Effect of Caffeine on Heart Rate in Daphnia
'Does Caffeine Affect Heart Rate In Daphnia?' Effect of Caffeine on Heart Rate in Daphnia TITLE 'Does caffeine affect heart rate?' HYPOTHESIS I predict that the water fleas heart rate will increase as caffeine is added. METHOD The Investigation was carried out in the following way: * A few strands of cotton wool were placed on a cavity slide (this helped restrict the movement of the water flea) * One large water flea was put on a cavity slide using a pipette * Water was removed from around the water flea using filter paper * One-Two drops of distilled water was added (This helped maintain sufficient oxygen supply to the flea) * To keep the temperature in control, a cavity slide was placed under the slide to minimise the amount of heat and light going through to the microscope * Water flea was viewed under low power * Focus was paid to its heart which could be seen through its translucent body * Stop watch was used to record the heart beats per minute * The procedure was repeated using different concentrations of caffeine * Results were recorded in a table RESULTS Table of results: [Caffeine] (mg dm ) Heart rate (bpm) Mean Heart rate (bpm) 0.0 20 26 38 20 32 32 38 32 26 44 30.8 2.5 50 56 62 50 50 62 56 62 68 50 56.6 5.0 92 86 80 92 92 210 216 216 222 216 202.2 7.5 216 210 210 216 222 204 210 216 210 294
The aim of this investigation is to try and determine whether the amount of exercise we do has any effect on our pulse rate.
Pulse Rate and Exercise Aim The aim of this investigation is to try and determine whether the amount of exercise we do has any effect on our pulse rate. Scientific Knowledge PULSE In order to complete this investigation successfully, we have to find out exactly what happens (scientifically), to our bodies when we exercise, and know exactly what our 'pulse rate' is. Pulse rate represents the beating of the heart, specifically the ejection of blood from the left ventricle to the general circulation of the body. Before the start of exercise, your pre-exercise rate usually rises above normal, and this is called an anticipatory response. During exercise, respiration increases based on the amount of work being done. When exercise is being completed, there is an increased demand for gas exchange, due to the circulatory system being under continuous stress. RESPIRATION All living things need energy to survive. Our energy comes from food. After we digest a meal, food substances travel in your blood and then into your cells. Here, they are respired, which means that they are broken down so that their energy can be released and put to work. Aerobic and Anaerobic Respiration There are two main types of respiration, aerobic and anaerobic. Aerobic respiration releases more energy than anaerobic respiration. This kind of respiration takes place inside a cell's mitochondria, and
These stories do not conform to the rules of murder mysteries so where does the mystery and suspense come from? The Tell-tale heart - Stone Cold
These stories do not conform to the rules of murder mysteries so where does the mystery and suspense come from? In both The Tell-tale heart and Stone Cold the rules of murder mystery are not applied. In a murder mystery you would expect to find out who the murderer is at the end of the book and you also expect a detective to be carrying out an investigation. Murder mysteries also normally use a 'Red Herring': this is when you are given false clues. Although The Tell-tale heart and Stone Cold don't involve either of these things and yet they are still murder mysteries. The way in which this is undermined is that you know whom the murderer and the victim is from the start. So the mystery is actually produced by other things. The plot builds up mystery in The Tell-tale heart as you are never sure if the heart is his own that he hears or someone else's. An example of when he is hearing the heart is - "It grew louder-louder-louder!" Personally I believe it is his own heart because it looks as if the author has written it in such a way so when he gets more nervous the noise gets louder This builds up the tension in The Tell-tale heart. The plot builds up mystery in both The Tell-Tale heart and Stone Cold in the same way due to the madness of both characters; by this I mean Shelter and the narrator from The Tell-tale heart. One reason why I believe that the narrator from The
Investigating the effect of exercise on heart rate.
