- Understand the composition and properties of blood and lymph.
- Explain the mechanisms of blood circulation in the human body.
- Describe the differences between blood and lymph.
- Identify the components of formed elements in blood and their functions.
- Discuss the significance of blood groups and compatibility in transfusions.
- Explain the process of blood coagulation and its importance.
- Describe the structure and function of the heart and its role in circulation.
- Understand the concept of double circulation and its significance in mammals.
- Explain the regulation of cardiac activity and factors affecting heart rate.
- Identify common disorders of the circulatory system and their implications.
Body Fluids and Circulation
Learning Objectives
TopRevision Notes & Summary
TopChapter 15: Body Fluids and Circulation
15.1 Blood
- Definition: Blood is a special connective tissue consisting of a fluid matrix, plasma, and formed elements.
15.1.1 Plasma
- Composition:
- 90-92% water
- 6-8% proteins (fibrinogen, globulins, albumins)
15.1.2 Formed Elements
- Components:
- Erythrocytes (RBCs): 5 million to 5.5 million/mm³, biconcave, contain hemoglobin.
- Leucocytes (WBCs): 6000-8000/mm³, nucleated, involved in immune response.
- Platelets (Thrombocytes): 1,500,000-3,500,000/mm³, involved in clotting.
15.1.3 Blood Groups
- ABO Grouping: Based on presence/absence of A and B antigens.
- Rh Grouping: Rh+ve (presence of Rh antigen) and Rh-ve (absence of Rh antigen).
- Compatibility:
- Universal Donor: O group
- Universal Recipient: AB group
15.1.4 Coagulation of Blood
- Process: Involves fibrinogen converting to fibrin via thrombin, requiring calcium ions and thrombokinase.
15.2 Lymph (Tissue Fluid)
- Definition: Fluid derived from blood, similar to plasma but with lower protein content.
- Function: Transports nutrients, hormones, and immune responses.
15.3 Circulatory Pathways
- Types: Open (arthropods, molluscs) and closed (annelids, chordates).
- Human Circulatory System: Closed system with a muscular heart and blood vessels.
15.4 Double Circulation
- Definition: Two separate circulatory pathways (pulmonary and systemic).
- Pathway: Right ventricle → pulmonary artery → lungs → left atrium → aorta → body tissues → right atrium.
15.5 Regulation of Cardiac Activity
- Myogenic Heart: Auto-regulated by nodal tissue; influenced by autonomic nervous system (ANS).
- Neural Regulation:
- Sympathetic: Increases heart rate and output.
- Parasympathetic: Decreases heart rate and output.
15.6 Disorders of Circulatory System
- Hypertension: Blood pressure higher than normal (e.g., 140/90 mm Hg).
- Coronary Artery Disease (CAD): Narrowing of arteries supplying the heart.
- Angina: Chest pain due to insufficient oxygen to heart muscle.
- Heart Failure: Ineffective pumping of blood by the heart.
Important Notes
- Cardiac Cycle: Sequence of events in the heart; average 72 cycles/min.
- Cardiac Output: Volume of blood pumped per minute (approx. 5 liters).
- ECG: Records electrical activity of the heart; segments include P-wave, QRS complex, T-wave.
Exam Tips & Common Mistakes
TopCommon Mistakes and Exam Tips
Common Pitfalls
- Blood Group Compatibility: Students often overlook the importance of matching blood groups during transfusions, which can lead to severe complications.
- Understanding Double Circulation: Many confuse the pathways of pulmonary and systemic circulation, leading to incorrect explanations of how blood flows through the heart.
- Coagulation Process: Misunderstanding the role of fibrinogen and thrombin in blood clotting can lead to errors in explaining the coagulation mechanism.
Exam Tips
- Memorize Blood Group Characteristics: Familiarize yourself with the ABO and Rh blood group systems, including antigens and antibodies present in each group.
- Diagram Practice: Practice drawing and labeling the heart's structure and the pathways of blood circulation to reinforce understanding.
- Clarify Terminology: Ensure you understand terms like systole, diastole, and cardiac cycle, as these are frequently tested.
