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Understanding Body Fluids and Circulation

Aug 5, 2024

Lecture Notes: Body Fluids and Circulation

Introduction

  • Good evening everyone!
  • Today's chapter: Body Fluids and Circulation
  • Important for NEET as it covers crucial concepts.

Chapter Overview

  • Human Physiology chapters have significant weightage in NEET.
  • It is a very interesting and easy chapter.
  • The chapter is divided into:
    • Body fluids: Blood and Lymph.
    • Circulatory pathways.
    • Heart functions and disorders.

Body Fluids

Key Fluids in the Body

  • Blood: Major circulating fluid.
  • Lymph: Derived from blood filtration.
  • Other fluids like cerebrospinal fluid also originate from blood filtration.

Composition of Blood

  • Plasma: 55% of blood, containing:
    • 90-92% water.
    • Proteins (Albumin, Globulins, Fibrinogen).
  • Formed Elements: 45% consisting of:
    • Red Blood Cells (RBCs).
    • White Blood Cells (WBCs).
    • Platelets.

Types of White Blood Cells (WBCs)

  • Neutrophils: 60-65%, main phagocytes.
  • Eosinophils: 2-3%, involved in allergic reactions.
  • Basophils: 1%, release histamine and heparin.
  • Monocytes: 6-8%, largest WBCs, differentiate into macrophages.
  • Lymphocytes: 20-25%, crucial for immune response.

Heart and Circulation

Heart Structure

  • Divided into atria and ventricles.
  • Valves: Ensure unidirectional blood flow.
    • Atrioventricular Valves: Tricuspid and Bicuspid (Mitral).
    • Semilunar Valves: Pulmonary and Aortic valves.

Heart Function

  • Cardiac Cycle: Sequence of events in a heartbeat.
    • Systole: Contraction phase.
    • Diastole: Relaxation phase.
  • Initiated by the SA node (pacemaker).

Conducting System of the Heart

  • SA Node: Main pacemaker; generates electrical impulses.
  • AV Node: Receives impulses from SA node and sends them to ventricles.
  • Bundle of His: Conducts impulses to the ventricles.
  • Purkinje Fibers: Spread the impulse throughout the ventricles.

Disorders Related to Circulation

Hypertension

  • High blood pressure (>140/90 mmHg).
  • Affects organs like brain and kidneys.

Coronary Artery Disease (CAD)

  • Caused by deposition of fat and cholesterol in coronary arteries.
  • Leads to reduced blood flow to the heart.

Angina Pectoris

  • Acute chest pain due to insufficient oxygen reaching the heart.

Cardiac Arrest vs. Heart Failure

  • Cardiac Arrest: Complete stop of heartbeats.
  • Heart Failure: Heart's inability to pump enough blood.

Summary

  • Key concepts: Body Fluids, Heart Function, Circulatory Pathways.
  • Importance of understanding disorders and cardiovascular health.

Conclusion

  • Aim to understand the functioning of body fluids and the cardiovascular system.
  • Prepare for NEET with a focus on diagrams and key processes.

Full transcript