Blood Composition
- Total blood = 6-8% of body weight
- Plasma = 55% of blood volume; Formed elements = 45%
- Plasma water content = 90-92%
- PCV (Haematocrit): Males 40-45%; Females 37-42%
Blood Cell Counts (Normal Values)
- RBC: Males 5-5.5 million/; Females 4.5-5 million/
- Total WBC: 6000-8000/
- Neutrophils: 3000-6000 (60-65% of WBCs)
- Eosinophils: 150-450 (2-3%)
- Basophils: 20-50 (0.5-1%)
- Lymphocytes: 1500-2500 (20-25%)
- Monocytes: 200-800 (6-8%)
- Platelets: 1.5-3.5 lakh/
Cell Lifespans
- RBC: 120 days
- Neutrophil: 5-90 hours
- Eosinophil: 8-12 days
- Basophil: hours to days
- Platelet: 5-9 days
- Monocyte/Macrophage: months
- Memory Lymphocyte: years to decades
Cardiac Parameters
- Heart rate (SAN intrinsic): 70-75 bpm
- AVN intrinsic rate: 40-60 bpm
- Purkinje intrinsic rate: 20-40 bpm
- AVN delay: ~0.1 second
- Cardiac cycle: 0.8 s (at 75 bpm)
- Atrial systole: 0.1 s
- Ventricular systole: 0.3 s
- Joint diastole: 0.4 s
- Stroke volume (rest): ~70 mL/beat
- Cardiac output (rest): ~5 L/min (formula: CO = SV × HR)
- Normal blood pressure: 120/80 mmHg
- Hypertension threshold: >140/90 mmHg
ECG Wave Summary
| Wave/Interval | Electrical Event | Normal Duration |
|---|---|---|
| P wave | Atrial depolarization | 0.08-0.10 s |
| PR interval | AV nodal conduction time | 0.12-0.20 s |
| QRS complex | Ventricular depolarization | 0.06-0.10 s |
| T wave | Ventricular repolarization | 0.16-0.30 s |
Blood Group Data
| Group | Antigen (RBC) | Antibody (Plasma) | Donate to | Receive from |
|---|---|---|---|---|
| A | A | Anti-B | A, AB | A, O |
| B | B | Anti-A | B, AB | B, O |
| AB | A and B | None | AB only | All (Universal Recipient) |
| O | None | Anti-A and Anti-B | All (Universal Donor) | O only |
- True universal donor = O-negative
- True universal recipient = AB-positive