- Review ECG Components: Be able to identify and explain the significance of the P-wave, QRS complex, and T-wave in an ECG.
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Practice Test – MCQs, True/False
TopMultiple Choice Questions
A.
They can donate blood to individuals of any blood group.
B.
They can receive blood from individuals of any blood group.
C.
They have no antigens on their red blood cells.
D.
They have both anti-A and anti-B antibodies in their plasma.
Correct Answer: B
Solution:
A person with AB blood group is considered a 'universal recipient' because they have no antibodies against A or B antigens, allowing them to receive blood from any ABO blood group.
A.
Leucocytes
B.
Erythrocytes
C.
Platelets
D.
Plasma
Correct Answer: B
Solution:
Erythrocytes, or red blood cells, contain hemoglobin which is responsible for the transport of respiratory gases.
A.
Oxygen transport
B.
Defense against infections
C.
Blood clotting
D.
Osmotic balance
Correct Answer: C
Solution:
Fibrinogen is a plasma protein that is essential for the clotting or coagulation of blood.
A.
Transport of oxygen to tissues
B.
Transport of nutrients to cells
C.
Removal of waste products from tissues
D.
Regulation of body temperature
Correct Answer: C
Solution:
The lymphatic system helps in the removal of waste products from tissues and also plays a role in immune responses.
A.
It acts as the heart's pacemaker by generating action potentials.
B.
It prevents the backflow of blood into the atria.
C.
It regulates the opening and closing of heart valves.
D.
It facilitates the exchange of gases in the lungs.
Correct Answer: A
Solution:
The sino-atrial node (SAN) is responsible for generating action potentials that initiate the heart's rhythmic contractions, thus acting as the pacemaker.
A.
They are nucleated
B.
They are biconcave in shape
C.
They are involved in immune response
D.
They secrete histamine
Correct Answer: B
Solution:
Erythrocytes or red blood cells (RBC) are biconcave in shape and devoid of nucleus in most mammals.
A.
To prevent backflow of blood from the ventricles to the atria
B.
To prevent backflow of blood from the arteries to the ventricles
C.
To facilitate the flow of blood from the atria to the ventricles
D.
To regulate the flow of blood between the left and right sides of the heart
Correct Answer: B
Solution:
The semilunar valves are located at the openings of the pulmonary artery and the aorta. They prevent the backflow of blood from these arteries into the ventricles after contraction.
A.
A
B.
B
C.
AB
D.
O
Correct Answer: D
Solution:
Individuals with blood type O are considered universal donors because they can donate blood to any other blood type without causing an immune reaction.
A.
To initiate the contraction of the atria.
B.
To delay the transmission of action potentials to the ventricles.
C.
To directly stimulate ventricular contraction.
D.
To regulate the opening of the semilunar valves.
Correct Answer: B
Solution:
The atrio-ventricular node (AVN) delays the transmission of action potentials from the atria to the ventricles, ensuring that the atria contract and empty their blood into the ventricles before ventricular contraction begins.
A.
To transport nutrients to body tissues
B.
To oxygenate blood in the lungs
C.
To remove waste products from tissues
D.
To regulate body temperature
Correct Answer: B
Solution:
The pulmonary circulation carries deoxygenated blood to the lungs for oxygenation.
A.
Transport of oxygen
B.
Immune response
C.
Blood clotting
D.
Nutrient transport
Correct Answer: C
Solution:
Platelets, or thrombocytes, release substances involved in the coagulation or clotting of blood.
A.
Fibrinogen
B.
Globulins
C.
Albumins
D.
Erythrocytes
Correct Answer: C
Solution:
Albumins help in maintaining the osmotic balance in the blood.
A.
It carries deoxygenated blood from the right ventricle to the lungs and returns oxygenated blood to the left atrium.
B.
It transports oxygenated blood from the left ventricle to the body and returns deoxygenated blood to the right atrium.
C.
It involves the movement of blood solely within the heart chambers.
D.
