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Hypnic Jerk

Submitted by robynfarrell on Mon, 03/20/2017 - 01:28

The hypnic jerk, which around 70% of people experience throughout their lifetime, occurs when an involuntary twitch occurs in our body causing us to to awake; it almost feels like you’re being startled. When this occurs our heart beat races, our breaths get quicker, we sweat, and sometimes even feel shock. This can occur right as you fall asleep, or when you sense a falling sensation in a dream. Though the cause is still unknown, scientists assume that it is due to anxiety, caffeine, stress, and/or strenuous activity. 

General and Local Anesthesia

Submitted by robynfarrell on Mon, 03/20/2017 - 00:45

There are two classes of anesthesia, general and local. Local, which is sometimes used at a dentist’s office in the form of Novocain, inhibits ion channels, such as the sodium channels, in the cell membrane of nerve cells. This causes the nerve transmission to be blocked, and due to that blockage the signal can not pass and get directed to the central nervous system. This is where it would have been “read” and a direction then be given on how to act. Now, thanks to the blockage there is no awareness of any of the pain that is occurring, causing it to be so beneficial in procedures such as filling cavities. General anesthesia’s mechanism on the other hand, is not very well known, though it has been used for over a century. Obviously, some kind of blockage is still occurring but to this day scientists are unsure on how this occurs and what exactly is being blocked since we still remain breathing, but just can not feel pain. 

Journal #21 – The Purr’s of Cats

Submitted by robynfarrell on Sun, 03/19/2017 - 23:01

Throughout my life I have encountered many cats, as most people do. I had always noticed how much (most) cats enjoyed being rubbed and pet, that I could feel and hear them purr. Was that their way of communicating their happiness? What caused them to purr?

A cats purr is multifaceted, as it doesn’t just have one meaning behind it. It can mean a wide array of different things.  It helps communicate their emotions. For most of us, it gives of the impression that the cat is content or happy when they purr, but that is not always the case. This is why the purr has been compared to a human smile. We tend to smile when we’re happy, but also when we feel uncomfortable, or even nervous. Whatever emotions hide under our smile, it lies under a cats purr as well. Purring is also used as a way to heal for cats. The frequency of a purr usually is in the range of 25 to 150 Hz, which is actually the frequency for physical healing and bone mending. I for one, though that was strange. I didn’t know that sound could provide healing (as in physical healing). So while they purr they are actually going through a healing process that benefits them. Cats purr’s also help us. Their purr gives us a sense of happiness since we assume them to be happy, and that in turn lowers our blood pressure and calms of our the stressors we face. 

Journal #20 – Peer Reviewed Article (HW Assignment)

Submitted by robynfarrell on Sun, 03/19/2017 - 21:33

Three mosses: Bryum pseudotriquetrum, Schistidium antarctici, and Ceratodon purpureus, located in Antartica, were measured over a period of time (20 years for the first two species, and 10 years for the last species) using steel pins. It was discovered that in that environment that those species only grow around 1 to 5 mm per year depending on the availability of water. Three methods were used: measurements against cranked wires (the pins), measurement of stems cut from turf, bagged or tired into bundles, replaces and remeasrued, and measurement of growth above a stain applied to stems.

Citation: Selkirk, P.M. & Skotnicki, M.L. Polar Biol (2007) 30: 407. doi:10.1007/s00300-006-0197-3

Journal #19 – Moths and Light

Submitted by robynfarrell on Sun, 03/19/2017 - 20:43

It’s always bothered me why moths literally plan their own death by flying straight into light and burning to death, in things such as campfires. I would have thought that evolution would have caused the ones that have died due to this to be not selected for (obviously, since they would be dead) and then generations proceeding to have a better mind in which they do not fly into the light. So what makes them do this?

Phototaxis explains this attraction. This is an organisms movement toward or away from light. So for moths, they would be considered to be positively phototactic since they move towards light, while cockroaches are considered negatively phototactic since they move away from the light. Moths migrate and they get their navigation from the night sky and the moon. The brightness of the moon and the internal compass helps provide a path for them to fly, but when things such as camp fire light interferes with that, it throws them off. This means that though the moon gives them the light to navigate, the campfire also provides light which in turns help them navigate and causes them to crash into the fire. They never expect to reach the moon, and nonetheless they never expected to reach the campfire as well. So it’s a state of confusion they’re in that causes their own demise.

I guess since moths need this phototaxis to help them navigate and live, it’s not a trait that nature will select against causing for this stupid decision to occur continuously through generations of moths. I think it’s an interesting phenomenon that occurs, and one that I personally did not know of. 

Journal #18 – Anesthesia

Submitted by robynfarrell on Sun, 03/19/2017 - 18:58

For a long time in my life I had dreamed about being an anesthesiologist. I’m not sure what drove that passion (though it still lies within me), but it had always seemed so “cool” to administer something that put someone to sleep in such a fashion, that they were unable to feel anything. It was such a great development to medicine, that I just wanted to be a part of it. Though today I know what an intense and scary career this is to have, I wanted to learn a little about how anesthesia does it job, and how it works.

Anesthesia is basically a medically induced coma. Through findings, I realized that it isn’t considered sleep, as people who sleep move, and the EEG readings of people in a coma are not consisted with those under anesthesia. People who are medically induced into a coma through anesthesia it stops the movement of our skeletal muscles, and reduces the sensation of pain. We remain unconscious under anesthesia.

