Flight or Fright? A Cardiovascular Lab

Have you ever been so scared that your heart feels like it is about to explode right out of your chest?  Have you ever experienced such a major thrill that it takes you a long period of time to calm down after?  Recently, in Anatomy and Physiology, many of my colleagues and I were given the chance to design and execute our own cardiovascular lab experiment.  We decided that it would be interesting to measure the heart under one of the most compulsory reactions the human body can undergo: fear.

The experiment was based on measuring the test subject’s heart rate while playing a very scary game, known as “Slender: The Arrival”.  The game is scary because it involves a dark setting, limited visibility, and a creature who is stalking you.  This game depends on “jump scares” (sudden appearances accompanied by loud, instant music) to scare the player.  We used this game to measure how heart rate changes when such startling events occur.

The experiment information was comprised into a poster, located outside of our classroom.  The poster, seen below, is the final product of our experiment:

The following slideshow presentation goes more in-depth, and shows each individual process, from beginning to end, of our lab.  It was created by myself, and my highly intellectual colleagues Michael Rees, Trevor Lopkoff, and Chuck Aaron.  We hope you enjoy our “Flight or Fright?” cardiovascular lab!

(*Note- I apologize for the poor quality of a couple of these pictures.  That is a result of me being a science student, not a photography student.  If you have trouble reading, please message me and I can clarify!)

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Heart + EKG = Lab!

The title obviously says it all! In my class, we are continuing to expand upon our study of the cardiovascular system. So far, my class has studied the anatomy of the heart in-depth, participated in a heart dissection, and looked at heart tissue under a microscope. Yet, as intriguing as these labs were, they pale in comparison to this lab. This lab allows us to observe the living, pumping hearts of our colleagues. You can’t deny, it doesn’t get much more interesting than this!

To perform this lab, we would be using an electrocardiogram, or EKG for short. The EKG measures the electrical signals that are fired throughout the heart, causing it to beat. These electrical signals come from what is known as the sinoatrial node, which is located in the right atrium (for more information, please see my previous post entitled A Post With A Lot of Heart).  Think of this node as the body’s natural pacemaker, keeping the heart pumping in a rhythmical way. Measuring the activity of the sinoatrial node is very important for doctors. They use EKG’s to identify disorders, abnormal rhythms, and injury to the heart tissue.

The graphical results of an EKG show individual heartbeats. The results are divided into five primary “sections”, which are labeled P,Q, R, S, and T. A typical EKG reading, with labeled sections, can be seen below:

The P, also known as the P-R Interval, represents the contraction of the right atrium, and the impulse created by the sinoatrial node. This signal travels through the atrium, though the atrioventricular node (within the right ventricle), and into the ventricles. The QRS section of the EKG is the result of movement within the ventricles of the heart. Finally, the T represents a concept known as “ventricular repolarization”, or in simpler terms, the time when the ventricles reset and prepare for the next pulse. The diagram below shows the four chambers of the heart, and expresses which part is responsible for P, QRS, and T. Take a look!

So now that we know how to read EKGs, it is possible for us to analyze real world data. This is when we connected an EKG sensor to fellow classmates (by placing sensors on key points on the subject’s arms), and recorded their hearts. For each of the three recordings in my group, I will label the P, QRS, and T. Please also take notice of the time, in seconds, that runs along the bottom of each graph.

My Heart’s EKG Results:

This is the heart beat of yours truly! The data shows that, for the most part, my heartbeat is regular. My T wave is slightly larger than the “typical” heartbeat, but still within the realm of normal. Also, by looking at the time, it can be seen that my heartbeat is relatively slow (only getting 3-4 beats across 3 seconds). This can be credited to my athleticism as a long distance runner.

Trevor Lopkoff’s EKG Results:

This is the heart beat of my colleague, Trevor Lopkoff. As you can see, he has a very clearly defined P, QRS, and T wave. His heartbeat, of the three students presented in this blog post, most closely resembles the example provided earlier in the post. The only irregular part of this graph is the frequency of each beat. Trevor is recorded having about 8 full beats across 4 seconds. This is unusually fast for a resting heart rate. However, he has been prescribed a special dosage of caffeine to combat a cardiovascular issue, which is probably the responsible factor.

Chuck Aaron’s EKG Results:

This is the EKG of my other colleague, Chuck Aaron. His P and QRS waves are relatively normal. The oddity of his heartbeat is that he has a particularly high T wave (much higher than what is deemed normal). While there is no definite explanation as to the cause, it must be taken into account that the equipment we used to measure our heart rates isn’t incredibly advanced. The sensor could have been off, or could have picked up other muscle signals. Chuck produced 5 heartbeats in 3 seconds. Also an athlete, this is somewhat slow.