It is responsible for the exchange of nutrients and waste products at the cellular level.
Correct Answer: A
Solution:
The pulmonary circulation involves the movement of deoxygenated blood from the right ventricle to the lungs for oxygenation, and then the return of oxygenated blood to the left atrium.
A.
Neutrophils
B.
Eosinophils
C.
Basophils
D.
Monocytes
Correct Answer: B
Solution:
Eosinophils are associated with allergic reactions.
A.
Oxygen transport
B.
Defense mechanism
C.
Blood clotting
D.
Osmotic balance
Correct Answer: C
Solution:
Fibrinogens are needed for clotting or coagulation of blood.
A.
To prevent backflow of blood from the ventricles to the atria during ventricular systole.
B.
To prevent backflow of blood from the aorta and pulmonary artery into the ventricles during ventricular diastole.
C.
To regulate blood flow between the atria and ventricles.
D.
To initiate the contraction of the atria.
Correct Answer: B
Solution:
The semilunar valves prevent the backflow of blood from the aorta and pulmonary artery into the ventricles during ventricular diastole, ensuring unidirectional blood flow.
A.
Arteries
B.
Veins
C.
Capillaries
D.
Lymphatic vessels
Correct Answer: B
Solution:
Veins are blood vessels that carry deoxygenated blood back to the heart from various parts of the body.
A.
They are involved in the transport of oxygen.
B.
They secrete heparin and are involved in inflammatory reactions.
C.
They are responsible for the immune responses of the body.
D.
They are primarily involved in the coagulation of blood.
Correct Answer: C
Solution:
Lymphocytes, which include B and T cells, are crucial for the body's immune responses, identifying and neutralizing pathogens like viruses and bacteria.
A.
Clotting of blood
B.
Defense mechanisms
C.
Osmotic balance
D.
Transport of oxygen
Correct Answer: D
Solution:
Plasma proteins like fibrinogen, globulins, and albumins are involved in clotting, defense, and osmotic balance, but not in the transport of oxygen.
A.
Contains high levels of hemoglobin
B.
Similar to blood but with fewer proteins
C.
Contains erythrocytes
D.
Transports oxygen to tissues
Correct Answer: B
Solution:
Lymph is similar to blood except for the protein content and the formed elements.
A.
To transport oxygen
B.
To fight infections
C.
To aid in blood clotting
D.
To maintain osmotic balance
Correct Answer: A
Solution:
Erythrocytes, or red blood cells, contain hemoglobin which is responsible for the transport of oxygen.
A.
Plasma
B.
Erythrocytes
C.
Leucocytes
D.
Platelets
Correct Answer: B
Solution:
Erythrocytes, or red blood cells, contain hemoglobin which binds to oxygen and facilitates its transport throughout the body.
A.
High blood pressure
B.
Acute chest pain
C.
Irregular heartbeat
D.
Excessive bleeding
Correct Answer: B
Solution:
Angina pectoris is characterized by acute chest pain due to insufficient oxygen reaching the heart muscle.
A.
It acts as the pacemaker of the heart.
B.
It prevents the backward flow of blood.
C.
It facilitates the exchange of gases.
D.
It regulates blood pressure.
Correct Answer: A
Solution:
The sino-atrial node (SAN) generates action potentials and sets the pace of the heart, hence it is called the pacemaker.
A.
It pumps blood to the lungs.
B.
It acts as a pacemaker.
C.
It filters blood.
D.
It strengthens the heart muscle.
Correct Answer: B
Solution:
The sino-atrial node generates action potentials that initiate and maintain the rhythmic contractile activity of the heart, thus acting as a pacemaker.
A.
It helps in the transport of oxygen
B.
It aids in the immune response
C.
It is essential for blood clotting
D.
It maintains osmotic balance
Correct Answer: C
Solution:
Fibrinogen is a plasma protein that is essential for the clotting or coagulation of blood.
A.
Angina
B.
Cardiac arrest
C.
Heart failure
D.
Coronary artery disease
Correct Answer: C
Solution:
Heart failure is a condition where the heart is unable to pump blood effectively to meet the body's needs, often resulting in lung congestion.
