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Q1. Name the valve present between the right atrium and the right ventricle. State the significance of the presence of the valve.

Solution

The tricuspid valve is present between the right atrium and the right ventricle. The presence of valves between these chambers prevents the backflow of blood during the ventricular systole.

Q2. Name the type of circulation which provides oxygen to body cells.

Solution

Systemic circulation

Q3. What is bundle of His?

Solution

Bundle of His constitutes the Purkinje fibres and the left and right branches which have originated from the AV bundle.

Q4. What is meant by Angina pectoris?

Solution

Angina pectoris occurs when arteries constrict and are unable to carry extra blood to the heart at the time of stress.

Q5. Name the cell from which thrombocytes originate. State the function of thrombocytes.   

Solution

Thrombocytes originate from the megakaryocytes. Thrombocytes are involved in blood coagulation.   

Q6. Write the formula for cardiac output.  

Solution

Cardiac output = Stroke volume × No. of beats per minute

Q7. State the location of the mitral valve.

Solution

The mitral valve is present between the left atrium and the left ventricle.

Q8. Write the names of the valves which are closed during the ventricular systole.

Solution

Tricuspid and mitral valves are closed during the ventricular systole.

Q9. What is serum? 

Solution

Serum is the plasma without any clotting factors. 

Q10. State the function of globulin.   

Solution

Globulin is involved in the defence mechanism of the body.   

Q11. Name the enzyme which facilitates the conversion of fibrinogen to fibrin.   

Solution

Thrombin  

Q12. Distinguish between atria and ventricles.

Solution

Atria Ventricles

They are the upper, receiving chambers.

They are the lower, pumping chambers.

Walls of atria are thin.

Walls of ventricles are thick.

Two atria are separated by the inter-atrial septum.

Two ventricles are separated by the inter-ventricular septum.

Atrial systole precedes the ventricular systole.

Ventricular systole follows the atrial systole.

 

Q13. State the normal systolic and diastolic blood pressure in a healthy individual.

Solution

The systolic pressure is 120 mm Hg, and the diastolic pressure is 80 mm Hg.

Q14. State the site of production of erythrocytes in humans. 

Solution

Red bone marrow 

Q15. State the location of the AV node.

Solution

The AV node is present at the lower left corner of the right atrium close to the atrioventricular septum.

Q16. Name the germinal layer from which the heart is derived in humans.

Solution

Mesoderm

Q17. What is an electrocardiogram? Name the instrument used to measure an electrocardiogram. State the significance of the electrocardiogram.

Solution

Electrocardiogram or ECG is the graphical representation of the electrical activity of the heart during a cardiac cycle. It is measured or monitored by an electrocardiograph. Any deviation or change in the shape of ECG indicates a cardiac disorder or abnormality.

Q18. Name the nodal tissue present in the walls of the right atrium.

Solution

SA node (sinoatrial node)

Q19. Name the fluid present in the protective covering of the heart.

Solution

Pericardial fluid

Q20. What is the duration of one cardiac cycle?

Solution

0.8 seconds

Q21. Name any one animal which shows single circulation. Explain single circulation.  

Solution

Pomfret. In single circulation, the heart pumps out deoxygenated blood to the gills. In gills, the blood is oxygenated and then sent to body parts.  

Q22. What does the letter P from ECG indicate?

Solution

The letter P from ECG indicates the depolarisation of the atria, i.e. the atrial systole.

Q23. Rutuja has a belief that the lub-dub sound produced by the heart is due to the forward and backward movements of the heart in the thoracic cavity.     Rutuja approaches her father to solve her doubts. Her father who is a doctor explains to her the human circulatory system and the cardiac cycle.    

Name the two chambers of the heart which pump blood.  

Name the valves present between the atria and ventricles.  

When are the lub and dub sounds present?  

What values do you learn here?  

Solution

The left and right ventricles are the pumping chambers of the heart.  

The tricuspid valve is present between the right atrium and the right ventricle, while the mitral valve is present between the left atrium and the left ventricle.  

When the tricuspid and bicuspid valves are present, the lub sound is produced. When the semilunar valves are closed, the dub sound is produced.  

We should always approach our parents for advice and proper knowledge when we face problems or questions in life.  

Q24. Name any two substances secreted by the basophils.   

Solution

Histamine and serotonin   

Q25. State the functions of neutrophils. 

Solution

Neutrophils are phagocytic in nature and destroy foreign substances entering the body. 

Q26. A cardiologist observed an enlarged QR wave in the ECG of a patient. What does it indicate?

Solution

It denotes ventricular contraction of the heart which may be normal or abnormal.

Q27. State the function of SAN.

Solution

SAN initiates and maintains the rhythmic contractile activity of the heart.

Q28. What is erythropoiesis? Where does it occur in foetus and after birth of young one?

Solution

Formation of RBCs is called erythropoiesis. It occurs in the liver and spleen in the foetus and in the red bone marrow after birth.

Q29. Name the vein which carries blood from the intestine to the liver.

Solution

Hepatic portal vein

Q30. Write the other name for coronary heart disease.

Solution

Atherosclerosis

Q31. State the adverse effects of hypertension in an individual.  

Solution

Hypertension causes heart diseases and affects organs such as the kidneys and brain.  

Q32. Name any two granulocytes. 

Solution

Eosinophils and neutrophils 

Q33. State the cardiac output of a healthy individual.

Solution

5 litres

Q34. How many action potentials SAN can generate per minute?  

Solution

SAN can generate 70-75 action potentials per minute.  

Q35. Name the state in a cardiac cycle during which all the four chambers of the heart are in the relaxed state.

Solution

Joint diastole

Q36. Enlist the events which occur during the ventricular systole.

Solution

During the ventricular systole, the ventricular pressure increases which causes the closure of the tricuspid and mitral valves. At the same time, the semi-lunar valves open which allows blood to enter the aorta and pulmonary arteries.

Q37. Explain the kind of circulation seen in frogs.

Solution

Frog is an amphibian; hence, it shows incomplete circulation. Frogs have a three-chambered heart. In frog, the left atrium receives oxygenated blood from the lungs or the skin. The right atrium receives deoxygenated blood from the body parts. Blood from both the atria get mixed in a single ventricle which pumps out the mixed blood into the circulation.

Q38. Name the protective covering of the heart.

Solution

Pericardium

Q39. What is the stroke volume? How much is the stroke volume of a healthy individual?

Solution

Stroke volume is the amount of blood pumped out by each ventricle during one cardiac cycle. The stroke volume of a healthy individual is 70 ml.

Q40. State the other term used for platelets. 

Solution

Thrombocytes