Biol 221 Exam 4 - Blood and the Heart Notes

Blood Overview

  • Blood is a vital fluid that performs critical functions in the body including transportation of nutrients, gases, and waste.

Formed Elements of Blood

  • Composed of three main types:

    • Erythrocytes (Red Blood Cells, RBCs)

    • Present in nearly all vertebrates

    • Anucleate in mammals (lack a nucleus)

    • Most abundant cells in the body (~70% of all cells)

    • Function: Transport of gases (oxygen and carbon dioxide) to and from tissues

    • Leukocytes (White Blood Cells)

    • Two main types:

      • Agranulocytes:
      • Lymphocytes (25-45% of WBC count):
        • Direct immune response
      • Monocytes (3-8% of WBC count):
        • Transform into macrophages that phagocytize pathogens
      • Granulocytes:
      • Neutrophils (50-70% of WBC count):
        • Phagocytize pathogens
      • Eosinophils (2-4% of WBC count):
        • Fight multicellular parasites (e.g., tapeworms)
      • Basophils (<1% of WBC count):
        • Release histamine and contain heparin

    • Platelets (Thrombocytes)

    • Small, anucleate fragments of cytoplasm

    • Important for clotting:

      • Too many can lead to thrombosis (blood clots)
      • Too few may cause excessive bleeding

Blood Types and Transfusion Compatibility

  • ABO Blood Type System:
    • Group A: A antigens, Anti-B antibodies
    • Group B: B antigens, Anti-A antibodies
    • Group AB: A and B antigens, No antibodies (universal recipient)
    • Group O: No antigens, Anti-A and Anti-B antibodies (universal donor)
Compatibility Chart
  • O-: Universal donor
  • AB+: Universal recipient
DonorRecipient
O-O+, A-, A+, B-, B+, AB-, AB+
O+O+, A+, B+, AB+
A-A+, AB+
A+A+, AB+
B-B+, AB+
B+B+, AB+
AB-AB+
AB+AB+

The Heart Anatomy

  • External Anatomy:

    • Major structures include:
    • Brachiocephalic trunk
    • Superior vena cava
    • Right/Left pulmonary arteries
    • Aorta and its branches

  • Internal Anatomy:

    • Chambers: Right atrium, Right ventricle, Left atrium, Left ventricle
    • Valves: Tricuspid, Bicuspid (Mitral), Pulmonary, Aortic valves
    • Major blood vessels: Inferior vena cava, Pulmonary trunk, Pulmonary veins

Blood Flow Through the Heart

  • Pathway of blood flow:
    1. Right atrium
    2. Tricuspid valve
    3. Right ventricle
    4. Pulmonary semilunar valve
    5. Pulmonary trunk
    6. Pulmonary arteries (to the lungs)
    7. Pulmonary veins
    8. Left atrium
    9. Bicuspid (Mitral) valve
    10. Left ventricle
    11. Aortic semilunar valve
    12. Aorta
    13. Body

Cardiac Muscle and Conduction System

  • Cardiac Muscle Features:

    • Striations and intercalated discs are unique to cardiac muscle tissue

  • Conduction Pathway:

    • Sinoatrial (SA) Node -> Atrioventricular (AV) Node -> Bundle of His -> Right and Left Bundle Branches -> Purkinje Fibers

Heartbeat and Blood Pressure

  • Electrocardiogram (EKG):

    • P wave: Atrial depolarization
    • QRS complex: Ventricular depolarization
    • T wave: Ventricular repolarization

  • Blood Pressure Measurement:

    • Expressed as Systolic Pressure/Diastolic Pressure (SP/DP):
    • Healthy range: ~120/80
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    • Variations occur based on individual characteristics (e.g., height)