Circulatory System 

1-Mark Questions & Answers (Short Answer/Definition)

Q1: What is blood?

A: Blood is a fluid connective tissue responsible for the transport of substances in the human body.

Q2: What are blood vessels?

A: Blood vessels are the narrow tubes or channels through which blood is transported in the body.

Q3: Name the three main parts of the circulatory system in human beings.

A: The three main parts of the human circulatory system are the heart, blood vessels, and blood.

Q4: What is the primary function of blood in human beings?

A: The primary function of blood is the transport of substances throughout the body.

Q5: Briefly describe the role of the circulatory system in human beings.

A: The circulatory system is responsible for the circulation of blood throughout the body. Blood, a fluid connective tissue, transports necessary substances through blood vessels (narrow tubes or channels) to and from different parts of the body.

Q6: List the components that constitute the human circulatory system.

A: The human circulatory system consists of three main parts: the heart, which pumps the blood; blood vessels, which are the network of tubes/channels for circulation; and blood, the fluid medium of transport.

 Q1: What is the average weight of the adult human heart?

    A: The adult human heart weighs about 300 grams.

 

 Q2: What is the pericardium?

    A: The pericardium is a double-walled protective sac that encloses the heart.

 

 Q3: What is the function of the pericardial fluid?

    A: The pericardial fluid lubricates the heart and absorbs the impact of its movement.

 

 Q4: Name the upper and lower chambers of the human heart.

    A: The upper chambers are called atria (singular—atrium), and the lower chambers are called ventricles.

 

 Q5: What is the role of the septum?

    A: The septum is a muscular wall that separates the left side of the heart from the right side, preventing blood from flowing from one side to the other.

 

 Q6: What is the primary function of the heart valves?

    A: The heart valves ensure that the blood flow is always in one direction and prevent the backflow of blood.

 Q7: Describe the size and location of the human heart.

    A: The heart is a remarkable pumping organ, about the size of a clenched adult fist (approximately 12 cm in length, 9 cm wide, and 6 cm in thickness). It is located in the middle of the chest, behind the breastbone and between the lungs, slightly tilted towards the left.

 

 Q8: Differentiate between the atria and the ventricles.

    A: The heart has four chambers. The atria (upper chambers) have thin walls and receive blood from different body parts. The ventricles (lower chambers) have thick walls and pump the blood out of the heart.

 

 Q9: Explain why the left side of the heart is generally felt more on the left side of the chest.

    A: The left ventricle of the heart pumps blood most forcefully (to the rest of the body). Because of this powerful pumping action, the heart's activity is generally felt more strongly on the left side of the chest, even though it is centrally located.

 

 Q10: Name and state the location of the two types of Atrioventricular (AV) valves.

    A: The two AV valves are:

      Tricuspid valve: Located between the right atrium and right ventricle.

      Bicuspid valve (Mitral valve): Located between the left atrium and left ventricle.

 

 Q11: Explain the function and location of the Semilunar valves.

    A: Semilunar valves are found between the ventricles and the major arteries connected to the heart. Their function is to prevent the backflow of blood from the arteries into the ventricles.

 Q12: What is a pacemaker?

    A: A pacemaker is a small device placed in the chest or abdomen of a patient to help control abnormal heart rhythms.

 

 Q13: Which blood vessel carries deoxygenated blood from the upper half of the body to the right atrium?

    A: The Superior Vena Cava.

 

 Q14: Name the largest vein in the human body.

    A: The Inferior Vena Cava.

 

 Q15: Which blood vessel originates from the right ventricle and carries deoxygenated blood?

    A: The Pulmonary Artery.

 

 Q16: What is the largest artery in the human body?

    A: The Aorta.

 

 Q17: Where does the Pulmonary Vein carry blood to?

    A: It carries oxygenated blood from the lungs to the left atrium of the heart.

 

 Q18: State the distinguishing characteristic of the Pulmonary Artery.

