Body Fluids and Circulation

Beginner - Story ModeTopper - Revision

1. Blood - Plasma and Formed Elements

Blood is fluid connective tissue 55% plasma 45% formed elements. Plasma 90-92% water, 6-8% proteins albumin globulin fibrinogen, glucose amino acids salts hormones.

RBC biconcave no nucleus hemoglobin 4 heme Fe2+ carries O2 as oxyhemoglobin 5 million/mm3 120 days made in red bone marrow. WBC 4000-11000 soldier cells: Neutrophil 60-65% multi-lobed phagocytic first responder, Eosinophil 2-3% bilobed allergy parasite, Basophil 0.5-1% S-shaped histamine heparin inflammation, Lymphocyte 20-25% large round nucleus B makes antibodies T cell-mediated, Monocyte 6-8% kidney-shaped largest becomes macrophage. Platelets 150k-350k fragments of megakaryocyte clotting.

Part 1A - Blood Plasma Composition 55%

Part 1B - Formed Elements RBC WBC Platelets Zoom

Revision: Blood 55% plasma 45% formed. Plasma 90-92% water 6-8% proteins albumin globulin fibrinogen. RBC 5 million biconcave no nucleus Hb 120 days. WBC 4000-11000 Neutro 60-65% Eosino 2-3% Baso 0.5-1% Lympho 20-25% Mono 6-8%. Platelets 150k-350k clotting.

2. Blood Groups, Lymph & Clotting

Why blood transfusion fails if group mismatched? Antigen antibody reaction agglutination clumping. ABO antigens on RBC A B, antibodies anti-A anti-B in plasma. Rh D antigen.

Group A antigen A antibody anti-B, Group B antigen B anti-A, Group AB both antigens no antibody universal recipient, Group O no antigen both antibodies universal donor. Rh+ has D antigen Rh- no D, if Rh- mother Rh+ fetus second pregnancy erythroblastosis fetalis. Lymph colourless filtered plasma no RBC low protein lymphocytes, drains via thoracic duct left subclavian and right lymphatic duct right subclavian, functions drainage immunity fat absorption via lacteals. Open circulation arthropods low pressure haemocoel, closed circulation vertebrates high pressure vessels. Clotting: Extrinsic VII + Intrinsic XII XI IX VIII → Prothrombin → Thrombin Ca2+ → Fibrinogen → Fibrin mesh trap RBC clot, needs Vitamin K Ca2+.

Part 2A - ABO Rh Groups Compatibility Chart

Part 2B - Lymph & Coagulation Cascade Zoom

Revision: A antigen A anti-B, B antigen B anti-A, AB both antigens no antibody universal recipient, O no antigen both antibodies universal donor O-. Rh D antigen, erythroblastosis fetalis. Lymph no RBC, drainage immunity fat. Clotting prothrombin thrombin fibrinogen fibrin Ca2+ Vit K.

3. Human Heart & Cardiac Cycle

Heart is 4 chambered muscular pump size fist weight 250-300g. 2 atria thin walls receiving, 2 ventricles thick walls pumping. Right side deoxygenated blue, left side oxygenated red.

External: Aorta systemic, Pulmonary artery to lungs, SVC IVC bring deoxygenated, Pulmonary veins bring oxygenated. Internal: Septum separates left right, Tricuspid 3 cusps right AV, Bicuspid Mitral 2 cusps left AV, Semilunar valves aorta pulmonary prevent backflow, Chordae tendineae papillary muscles hold valves. Cardiac cycle 0.8 sec: Joint diastole 0.4s all relaxed AV open semilunar closed EDV 135ml, Atrial systole 0.1s 20% filling P wave, Isovolumetric contraction 0.05s AV slam closed S1 LUB, Ventricular ejection 0.25s semilunar open QRS, Isovolumetric relaxation 0.05s semilunar slam closed S2 DUB. Heart sounds S1 AV closure S2 semilunar closure.

