Full HUMAN PHYSIOLOGY In Just 2 Hrs🔥| ऐसा Revision नहीं देखा होगा😱| Neet 2024

Human Physiology: Complete Summary

Key Concepts: Blood composition, plasma proteins, blood cell formation, RBCs, WBCs, platelets, blood clotting, lymph, blood grouping (ABO, Rh), double circulation, heart anatomy, cardiac cycle, ECG, blood pressure, respiratory system anatomy, breathing mechanism.

1. Blood and its Components

• Hematology: Study of blood.
• Blood pH: 7.4 (slightly alkaline).
• Blood as Connective Tissue: Blood is classified as a type of connective tissue.
• Blood Volume: 7-8% of body weight.
• Blood Composition:
  • Plasma (55%): Liquid portion of blood.
  • Formed Elements (45%): Solid portion, including blood cells.
• Packed Cell Volume (PCV): The percentage of total blood volume occupied by cells (approximately 45%).
• Plasma Color: Pale yellow due to bilirubin.
• Formed Elements:
  • RBCs (Erythrocytes): Most abundant.
  • WBCs (Leukocytes): 5-8% of formed elements.
  • Platelets (Thrombocytes): Involved in blood clotting.
• Plasma Proteins: Proteins present in plasma.
  • Clotting Factors: Essential for blood coagulation.
  • Other Components: Minerals, glucose, lipids, amino acids, etc.
• Serum: Plasma without clotting factors.
• Major Plasma Proteins:
  • Albumin: Maintains blood colloid osmotic pressure.
  • Fibrinogen: Involved in blood clotting.
  • Globulin: Functions in immunity.
• Number of Blood Cells (per cubic millimeter of blood):
  • RBCs: 5 to 5.5 million.
  • WBCs: 6,000 to 8,000.
  • Platelets: 1.5 to 3.5 lakh.
• Blood Cell Formation (Hematopoiesis): Occurs in the red bone marrow of long bones.
  • Stem Cells: Present in red bone marrow, responsible for blood cell formation.
  • Embryonic Stage: Yolk sac, liver, and spleen.
  • Adult Stage: Bone marrow.

2. Red Blood Cells (RBCs)

• Shape: Biconcave.
• Size: 7.5 micrometers in diameter.
• Nucleus: Absent.
• Color: Red due to hemoglobin.
• Formation:
  • Embryo: Yolk sac, liver, spleen.
  • Adult: Bone marrow.
• Mitochondria: Absent (anaerobic respiration).
• Erythropoiesis: Process of RBC formation.
• Lifespan: 120 days.
• Graveyard: Spleen.
• Hemoglobin:
  • Composition: Heme (5%) + Globin (95%).
  • Heme: Iron + Porphyrin ring.
  • Globin: Four polypeptide chains (two alpha, two beta).

3. White Blood Cells (WBCs)

• Types:
  • Granulocytes: Neutrophils, basophils, eosinophils (acidophils).
  • Agranulocytes: Monocytes, lymphocytes.
• Abundance Order (Most to Least): " नीलिमा भाभी " (Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils).
• Nucleus Morphology:
  • Neutrophils: 3-5 lobed nucleus.
  • Eosinophils: Bilobed nucleus.
  • Basophils: 2-3 lobed, S-shaped nucleus.
  • Monocytes: Kidney or bean-shaped nucleus.
  • Lymphocytes: Large nucleus, peripheral cytoplasm.
• Function:
  • Neutrophils: Phagocytic.
  • Monocytes: Phagocytic.
  • Eosinophils: Associated with allergies.
  • Basophils: Secrete histamine, heparin, serotonin.
  • Lymphocytes: Immunity (B and T lymphocytes).

4. Platelets

• Formation: Fragmentation of megakaryocytes (cells with large nuclei).
• Function: Blood clotting.
• Blood Clotting Process:
  1. Injury activates platelets.
  2. Cascade process (requires calcium and vitamin K).
  3. Thrombokinase is formed.
  4. Prothrombin converts to thrombin.
  5. Fibrinogen converts to fibrin.
  6. Fibrin clot forms.

