Body Fluids and Circulation
[PREMIUM NCERT MODULE • CARDIOVASCULAR SYSTEM]
Blood is a fluid connective tissue consisting of Plasma and Formed Elements.
- Plasma (55%): 90% water, 6-8% proteins (Fibrinogen, Globulins, Albumins).
- Formed Elements (45%):
--> Erythrocytes (RBC): 5-5.5 million/mm3. No nucleus. Lifespan: 120 days.
--> Leukocytes (WBC): Granulocytes (Neutrophils, Basophils, Eosinophils) and Agranulocytes (Lymphocytes, Monocytes).
--> Platelets (Thrombocytes): 1.5 - 3.5 lakh/mm3. Involved in clotting.
- ABO Grouping: Based on antigens A and B on RBCs.
--> O-ve: Universal Donor.
--> AB+ve: Universal Recipient. - Rh Grouping: Presence of Rh antigen (D-antigen).
--> Erythroblastosis Fetalis: Rh-ve mother carrying Rh+ve fetus.
Four-chambered, mesodermally derived organ. Protected by double-walled Pericardium.
- Nodal Tissue: Specialized cardiac muscle.
--> SA Node (Sino-atrial): In right atrium. "Pacemaker".
--> AV Node: Atrio-ventricular.
--> Bundle of His: Transmits impulse to ventricles.
- Joint Diastole: All four chambers relaxed. TR/BI valves open.
- Atrial Systole: Atria contract, pushing 30% more blood into ventricles.
- Ventricular Systole: Ventricles contract. AV valves close (S1 sound - LUB). Semilunar valves open.
- Ventricular Diastole: Ventricles relax. Semilunar valves close (S2 sound - DUB).
- P-wave: Atrial depolarization (contraction).
- QRS Complex: Ventricular depolarization (major contraction).
- T-wave: Ventricular repolarization (relaxation).
- Hypertension: BP > 140/90 mmHg.
- CAD (Atherosclerosis): Deposition of Ca++, fat, cholesterol in arteries.
- Angina Pectoris: Acute chest pain due to low O2 reaching heart muscle.
- Heart Failure: Heart not pumping blood effectively.
Body Fluids HOTS Questions
[ CARDIAC LOGIC & BLOOD MATH ]
The Left Ventricle pumps oxygenated blood into the Systemic Circulation (the whole body), which involves high resistance and a long distance. The Right Ventricle only pumps to the lungs (Pulmonary Circulation), which is nearby and low pressure. Hence, more muscular force is needed on the left.
There is a slight delay (~0.1s) when the impulse travels through the AV node and Bundle of His. This ensures that the Atria complete their contraction and empty blood into the ventricles before the ventricles start their contraction (Systole). Without this delay, both would contract simultaneously, leading to inefficient pumping.
During the first delivery, some Rh+ve blood from the fetus may mix with the Rh-ve mother's blood, causing her to produce Rh-antibodies. In the second pregnancy, these antibodies can cross the placenta and destroy the fetal RBCs (Erythroblastosis fetalis), causing severe anemia or jaundice in the baby.
Calcium (Factor IV) is essential in almost every step of the coagulation cascade. It acts as a cofactor in the conversion of Prothrombin to Thrombin and the formation of the Fibrin mesh. Without Calcium, clotting cannot happen effectively.
Plasma is the liquid part of blood containing water, proteins, and clotting factors. Serum is the liquid that remains after blood has clotted; essentially, Serum = Plasma - Clotting Factors (like Fibrinogen).
It generates the highest rate of action potentials (~70-75/min).
LUB: Closure of AV valves. DUB: Closure of Semilunar valves.
Athlete has higher stroke volume, hence higher CO even with lower HR.
Carries nutrients from intestine to liver before general circulation.
Absorbs fats via lacteals and drains excess tissue fluid.
Red bone marrow.
Failure: Inefficient pumping. Attack: Muscle damage due to low blood supply.
One heartbeat (Ventricular contraction).
Pulmonary (Lungs) and Systemic (Body) circulation.
In the ventricular walls; conduct impulses to cardiomyocytes.
Phagocytosis (destroy foreign organisms).
Histamine, Serotonin, and Heparin (inflammation).
Bleeding disorders; inability to clot blood.
Artery: Thick walls, no valves. Vein: Thin walls, has valves.
SV = End Diastolic Volume - End Systolic Volume.
Circulation: 50 Mastery Facts
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