The purpose of this lab was to gain familiarity with a primary medical process for observing the heart. As you can see, it is very easy to use an EKG reading to analyze a patient’s heart for defects or abnormalities. While it is possible to notice any problems with stethoscopes and sphygmomanometers (blood pressure cuff), EKGs are generally preferred in the medical community as they show the results through visual representation. Like I said in the beginning, this was the most intriguing and ultimately interesting cardiology lab thus far. It is also one of the more simple labs as well- all you need for the lab is a heart, and an EKG!

Heart Microscopy

A Post With A Lot of Heart!

Lub dub…lub dub…lub dub…

Can you hear that? It’s the beating of a heart. You can’t deny that there is something enchanting about the rhythmic beating of a human heart. This organ, responsible for pumping blood throughout the body 24/7, is by far one of the most vital within the body. As you can probably assume by now, its time to study the heart in my Anatomy and Physiology class! Whooo!

To get the blood flowing (pun definitely intended!) with this new unit, we started with a heart dissection.However, this wasn’t like any normal dissection. You see, the class was distributed sheep and pig hearts to cut open. These by themselves aren’t very large in size. My group, however, was an exception. We were given something bigger.Something way more interesting- we were given a cow heart! Let me just put the size of a cow’s heart in perspective. Below are my good colleagues Trevor Lopkoff and Chuck Aaron, posing with the organ:

Holy cow! (Yes, I intended that one also!). See what I mean when I say it’s huge? It fills the entire dissection tray! For this dissection, we cut the heart along the frontal plane, meaning we cut it down the middle and separated the anterior side from the posterior side. This way, we are able to see the chambers, valves, and inner components of the heart much more clearly! Take a look!

The purpose of this lab was to learn theanatomical structures of the heart, while also comparing the sizes of the hearts of different animals. We ended up taking some measurements on the cow heart. In short, they are listed below:

Aorta: 2.5 cm thick
Left Atrium: 10 cm thick
Left Ventricle: 2.5 cm thick
Right Atrium: 8 cm thick
Right Ventricle: 3.5 cm thick
Outer Wall: 2.5-3 cm thick

Now, for comparison purposes, let’s look at the measurements of a sheep’s heart, as provided by another group in my class:

Aorta: 1 cm thick
Left Atrium: 3.5 cm thick
Left Ventricle: 2 cm thick
Right Atrium: 4 cm thick
Right Ventricle: 0.75 cm thick
Outer Wall: 1.5-2 cm thick

You don’t have to be a mathematician to realize just how significant the discrepancy is between these two animals! It is truly amazingto think that a heart, nearly identical in appearance to a human, can be so much larger than ours! That’s incredible!

After the excitement of dissection was over, it was time to learn about the components of the heart. For this post, I will provide only the basics. After all, the heart is such a complex organ! To explain the components of the heart, I will be using a diagram of a heart that was labeled by yours truly! (It was technically a quiz for my class, but I aced it!). A secondary diagram is included below the description in case my quiz is too difficult to read.

The heart is divided into four main chambers: the Right Atrium, Right Ventricle, Left Ventricle, and Left Atrium. The heart also has four valves: the Tricuspid Valve (right side), the Pulmonary Valve (right side), the Aortic Valve (left side), and the Mitral Valve (left side).

The heart works in the following way: De-oxygenated blood that has been circulating through the body gets returne

d through the Vena Cava (the Superior Vena Cava receives blood from the upper part of the body, while the Inferior Vena Cava receives the blood from the lower half). This “used” blood enters the Right Atrium. The Atrioventricular (AV) and Sinoatrial (SA) Nodes are located here, and are designed to help maintain a rhythm for the heart to pump blood with.

From here, the blood passes through the Tricuspid Valve and enters the Right Ventricle. The next step is to pass through the Pulmonary Valve, and enter the Pulmonary Artery. This pathway leads directly to the lungs, where blood passes through arterioles, capillaries, and venules (in that order) to obtain oxygen. After getting oxygen from the lungs, the blood is reinserted into the heart through the Pulmonary Vein.

The Pulmonary Vein releases blood into the Left Atrium. Then the blood passes through the Mitral Valve and enters the Left Ventricle. The final step is to pass through the Aortic Valve and enter the Aorta, which distributes the blood through the rest of the body.

Also, it is important to note that the muscle that separates the two sides of the heart (between the right and left ventricules) is called the Septum.

