Body Fluids and Circulation Lecture Notes

Introduction

• Instructor: Diksha Ma'am
• Topic: Body Fluids and Circulation
• Objective: Cover detailed NCERT topics, address previous year questions, provide thorough exam preparation.

Course Advice

• Preparation Tips: Attend lectures, make detailed notes, solve previous year questions (PYQs), and actively engage with the material.
• NCERT Focus: Important for exams as many questions are directly picked from NCERT lines.
• Interactive Study: Address relevant questions in comments.

Overview of Chapter

1. Body Fluids: Blood and Lymph
2. Circulatory System: Heart and Blood Vessels
3. Disorders and Physiology

Blood

Functions

• Connective Tissue: Specialized type
• Color: Red due to hemoglobin
• Composition: 55% plasma, 45% formed elements
  • Formed Elements: Erythrocytes, Leukocytes, Thrombocytes (Platelets)

Formed Elements

Erythrocytes (RBCs)

• Most abundant: 5-5.5 million per mm³ of blood
• Nucleus: None
• Shape: Biconcave
• Lifespan: 120 days
• Formation: Red bone marrow
• Hemoglobin: Iron-containing protein, carries oxygen

Leukocytes (WBCs)

• Count: 6,000-8,000 per mm³
• Function: Defense and immunity
• Types: Granulocytes (Eosinophils, Neutrophils, Basophils) and Agranulocytes (Lymphocytes, Monocytes)

Thrombocytes (Platelets)

• Origin: Megakaryocytes
• Function: Blood clotting
• Count: 1.5-3 lakh per mm³
• Structure: Biconvex

Plasma

• Water: 90-92%
• Plasma Proteins: Albumin (osmotic balance), Globulin (defense), Fibrinogen (clotting)
• Other Components: Nutrients, ions, gases, waste products

Blood Clotting

Process

1. Wound: Blood vessels damaged
2. Tissue Factor Release: Thromboplastin from damaged tissues
3. Platelets: Temporary blockage, release growth factor
4. Clotting Factors Activation: Forms thrombokinase
5. Thrombokinase: Converts prothrombin to thrombin
6. Thrombin: Converts fibrinogen to fibrin, forms clot
7. Clot Retraction: Tightening, serum oozes out

Important Factors

• Calcium: Essential for clotting
• Clotting Factors: Present in inactive form in plasma
• Clotting Disorders: Low platelet count can lead to disorders

Lymph

• Composition: Similar to interstitial fluid, filtered blood
• Formation: Filtration of plasma, enters lymph capillaries
• Functions: Transport of nutrients, immune response, absorbs fats
• Structure: Lymph capillaries, lymph vessels, lymphatic trunk, drains into veins (jugular and subclavian)

Circulatory System

Heart Structure

• Chambers: Four (2 atria, 2 ventricles)
• Walls: Endocardium (inner), Myocardium (muscle), Pericardium (outer, double layer)
• Septum: Interatrial, Interventricular, Atrioventricular
• External Grooves: Sulci
• Valves: Atrioventricular (AV), Semilunar (SL)

Types of Circulation

• Pulmonary Circulation: Right ventricle to lungs via pulmonary artery, back to left atrium via pulmonary vein
• Systemic Circulation: Left ventricle to body via aorta, back to right atrium via vena cava
• Coronary Circulation: Blood supply to heart muscles via coronary arteries
• Hepatoportal System: Blood from gut to liver via hepatic portal vein before systemic circulation

Blood Vessels

• Types: Arteries, Veins, Capillaries
• Structure: Tunica interna (endothelium), Tunica media (smooth muscle, elastic fibers), Tunica externa (connective tissue)
• Function: Transport blood, exchange of gases and nutrients

Electrical Activity of the Heart

• Myogenic: Generates own electrical impulses
• Nodal Tissues: SA node (pacemaker), AV node, Bundle of His, Purkinje fibers
• Depolarization and Repolarization: Electrical events of the heart

Cardiac Cycle

• Phases: Joint Diastole, Atrial Systole, Ventricular Systole, Ventricular Diastole
• Sounds: First heart sound (lub), Second heart sound (dub)
• Cardiac Output: Stroke volume x Heart rate

ECG (Electrocardiogram)

• Leads Placement: Standard (3 leads), Special (6 chest leads)
• Waves: P wave (atrial depolarization), QRS complex (ventricular depolarization), T wave (ventricular repolarization)

Disorders

Hypertension

• Definition: Sustained high blood pressure
• Causes: Obesity, unhealthy diet, lifestyle
• Effects: Heart disease, kidney problems

Coronary Artery Disease (Atherosclerosis)

• Cause: Cholesterol plaque deposits
• Effect: Reduced blood flow to heart muscles, myocardial ischemia (low oxygen), myocardial infarction (heart muscle death)
• Symptoms: Angina pectoris (chest pain), heart attack

Heart Failure

• Definition: Inadequate blood pumping, often seen in elderly
• Symptoms: Congestion of lungs (congestive heart failure)

Conclusion

• Focus on NCERT: Essential for exam preparation
• Study Tips: Engage with lectures, solve questions, make detailed notes
• Encouragement: Dedicate time to studies, communicate with the instructor