5. Lymph

• Tissue Fluid: Also known as tissue fluid.
• Color: Colorless (absence of RBCs).
• Composition: Mainly WBCs, few proteins.
• Differences from Blood: Lacks RBCs, fewer proteins.

6. Blood Grouping

• ABO Grouping: Based on the presence of antigens on RBCs and antibodies in plasma.
  • Blood Group A: Antigen A, Antibody B.
  • Blood Group B: Antigen B, Antibody A.
  • Blood Group AB: Antigens A and B, No antibodies.
  • Blood Group O: No antigens, Antibodies A and B.
• Donor Compatibility:
  • A: Can receive from A, O.
  • B: Can receive from B, O.
  • AB: Can receive from A, B, AB, O (Universal Recipient).
  • O: Can receive from O (Universal Donor).
• Rh Factor: Presence or absence of Rh antigen.
  • Rh Positive: Rh antigen present.
  • Rh Negative: Rh antigen absent.
• Erythroblastosis Fetalis: Occurs when an Rh-negative mother carries an Rh-positive fetus.
  • During the first pregnancy, mixing of blood at birth can cause the mother to develop Rh antibodies.
  • In subsequent Rh-positive pregnancies, these antibodies can attack the fetal RBCs.

7. Heart Anatomy and Circulation

• Origin: Mesodermal.
• Size: Clenched fist.
• Weight: 300 grams.
• Location: Thoracic cavity, between lungs, slightly left.
• Pericardium: Double-layered covering of the heart.
  • Pericardial Space: Between layers, contains pericardial fluid (reduces friction).
• Circulatory Pathways:
  • Open: Blood flows freely in cavities (e.g., arthropods, mollusks).
  • Closed: Blood circulates within vessels (e.g., humans, chordates, annelids).
• Double Circulation: Blood passes through the heart twice in one complete cycle.
  • Pulmonary Circulation: Deoxygenated blood from the right ventricle to the lungs and oxygenated blood back to the left atrium.
  • Systemic Circulation: Oxygenated blood from the left ventricle to the body and deoxygenated blood back to the right atrium.
• Arteries vs. Veins:
  • Artery: Carries blood away from the heart.
  • Vein: Carries blood towards the heart.
  • Pulmonary Artery: Carries deoxygenated blood.
  • Pulmonary Vein: Carries oxygenated blood.
  • Lumen: Arteries have smaller lumen than veins.
  • Valves: Veins have valves, arteries do not.
• Heart Chambers:
  • Right Atrium
  • Left Atrium
  • Right Ventricle
  • Left Ventricle
• Heart Walls: Composed of muscles.
  • Ventricle walls are thicker than atria walls.
  • Left ventricle is the most muscular chamber.
• Septa:
  • Interatrial Septum: Between the two atria (thin).
  • Interventricular Septum: Between the two ventricles (thick).
  • Atrioventricular Septum: Between atria and ventricles.
• Valves:
  • Cuspid Valves: Located between atria and ventricles.
    • Tricuspid Valve: Right atrium and right ventricle (three flaps).
    • Bicuspid (Mitral) Valve: Left atrium and left ventricle (two flaps).
  • Semilunar Valves: Located at the exit of ventricles.
• Heart Sounds: "Lubb" (S1) and "Dubb" (S2).
  • Lubb: Closure of AV valves (tricuspid and bicuspid).
  • Dubb: Closure of semilunar valves.
• Columnae Carneae: Muscular ridges on the inner surface of the ventricles.
• Papillary Muscles: Extensions of columnae carneae, help in opening and closing of AV valves.
• Heart Types:
  • Neurogenic Heart: Nerve impulses initiate heartbeat (external impulse).
  • Myogenic Heart: Muscle tissue generates impulses (internal impulse).
• Nodal Tissue: Specialized tissue in the heart that generates electrical impulses.
  • SA Node (Sinoatrial Node): Pacemaker, initiates heartbeat. Located in the upper right corner of the right atrium.
  • AV Node (Atrioventricular Node): Located in the lower left corner of the right atrium.
  • Bundle of His: Conducts impulses from the AV node to the ventricles.
  • Purkinje Fibers: Distribute impulses throughout the ventricles.

