Heart rate

The heart is one of the strongest muscles in the human body. It is mostly made up of cardiac muscle, which causes the contractions of the heart, or heartbeat. The cardiac muscle works constantly to pump blood throughout the body and is one of the three major types of muscle. The cells in the heart are closely connected so that they all beat at the same time, and they form the thick middle layer of the heart, in between the outer epicardium and the inner endocardium layers. There are two main…

Introduction Atrial fibrillation (AF) is the most common heart rhythm disorder. It is an irregular and rapid heart rate caused by heart tissue giving out erratic electrical signals that can increase a person’s risk of stroke, heart failure and other heart-related complications. The risk of AF increases with age with people over the age of 40 having a 25% chance of developing AF. With the increase in aging population in Singapore, there will be higher incidence of AF. Thus there is a need to come…

by multiplying the heart rate and stroke volume. Increasing the heart rate would increase the cardiac output. Sympathetic stimulation releases NE and this shortens repolarization and speeds up depolarization, which increase heart rate. An increase in venous return causes the heart rate to increase by stretching the nodal cells, and the force of contraction increase, and this increases the stroke volume. The parasympathetic stimulation releases ACh, which slows down the heart rate. 21. If…

Introduction: The heart plays a crucial role in the human circulatory system. The large organ pumps the blood through arteries, veins, and capillaries to distribute oxygen and nutrients to the body. The circulatory system also plays a part in removing our waste products. Humans have double circulation, meaning the blood passes through the heart twice before completing one round; this allows for the blood to be “re-pressurized”. Once the right side of the heart receives blood from the body,…

narrow the arteries, which makes it more difficult for blood to pass through. This causes hypertension. The heart has to work harder to pump the blood through the narrowed arteries. If the coronary arteries become narrowed coronary artery disease occurs. The coronary arteries supply the heart muscle with blood. When blood is restricted to the heart chronic heart failure can occur. The heart cells become deprived of oxygen and die. C.M is taking atorvastatin to lower his LDL levels and…

test the effect of different concentrations of caffeine on the heart. We used ECG stimulator on LabScribe 2 software to monitor the heart rate. We used frogs as a test subject, since both frogs and humans have a closed cardiovascular system, therefore the effect on the frog’s heart would parallel the situation of a human heart. We quantitatively measured the heart rate and found out that caffeine significantly increases the heart rate of the Rana sphenocephala Introduction: Although unclear of…

function seems to be dependent upon the type of seizure occurring. The majority of complex partial, tonic-clonic and temporal lobe seizures are associated with increased heart rate. This increase in heart rate trends in a steep acceleration initially then has marked variations at the time of seizure and postictally. Tachycardia rates that reach a certain threshold may cause low cardiac output and possibly lead to cardiogenic shock. (91) Tachycardia…

in cardiac output which is a function of the amount of blood pumped in one stroke by the heart (stroke volume) and the rate of cardiac contraction (heart rate). The stroke volume does not increase drastically for bouts of exercise, but heart rate will change markedly, up to three times the resting rate. O Dynamic exercise causes other cardiovascular responses in addition to increased stroke volume and heart rate. For example, exercise will result in a general, sympathetic vasoconstriction of…

Population of the United States The World Heart Federation (2012) defines Cardiovascular Disease (CVD) as “a broad range of diseases that affect the heart and blood vessels” (n.p.). CVD is also known as Heart Disease (American Heart Association [AHA], 2015). According to Roger, Lloyd-Jones, Berry, et al. (2011) there are numerous types of cardiovascular diseases including: hypertension, coronary artery disease, congenital cardiovascular defects, stroke, congestive heart failure, atherosclerosis…

Currently only 21% of Americans meet the physical activity guidelines set forth by the Centers for Disease Control and Prevention (CDC). This has become a major concern in today's society, as many of its effects are being seen. One of ten deaths worldwide result from insufficient physical activity (WHO). Physical activity is any type of movement that requires energy. Being physically active contributes to a person's overall fitness, which is a general state of health and wellbeing. Physical…