There are two classes of anesthesia, general and local. Local, which is sometimes used at the dentist’s office such as Novocain, inhibits ion channels, such as the sodium channels, in the cell membrane of nerve cells. That causes the nerve transmission to be blocked, and with that blocked the signal can not pass and get directed to the central nervous system, where it would be usually “read” and a direction then be given on how to act. Now, thanks to the blockage we have no awareness of any of the pain that is occurring causing it to be so beneficial in procedures such as filling cavities. General anesthesia on the other hand, is not very well known, though it has been used for over a century. Obviously, some kind of blockage is still occurring but to this day scientists are unsure on how this occurs and what exactly is being blocked since we still remain breaking, but just can not feel pain. 

Journal #17 – Hypnic Jerk

Submitted by robynfarrell on Sat, 03/18/2017 - 20:56

The other night I woke up from a dream with a start, one of those dreams where you fall, and you find yourself waking up with a start. It’s happened so often throughout my lifetime, and other peoples as well, and I’ve never known the word for it. This sensation is called the “hypnic jerk”.

The hypnic jerk occurs with and involuntary twitch occurs in our body causing us to to awake, it almost feels like you’re being startled. When this occurs our heart beat usually races, our breathes get quicker, we sweat, and sometimes even feel shock. This can occur right as you fall asleep, or in situations like mine. Though the cause is still kind of unknown, scientists assume that it is due to anxiety, caffeine, stress, and strenuous activity. It’s crazy to know that around 70% of people in the world experience this throughout their lifetime, and if those causes are the main causes it shows you how stressed people feel in their daily lives.

 

Journal #16 – Ice

Submitted by robynfarrell on Sat, 03/18/2017 - 18:01

Through these last few days we’ve been getting a lot of snow hear in the Northeast. When it snows, my driveway ends up getting turned into an ice rink. I had always wondered what was the reasoning behind ice being so slippery. I know that ice is relatively pretty smooth (at least the thin sheets that form on my driveway), and does that make a frictionless surface causing the slipperiness? I guess to this day, this question is unsolved, but I wanted to look into more of ice’s properties to understand a little more about it.

There are a lot of theories that surround this. One is that people believed the pressure of an ice skate, or a foot, caused the melting point of the top layer of ice to be lowered, and then with a thin layer of water it caused an easy gliding surface.

Another theory is that though the melting point of the top layer does get lowered, it only does so by a fraction of a degree, which doesn’t make an impact. So they thought that the friction from the ice skate causes the ice to melt and then again cause that gliding surface.

Another theory is that they believe that ice is such a mysterious solid that it contains a natural fluid layer, that is very unstable. The instability of this makes it crave stability, so they move fast and crazily that the ices surface becomes slippery.

Either way these theories all revolve around one thing, the thin layer of fluid that forms on the top of the ice which causes this slippery surface, which in my head makes sense as water is very slippery when it’s spilled on a surface such as wood, etc. 

Journal #15 - Even more terms!

Submitted by robynfarrell on Fri, 03/17/2017 - 12:48

Some other terms I came across were “bradycardia”, “ventricular fibrillation”, and “atrial fibrillation”.

I should have thought logically, and realized if tachycardia meant fast heart rate, that bradycardia would mean the opposite, slow heart rate. Usually bradycardia is classified when you have a heart rate of 60 beats per minute or less, and again this can vary depending on how old you are, and the physical condition of your body. Things such as dizziness, lightheadedness, near fainting spells, short of breath are all symptoms of bradycardia. Unlike like tachycardia, from what I could find, this does not have subcategories, which I thought was interesting and wondered why that would be the case. Why can’t this stem from different origins, just like tachycardia?

Ventricular fibrillation, which I offer hear them referring to as v-fib, had it’s negative connotation when it was talked about. It is actually when the lower chambers of your heart quiver, causing the blood flow to stop, causing cardiac arrest. The impulses because so erratic that rapid contractions happen in the lower chamber causing such a serious cardiac rhythm disturbance. It’s pretty rare (less than 200,000 ppl affected a year) for this to occur.

On the other hand, atrial fibrillation, also known as a-fib, is common where more than 200,000 ppl are affected. Atrial fibrillation is when the quivering in your heart, along with irregular heartbeats lead to either clots, strokes, or even heart failure. Millions people in the U.S. live with a-fib, as it’s usually not life threatening as long as it’s treated.

I wonder what makes afib so much better than vfib, even though both are a curse to live with.

Journal #14 - Terms

Submitted by robynfarrell on Fri, 03/17/2017 - 11:56

The more I shadow in the Cardiology Department, the more I realize that terms that they use so often are so unfamiliar to me. So I thought that I would try to add them to my vocabulary and dive a little deeper to understand them.

One of the words I heard being used often was “arrhythmia”. When I heard it, it sounded like a term used in music meaning like rhythm, which made me believe that it had to do something with the rhythm of the heart. Through exploring the internet, I came to learn that this means any change in the normal sequence of impulses of the heart. This could mean that the impulses could either be too fast, too slow, or even sporadic. Obviously, this isn’t a good thing due to the fact that the heart controls blood pumping, and if it isn’t doing that job effectively due to change in the impulses it can effect major organs such as the lungs and the brains which in turn can cause our body to get damaged, or even shut down.

Another term that was used often was “tachycardia”. I wasn’t sure what it meant at first but from the context clues I knew that it had to do with something being too fast. I came to realize that tachycardia means fast heart rate. This is typically when your heart beats more than 100 beats per minute, but this can also vary depending on your age and physical condition. I also realized that tachycardia has different categories such as atrial or supraventricular, sinus, and ventricular. Atrial and supraventricular is when the fast heart rate starts in the upper chamber of your hearts, hence the naming of this type of tachycardia. Sinus means that there is fast but steady heart rate, this is due to the sinoatrial node (the pacemaker) sending out signals faster than usual, but it still allows for the heart to beat properly. Ventricular tachycardia is when the fast heart rate starts in the lower chambers of the heart, and this can be very life threatening if not caught and treated quick enough. 

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