Circulatory system - blood - class-X

The stethoscope was invented in France in 1816 by Rene Laennec in Paris. 

The arterial pulse is a measurement of the heart’s contraction rate because a pulse wave is created when the left ventricle contracts. The arteries expand in response to this contraction and increase in volume. Once expanded, the arteries will contract forcing blood to circulate to the capillaries and then to the veins. The arterial pulse is evaluated for the contour of the pulse wave and its volume, rate and rhythm. The carotid pulse is the most accurate reflection of central aortic pulse. Thus, option B is correct. 

Pulse is the regular, recurrent expansion and contraction of an artery, produced by waves of pressure, caused by the ejection of blood from the left ventricle of the heart as it contracts. Pulse is easily detected on superficial arteries, such as the radial and carotid arteries, and corresponds to each beat of the heart.

Resting heart rate is the heart pumping the lowest amount of blood you need because you’re not exercising. If you’re sitting or lying and you’re calm, relaxed and aren’t ill, your heart rate is normally between 70 (beats per minute) and 80 (beats per minute). But a heart rate lower than 60 doesn’t necessarily signal a medical problem. It could be the result of taking a drug such as a beta blocker. A lower heart rate is also common for people who get a lot of physical activity or are very athletic, Stein said. Active people often have lower heart rates because their heart muscle is in better condition and doesn’t need to work as hard to maintain a steady beat. 

Pulse is a term that signifies the throbbing of arteries as an effect of heartbeat and is counted by the number of beats per minute. The normal pulse rate ( count of arterial pulse beats per minute ) in a healthy adult at rest ranges from 72 to 80 beats per minute. However, the pulse rate may fluctuate with exercise, illness, injury, and emotions.
Pulse rate in an individual can be checked at various points on the body. This is because the pulse may palpate at any place in the human body where an artery can be compressed against a  bone. These are the neck, inside of the elbow,  the wrist,  groin,  behind the knee, ankle joint and foot.

The rate at which the heart beats is pulse rate. As the heart pumps blood through the body, the pulse can be felt in some of the blood vessels close to the surface of the skin such as wrist, neck or upper arm. Hence pulse represents tactile arterial palpation. Thus the correct answer is option A.

A normal pulse is regular and strong. Heart rates, and therefore pulse rates (number of beats per minute) change with age and can vary between individuals of the same age.

• Pulse is a pressure wave that travels through the arteries after each ventricular systole.
• Since each heartbeat generates one pulse in the arteries, the pulse rate per minute indicates the heart rate.
• Thus, pulse rate is the same as that of heart rate, between 60 to 100 beats per minute. 

Pulse is a pressure wave that travels through the arteries after each ventricular systole. The pulse can be felt in any artery that lies near the surface of the body. Carotid artery (neck region), radial artery (forearm) and femoral artery (legs) all of them are situated near the surface of the body. Thus pulse can be palpated from all of them.

The arteries are superficial at some points in the body. In these places, the heart beat is felt as pulses like the radial, brachial pulse. 

The heart is pumping organ of human body and is situated in the thoracic cavity in the space between two lungs which is known as mediastinum. Heartbeat is rhythmic contraction and relaxation of heart muscles is called as a heart beat. Heart rate is the speed of heart beat measured by a number of contraction of the heart per minute. There is no term like heart stroke. When the blood vessel supplying blood to the brain are clogged it is known as brain stroke. Thus the correct answer is C.

The stethoscope is an acoustic (hearing) medical device used for auscultation(listening of internal sounds of the body. The doctor will place a small metal circle called a bell (hallow disc) or diaphragm (plastic disc), against the chest, at the spot where a person can feel the heartbeat. The stethoscope is composed of rubber tube, earpiece and diaphragm.

The human circulatory system consists of a muscular four-chambered heart, a network of closed branching blood vessels and blood, the fluid which is circulated. The heart is mesodermal in origin. It is situated in the thoracic cavity, in between the two lungs. The rib cage partially encloses and protect chest cavity. In the chest cavity heart and lungs are present. Hence, the heart is protected by the rib cage.

A stethoscope requires a flexible tube to transmit sound waves from the chest piece to the earpieces. Rubber is the standard material due to its flexibility and acoustic properties.

Steps to construct a stethoscope at home:

In humans, heart is present in the chest region. It is located between the lungs and above the diaphragm. The heart is made of auricles and ventricles. Ventricles are the pumping chambers of the heart. The right ventricles pump blood to the lungs and the left ventricles pump blood to the whole body. The heart is slightly tilted towards the left side and so a stronger heartbeat can be felt on left side. Hence the doctor will keep the stethoscope for hearing Raman's heartbeat on the left side of his chest.

This sequential event in the heart which is cyclically repeated is called the cardiac cycle. Each cardiac cycle consists of systole and diastole of both the atria and ventricles. Each cardiac cycle represents one heartbeat. The normal heart rate is about 72 beats per minute. The heart rate is same as pulse rate because the pumping action of the heart causes an increase in blood pressure in arteries. Hence the movement in the vessels on the wrist is due to the pulse.