A.
Initiates the heartbeat
B.
Prevents backflow of blood
C.
Conducts action potentials to the ventricles
D.
Generates action potentials
Correct Answer: C
Solution:
The AVN conducts action potentials to the ventricular side, facilitating ventricular contraction.
A.
A
B.
B
C.
AB
D.
O
Correct Answer: D
Solution:
Blood group 'O' is considered a universal donor because it lacks A and B antigens, preventing immune reactions in recipients of any blood group.
A.
It represents the depolarisation of the atria.
B.
It indicates the repolarisation of the ventricles.
C.
It signifies the depolarisation of the ventricles.
D.
It marks the end of systole.
Correct Answer: C
Solution:
The QRS complex in a standard ECG represents the depolarisation of the ventricles, which initiates ventricular contraction.
A.
Oxygen transport
B.
Blood clotting
C.
Immune response
D.
Nutrient transport
Correct Answer: C
Solution:
Lymphocytes are a type of white blood cell that play a crucial role in the immune response by recognizing and responding to foreign pathogens.
A.
It generates the maximum number of action potentials per minute, acting as the heart's pacemaker.
B.
It delays the transmission of action potentials to ensure the atria contract before the ventricles.
C.
It directly stimulates the contraction of the left ventricle.
D.
It is responsible for the depolarization of the ventricles.
Correct Answer: B
Solution:
The atrio-ventricular node (AVN) delays the action potential transmission, allowing the atria to contract and fill the ventricles with blood before ventricular contraction begins.
A.
They prevent the backflow of blood from the ventricles into the atria.
B.
They prevent the backflow of blood from the arteries into the ventricles.
C.
They prevent the backflow of blood from the atria into the veins.
D.
They prevent the backflow of blood from the veins into the atria.
Correct Answer: B
Solution:
The semilunar valves, located at the openings of the pulmonary artery and the aorta, prevent the backflow of blood from these arteries into the ventricles after ventricular contraction.
A.
Transport of oxygen
B.
Transport of nutrients
C.
Transport of waste materials
D.
Transport of hormones
Correct Answer: C
Solution:
Lymph helps in the transport of certain substances, including waste materials, from tissues to the blood.
A.
Fibrinogen
B.
Globulins
C.
Albumins
D.
Erythrocytes
Correct Answer: C
Solution:
Albumins are major proteins in plasma that help maintain osmotic balance by regulating the water content in blood.
A.
Transport of oxygen
B.
Clotting of blood
C.
Immune responses
D.
Regulation of blood pressure
Correct Answer: C
Solution:
Lymphocytes are responsible for the immune responses of the body.
A.
A
B.
B
C.
AB
D.
O
Correct Answer: C
Solution:
Individuals with blood group AB can accept blood from all other groups, making them universal recipients.
A.
Gas transport
B.
Blood coagulation
C.
Phagocytosis of foreign organisms
D.
Osmotic balance
Correct Answer: C
Solution:
Neutrophils are a type of white blood cell that are primarily involved in phagocytosis, helping to destroy foreign organisms that enter the body.
A.
Hypertension
B.
Angina
C.
Coronary Artery Disease (CAD)
D.
Heart Failure
Correct Answer: C
Solution:
Coronary Artery Disease (CAD), also known as atherosclerosis, is characterized by the narrowing of coronary arteries due to deposits of calcium, fat, cholesterol, and fibrous tissues.
A.
Fibrinogen
B.
Globulin
C.
Albumin
D.
Hemoglobin
Correct Answer: A
Solution:
Fibrinogen is a plasma protein that is converted into fibrin during blood coagulation, forming a stable mesh that constitutes the blood clot.
A.
To act as a pacemaker by generating action potentials
B.
To facilitate blood clotting
C.
To transport nutrients
D.
To filter lymph
Correct Answer: A
Solution:
The sino-atrial node (SAN) generates action potentials that initiate and maintain the rhythmic contractile activity of the heart, thereby acting as the pacemaker.
