Our bodies are constantly at war, fending off pathogens at the microscopic level. The innate immune system is our body's first line of defense in this never ending battle. It is non-specific and fights anything that tries to invade. Let's dive in deeper!⬇️(1/6)
If a pathogen breaches physical barriers like skin or mucus, our Complement System comes into play. It identifies, tags, and even perforates pathogens! Tagged pathogens attract macrophages to engulf and destroy them. Complement helps distinguish self from non-self.⬇️(2/6) twitter.com/i/web/status/1…
Another weapon in our arsenal is defensins, tiny peptides (short strings of amino acids) that imbed themselves in the membranes of bacteria and viruses, causing damage.⬇️(3/6)
Yet another tool are Toll-Like Receptors (TLRs) on macrophages. These recognize certain proteins released from bacteria, which begins the body's inflammation response through release of cytokines. This also raises the alarm to recruit help!⬇️(4/6)
Now that the alarm has been raised, more macrophages and neutrophils arrive and get to work, gobbling up the invading pathogens, and exposing them to digestive enzymes. Meanwhile, this induces yet more cytokine release and more inflammation.⬇️(5/6)
Remember, innate immunity is always on duty, providing rapid responses to infections. But it's just part of our immune system. There's also the adaptive immunity, which is more precise and learns from past encounters. That will be covered in another thread though.(6/6)
There is more that wasn't covered, such as natural killer cells and the coagulation system, but I felt like the above grasped the major concepts. Do let me know what you think!
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To this day we don't have a picture of our home galaxy, from the outside. This is because it is so large that sending a probe far enough to grab the selfie would take far too long. If we can't see it from the outside then how do we know its size and our location within it?⬇️1/6
Harlow Shapley, an American astronomer (1885-1972), began by studying the distribution of globular clusters (dense collections of ancient stars) in the sky. He noted that these clusters were not uniformly distributed, but instead were more concentrated in one part of the sky⬇️2/
Shapley used variable stars within these clusters to estimate their distances. These variable stars have an intrinsic (actual) brightness and apparent (what we see) brightness. By comparing the intrinsic and apparent brightness, Shapley estimated how far away they were.⬇️3/6
This Physicist Friday goes to Lise Meitner. Meitner (1878-1968) was an Austrian-Swedish physicist known for her role in the discovery of nuclear fission. Working with chemist Otto Hahn, they bombarded uranium atoms with neutrons, splitting the nucleus and detecting barium. ⬇️1/4
Meitner, along with her nephew Otto Frisch, interpreted the results using Einstein's E=mc^2 to explain the observed energy release. They realized that the splitting of the atomic nucleus into smaller nuclei released a significant amount of energy.⬇️2/4
This insight was crucial in understanding the potential applications of nuclear fission, such as nuclear power generation and atomic weapons.⬇️3/4
Snake venoms are complex mixtures of proteins, peptides, and other molecules that have evolved for various purposes, such as prey immobilization and digestion. This video demonstrates how procoagulants in some snake venom promote blood clotting. How does this work? See Next⬇️1/3
These procoagulants directly interact with proteins involved in the blood clotting process. Often these are proteases (cleave proteins) which ultimately lead to the rapid formation of fibrin, the protein mesh that stabilizes blood clots. ⬇️2/3
Retrograde motion is the apparent backwards motion that planets make as they travel across the sky.
Prior to the sun-centered model of the solar system, it was believed planets made loopty loops as they circled the earth.
The Copernican model explains this motion w/o loops. (1/2)