Investigating the effect of exercise on heart rate Planning The heart is a four-chambered muscular pump; left and right atrium and left and right ventricles. The heart contains veins and arteries. The arteries are thick walled muscular tubes, which carry blood away from the heart. The artery leading from the heart to the lung, the pulmonary artery is the only artery that carries de-oxygenated blood. Veins are thin walled tubes, which carry blood back to the heart; they have a large diameter and valves. The veins returning blood from all of the body minus the lungs are called the venae cavae; the vein from the lungs is called the pulmonary vein and is the only vein to carry oxygenated blood. Heart rate is the measuring of the number of times the heart beats per minute. During exercise the heart rate increases to pump more blood to the muscles all over the body, which need to work harder. The amount of blood that the heart pumps out to the body, the cardiac output, increases. The heart rate and the cardiac output are proportional to each other. The heart has to supply more oxygen to the muscles when you take exercise so it has to beat faster. If a person is not fit, even though their heart beats faster they still do not get enough oxygen to their muscles and so they build up an oxygen debt. This causes their muscles to respire anaerobically and make lactic acid. It
Stem Cell Research
A Stem Cell is a cell that has the ability to become any type of cell in an organism. They are found in large quantities in developing embryos. They can be self-renewing, therefore they can make additional stem cells; or they can differentiate into various specific types of cells. As a result of these useful characteristics, stem cells come under close scientific scrutiny. They present new opportunities to develop new therapies, to treat diseases where the functions of repair, replacement and regeneration are impeded. There are two types of stem cells: Embryonic stem cells, which can be taken from embryos 4-5 days after fertilisation. They are pluripotent, in that they are able to specialize into different types of cells. Their use is highly controversial. Adult Stem Cells, multipotent adult stem cells can be found in certain tissues of the body, including umbilical cord blood and bone marrow. Their use is not controversial, as there is no need for the destruction of an embryo. They are used to regenerate and repair organs due to their ability to divide indefinitely. Stem cells show potential for many different areas of health and medical research, and studying them can help us understand how they transform into the many specialised cells that make us up. Some of the most serious medical conditions, such as cancer and birth defects, are caused by problems that occur in
How Ultrasound Works.
How Ultrasound Works by Craig C. Freudenrich, Ph.D. There are many situations in which ultrasound is performed. Perhaps you are pregnant, and your obstetrician wants you to have an ultrasound to check on the developing baby or determine the due date. Maybe you are having problems with blood circulation in a limb or your heart, and your doctor has requested a Doppler ultrasound to look at the blood flow. Ultrasound has been a popular medical imaging technique for many years. Photo courtesy Philips Research Ultrasound examination during pregnancy In this edition of How Stuff Works, we will look at how ultrasound works, what type of ultrasound techniques are available and what each technique can be used for. What is Ultrasound? Ultrasound or ultrasonography is a medical imaging technique that uses high frequency sound waves and their echoes. The technique is similar to the echolocation used by bats, whales and dolphins, as well as SONAR used by submarines. In ultrasound, the following events happen: . The ultrasound machine transmits high-frequency (1 to 5 megahertz) sound pulses into your body using a probe. 2. The sound waves travel into your body and hit a boundary between tissues (e.g. between fluid and soft tissue, soft tissue and bone). 3. Some of the sound waves get reflected back to the probe, while some travel on further until
To what extent does stress cause Cardiovascular Disorders?
Physiological Psychology. To what extent does stress cause Cardiovascular Disorders? A cardiovascular disorder is any disorder effecting the heart and circulatory system. There is evidence that links stress plays a role in the development of two types of cardiovascular disorders, hypertension (high blood pressure) and coronary heart disease (CHD), which reduces the flow of blood to the heart. Stress may directly cause cardiovascular problems by; rising heart rate which wears the lining of the blood vessels, increasing blood pressure which causes too much pressure on the blood vessels resulting in damage, also mounting glucose levels leading to blocked blood vessels. Stress can also have an effect on our lifestyle, we may find that smoking or drinking helps to take away the strain, yet this can have an immense negative effect on our cardiovascular system. Krantz et al (1991) devised a study to look into the extent to which mental stress could be revealed to enlarge the heart condition called Myocardial Ischemia, also for patients suffering coronary artery disease; they looked to see if they reacted in a different way to those without cardiovascular problems. The test involved patients undertaking three mental tasks: arithmetic; a Stroop test; and simulation of public speaking. It was concluded that there is a direct link among performing a mild cognitive task and a
How does caffeine and ethanol affect the heart rate?