A.
Fibrinogen
B.
Globulins
C.
Albumins
D.
Hemoglobin
Correct Answer: C
Solution:
Albumins are the major plasma proteins responsible for maintaining osmotic balance in the blood.
A.
Coagulation of blood
B.
Osmotic balance
C.
Defense mechanisms
D.
Transport of oxygen
Correct Answer: B
Solution:
Albumins help in maintaining the osmotic balance in the blood.
A.
Transport of nutrients
B.
Transport of oxygen
C.
Transport of waste products
D.
Transport of immune cells
Correct Answer: D
Solution:
Lymph plays a crucial role in transporting immune cells, particularly lymphocytes, throughout the body, contributing to the immune response.
A.
Fibrinogen is essential for blood clotting.
B.
Globulins are primarily involved in oxygen transport.
C.
Albumins are responsible for the defense mechanisms of the body.
D.
Fibrinogen helps in the osmotic balance of the blood.
Correct Answer: A
Solution:
Fibrinogen is a plasma protein that plays a crucial role in the coagulation of blood, which is essential for preventing excessive bleeding.
A.
Plasma
B.
Leucocytes
C.
Erythrocytes
D.
Platelets
Correct Answer: C
Solution:
Erythrocytes, or red blood cells, contain hemoglobin, which binds to oxygen and carbon dioxide, facilitating the transport of these gases in the blood.
A.
60 beats per minute
B.
70 beats per minute
C.
80 beats per minute
D.
90 beats per minute
Correct Answer: C
Solution:
The sino-atrial node (SAN) is the pacemaker of the heart, and it sets the pace of the heart rate. If it generates 80 action potentials per minute, the heart rate would be 80 beats per minute.
A.
Atrio-ventricular node
B.
Sino-atrial node
C.
Purkinje fibers
D.
Bundle of His
Correct Answer: B
Solution:
The sino-atrial node (SAN) generates the maximum number of action potentials and initiates the heartbeat, thus acting as the pacemaker.
A.
Eosinophils
B.
Basophils
C.
Neutrophils
D.
Lymphocytes
Correct Answer: C
Solution:
Neutrophils are phagocytic cells that destroy foreign organisms entering the body.
A.
They prevent the backflow of blood into the atria.
B.
They prevent the backflow of blood into the ventricles.
C.
They regulate blood flow between the atria and ventricles.
D.
They initiate the contraction of the heart muscles.
Correct Answer: B
Solution:
The semilunar valves prevent the backflow of blood from the arteries into the ventricles after ventricular contraction.
A.
Erythrocytes
B.
Leucocytes
C.
Platelets
D.
Plasma
Correct Answer: B
Solution:
Leucocytes, or white blood cells, are primarily involved in the body's defense mechanisms.
A.
It initiates the heartbeat
B.
It delays the impulse to allow atrial contraction before ventricular contraction
C.
It directly contracts the ventricles
D.
It regulates the heart rate in response to physical activity
Correct Answer: B
Solution:
The AVN delays the electrical impulse from the atria to the ventricles, allowing the atria to contract and empty their blood into the ventricles before the ventricles contract.
A.
It represents atrial depolarization.
B.
It indicates the repolarization of ventricles.
C.
It marks the depolarization of ventricles.
D.
It shows the relaxation of atria.
Correct Answer: C
Solution:
The QRS complex represents the depolarization of the ventricles, initiating ventricular contraction.
A.
Depolarisation of the atria
B.
Repolarisation of the ventricles
C.
Depolarisation of the ventricles
D.
Repolarisation of the atria
Correct Answer: B
Solution:
The T-wave in an ECG represents the repolarisation of the ventricles, marking the return to the normal state after contraction.
A.
Gas transport
B.
Blood clotting
C.
Immune response
D.
Osmotic balance
Correct Answer: C
Solution:
Lymphocytes are a type of white blood cell responsible for the immune responses of the body.
A.
Defense mechanisms
B.
Osmotic balance
C.
Clotting or coagulation
D.
