Wednesday, March 2, 2011

You Have a Heart Disease... Well, Which One?

I have come to find that there are several diseases that can be considered harmful to the heart. Finding out which kind of heart disease you have is the question and concern that is answered when you are trying to find a cure for your condition.

One disease is Coronary Heart Disease: This is the most common heart related problem. It occurs when the arteries become smaller (usually with build-up) and the heart is not getting enough blood supply.

Heart Attack: This is also another very common heart problem found in places where cheeseburgers, french fries, and milkshakes can be consumed daily. High amounts of cholesterol and salts are not good for the heart and cause even greater amounts of build up.

Ischemic Heart Disease: This is where the heart is not pumping fast enough to supply the heart and body with enough blood. A common reason for this disease to occur is obesity and lack of exercise because the heart is never put through the hardship of pumping faster. A cure for this disease would be to exercise more often.

Tachycardia: This is were the heart is beating at an extremely high and dangerous pace. Usually this is felt after extraneous exercise which is normal, but if the heart continues to beat at a fast pace 10 minutes after exercise, there is something wrong and it needs to be checked.

Rheumatic Heart Disease: This is where the valves in the heart are not able to close properly leading to blood spilling out into the wrong parts of the heart. This can lead to heart failure.

Pulmonary Heart Disease: This is caused by abnormal pressure on the lungs due to improper blood flow. The cure for pulmonary disease is very little to nothing, but it should still be kept under watch.
High Blood Pressure or Hyptertension: This is when your blood pressure is too high. High blood pressure is also caused by fatty foods and is very common to millions of people. The symptoms are sometimes serious, but most are faint and are unable to be detected without professional observation.
With so many Heart Diseases, how can we tend to them all? In modern days, we rely on technology, knowledge, and trust that the doctors and engineers are doing everything they can to solve heart failure problems. I found a recent device that does just that!

Monday, February 28, 2011

The Cardiovascular System: Processes, Experiments, and Results

I was able to paticipate in an interactive heart dissection to observe the structure of the heart and the process in which blood flows through an actual active living heart. I was presented with a cow, pig, and sheep heart to compare and contrast the structures of each individual. Overall, the only difference between the three hearts was ultimately the size of the heart and the color of the surrounding muscles and tissues. The cow resulted in having the largest heart and the sheep had the smallest. Logically, the heart would have to be bigger for a bigger body because the amount of blood that needs to pass in and out of the heart, while contributing a steady blood flow throughout the entire body, can only be stable with a larger and stronger heart. This can also explain the smaller heart for the small sized sheep.

Above is a picture of a dissected cow heart which was dissected in this specific lab. Being able to actually see and dissect the heart has made it incredibly easier to understand the functions and structures of the heart.


After the heart dissection, I was able to use the microscope the view cardiac muscle from the heart as well as compare and contrast arteries and veins. Arteries had a thicker membrane than the veins. This is because arteries are the exit source of blood from the heart. The aorta is the largest artery in the entire body because this is where all the blood from the heart is being released and carried throughout the rest of the body. The membrane has to be thicker to be able to withstand all the the pressure that is forced upon its walls. Veins on the other hand are smaller do to the fact that blood is being returned to the heart through them. They do not take on as much force as arteries do.

Above: To the left is an artery and to the right is a vein

Along with the slides of arteries and veins, there was a slide of an artery with atherosclerosis. This is a disease in which fatty materials and other substances begin to build-up on the walls of arteries and can eventually block off the blood flow and cause life threatening problems such as heart attacks.


In class we analyzed the heart with EKG to create a graphical recording of the electrical events that are occurring within the heart. With a healthy beating heart it was easy to see the five processes that create the beating of a heart. These five beats are labeled P, Q,R,S, and T. The P wave is the starting of the beat where an electrical message is sent from the nodes in the atrium to the ventricles. The QRS complex is where the ventricules contract and depolarize. The T wave is the repolarization of the ventricles back to its regular resting state.

In this experiement, we recorded the normal electrical acvtivity of the heart and then switched the red and green EKG sensors to record the electrical activity of the heart that can occur when a heart undergoes myocardial infarcation (Heat Attack).

After recording the heart beats and anaylzing the data, I found it incredibly difficult to read EKG recordings of various hearts and try to find abnormalties or disorders. With time and practice it would become habit and instinct to recognize any abnormalty. Every heart beat is different, but some hearts miss the QRS complex which means that the electrical impulse sent from the P wave was blocked before it could reach the ventricles. This blockage could be caused by tissue injury from previous injuries or myocardial infarction. Recording the intervals between the contractions within the five step process allows us to detect the heart rate and allows us to see how long the heart is taking to react to the electrical impulses.


A final activity that was presented in class was the use of stethoscopes and sphygmomanometers (blood pressure measuring device) to listen to the heart beat and record blood pressure. The normal blood pressure rate is 120 / 80. The blood pressure that is being recorded is the force of the blood on the walls of blood vessels, both when the heart is beating (systolic 120) and when the heart is at rest (diastolic 80). Since the normal blood pressure is at 120, the sphygmomanometer is pumped to a pressure of 140. Here the pressure valve will "tick" as the pressure of the blood vessels change with the beating of the heart. Over the years technology has advanced sphygmomanometers making it a fast and efficient process. The first place I have personally witnessed a sphygmomanometer was in the vet clinic when an animal was undergoing surgery and under anesthesia. The blood pressure was kept on a constant watch and the anesthesia was turned up or down according to the blood pressure readings. Such a simple contraption has made huge progress!

Above: Stethoscope and Sphygmomanometer!

Friday, January 14, 2011

Leech Neurophysiology Lab

Purpose: To record the electrical activity of neurons that are found on the leech and identify which neurons respond to certain stimuli.

Hypothesis: With knowledge of the leeches nervous system and small brain, it will be fairly easy to identify the electrical activity of the leech because the ganglia is large and they all will respond to the same stimuli.

Materials: Leech tank, dissection tray, 20% ethanol, dissecting microscope, mircomanipulator probe, forceps, scissors, dissection pins, leech tongs, Oscilloscope

Procedure: Anesthetize and dissect the leech, Remove the innards and observe the ganglion, Cut out the ganglion window, Isolate one ganglion from the others, Cut the ganglion sinus, Probe and identify the ganglion sensory cells using different stimuli (Feather, Probe, and Forceps), fluorescent dye, and UV light.

Results/Conclusions: One ganglion consists of many cells that are stimulated by different or similar stimuli. Since the leech has such a small system, there are five manageable cell types that can be found. (Cell Types N, T, P, R, and X) Each cell or neuron was found by responding to the feather (weak probing), probe (medium probing), and forceps (strong probing). Some of the cell types responded to all three of the stimuli, but some only responded to a couple stimuli and remained unresponsive. The many responses to a single ganglia portrays the immense amount of stimulation that the entire nervous system of the leech undergoes. Although it is a simple nervous system to work with, it is very complex.

These are the five different cell types that were found within a single ganglia within the leeches nervous system. As the image shows, different stimuli caused similar and differing responses.