    A: The Pulmonary Artery is the only artery in the body that carries deoxygenated blood. It transports this blood from the right ventricle to the alveolar capillaries of the lungs to be oxygenated.

 

 Q19: Explain why the Pulmonary Vein is still considered a vein despite carrying oxygenated blood.

    A: A blood vessel is classified as a vein if it carries blood towards the heart. The Pulmonary Vein carries oxygenated blood from the lungs to the left atrium of the heart, satisfying the definition of a vein.

 

 Q20: What is the main function of the Aorta?

    A: The Aorta is the largest artery and its function is to distribute blood, pumped from the left ventricle through the aortic valve, to the entire body. Its high elasticity helps maintain blood pressure.

 

 Q21: Briefly describe the function of the Vena Cavae.

   A: The Superior Vena Cava carries deoxygenated blood from the upper body, and the Inferior Vena Cava (the largest vein) carries it from the lower body. Both vessels empty this deoxygenated blood into the right atrium of the heart.

 

 Q22: What is the function of the Coronary Artery?

   A: The Coronary Artery is the blood vessel that supplies oxygenated blood to the muscles of the heart itself.

 

 Q23: Which blood vessel collects deoxygenated blood from the heart muscles?

    A: The Coronary Vein, which empties the deoxygenated blood into the right auricle (atrium).

 

 Q24: Name the chambers where deoxygenated blood is received by the heart.

    A: Deoxygenated blood is received in the Right Atrium (or Right Auricle).

 

 Q25: Where does the right ventricle pump blood to?

    A: The right ventricle pumps the deoxygenated blood to the lungs for purification via the pulmonary artery.

 

 Q26: What is the term used for the circulation of blood where it enters the heart twice in one full cycle?

    A: Double Circulation.

 

 Q27: To which chamber does the pulmonary vein bring blood?

    A: The pulmonary vein brings oxygenated blood to the Left Atrium (or Left Auricle).

 

 Q28: Describe the path of deoxygenated blood from the body into the heart.

    A: Deoxygenated blood from the body is carried to the heart by the two major veins: the Superior Vena Cava (from the upper body) and the Inferior Vena Cava (from the lower body). Both vessels empty this blood into the Right Atrium.

 

 Q29: What happens to the blood when it reaches the lungs?

    A: When the blood reaches the lungs (via the pulmonary artery), it undergoes purification or oxygenation. During this process, the blood gives out carbon dioxide and takes in oxygen from the lungs.

 

 Q30: Explain the final step of systemic circulation, where oxygenated blood leaves the heart.

    A: The oxygenated blood is pumped from the Left Atrium into the Left Ventricle. The Left Ventricle then pumps this blood with great force through the Aorta to the various body parts. The blood then divides into smaller arteries and capillaries to supply oxygen and nutrients.

 

 Q31: Briefly explain why human circulation is termed 'Double Circulation'.

    A: Human circulation is termed Double Circulation because in one complete circuit throughout the body, the blood enters the heart twice. First, it enters the right side (via the Vena Cavae) as deoxygenated blood, and the second time, it enters the left side (via the pulmonary vein) as oxygenated blood.

 

 Q32: Define pulmonary circulation.

    A: Pulmonary circulation is the circulation of blood between the heart and the lungs.

 

 Q33: Define systemic circulation.

    A: Systemic circulation is the circulation of blood between the heart and the body organs.

 

 Q34: What is a blood transfusion?

    A: Blood transfusion is the process of transferring blood from a donor to a recipient.

 

 Q35: What is the main danger if incompatible blood types are mixed during a transfusion?

    A: The red blood cells may clump together (agglutination), leading to serious consequences and even death.

 

 Q36: What are the two types of antigens and antibodies used to classify blood groups?

    A: Antigen A and Antigen B; Antibody a and Antibody b.

 

 Q37: Which blood group is known as the universal recipient?

    A: Blood group AB is called the universal recipient.

 

 Q38: Which blood group is known as the universal donor?

    A: Blood group O is called the universal donor.

 

 Q39: State the difference between pulmonary circulation and systemic circulation.