How does caffeine and ethanol affect the heart rate? Introduction At rest a normal adult heart beats around 75 times per minute. During strenuous exercise it may rise to 200 beats per minute. The SAN (sino-atrial node) controls the heart rate. Information is sent via two autonomic nerves that link the SAN with cardiovascular centre in the medulla of the brain, the rate increases or decreases depending on the information received. Factors, which affect the heart: > The secretion of adrenaline. This may be under stress, excitement or other emotions. > Movement of the limbs (exercise). Heart rate and breathing rate increase due to oxygen levels falling and levels of carbon dioxide rising. > Blood pressure. When blood pressure is too high, a mechanism prevents increase in heart rate. Adrenaline is a hormone, which is produced by the adrenal gland; it is usually secreted in tiny amounts, when stressed or scared. It raises your heart rate immediately. Adrenaline improves the strength of the contractions of the heart. Caffeine is a methylxanthine and it blocks adenosine receptors. The chemical formula for caffeine is C8 H10 N4 O2. Medically, caffeine is useful as a cardiac stimulant. Most people associate caffeine to provide a 'boost of energy'. People can become addicted to caffeine; it operates using the same mechanisms that cocaine and heroin use to stimulate the
Creative Writing : “You’re only a survivor when you’re rescued; until then, you’re a victim…”
Alex Cresswell Miss. Metcalfe Creative Writing : "You're only a survivor when you're rescued; until then, you're a victim..." Inevitable strangulation loomed - the grim promise of a gradual, agonising demise. Another nauseating crack as the aching bones in my neck snapped like raw carrots, my bloodshot eyes bulged excruciatingly in their restricting sockets; palpitating veins on the verge of rupture. Breathing evolved into a sequence of increasingly urgent gasps; limbs swelled with blood as the persistent python tightened its pestilent grip around my limp body, consciousness fading... slowly... away... I awoke abruptly; panting heavily, sweat gushing down my scrawny torso and onto the tangled mess of bedclothes. Beads of sweat accumulated on my palm as I thrust a trembling hand through the mass of sweaty hair on my head. Relax - it was only a dream. I flung the saturated quilt to one side, sat up, and thought. One million pounds - a lot of money. But is it really worth risking my life for? ...What am I saying? I leave tomorrow, so it's far too late to back out now. I mean how difficult can it be? This island is supposed to supply me with everything I need - food, water... and I'm allowed to bring a few choice items with me. Guess it's time to choose. I'll need a knife, no doubt, and maybe a woolly jumper to keep warm, and some matches too - to light
GAS EXCHANGE IN DIFFERENT ORGANISMS
GAS EXCHANGE IN DIFFERENT ORGANISMS Gas exchange in mesophytes Gases enter and leave plants mainly through the stomata in the leaves and the lenticles in stems. The main gas exchange surface is the spongy mesophyll layer found inside the leaves.. The spongy mesophyll cells are loosely packed thus increasing the surface area for gas exchange. Gases are needed for both respiration and photosynthesis. The spongy mesophyll layer is specially adapted for gas exchange. The cells are coated in a layer of water in which gases can dissolve. The cell walls are thin so reducing the distance for diffusion of gases into the cell. The many widely spaced cells present a large surface area of gas exchange, easily reached by air entering through the stomata. A concentration gradient is maintained due to the rapid diffusion of gases in air. Air enters through the stomata by diffusion; there is no ventilation process. At night, when only respiration is taking place oxygen readily dissolves and diffuses through the walls of the spongy mesophyll cells and is transported along to other cells by diffusion. This maintains a lower concentration of oxygen in the spongy mesophyll cells than is present in the air in the leaf. This difference in concentration ensures continued diffusion of oxygen into the spongy mesophyll cells Carbon dioxide produced during respiration diffuses from the
