Tag: blood circulatory system of human
Questions Related to blood circulatory system of human
Life span of blood platelets in mammals is about
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3 days
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8 days
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1 month
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20 days
Which of the following results from cell fragmentation?
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RBC
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WBC
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Plasma
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Platelets
Platelets are the cells found in blood which helps in the clotting of the blood. The formation of platelets takes place in bone marrow from large bone marrow cells known as megakaryocytes. These cells after becoming mature enough, undergo the process of cell fragmentation to produce platelet cells. The hormone that help in platelet production is thrombopoietin.
Low platelet count results in
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Low bleeding
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Excessive bleeding
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Growth
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Both B and C
Platelets are the parts of the blood that help the blood clot. They are smaller than red or white blood cells. If the number of platelets is too low, excessive bleeding can occur. However, if the number of platelets is too high, blood clots can form thrombosis, which may obstruct blood vessels and result in such events as a stroke.
With reference to the blood in a normal person, which one of the following statements is correct?
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Compared to arteries, veins are less numerous and hold less of the body's blood at any given time.
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Blood cells constitute about 70 percent of the total volume of the blood.
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White blood cells (WBC) are made by lymph nodes only.
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The blood has more platelets than WBC.
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Transporting oxygen and nutrients to the lungs and tissues.
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Forming blood clots to prevent excess blood loss.
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Carrying cells and antibodies that fight infection.
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Bringing waste products to the kidneys and liver, which filter and clean the blood.
- Regulating body temperature.
Megakaryocytes, special cells in the bone marrow that produce cell fragments are called :
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Leucocytes
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Erythrocytes
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Thrombocytes
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Fibrinogen
Megakaryocyte is a large bone marrow cell which are responsible for the production of thrombocytes. Thrombocytes help in normal blood clotting.
Select the incorrectly matched pair.
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Leukopenia - Fall in WBCs count
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Polycythemia - Abnormal rise in RBCs count
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Thrombocytosis - Decrease in number of platelets
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Erythrocytopenia - Decrease in number of RBCs
(a) Leukopenia is the decrease in the white blood cell count in the cells.
Tooth extraction in a person causes death due to excessive bleeding. This is because of
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Absence of prothrombin
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Presence of plasma factor that causes haemorrhage
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Presence of plasma factor that prevents blood clotting
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Absence of plasma factor required for haemorrhage
Prothrombin is a glycoprotein occurring in blood plasma and is an essential component of the blood-clotting mechanism. Prothrombin is transformed into thrombin by a clotting factor known as factor X or prothrombinase; thrombin then acts to transform fibrinogen, also present in plasma, into fibrin, which, in combination with platelets from the blood, forms a clot (coagulation). Under normal circumstances, prothrombin is changed into thrombin only when an injury occurs to the tissues or circulatory system or both; therefore, fibrin and blood clots are not formed except in response to bleeding. Hypoprothrombinemia, a deficiency in prothrombin, is characterized by a tendency to prolonged bleeding. It is usually associated with a lack of vitamin K, which is necessary for the synthesis of prothrombin in the liver cells.
Contraction of heart is
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Diastole
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Systole
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Joint diastole
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None of the above
Systole is defined as the ventricular contraction of heart which occurs between the first and second heart sounds of the cardiac cycle. There is pumping of blood into the aorta and pulmonary trunk and lasts for 0.3-0.4 second. During systole arterial blood pressure is maximum.
Frequency of cardiac cycle is described by
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Systole
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Diastole
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Heart-rate
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Pulse
The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat. The frequency of the cardiac cycle or the heart rate is expressed as heart beats per minute.
'Dupp' sound is produced during closure of
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Semilunar valves
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Bicuspid valve
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Tricuspid valve
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Both B and C
During each cardiac cycle two prominent sounds are produced, which can be easily heard through a stethoscope. The first heart sound (lubb) is associated with the closure of the tricuspid and bicuspid valves, whereas the second heart sound (dupp / dubb) is associated with the closure of the semilunar valves. These sounds are of clinical diagnostic significance.