    A: Pulmonary circulation involves the movement of blood between the heart and the lungs (for oxygenation). Systemic circulation involves the movement of blood between the heart and the rest of the body organs (to deliver oxygen and nutrients).

 

 Q40: Briefly explain the concept of agglutination during blood transfusion.

    A: Agglutination, or clumping, occurs when incompatible blood is transfused. It is a reaction between the antigens in the donor's blood and the antibodies present in the recipient's blood, which can lead to blockage of blood vessels and death.

 

 Q41: Why is a person with blood group O called a universal donor?

    A: A person with blood group O is called a universal donor because their blood can give blood to all types of blood groups. This is because their red blood cells have neither Antigen A nor Antigen B, so there are no antigens to react with the recipient's antibodies.

 

 Q42: Why is a person with blood group AB called a universal recipient?

    A: A person with blood group AB is called a universal recipient because they can receive blood from all blood groups. This is because their plasma contains neither Antibody a nor Antibody b, meaning they won't cause clumping with antigens from any other blood type.

 Q43: Define Blood Pressure.

    A: Blood pressure is the pressure exerted by circulating blood on the inner walls of the arteries.

 

 Q44: What is systolic pressure?

    A: Systolic pressure is the pressure produced in the ventricles when they contract and pump blood into the aorta and pulmonary artery.

 

 Q45: What is diastolic pressure?

    A: Diastolic pressure is the pressure produced when the ventricles relax and get filled with blood from the auricles (atria).

 

 Q46: State the normal blood pressure of a healthy adult.

    A: The normal blood pressure of a healthy adult is 120/80 mm of mercury.

 

 Q47: What is hypertension?

    A: Hypertension is a rise in blood pressure above 140/90 mm of mercury (high blood pressure).

 

 Q48: What is the medical term for low blood pressure?

    A: Hypotension (low blood pressure).

 

 Q49: Name the instrument used to measure blood pressure.

    A: Blood pressure is measured by a device called a sphygmomanometer.

 

 Q49: Define Cardiac Arrest.

    A: Cardiac arrest is a sudden and frequently fatal event that occurs when the blood circulation system malfunctions, causing the heart to stop beating.

 Q50: Briefly explain the symptoms of Palpitations and list some common causes.

    A: Palpitations give a feeling that the heart is beating too hard or too fast, skipping a beat, or fluttering. They are commonly caused by stress and anxiety, overconsumption of caffeine, nicotine, or alcohol, and may also occur during pregnancy. 

 Q51: Explain the significance of the two limits of blood pressure (Systolic and Diastolic).

    A: The two limits indicate the maximum and minimum pressure in the arteries. Systolic pressure (upper limit, normal value 120\text{ mmHg}) reflects the pressure during heart contraction (pumping). Diastolic pressure (lower limit, normal value 80\text{ mmHg}) reflects the pressure during heart relaxation (filling).

 

 Q52: What immediate action should be taken if palpitations are accompanied by shortness of breath or chest pain?

    A: While palpitations are usually not serious, if they are accompanied by shortness of breath, dizziness, chest pain or fainting, it is advisable to consult a doctor immediately as this could be a sign of a more serious heart condition.

 

 Q53: List some known causes or symptoms that may precede Cardiac Arrest.

    A: Smoking, drinking alcohol, high blood pressure, and obesity are some of the reasons that may cause cardiac arrest. Symptoms may occur sometimes hours before the event, though it often comes without warning.

 Q54: Define Blood Pressure.

    A: Blood pressure is the pressure exerted by circulating blood on the inner walls of the arteries.

 

 Q55: What is systolic pressure?

    A: Systolic pressure is the pressure produced in the ventricles when they contract and pump blood into the aorta and pulmonary artery.

 

 Q56: What is diastolic pressure?

    A: Diastolic pressure is the pressure produced when the ventricles relax and get filled with blood from the auricles (atria).

 

 Q57: State the normal blood pressure of a healthy adult.