8. Cardiac Cycle and Regulation

• Heart Beat: Number of times the heart beats per minute (normal = 72).
• Cardiac Cycle: Sequence of events during one heartbeat (0.8 seconds).
  • Atrial Systole: Contraction of atria (0.1 seconds).
  • Ventricular Systole: Contraction of ventricles (0.3 seconds).
  • Joint Diastole: Relaxation of both atria and ventricles (0.4 seconds).
• Stroke Volume: Volume of blood pumped by each ventricle per beat (70 mL).
• Cardiac Output: Volume of blood pumped by each ventricle per minute (5 liters).
  • Cardiac Output = Stroke Volume x Heart Rate (70 mL x 72 beats/min = 5040 mL/min ≈ 5L).
• Regulation of Heart Beat:
  • Nervous Control: Medulla oblongata.
    • Parasympathetic: Decreases heart rate.
    • Sympathetic: Increases heart rate.
  • Hormonal Control:
    • Adrenaline, Noradrenaline, Thyroxine: Increase heart rate.

9. ECG and Cardiovascular Disorders

• ECG (Electrocardiogram): Graphical representation of the electrical activity of the heart.
  • Leads: Three leads placed on the right wrist, left wrist, and left ankle.
  • Waves: P, QRS complex, T.
    • P Wave: Depolarization of atria.
    • QRS Complex: Depolarization of ventricles.
    • T Wave: Repolarization of ventricles.
• Blood Pressure: Force exerted by blood against the walls of blood vessels (normal = 120/80 mmHg).
  • Systolic Pressure: Pressure during ventricular contraction (120 mmHg).
  • Diastolic Pressure: Pressure during ventricular relaxation (80 mmHg).
  • Sphygmomanometer: Instrument used to measure blood pressure.
  • Pulse Pressure: Difference between systolic and diastolic pressure (120 - 80 = 40 mmHg).
• Cardiovascular Disorders:
  • Heart Attack (Myocardial Infarction): Death of heart muscle due to lack of blood supply.
  • Cardiac Arrest: Sudden cessation of heart beat.
  • Heart Failure: Inability of the heart to pump enough blood to meet the body's needs.
  • Angina Pectoris: Acute chest pain due to insufficient oxygen supply to the heart muscle.
  • Coronary Artery Disease (Atherosclerosis): Narrowing of coronary arteries due to deposition of calcium, fat, cholesterol, and fibrous tissue.

10. Breathing and Exchange of Gases

• Respiratory System: Involved in the exchange of oxygen and carbon dioxide.
• Anatomy:
  • Nostrils/Mouth: Air enters through these openings.
  • Pharynx: Common passage for food and air.
  • Larynx: Sound box, involved in sound production.
  • Epiglottis: Cartilaginous flap that prevents food from entering the trachea.
  • Trachea (Windpipe): Tube that carries air to the lungs.
  • Esophagus (Foodpipe): Tube that carries food to the stomach.
  • Glottis: Opening of the windpipe.
  • Glet: Opening of the foodpipe.
  • Primary Bronchi: First division of the trachea.
  • Secondary Bronchi: Second division of the primary bronchi.
  • Tertiary Bronchi: Third division of the secondary bronchi.
  • Initial Bronchioles: Division of the tertiary bronchi.
  • Terminal Bronchioles: Final division of the bronchioles.
  • Alveoli: Air sacs where gas exchange occurs.

11. Synthesis/Conclusion

The video provides a comprehensive overview of human physiology, covering blood composition, blood cell types and their functions, blood grouping, heart anatomy and function, the cardiac cycle, and common cardiovascular disorders. It also introduces the basic anatomy of the respiratory system and the process of breathing. The information is presented with clear explanations and examples, making it accessible for students and anyone interested in learning about the human body.