Smaller organisms have a higher surface-area-to-volume ratio, leading to faster heat loss and higher metabolic rates. The heart rate comparison is a valid physiological example of this trend.

This sequential event in the heart which is cyclically repeated is called the cardiac cycle. Each cardiac cycle consists of systole and diastole of both the atria and ventricles. Each cardiac cycle represents one heartbeat. The normal heart rate is about 72 beats per minute. The heart rate is same as pulse rate because the pumping action of the heart causes an increase in blood pressure in arteries that leads to noticeable pulse. Hence the pulse rate per minute describes the heartbeat.

The entire heart is made of cardiac muscles. A specialized cardiac musculature called the nodal tissue is also distributed in the heart i.e sino-atrial node (SAN- A patch of this tissue is present in the right upper corner of the right atrium )and atrioventricular node (AVN- mass of this tissue is seen in the lower left corner of the right atrium close to the atrioventricular septum). The nodal musculature has the ability to generate action potentials without any external stimuli, i.e., it is autoexcitable. Hence, the rhythmic beating of the heart is due to the action of muscles in the atria and ventricle.

Pulse pressure is defined as the difference between the systolic blood pressure and the diastolic blood pressure.

Atrial natriuretic factor (ANF) is a hormone secreted by the atrial cells of the heart in response to high blood pressure to help lower it.

• Human heart is a four chambered structure where t he upper 2 chambers are the atria and the lower 2 chambers are the ventricle.
• Atria are the chambers of the heart that receive the blood from various organs of the body. Right atria receives deoxygenated blood from the body organs other than lungs through the vena cana, where as the left atria receives blood that is oxygenated from the lungs via pulmonary vein.
• The blood from both the atria is to be transferred to the respective ventricles and for that the valves that guard the atrio ventricular opening should be opened and closed after the blood is transferred from one chamber to the other so as to prevent the backward flow of the blood.
• For this opening and closing of the valve and also for the systole and dystole movement of the chambers stimulus is required which is provided by the sino atrial node that is present at the upper right corner of the right atria.
• This node generates the action potential which travels from the SA node to the atrio ventricular node that is AV node which is present at the lower left corner if the right atria. From the AV node the potential travels along the Purkenej fibers in the wall of atrio ventricular septum and the potential then spreads to the cardiac muscle of the heart.
• Therefore the whole functioning of the heart is dependent upon the action potential that is generated from the SA node in the atria.
• Therefore the answer 'Action mentioned in Statement 1 is dependent on action mentioned in Statement 2' is correct.
  

The numeric difference between systolic and diastolic blood pressure is called pulse pressure. For example, if the resting blood pressure is 120/80 millimeters of mercury (mm Hg), pulse pressure is 40 which is considered a normal and healthy pulse pressure.

There are four heart sounds, each corresponding to a particular event in the cardiac cycle. The first two are most easily distinguished, and sound through the stethoscope like 'lubb dup'. The first sound, 'lubb', is fairly loud and is due to the closure of the atrioventricular valves. This closure corresponds with the start of the Ventricular systole.

Erythroblastosis foetalis occurs when an Rh-negative mother develops Rh antibodies against the blood of an Rh-positive fetus, which then cross the placenta and destroy fetal red blood cells.

Donors and recipients in a blood transfusion process can be : father and son, brother and sister and maternal uncle and niece. This kind of blood transfusions are maximum compatible.

In the blood transfusion process, transfer of blood is possible between son and father, brother and sister, maternal uncle and niece.

So,
the correct option is ‘All the above’.

Individuals with type O blood do not produce ABO antigens.  Therefore, their blood normally will not be rejected when it is given to others with different ABO types.  As a result, type O people are universal donors for transfusions, but they can receive only type O blood themselves.

So, the correct option is O and Rh-.'.

HIV infection leading to AIDS  can be transmitted through the blood transfusion because HIV virus infects blood and multiplies in blood cells only.

B$^{+}$ blood group contain antibody-A and type B antigen. A person with blood group B$^{+}$ can receive blood from B$^{-}$ as due to the presence of same type of antigen in them, there won't be any transfusion reactions. While O$^{+}$ blood group does not contain any type of antibody. 

Blood transfusion is generally the process of receiving blood into one's circulation intravenously. Antigens are present on the surface of red blood corpuscles, while antibodies are present in the plasma of the blood, for e.g., people with blood group A have surface antigen A on their RBC's and antibodies to antigen B in their plasma. So, when RBC's are donated, transfer of antibodies doesn't take place. But as the RBC's of the donor have a surface antigen, it should be ensured that recipient's serum should not contain antibodies against the antigen on red blood corpuscles of the donor. Otherwise, if transfusion is made between incompatible donor and recipient, the reaction between antigens on the RBC (from the donor) and antibodies in the plasma (of the recipient) will produce clots and clog capillaries. Thus, the correct answer is option D.

Rhesus (Rh) factor is a protein found on the surface of red blood cells. If blood lacks the protein called as Rh negative and if present, called as Rh positive . Rh positive is the most common blood type. Having a Rh negative blood type is not an illness and usually, does not affect health. It should be tested before blood transfusion because it can harm the blood cell and other organs due incompatibility of blood. Thus, option A is correct.