The heart has a relatively long refractory period due to the plateau phase. The plateau phase occurs from the maintenance of a high calcium conductance and a delay in the subsequent increase in potassium conductance after a cardiac action potential. The heart membrane remains in a refractory or contracted state until the heart has fully returned to a relaxed state; therefore, tetanus or wave summation does not occur in cardiac muscles (Randall, 2002). When the frog’s heart was stimulated with single stimuli, an extrasystole and an increase in frequency was observed during the relaxation phase, but the amplitude remained constant. These results were analogous to the multiple stimuli treatment, which we expected. Because both single and multiple
In this lab, I took two recordings of my heart using an electrocardiogram. An electrocardiogram, EKG pg. 628 Y and pg. 688 D, is a recording of the heart's electrical impulses, action potentials, going through the heart. The different phases of the EKG are referred to as waves; the P wave, QRS Complex, and the T wave. These waves each signify the different things that are occurring in the heart. For example, the P wave occurs when the sinoatrial (SA) node, aka the pacemaker, fires an action potential. This causes the atria, which is currently full of blood, to depolarize and to contract, aka atrial systole. The signal travels from the SA node to the atrioventricular (AV) node during the P-Q segment of the EKG. The AV node purposefully delays
The experiment studies the effects of Red Bull and its major components on the heart rate of a Daphnia. The experiment focuses on the effects of conditions on the cardiovascular system. The Cardiovascular system is responsible for the transport of blood, oxygen, nutrients and waste circulating the body. It consists of the heart, vessels, and blood as in closed circulatory system and hemolymph in open circulatory system, the cardiovascular system is also responsible for thermoregulation in the body. (Gonzalez, 2012). The heart helps pump blood to the lungs and rest of the body. The pumping of heart or the contraction and relaxation of heart determines the heart rate and depends on multiple chemicals that we could influence by using stimulants, depressants, varying temperatures, aerobic, and anaerobic
O’Rourke [13] describes the pulse wave shape as: “A sharp upstroke, straight rise to the first systolic peak, and near-exponential pressure decay in the late diastole.” Arteries are compliant structures, which buffer the pressure change resulting from the pumping action of the heart. The arteries function by expanding and absorbing energy during systole (contraction of the cardiac muscle) and release this energy by recoiling during diastole (relaxation of the cardiac muscle). This function produces a smooth pulse wave comprising a sharp rise and gradual decay of the wave as seen in Figure 5. As the arteries age, they become less compliant and do not buffer the pressure change to the full extent. This results in an increase in systolic pressure and a decrease in diastolic pressure.
Two heart sounds are normally heard through a stethoscope on the chest wall, "lab" "dap". The first sound can be described as soft, but resonant, and longer then the second one. This sound is associated with the closure of AV valves (atrioventricular valves) at the beginning of systole. The second sound is louder and sharp. It is associated with closure of the pulmonary and aortic valves (semilunar valves) at the beginning of diastole. There is a pause between the each set of sounds. It is a period of total heat relaxation called quiescent period.
Diagnostic medical sonography is a profession where sonographers direct high-frequency sound waves into a patient’s body through the use of specific equipment to diagnose or monitor a patient’s medical condition. As described by the Bureau of Labor Statistics, this examination is referred to as an ultrasound, sonogram, or echocardiogram. The high-frequency sound waves emitted from the handheld device, called a transducer, bounce back creating an echo and therefore produce an image that can be viewed on the sonographers computer screen. This image provides the sonographer and physician with an internal image of the patient’s body that will be used in the diagnosis. The most familiar use of ultrasound is used in monitoring pregnancies and is provided by obstetric and gynecologic sonographers, who also provide imaging of the female reproductive system. Other types of sonography include; abdominal sonography, breast sonography, musculoskeletal sonography, neurosonography and cardiovascular sonography. Due to the vast nature of uses in sonography, most professionals study one field that they choose to specialize in. Diagnostic medical sonography is a rapidly growing field because of the increase in medical advances. The area of Cleveland, Ohio has continued to rise in the medical field with great strides, providing better career prospects with the availability of numerous employment positions.
The second part of this lab was a computer simulation program to illustrate a frog’s electrocardiogram using various drugs in an isolated setting. The computer program entitled “Effects of Drugs on the Frog Heart” allowed experimental conditions to be set for specific drugs. The different drugs used were calcium, digitalis, pilocarpine, atropine, potassium, epinephrine, caffeine, and nicotine. Each of these drugs caused a different electrocardiogram and beats per minute reading. The calcium-magnesium ration affects “the permeability of the cell membrane”(Fox). When calcium is placed directly on the heart it results in three physiological functions. The force of the heart increases while the cardiac rate decreases. It also causes the appearance of “ectopic pacemakers in the ventricles, producing abnormal rhythms” (Fox). Digitalis’ affect on the heart is very similar to that of calcium. It inhibits the sodium-potassium pump activated by ATP that promotes the uptake of extracellular calcium by the heart. This in return strengthens myocardial contraction (Springhouse). Pilocarpine on the other hand
Tetanus: acute infectious disease of the central nervous system caused by the toxins of Clostridium Tetani.
