#human physiology

Greetings, Tumblr community! 🧠💡 Let's engage in a comprehensive exploration of the sodium-potassium pump, dissecting its molecular intricacies and elucidating its critical role in cellular homeostasis.

Introduction:

The sodium-potassium pump, residing within the cellular membrane, is an adenosine triphosphate (ATP)-dependent transmembrane protein pivotal for maintaining ionic balance. Its primary function is to actively transport three sodium ions out of the cell while concurrently importing two potassium ions.

Functional Mechanism:

In terms of mechanistic precision, the sodium-potassium pump operates as an ATPase enzyme, utilizing the energy derived from ATP hydrolysis. This primary active transport process involves sequential conformational changes within the pump's structure.

The process commences with the binding of intracellular sodium ions to high-affinity sites on the pump. Subsequent phosphorylation, facilitated by ATP, induces conformational alterations that render the pump receptive to extracellular potassium ions. This triggers dephosphorylation, allowing potassium ions to be released intracellularly.

This orchestrated ion exchange serves to uphold the electrochemical gradient across the cellular membrane, establishing and preserving the resting membrane potential. In essence, the sodium-potassium pump is the architect of the delicate balance between sodium and potassium concentrations.

Physiological Significance:

The physiological ramifications of this meticulous ion transport extend to neuronal excitability and osmoregulation. By contributing to the establishment of the resting membrane potential, the pump plays a pivotal role in regulating action potentials and facilitating the propagation of nerve impulses.

Additionally, the pump actively participates in cellular volume control through osmoregulation. Its influence on water movement prevents cellular swelling or shrinkage, underscoring its significance in maintaining cellular integrity.

For those seeking empirical validation, consider consulting the following authoritative sources:

1. **Alberts B, Johnson A, Lewis J, et al.** Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Section 11.3, The Plasma Membrane.

2. **Nelson DL, Cox MM.** Lehninger Principles of Biochemistry. 7th edition. New York: W.H. Freeman; 2017. Chapter 11, Active Transport and the Cytoskeleton.

3. **Lodish H, Berk A, Zipursky SL, et al.** Molecular Cell Biology. 4th edition. New York: W. H. Freeman; 2000. Section 15.1, The Transport of Small Molecules Across Membranes.

The feeling of lump in the troat when you're about to cry is due to your amygdala(the part of brain that is responsible for emotions) activates your hypothalamus which in turn activates your sympathetic system which causes constriction on the muscles in your troat.

I only answer this because I remain rather astonished that my wife answered this very intimate question herself. Even after over a decade of having these presences, we are still both frequently surprised by what the other is willing to share with the internet.

life lately <3

- visited the science museum with my mom to donate blood, was very disappointed not to see any bacteria exhibits

- finally made a friend in my human physiology lecture!!! she got my number and we did our group quiz together :) she is pre-nursing

- drank for the first time and learned that my anxiety disappears when im tipsy-ish, also pet a stray cat

- had my first human physiology lab, not too sure about my group mates so far... but we'll see!

life is going really well, but i miss a lot of my friends who i dont see as often now.

ID: a Facebook post by Em Jay:

“Do any of you remember when I was posting about the recent scientific revelation that Cheddar Man was actually very dark-skinned and how pale skin is soooo much of a newer phenomenon (according to studies, pale skin began appearing in the human genome roughly 4,000 years ago as opposed to the previous assumption of 40,000 years ago) than originally surmised? A new genome sequencing study adds the famous 'Otzi the Iceman' to the list of incorrectly reconstructed (referring to the long-haired, pale-skinned rendering of him found in the Italian museum next to his real remains) ancient humans, as it has been revealed he was dark skinned and balding! The initial discovery of Otzi the Iceman in 1991 (on the Italian side of the Italian/Austrian border) was of enormous import for the scientific community for several reasons; Otzi is the oldest 'wet mummy' yet found and the clothes and equipment he was unearthed with are incomprehensibly unique as no other organic material from the Copper Age has survived. He also became popular for his 61 tattoos, which are the oldest preserved tattoos known to date. I absolutely love studies/revelations like this because (borrowing a lovely sentiment from co-author of the study Johannes Krause) they truly reflect our own biases in assuming what a person from that time looked like, and to use my own words, challenges many of us to re- examine the appearance of our ancient human ancestors in general. "The Iceman's new genome also reveals he had male-pattern baldness and much darker skin than artistic representations suggest. Genes conferring light skin tones didn't become prevalent until 4,000 to 3,000 years ago when early farmers started eating plant-based diets and didn't get as much vitamin D from fish and meat as hunter-gathers did, Krause says.

“As Ötzi and other ancient people's DNA illustrate, the skin color genetic changes took thousands of years to become commonplace in Europe. 'People that lived in Europe between 40,000 years ago and 8,000 years ago were as dark as people in Africa, which makes a lot of sense because [Africa is] where humans came from," he says. "We have always imagined that [Europeans] became light-skinned much faster. But now it seems that this happened actually quite late in human history!" (excerpt in quotations from Science News article by Tina Hesman Seay) Below are photos of Otzi, the first taken in 1991 shortly after he was discovered by 2 hikers, his naturally mummified body after he was carefully unearthed from the ice and his incorrect/false rendering with pale skin of 2011, and I hope to return to add a correct/more accurate rendering of him if/when a new one is made!”