<span>True, the average menstrual cycle does indeed last around 28 days. This varies between women, however, and can range from between 21 and 35 days after puberty. The menstrual cycle is controlled by fluctuating hormones in the female body.</span>
Head injury, as your head is your skull, damaging your skull is very serious as your brain is located there and damaging your brain could probably kill or limit some abilities
Answer:
so that you can find a match for their blood type.
Explanation:
Certain blood types don't react well with others and cause their immune system to attack, while other blood types react fine with a certain one. Group o+, for example, can donate to any + blood type.
Answer:
Ventricular fibrillation a type of arrhythmia characterized by a very fast heart rate which causes no blood to reach vital organs causing cardiac arrest.While Atrial fibrillation is an atrial tachyarrhythmia characterized by the fact that the atria beat in an uncoordinated way at a very high rate that exceeds 350 beats per minute. As a result, the atria are no longer effective in pumping blood to the ventricles.
Explanation:
Under normal conditions the heart contracts rhythmically and synchronously. This contraction is the result of an electrical impulse that is generated in the atrium, reaches the ventricle and results in a heartbeat. In an arrhythmia there is an alteration of this mechanism that leads to the heart not contracting regularly, generating a rhythm disorder. The contraction of the ventricles pumps blood to the rest of the body. In ventricular fibrillation, the heart rhythm is very fast and chaotic (up to 300 beats per minute) and is characterized by not being able to provoke an efficient heart beat. Thus, the lack of contraction of the ventricles causes the blood to barely be pumped from the heart, producing a collapse of the cardiovascular system and cardiac arrest. Atrial fibrillation is characterized by disorganized and very rapid atrial activity (350-600 beats / min). This leads to an irregular ventricular response (150-200 beats / min) and an irregular pulse.During atrial fibrillation, the atrial contraction that helps fill the ventricles with blood is lost; this can significantly reduce cardiac output, particularly in patients with mitral stenosis, hypertension, or hypertrophic cardiomyopathy.It is associated with an increased risk of thromboembolism (formation of blood clots in the heart that can dislodge and go through the bloodstream until impacted on the a blood vessel, causing lack of irrigation in that area) and therefore stroke (cerebral thromboembolic accident).
