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Human Physiology - Body Fluids and Circulation (Blood, Lymph, Heart Structure, Cardiac Cycle)

Grade 11ICSEBiology

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Blood is a fluid connective tissue composed of 55%55\% plasma and 45%45\% formed elements (Erythrocytes, Leucocytes, and Thrombocytes).

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Erythrocytes (RBCsRBCs) contain the iron-bearing protein Haemoglobin (HbHb), which facilitates the transport of O2O_2 and CO2CO_2.

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Blood Coagulation follows a cascade mechanism: Prothrombin→Thrombokinase,Ca2+ThrombinProthrombin \xrightarrow{Thrombokinase, Ca^{2+}} Thrombin, followed by Fibrinogen→ThrombinFibrinFibrinogen \xrightarrow{Thrombin} Fibrin.

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The Human Heart is four-chambered and myogenic. The rhythm is initiated by the Sino-atrial Node (SANSAN), also known as the natural pacemaker.

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The Cardiac Cycle consists of Atrial Systole (0.1 s0.1\ s), Ventricular Systole (0.3 s0.3\ s), and Joint Diastole (0.4 s0.4\ s), totaling 0.8 s0.8\ s.

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Double Circulation involves Pulmonary Circulation (Right Ventricle →\rightarrow Lungs →\rightarrow Left Atrium) and Systemic Circulation (Left Ventricle →\rightarrow Body →\rightarrow Right Atrium).

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Lymph is a colorless fluid containing lymphocytes, filtered from blood capillaries into intercellular spaces, serving as a 'middleman' for nutrient/gas exchange.

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Electrocardiogram (ECGECG) waves represent electrical activities: PP-wave (Atrial Depolarisation), QRSQRS complex (Ventricular Depolarisation), and TT-wave (Ventricular Repolarisation).

📐Formulae

Cardiac Output (CO)=Stroke Volume (SV)×Heart Rate (HR)Cardiac\ Output\ (CO) = Stroke\ Volume\ (SV) \times Heart\ Rate\ (HR) accounts for approximately 5000 mL/min5000\ mL/min.

Stroke Volume (SV)=End Diastolic Volume (EDV)−End Systolic Volume (ESV)Stroke\ Volume\ (SV) = End\ Diastolic\ Volume\ (EDV) - End\ Systolic\ Volume\ (ESV) usually 70 mL70\ mL.

Mean Arterial Pressure (MAP)=Diastolic BP+13(Systolic BP−Diastolic BP)Mean\ Arterial\ Pressure\ (MAP) = Diastolic\ BP + \frac{1}{3}(Systolic\ BP - Diastolic\ BP)

Pulse Pressure=Systolic Blood Pressure−Diastolic Blood PressurePulse\ Pressure = Systolic\ Blood\ Pressure - Diastolic\ Blood\ Pressure

Duration of Cardiac Cycle=60 secondsHeart Rate (beats per minute)Duration\ of\ Cardiac\ Cycle = \frac{60\ seconds}{Heart\ Rate\ (beats\ per\ minute)}

💡Examples

Problem 1:

Calculate the Cardiac Output (COCO) of a healthy individual whose heart rate is 75 beats/min75\ beats/min and stroke volume is 70 mL70\ mL.

Solution:

CO=75×70=5250 mL/min=5.25 L/minCO = 75 \times 70 = 5250\ mL/min = 5.25\ L/min

Explanation:

Cardiac output is the volume of blood pumped by each ventricle per minute, found by multiplying the volume per beat (Stroke Volume) by the number of beats per minute (Heart Rate).

Problem 2:

If the total time of one cardiac cycle is reduced to 0.6 s0.6\ s due to a high heart rate, calculate the beats per minute.

Solution:

HR=600.6=100 beats/minHR = \frac{60}{0.6} = 100\ beats/min

Explanation:

The heart rate (HRHR) is the inverse of the duration of one cardiac cycle, scaled to a minute (60 s60\ s).

Problem 3:

Determine the Pulse Pressure if a patient's blood pressure reading is 130/90 mmHg130/90\ mmHg.

Solution:

Pulse Pressure=130 mmHg−90 mmHg=40 mmHgPulse\ Pressure = 130\ mmHg - 90\ mmHg = 40\ mmHg

Explanation:

Pulse pressure is the difference between the systolic (higher value) and diastolic (lower value) blood pressure readings.

Body Fluids and Circulation (Blood, Lymph, Heart Structure, Cardiac Cycle) Revision - Class 11…