With that, we have now achieved the two main goals for this post: we have learned about the heart through a detailed explanation

of how it works, and we have seen it on a grand scale through an awesome dissection. The most important thing to realize is that the heart is the muscle that works constantly to keep the blood in the body circulating. It is a vital part of the human body! And to study it, might I add, is something you just can’t beat! (Get it?)

The Dissection of the Brain

As is custom with many science classes, experiments and hands on projects are normal in my Anatomy and Physiology class. Don’t get me wrong, learning from a slide show or video about the way the brain works is super interesting (how can the brain not be interesting?). However, to have a hands on lab about the brain is all the more exciting! Of course, that raises quite the question: how do you do a lab with the brain? Surely it would be too complicated to get hands on with your classmate’s brain, right? Yeah, I bet your lab partner wouldn’t be too fond of that either! But you’re in luck- insert the brain dissection!

In Anatomy and Physiologyclass, we did a dissection on the brain. The purpose of the lab was simple: get a hands on experience with a brain, and understand what the brain truly looks like. So, that’s what we did! Take a look at some of the pictures from the dissection below:

Pretty neat, don’t you think? We cut our brain specimen using transverse layers, meaning we cut strips from the top of the brain going down. The pictures up above show the multiple layers spread out across the dissection tray. Based on how we cut, the top of the brain is on the right hand side, and the bottom of the brain is on the left.

As for understanding the names of each section of the brain, refer to this handy labeled chart:

So now you’ve seen a real brain, and seen the names of the components within the brain. But what does each section do? While there are entire year long college classes dedicated toward this prospect, I’ve narrowed it down to some of the basic key sections of the brain.

First off, the entire top part of the brain is known as the cerebrum. This section, the top “wrinkly” part of the brain, is divided into hemispheres and lobes. In short, this is the part of your brain that allows you to think. The left hemisphere, generally, controls reading, speaking, and math problems. The right hemisphere controls music and art. Sadly, they aren’t shown in pictures.

Below the cerebrum is the cerebellum. This section is all about coordination, and controlling your muscles. Thank this section for allowing you to walk, run, and move!

The Thalmus and Hypothalmus are also worth mentioning within the brain. The Thalmus is the section of the brain that receives the nerve signals that travel up the spinal cord (the pons, as seen on the diagram, is the relay between spinal cord and brain). It then processes the information, and sends it to the cerebrum. The Hypothalmus is, in short, the part of the brain that controls desire. What I mean by this is that the hypothalmus is what controls hunger, thirst, mood, and body temperature.

Last but not least, the optic nerves are for processing signals from your eyes, and the olfactory bulb is responsible for your sense of smell. These in themselves are pretty self explanatory, but definitely important enough to mention!

See? Isn’t a dissection so much more entertaining than a simple presentation? (Yes, I realize that this blog post in itself is merely a presentation, but you know what I mean!). You should now have at least a basic understanding of how the brain looks, and the general function of its features. While I didn’t cover everything the brain can do, I did mention some of the more important parts. Be sure to do some exploring for yourself! The brain has unlimited information waiting to be learned about!

The Mystery of Memory

Have you ever wondered how the human brain works?  What allows us to think?  How can we process information?  While most of these questions are still waiting for definitive answers, scientists are starting to uncover information that explains how our brains operate.  Along with my intelligent colleague Trevor Lopkoff, I have created a presentation that pulls back the curtain on one of the most interesting, yet still widely debated, functions of our brain: the mystery of memory.

This presentation begins to unlock the secrets of how our memory works.  What makes it work, its types, and a brief look into what happens when it malfunctions is just a click away.  Enjoy!

To see the presentation, click here.

Note: I am responsible for creating the beginning “How Is Memory Stored?” and ending “I Don’t Remember This Part…” sections.  Trevor Lopkoff wrote the “Types of Memory” section in the middle.

Leeches Have Feelings!?

An answer to a question such as that greatly depends upon the individual you’re asking.  To some, leeches are just another component in the great Circle of Life (thank you Elton John for making that phrase forever associated with the phrase “Aaaaaashawaynaaaaa”).  To others, particularly young girls, they are slimy, disgusting, genuinely gross creatures that can never be far enough away.  And yes, that hurts the feelings of leeches.  I mean, how would you like to be called gross?  It’s emotionally scarring, I’m sure!  However, this blog post isn’t about the emotional problems of the common leech (though that probably hurt their feelings as well).  Regardless, this post is about a virtual lab on the internet that is created by the Howard Hughes Medical Institute.  The purpose of this project is to simulate an experiment involving nerve cells within leeches. This step by step virtual lab provides an understanding of how to measure nerve impulses, how these nerve impulses vary under different conditions, and provides basic information as to how nerves are identified.  Shall we get started?