    A: The normal blood pressure of a healthy adult is 120/80 mm of mercury.

 

 Q58: What is hypertension?

    A: Hypertension is a rise in blood pressure above 140/90 mm of mercury (high blood pressure).

 

 Q59: What is the medical term for low blood pressure?

    A: Hypotension (low blood pressure).

 

 Q60: Name the instrument used to measure blood pressure.

    A: Blood pressure is measured by a device called a sphygmomanometer.

 

 Q61: Define Cardiac Arrest.

    A: Cardiac arrest is a sudden and frequently fatal event that occurs when the blood circulation system malfunctions, causing the heart to stop beating.

 

 Q62: Briefly explain the symptoms of Palpitations and list some common causes.

    A: Palpitations give a feeling that the heart is beating too hard or too fast, skipping a beat, or fluttering. They are commonly caused by stress and anxiety, overconsumption of caffeine, nicotine, or alcohol, and may also occur during pregnancy.

 

 Q63: Explain the significance of the two limits of blood pressure (Systolic and Diastolic).

    A: The two limits indicate the maximum and minimum pressure in the arteries. Systolic pressure (upper limit, normal value 120{ mmHg}) reflects the pressure during heart contraction (pumping). Diastolic pressure (lower limit, normal value 80{ mmHg}) reflects the pressure during heart relaxation (filling).

 

 Q64: What immediate action should be taken if palpitations are accompanied by shortness of breath or chest pain?

    A: While palpitations are usually not serious, if they are accompanied by shortness of breath, dizziness, chest pain or fainting, it is advisable to consult a doctor immediately as this could be a sign of a more serious heart condition.

 

 Q65: List some known causes or symptoms that may precede Cardiac Arrest.

    A: Smoking, drinking alcohol, high blood pressure, and obesity are some of the reasons that may cause cardiac arrest. Symptoms may occur sometimes hours before the event, though it often comes without warning.

 

 Q66: What is lymph?

    A: Lymph is the fluid collected in the lymphatic vessels. It is formed when plasma and leucocytes filter out from the blood capillaries into the tissue spaces.

 

 Q67: What is the color and composition of lymph?

    A: Lymph is slightly yellowish in colour. It is similar in composition to blood plasma, but contains less proteins, no red blood cells, no platelets, and more lymphocytes.

 

 Q68: Name the components of the lymphatic system.

    A: The lymphatic system consists of lymph vessels, lymph nodes, and lymph.

 

 Q69: Where do lymph vessels ultimately pour their contents?

    A: Lymph vessels ultimately pour their contents into veins near the heart, where lymph rejoins the main blood circulation.

 

 Q70: What are lymph nodes?

    A: Lymph nodes are small, globular masses into which the lymph vessels drain the lymph.

 

 Q71: Why is lymph considered a source of nutrients for some cells?

    A: Lymph carries food and oxygen to those parts of the body where blood cannot reach.

 Q72: Describe the movement of lymph in the lymphatic system.

    A: The lymphatic system does not have a pump (like the heart). Therefore, the movement of lymph depends on the contraction of the surrounding muscles that squeeze the vessels, pushing the lymph forward.

 

 Q73: Explain how lymph is formed.

    A: Lymph is formed when blood flows through capillaries and some of the plasma and leucocytes filter out from the capillaries into the spaces between the cells to form tissue fluid. This fluid then enters the minute channels called lymph vessels to become lymph.

 

 Q74: List two key functions of lymph.

    A: Two key functions are:

      Transport/Nutrition: Lymph carries food and oxygen to parts of the body where blood cannot reach.

      Immunity/Defense: The lymphocytes present in lymph help in fighting infections and diseases.

 

 Q75: Explain the circulatory role of the lymphatic system.

    A: The lymphatic system serves as a drainage system. It drains lymph, which contains nutrients, wastes, and digested fats, and pours its contents into the lymph nodes. Eventually, the lymph vessels empty their contents into the veins near the heart, completing the circuit by joining the blood circulation.