Thanksgiving: What To Be Thankful For – Revisited
November 20, 2022 at 8:37 p.m.
By Max [email protected]
Cells
You could begin as does Siddhartha Mukherjee in his new book with the most basic — the human cell, the unit of life.
All of us, in fact all organisms, are made of these elementary particles. A group of them must unite to form tissues, organs and organ systems. They do that on their own. Despite their microscopic size, they also have locomotory properties and well-organized cell organelles that carry out a variety of tasks, including the plasma membrane, centriole, peroxisome, lysosome, ribosomes, mitochondria, endoplasmic reticulum, cytoplasm, nucleus, nucleolus, nuclear envelope and Golgi apparatus.
The cooperative, organized accumulations of these autonomous living units — tissues, organs and organ systems — enable profound forms of physiology: immunity, reproduction, sentience, cognition, repair and rejuvenation. If allowed to continue you could then talk about collective groups of cells and start with the immune system.
The Immune System
The immune system consists of two different responses to anything that enters the body that doesn't belong, innate and adaptive. The innate immune system is responsible for the first wave of defense when confronted with an invader, whether it is bacteria, virus or venom. The adaptive system remembers previous attackers and allows the body to mount a better response the next time those invaders attempt to reenter the body.
As soon as invaders are detected the innate system takes action. Mast cells, packed with histamine and heparin and macrophages engulf anything that does not belong there. Inflammation is triggered – it is a carefully regulated response to kill some types of bacteria and viruses without damaging the body.
Macrophages eat bacteria, viruses and other foreign particles. If the macrophages do not destroy all of the invaders, they release compounds which attract neutrophils, a type of white blood cell. As the battle continues between the innate system and the unwelcome visitors, the adaptive system kicks in. It includes dendritic cells and T cells. All T cells contain have specialized receptors and only those whose receptors match what the dendritic cells are presented will be activated. Some will remain as memory T cells, while others become killer T cells to help macrophages and neutrophils. A third subset activate B cells, which are the body's antibody factories. Just imagine trying to orchestrate that cascade under your direction.
The Liver
When you finish profusely thanking the immune system you can extol the virtues of your liver. Its to-do list is second only to the brain and numbers well over 300 items. This includes systematically reworking the food we eat into usable building blocks for our cells; neutralizing harmful potentially harmful substances we incidentally ingest; generating a vast store house of hormones, enzymes, clotting factors and immune molecules; controlling blood chemistry, and so on. There is no machine available to replace all of the liver's diverse functions. The liver is our largest internal organ, weighing three and half pounds and measuring six inches long. It is always flush with blood, holding about 13% of the body's supply at any given time. Finally, it is the liver's responsibility to keep track of the body's moment-to- moment energy demands, releasing glucose as needed from its stash of stored glycogen, along with any vitamins, minerals, lipids, amino acids or other micronutrients that might be required.
The Pancreas
If you still have an audience at the dinner table you can then praise your pancreas. It, indeed, is a miraculous organ and performs a number of vital functions without our instructions or knowledge. The pancreas is composed of two main elements, exocrine and endocrine tissues. The exocrine tissue is organized into a large number of sac-like structures lined with cells that secrete various enzymes important to the digestive process.
As these pancreatic juices are made, they flow into the main pancreatic duct connecting the pancreas to the liver and gall bladder. Scattered throughout the exocrine tissue are small, isolated pockets of endocrine tissue, these pockets are known as the islets of Langerhans. Islets may be composed of several types of cells, predominantly alpha and beta cells. Granules in the beta cells produce insulin, while those in the alpha cells provide glucagon. Insulin helps control carbohydrate metabolism, while glucagon counters the action of insulin. Strangely, the pancreas can churn out huge quantities of enzymes to rapidly reduce our fast food diets into particles of amino acids, carbohydrates and fats, miraculously without digesting its own tissue in the process.
The Central
Nervous System
Anyone remaining could then be lectured about the central nervous system including the brain and spinal cord, blood, hormones, respiration and circulation. None of course are under our immediate supervision or control.
Final Thoughts
I doubt that any questions will follow your talk or that anyone will be awake. We do indeed have a lot to be thankful for.
Max Sherman is a medical writer and pharmacist retired from the medical device industry. His new book “Science Snippets” is available from Amazon and other book sellers. It contains a number of previously published columns. He can be reached by email at [email protected].