Part 3A - Heart Structure Valves

Part 3B - Cardiac Cycle 0.8 sec Wiggers Zoom

Revision: 4 chambered 2 atria 2 ventricles, Tricuspid right Bicuspid left Semilunar aorta pulmonary, Chordae papillary. Cycle 0.8s Joint diastole 0.4s Atrial systole 0.1s Isovol contraction S1 LUB Vent ejection QRS Isovol relaxation S2 DUB. EDV 135ml.

4. ECG, Cardiac Output & Double Circulation

ECG is electrical story of heart. P wave atrial depolarization, QRS ventricular depolarization, T wave ventricular repolarization. PR 0.12-0.20s, QRS 0.06-0.10s.

Cardiac output CO = HR x SV, HR 72 bpm SV 70ml CO 5L/min, EDV-ESV = SV, Ejection fraction 55-60%. Double circulation: Pulmonary RA→RV→Pulmonary Artery→Lungs→Pulmonary Veins→LA deoxygenated to oxygenated, Systemic LA→LV→Aorta→Body→SVC IVC→RA. Portal hepatic portal intestine→hepatic portal vein→liver→hepatic vein→IVC filters. Coronary Aorta→Coronary arteries→Heart muscle→Coronary sinus→RA. Single circulation fish only.

Part 4A - ECG P QRS T & Cardiac Output

Part 4B - Double Circulation Pulmonary Systemic Zoom

Revision: ECG P atrial depol QRS ventricular depol T ventricular repol PR 0.12-0.20 QRS 0.06-0.10. CO HRxSV 72x70=5L/min EDV-ESV SV EF 55-60%. Double pulmonary RA RV lungs LA systemic LA LV body RA. Hepatic portal intestine liver IVC. Coronary heart muscle.

5. Vessels, Regulation & Pathways

Artery thick wall elastic carries away from heart high pressure no valves, Vein thin wall low pressure valves prevent backflow, Capillary one cell thick exchange.

Artery tunica externa media interna, Vein large lumen thin media valves. Pulse is artery expansion with systole. Regulation: Medulla cardiac centre, Sympathetic fight flight norepinephrine ↑ HR ↑ contractility, Parasympathetic rest digest vagus acetylcholine ↓ HR. Baroreceptors carotid aortic sense pressure, Chemoreceptors sense O2 CO2 pH, adrenal medulla epinephrine ↑ HR. Blood flow: Aorta→Arteries→Arterioles→Capillaries→Venules→Veins→Vena cava.

Part 5A - Artery Vein Capillary & Regulation

Part 5B - Circulatory Pathways Schematic Zoom

Revision: Artery thick elastic high pressure no valve, Vein thin low pressure valve, Capillary one cell exchange. Regulation medulla sympathetic ↑ HR norepinephrine parasympathetic ↓ HR acetylcholine vagus baroreceptors chemoreceptors adrenal epinephrine.

6. Disorders & Final Summary

Hypertension high BP ≥130/80 headache blurred vision. CAD coronary artery narrowing plaque angina chest pain radiating. Heart failure pump insufficient edema. Atherosclerosis fatty plaque hardening.

Hypertension cause salt obesity smoking stress, control diet exercise no smoking BP monitoring. CAD plaque narrows coronary arteries ischemia angina, treatment stents bypass. Heart failure heart cannot pump enough edema lungs legs, causes CAD hypertension. Atherosclerosis cholesterol plaque. Tissue fluid: Blood pressure 35mmHg arterial end filtration → tissue spaces → 90% reabsorbed venule end 15mmHg → 10% lymph → thoracic duct right lymphatic duct → subclavian veins → blood. Edema excess tissue fluid pitting. Lymph vs Blood RBC absent WBC abundant low protein slow clotting pale yellow.

Part 6A - Disorders HTN CAD Angina Heart Failure

Part 6B - Lymph vs Blood & Tissue Fluid Summary Zoom

Revision: HTN ≥130/80, CAD plaque narrowing angina chest pain, Heart failure insufficient pump edema, Atherosclerosis fatty plaque. Tissue fluid 90% reabsorbed 10% lymph thoracic duct right duct subclavian. Edema pitting. Lymph no RBC WBC abundant low protein.