Clostridium tetani more commonly known as Tetanus is an acute infectious disease. Tetanus is not contagious and is a neurotoxin produced by Clostridium tetani. It is characterized by muscular spasms that mainly involve the voluntary muscle groups. Tetanus can affect horses, goat, swine, cat, dog, sheep, cattle and many other domestic animals. In cattle the disease is relatively rare, but in some cases can spread through a herd causing substantial economic loss. Clostridium tetani is a gram-positive anaerobic bacteria that can be found in the soil, intestines of many animals and therefore it is also naturally found in the feces of most animals. Tetanus is more common during warmer months and less common during the colder months when the ground is frozen. Tetanus enters the body through a wound, most commonly in cattle via a castration site or umbilical location of a newborn calf.
The purpose of this experiment was to gather data on how the amount of time spent active impacts the speed of heart rate in beats per minute. The hypothesis stated that if the amount of time active is lengthened then the speed of the heart rate is expected to rise because when one is active, the cells of the body are using the oxygen quickly. The heart then needs to speed up in order to maintain homeostasis by rapidly providing oxygen to the working cells. The hypothesis is accepted because the data collected supports the initial prediction. There is a relationship between the amount of time spent active and the speed of heart rate: as the amount of time spent active rose, the data displayed that the speed that the heart was beating at had also increased. This relationship is visible in the data since the average resting heart rate was 79 beats per minutes, while the results show that the average heart rate after taking part in 30 seconds of activity had risen to 165 beats per minute, which is a significantly larger amount of beats per minute compared to the resting heart rate. Furthermore, the average heart rates after 10 and 20 seconds of activity were 124 and 152 beats per minute, and both of which are higher than the original average resting heartbeat of 79.
Tetanus is an often fatal disease caused by bacteria known all over the world. Stepping on a rusty nail is a very common example of how someone can get tetanus. However, there are many more factors to the disease.
Investigating the Effect of Exercise on the Heart Rate Introduction For it's size the heart has the huge capacity of pumping large amounts of blood, in the average adult's heart beats 60 to 100 times a minute, pumps between 70ml and 100ml of blood with each beat, circulates 5 to 6 litres of blood around the body per minute and about 13 litres of blood per minute during vigorous exercise. The heart will beat more then 2.5 billion times during an average lifetime. This investigation will be looking at the effect of exercise on the heart rate. Aim The aim of this investigation is to find out how exercise affects the heart rate, using research & experimenting on changes and increases in the heart rate using exercise. Research â— The heart The normal heart is a strong, hardworking pump made of muscle tissue.
The heart is a pump with four chambers made of their own special muscle called cardiac muscle. Its interwoven muscle fibers enable the heart to contract or squeeze together automatically (Colombo 7). It’s about the same size of a fist and weighs some where around two hundred fifty to three hundred fifty grams (Marieb 432). The size of the heart depends on a person’s height and size. The heart wall is enclosed in three layers: superficial epicardium, middle epicardium, and deep epicardium. It is then enclosed in a double-walled sac called the Pericardium. The terms Systole and Diastole refer respectively and literally to the contraction and relaxation periods of heart activity (Marieb 432). While the doctor is taking a patient’s blood pressure, he listens for the contractions and relaxations of the heart. He also listens for them to make sure that they are going in a single rhythm, to make sure that there are no arrhythmias or complications. The heart muscle does not depend on the nervous system. If the nervous s...
A normal heart rhythm begins at the sinoatrial node and follows the hearts conduction pathway without any problems. Typically the sinoatrial node fires between 60-100 times per minute (Ignatavicius & Workman, 2013). When a person has Atrial Fibrillation, the sinoatrial node releases multiple quick impulses at a rate of 350 -600 times per minute. When this happens, the ventricles respond by beating around 120- 200 beats per minute, making it tough to identify an accurate heart rate. This arrhythmia can be the result of various things. During a normal heart beat, the electrical impulse begins at the sinoatrial node and travels down the conduction pathway until the ventricles contract. Once that happe...
The data refutes the hypothesis that decreasing the potassium concentration in a cell will increase the height of the peak of the action potential. Instead, the decreasing potassium concentration in a cell will decrease the height of the peak action potential. A cardiac cell has a unique action potential shape because of the presence of calcium channels [REF 7]. The action potential of a cardiac cell begins with a resting potential near -90mV. This is because of the much larger potassium Nernst potential. At this point the sodium and calcium channels are closed. Then an action potential from a nearby cell causes the membrane potential to rise above -90mV [REF 7]. Sodium channels begin to open and sodium ions leaks into the cell further raising
Viral infections are potential causes both congenital and acquired hearing loss (1,2,3,4), and vaccination has been associated with decreased prevalence of hearing impairment (5). However, despite promising prospect of vaccines in prevention of hearing loss, literatures exist which described cases of hearing impairment attributable to vaccination (6,7,8,9,10,11). These reports can be controversial, given the important role of vaccination in primary prevention of communicable diseases. Therefore, objective evaluation of existing reports is of paramount importance to validate or refute the link between vaccination and hearing loss.