Cells
You could begin as does Siddhartha Mukherjee in his new book with the most basic — the human cell, the unit of life.
All of us, in fact all organisms, are made of these elementary particles. A group of them must unite to form tissues, organs and organ systems. They do that on their own. Despite their microscopic size, they also have locomotory properties and well-organized cell organelles that carry out a variety of tasks, including the plasma membrane, centriole, peroxisome, lysosome, ribosomes, mitochondria, endoplasmic reticulum, cytoplasm, nucleus, nucleolus, nuclear envelope and Golgi apparatus.
The cooperative, organized accumulations of these autonomous living units — tissues, organs and organ systems — enable profound forms of physiology: immunity, reproduction, sentience, cognition, repair and rejuvenation. If allowed to continue you could then talk about collective groups of cells and start with the immune system.
The Immune System
The immune system consists of two different responses to anything that enters the body that doesn't belong, innate and adaptive. The innate immune system is responsible for the first wave of defense when confronted with an invader, whether it is bacteria, virus or venom. The adaptive system remembers previous attackers and allows the body to mount a better response the next time those invaders attempt to reenter the body.
As soon as invaders are detected the innate system takes action. Mast cells, packed with histamine and heparin and macrophages engulf anything that does not belong there. Inflammation is triggered – it is a carefully regulated response to kill some types of bacteria and viruses without damaging the body.
Macrophages eat bacteria, viruses and other foreign particles. If the macrophages do not destroy all of the invaders, they release compounds which attract neutrophils, a type of white blood cell. As the battle continues between the innate system and the unwelcome visitors, the adaptive system kicks in. It includes dendritic cells and T cells. All T cells contain have specialized receptors and only those whose receptors match what the dendritic cells are presented will be activated. Some will remain as memory T cells, while others become killer T cells to help macrophages and neutrophils. A third subset activate B cells, which are the body's antibody factories. Just imagine trying to orchestrate that cascade under your direction.
The Liver
When you finish profusely thanking the immune system you can extol the virtues of your liver. Its to-do list is second only to the brain and numbers well over 300 items. This includes systematically reworking the food we eat into usable building blocks for our cells; neutralizing harmful potentially harmful substances we incidentally ingest; generating a vast store house of hormones, enzymes, clotting factors and immune molecules; controlling blood chemistry, and so on. There is no machine available to replace all of the liver's diverse functions. The liver is our largest internal organ, weighing three and half pounds and measuring six inches long. It is always flush with blood, holding about 13% of the body's supply at any given time. Finally, it is the liver's responsibility to keep track of the body's moment-to- moment energy demands, releasing glucose as needed from its stash of stored glycogen, along with any vitamins, minerals, lipids, amino acids or other micronutrients that might be required.
The Pancreas
If you still have an audience at the dinner table you can then praise your pancreas. It, indeed, is a miraculous organ and performs a number of vital functions without our instructions or knowledge. The pancreas is composed of two main elements, exocrine and endocrine tissues. The exocrine tissue is organized into a large number of sac-like structures lined with cells that secrete various enzymes important to the digestive process.
As these pancreatic juices are made, they flow into the main pancreatic duct connecting the pancreas to the liver and gall bladder. Scattered throughout the exocrine tissue are small, isolated pockets of endocrine tissue, these pockets are known as the islets of Langerhans. Islets may be composed of several types of cells, predominantly alpha and beta cells. Granules in the beta cells produce insulin, while those in the alpha cells provide glucagon. Insulin helps control carbohydrate metabolism, while glucagon counters the action of insulin. Strangely, the pancreas can churn out huge quantities of enzymes to rapidly reduce our fast food diets into particles of amino acids, carbohydrates and fats, miraculously without digesting its own tissue in the process.
The Central
Nervous System
Anyone remaining could then be lectured about the central nervous system including the brain and spinal cord, blood, hormones, respiration and circulation. None of course are under our immediate supervision or control.
Final Thoughts
I doubt that any questions will follow your talk or that anyone will be awake. We do indeed have a lot to be thankful for.
Max Sherman is a medical writer and pharmacist retired from the medical device industry. His new book “Science Snippets” is available from Amazon and other book sellers. It contains a number of previously published columns. He can be reached by email at [email protected].
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