overlaps on white surfaces or the surgical field. Clothing of blue or green colour neutralises the afterimage and is much easier on the eyes, reducing the fatigue. Lastly, blue-green colours have a calming psychological effect, which helps in a high-tension, stressful environment such as in an operating theatre.

Posted in Psychology & Medicine

Hypothermia

Posted on by Jinavie

A person’s body temperature is always maintained between 36.5~37.5°C. This is because enzymes, which are crucial in all physiological reactions in the body, work most efficiently at this temperature. As physiology is essentially a series of chemical reactions, it is heavily dependent on temperature. If the temperature falls, chemical reactions occur slower and vice versa. When body temperature falls below 35°C, metabolism becomes too slow and it poses a risk to the person’s health. This is known as hypothermia.

How does hypothermia affect the body? Hypothermia is categorised into three classes depending on the severity.

  • Mild hypothermia (32~35°C) leads to the slowing of bodily functions, tremors and difficulty in walking. The patient’s speech is impeded and other neurological symptoms such as decreased judgement skills and confusion start to appear. Also, blood pressure, pulse and breathing rate rise.
  • Moderate hypothermia (28~32°C) causes paralysis of muscles and extreme fatigue (they may complain of being sleepy). As blood (carrying heat) is rerouted to major organs, the skin (especially lips and extremities) become white or purple and very cold. Neurological symptoms worsen with amnesia, memory loss, severe confusion and delusion beginning to show. As sustained hypothermia leads to the tremors stopping, one should not take the lack of tremors as a good sign. Heart rate becomes irregular and arrhythmia may occur.
  • Severe hypothermia (20~28°C) leads to chemical reactions becoming so slowed that physiological functions that support life decline dramatically. Heart rate, blood pressure and breathing all lower to dangerous levels and the heart and lungs may stop functioning. As the patient’s major organs begin to shut down, they enter a state of unconsciousness and eventually, clinical death.

As you can see, hypothermia is a highly dangerous situation that can kill. There are some other fascinating facts about hypothermia.

20~50% of hypothermia death cases are associated with paradoxical undressing. This is a strange phenomenon where the person begins to take off their clothes due to confusion and a lack of judgement from the hypothermia. One theory suggests it is related to the cold damaging the hypothalamus (which controls body temperature), causing the brain to think that the body temperature is rising. Whatever the reason, it is extremely dangerous as it worsens the hypothermia.

As explained above, severe hypothermia leads to death. But interestingly, hypothermia also protects organs. This is why organs for transplanting are transported in ice. Similarly, there are examples of people who “died” from hypothermia recovering with no brain damage. Because of this, medical professionals traditionally say: “they’re not dead until they’re warm and dead”. In fact, if there is something wrong with the patient’s circulation and there is risk of damage to their organs (such as in surgery), sometimes the patient’s body temperature is forced down with ice water injections and cooling blankets, known as protective hypothermia.

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