Interesting facts

What are some interesting features of the human nervous system? 🔴 The human nervous system can transmit signals at speeds of 100 meters per second. 🔴 The slowest signal transmission occurs inside the skin. 🔴 Every square cm of human skin contains around 200 pain receptors but only 15 receptors for pressure, 6 for cold and 1 for warmth. 🔴 In the human PNS, nerve cells can be threadlike—their width is microscopic, but their length can be measured in meters. 🔴 There are over millions of nerve cells in human CNS, 100 billion neurons in the human brain and around 13,500,000 neurons in the spinal cord. 🔴 Sciatic nerve is the longest and broadest single nerve in the human body. 🔴An optic (cranial) nerve is the fundamental part of the CNS, and the human eye's most significant sensory nerve. 🔴 B vitamins must be replenished daily as they are only stored in the body in a very small amount. ⬆️ Look at the human nervous system depicted using advanced computer modeling. Subscribe- t.me/askmenow

Perverted amusements of wealthy ladies of the 18th century In those days, rich women loved to mock maids or girls from lower society in every possible way. One of the most perverted and cruel amusements was the following: the ladies invited a maid to their room and chewed it to the bone. Then they grabbed her, spread her legs and put their feet right in...read more (18+)

Graceful dolphins and crimson sunset 😍

An extraordinary marine rodeo 🤠

💵 💰 The curious origins of the dollar symbol 💵 💰 The dollar sign ($) is a globally recognized symbol, representing not just the currency of the United States but also embodying a broader array of concepts, from the American dream to consumerism and capitalism. Its origins are unclear, with competing theories, including connections to Bohemian coins, the Pillars of Hercules, and harried merchants. Some mistakenly believe it stands for "United States," but this is unlikely since the US was known differently before 1776. The British pound sign has a long history, but the dollar sign is relatively young. One theory links the dollar sign to the Bohemian thaler, featuring a serpent on a Christian cross, alluding to the story of Moses. Another theory connects it to the Pillars of Hercules, which appeared on Spanish dollars. The most accepted theory involves Spanish coinage, where the peso de ocho reales was abbreviated as 'P' with an 'S' in superscript. Over time, this merged into the familiar dollar sign. 📌 In the American colonies, trade between Spanish Americans and English Americans was thriving, and the peso, or peso de ocho reales, was used as legal tender in the United States until 1857. Merchants and scribes often abbreviated the peso to 'P' with an 'S' in superscript. Over time, as a result of hurried writing and scrawled script, the 'P' merged with the 'S' and lost its curve, leaving the vertical stroke like a stake down the center of the 'S.' Given that a Spanish dollar was roughly equivalent to an American dollar, it's plausible that the dollar sign originated from this abbreviation. 🧐 As with many aspects of American history, there is a partisan dimension to the debate surrounding the dollar sign's ancestry. One faction believes it is a homegrown symbol, while another asserts that it was imported. This debate reflects the complex and diverse history of the United States. The dollar sign is undeniably an American invention regardless of its precise origins. While Oliver Pollock, an Irish-born trader and early supporter of the American Revolution, may not have been its sole creator, his correspondence has led many historians to cite him as its originator. 👉 The first printed dollar sign was produced on a Philadelphia printing press in the 1790s, created by Archibald Binny, a fervent American patriot with Scottish roots, who is also remembered as the creator of the Monticello typeface. 💵 💵 💵 👁 Intriguingly, the dollar sign's history is just one layer of the mystery surrounding American currency. The design of the American dollar bill, with its intricate symbolism, including the Eye of Providence, continues to captivate scholars and curious minds alike, inviting us to explore the hidden meanings and historical connections embedded within this iconic symbol of wealth and prosperity. Source: http://www.bbc.com/capital/story/20190528-the-curious-origin-of-the-symbol

💵 💰 The curious origins of the dollar symbol 💵 💰

What are some amazing facts about the animals’ nervous system? ℹ️Sponges are the only multicellular animals without a nervous system. 🪱🐘The size of the nervous system ranges from a few hundred cells in the simplest worms, to around 300 billion cells in elephants ⬆️. 🔰 The minuscule C. elegans nematode worm has just 302 neurons, but it’s able to carry out the same functions as the nervous systems of higher organisms. 🔰 The tiny Megaphragma mymaripenne wasp ⬆️ only lives for 5️⃣ days and has just 7️⃣4️⃣0️⃣0️⃣ neurons. As it changes from a larva into an adult, it destroys the majority or its neural nuclei until just a few hundred are left, because there’s not enough room in its head. 🔰 At a larval stage, sea squirts have the same anatomical characteristics as most vertebrates, but as they grow, they lose their minds – literally. They digest their own cerebral ganglia, which controls movement, because once they’re sedentary, they no longer need it. Subscribe- t.me/askmenow

The Sea Devil in all its glory 😍

How to catch catfish. Don't thank me! 😉

What are the components of the nervous system? ✍️The nervous system of vertebrates has two components: the central nervous system (CNS) and the peripheral nervous system (PNS). ☑️The CNS is the largest part, and includes the brain and the spinal cord. ☑️Structures that do not lie within the CNS, are called the PNS. The majority of nerves belong to the PNS, even when the cell bodies of the neurons to which they belong reside within the brain or spinal cord. The PNS is divided into: 🔘the somatic part consisting of the nerves that innervate the skin, joints, and muscles. 🔘the visceral part, or the autonomic nervous system, that contains neurons that innervate the internal organs, blood vessels, and glands, and itself has two parts: ▪️the sympathetic nervous system and ▪️the parasympathetic nervous system. ℹ️Some authors also include sensory neurons whose cell bodies lie in the periphery (for senses such as hearing) as part of the PNS; others, however, omit them. Subscribe- t.me/askmenow

Amazing marine life — Ophiura 👾

Very young, and already a punk 😁

What are glial cells? ✔️The second main type in the nervous system are glial cells. Glial cells (named from the Greek word for "glue") are non-neuronal cells that provide support and nutrition, maintain homeostasis, form myelin, and participate in signal transmission in the nervous system. Among the most important functions of glial cells are: 📍to support neurons and hold them in place 📍to supply nutrients to neurons 📍to insulate neurons electrically 📍to destroy pathogens and remove dead neurons 📍to provide guidance cues directing the axons of neurons to their targets. ✍️A very important set of glial cell generate layers of a fatty substance called myelin that wrap around axons and provide electrical insulation that allows them to transmit signals much more rapidly and efficiently. ✍️🧠In the human brain, it is currently estimated that the total number of glia roughly equals the number of neurons, although the proportions vary in different brain areas. Subscribe- t.me/askmenow

What do we know about neurons? ✔️One of the two main types of cells in the nervous system are neurons. 🔬✍️They can be distinguished from other cells in a number of ways, but their most fundamental property is that they communicate with other cells via synapses, which are junctions containing molecular machinery allowing rapid transmission of electrical or chemical signals. 🔬✍️Many types of neuron possess an axon, a protoplasmic protrusion that can extend to distant parts of the body and make thousands of synaptic contacts. ✍️Even in the nervous system of a single species, hundreds of different types of neurons exist, with various morphologies and functions. For example, sensory neurons transmute physical stimuli such as light and sound into neural signals, and motor neurons transmute neural signals into activation of muscles or glands. In many species, though, the majority of neurons receive all of their input from other neurons and send their output to other neurons. Subscribe- t.me/askmenow