You might be wondering, out of all the creatures of the Earth, why a lab (especially a virtual lab) would use leeches as a dissection subject?  As you are about to see, this virtual lab strives to be as accurate as possible.  Leeches are the most practical choice for a science lab because they are relatively small, come in great supply, and are genuinely easy to tolerate (they don’t require a daily walk around the block, a refill of kitty litter, or even a changing of newspaper!).  Furthermore, they have relatively simple nervous systems.  These systems are similar to that of a human nervous system.  They are easy to understand as a whole, and what is learned by them can easily be applied to the human body.

The virtual lab is located here.  Feel free to do this lab yourself, and use this post as a supplement along the way.  It will help in your understanding of this post by having knowledge of the lab itself (or visa versa).  Shall we get started?

This lab requires a laundry list of materials.  The purpose of each material, some are more self-explanatory than others, will become clear throughout the process of the lab.  The list is:

• Leech Tank (with Leech of course)
  
• Leech Tongs
• Dissection Tray
• Dissection Pins
• Scalpel
• Probe
• Forceps
• Feather (weren’t expecting this one, were you?)
• Scissors
• Dissection Microscope
• Oscilloscope
• Micromanuoulator (pronunciation not included)
• Solution of 20% ethanol

The lab that you will find online goes through each individual step of this dissection.  This includes things such as grabbing the leech and stretching the leech on the tray (like I said, the lab is very realistic).  The following steps that I provide are more condensed and general.  To get the full effect of what is happening, please do the lab yourself!

(Note- the link is above.  Below is just the starting screen of the lab.  You cannot click the picture to go to the lab).

Step 1: Take the leech, and anesthetize it with the 20% ethanol solution.  Lay the leech on the dissection tray (dorsal side up) and pin it with dissection pins.

Step 2: Use scissors to cut open the leech, and forceps to open the incision.  Remove the internal organs to expose the nerve cord (which is on the ventral side).

Step 3: Under the dissection microscope, identify the sinus and cut a window around a ganglion.  The Sinus of a leech is a component of the leech’s circulatory system (you see, leeches have their nervous system within their blood vessels).  A ganglion is a collection of neuron cell bodies.  These ganglia are apparent in this step of the lab.

Step 4: Cut the leech into sections, so only a body section with the area from step 3 remains.  Then flip the body section over, and cut the sinus (this should reveal the ganglion).

Step 5:  Use the micromanuoulator.  This is an electrode that can be inserted into individual neurons.  The oscilloscope monitor is also visible, and shows the impulses that is being created by that neuron.  (The virtual lab comes equipped with multiple neurons.  So each one may have a different impulse visual, based on where you inserted the electrode).

Staying true to the real structures of lab procedures, I decided to make a hypothesis of what I was about to find.  My thoughts were:  If I alter the type of stimuli given to an exposed neuron within a leech, then I will be able to identify the type of neuron, because each neuron picks up different signals from the body- each one specific to a type of stimuli.

Step 6: Use different stimuli to check the responses of the neuron.  The feather represents a light touch, the probe a medium touch, and the forceps a strong touch.

Step 7: At the same time as step 6, you can also inject a fluorescent dye (known as Lucifer Yellow, as it turns bright yellow-green under UV light) into the neuron.  By hitting the Ultra Violet switch, you can see the cell body (the studying of the form and structure of an organism and its parts, such as this, is known as morphology by the way).

Step 8: Use the data table (seen below), and the research you collected, to identify the type of cell you found.  Take special notice how each cell, determined by a letter, responds differently to different stimuli.  Repeat steps 5-8 to your hearts content!

As far as statistical data, there is not a lot of information to be retrieved from this lab (the majority of what was discovered was from observations).  However, there is still a lot of information and knowledge that can be gained.  First and foremost, this entire lab is about doing what is referred to as “electrophysiology”, or more commonly called “neurophysiology”.  These terms are defined as “the study of life processes and of the physical and chemical processes involved, particularly the electrical aspects”.  By doing such a procedure, it is possible to see how different neurons react to different conditions.  It can be concluded that each neuron reacts differently, and looks different for that matter, because each one is responsible for detecting a specific stimuli.  It can also be concluded that these specific impulses can be used to identify what type of neuron is being observed.  Lastly, a lab like this can show how neurons work in general, as well as the steps scientists undergo to observe such a process.

That about does it for this blog post.  Looking back, we have really been quite productive!  We have identified the purpose and materials required to dissect a leech, gone through each step of that dissection, and then analyzed our results and what it means to the overall study of the nervous system.  And as a final note, it is important to say that no leeches were harmed in the making of this blog post or the lab…at least, not physically anyway!