Gas transport
Correct Answer: C
Solution:
Fibrinogens are essential for the clotting or coagulation of blood.
A.
Pulmonary artery
B.
Aorta
C.
Pulmonary vein
D.
Vena cava
Correct Answer: C
Solution:
The pulmonary veins carry oxygenated blood from the lungs to the left atrium of the heart.
A.
Pulmonary circulation involves the left atrium and left ventricle.
B.
Systemic circulation involves the right atrium and right ventricle.
C.
Pulmonary circulation carries deoxygenated blood to the lungs.
D.
Systemic circulation carries deoxygenated blood to the lungs.
Correct Answer: C
Solution:
Pulmonary circulation involves the right ventricle pumping deoxygenated blood to the lungs for oxygenation.
A.
Arteries
B.
Veins
C.
Capillaries
D.
Lymphatic vessels
Correct Answer: B
Solution:
Veins have a comparatively thinner tunica media than arteries.
A.
Erythrocytes; anemia occurs
B.
Leucocytes; increased infection risk
C.
Platelets; excessive bleeding occurs
D.
Plasma; dehydration occurs
Correct Answer: C
Solution:
Platelets, or thrombocytes, are responsible for blood clotting. A low platelet count can lead to excessive bleeding due to impaired clotting.
A.
To separate the atria from the ventricles
B.
To prevent backward flow of blood
C.
To generate action potentials
D.
To regulate blood pressure
Correct Answer: B
Solution:
Semilunar valves prevent any backward flow of blood from the arteries into the ventricles.
True or False
Correct Answer: True
Solution:
Blood is a special connective tissue consisting of a fluid matrix, plasma, and formed elements.
Correct Answer: True
Solution:
The formed elements of blood include erythrocytes (RBCs), leucocytes (WBCs), and platelets, which together make up about 45% of blood.
Correct Answer: False
Solution:
Platelets, or thrombocytes, are primarily involved in blood clotting, not in resisting infections. It is the role of certain white blood cells like eosinophils.
Correct Answer: True
Solution:
Coronary artery disease, also known as atherosclerosis, is characterized by the narrowing of arteries due to deposits of calcium, fat, cholesterol, and fibrous tissues.
Correct Answer: False
Solution:
Platelets, or thrombocytes, are cell fragments, not nucleated cells, and they play a crucial role in blood clotting.
Correct Answer: True
Solution:
The SAN generates the maximum number of action potentials, 70-75 per minute, and is responsible for initiating and maintaining the rhythmic contractile activity of the heart.
Correct Answer: True
Solution:
Platelets release substances involved in the coagulation or clotting of blood.
Correct Answer: True
Solution:
The sino-atrial node (SAN) generates the maximum number of action potentials per minute and is responsible for initiating and maintaining the rhythmic contractile activity of the heart.
Correct Answer: True
Solution:
Blood plasma is indeed a straw-colored, viscous fluid that makes up about 55% of the total blood volume, and it contains 90-92% water.
Correct Answer: False
Solution:
Lymph is similar to blood but differs mainly in its protein content and the absence of formed elements.
Correct Answer: True
Solution:
In pulmonary circulation, the right ventricle pumps deoxygenated blood to the lungs via the pulmonary artery, where it gets oxygenated.
Correct Answer: False
Solution:
In humans, both blood and lymph are responsible for the transport of substances to and from cells. Lymph also helps in the transport of certain substances.
Correct Answer: False
Solution:
Pulmonary circulation involves the movement of deoxygenated blood from the heart to the lungs, where it becomes oxygenated.
Correct Answer: True
Solution:
When clotting factors are removed from plasma, the remaining fluid is referred to as serum.
Correct Answer: False
Solution:
Systemic circulation involves the transport of oxygenated blood from the heart to the body tissues and the return of deoxygenated blood to the heart. The pulmonary circulation is responsible for transporting deoxygenated blood from the heart to the lungs.
Correct Answer: True
Solution:
Erythrocytes, or red blood cells, are the most abundant cells in the blood and contain hemoglobin, which is responsible for the transport of respiratory gases.
Correct Answer: True
Solution:
Plasma is a straw-colored, viscous fluid constituting nearly 55% of the blood. It is composed of 90-92% water and 6-8% proteins.
Correct Answer: True
Solution:
In pulmonary circulation, deoxygenated blood is carried to the lungs where it is oxygenated and then returned to the left atrium.
Correct Answer: False
Solution:
The human heart is located in the thoracic cavity, between the two lungs.
Correct Answer: False
Solution:
In pulmonary circulation, deoxygenated blood is carried from the right ventricle to the lungs, where it is oxygenated and then returned to the left atrium.
Correct Answer: True
Solution:
Erythrocytes, also known as red blood cells, are the most abundant cells in blood and contain hemoglobin, which is crucial for transporting oxygen and carbon dioxide.
Correct Answer: True
Solution:
The pericardium is a double-walled sac that encloses the heart, providing protection and reducing friction as the heart beats.
Correct Answer: False
Solution:
Heart failure refers to the heart not pumping blood effectively enough to meet the body's needs, whereas cardiac arrest is when the heart stops beating.
Correct Answer: False
Solution:
The QRS complex represents the depolarization of the ventricles, which leads to their contraction. The P-wave represents the depolarization of the atria.
Correct Answer: True
Solution:
The human heart consists of four chambers: two upper atria and two lower ventricles, separated by the inter-atrial and inter-ventricular septa.
Correct Answer: True
Solution:
The sino-atrial node generates the maximum number of action potentials per minute and initiates the rhythmic contractile activity of the heart, making it the pacemaker.
Correct Answer: False
Solution:
The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs.
Correct Answer: False
Solution:
The ventricles have thicker walls than the atria because they need to pump blood to the entire body.
Correct Answer: True
Solution:
Coronary Artery Disease (CAD) is indeed caused by the narrowing of arteries due to deposits of calcium, fat, cholesterol, and fibrous tissues.
Correct Answer: True
Solution:
Systemic circulation carries oxygenated blood from the left ventricle through the arteries to the capillaries in the tissues of the body. From the tissue capillaries, the deoxygenated blood returns through a system of veins to the right atrium of the heart.
Correct Answer: True
Solution:
The sino-atrial node (SAN) is called the pacemaker of the heart because it generates the maximum number of action potentials per minute, setting the pace for heart activity.
Correct Answer: False
Solution:
Heart failure refers to the heart not pumping blood effectively enough to meet the body's needs, whereas cardiac arrest is when the heart stops beating.
Correct Answer: False
Solution:
The sino-atrial node (SAN) is located in the right atrium, not the left.
Correct Answer: True
Solution:
An ECG records the electrical activity of the heart and is used to detect heart abnormalities, making it clinically important.
Correct Answer: True
Solution:
The sino-atrial node generates the maximum number of action potentials per minute and is known as the pacemaker of the heart.
Correct Answer: True
Solution:
Blood is classified as a connective tissue because it has a fluid matrix (plasma) and formed elements (cells) that perform connective functions.
Correct Answer: True
Solution:
Eosinophils resist infections and are also associated with allergic reactions.
Correct Answer: True
Solution:
Plasma is a straw-colored, viscous fluid that makes up about 55% of blood. It contains proteins like fibrinogen, globulins, and albumins which play various roles in the body.
Correct Answer: True
Solution:
Serum is the component of blood that is left after the removal of clotting factors from plasma.
Correct Answer: True
Solution:
Eosinophils play a role in resisting infections and are associated with allergic reactions.
Correct Answer: False
Solution:
Neutrophils are actually the most abundant type of white blood cells, comprising 60-65% of the total WBCs, while lymphocytes make up 20-25%.
Correct Answer: True
Solution:
Systemic circulation starts with the left ventricle pumping oxygenated blood into the aorta, which distributes it to the body tissues.
Correct Answer: True
Solution:
The sino-atrial node (SAN) generates the maximum number of action potentials per minute (70-75/min) and sets the pace of the heart's activities, acting as the pacemaker.