In-depth Study Notes on Blood Typing and Respiratory Physiology.

Warm-Up Scenario

• An allergy victim ingests peanut allergens, causes difficulty breathing due to esophageal swelling.

• Expected blood draw results: respiratory acidosis (A), option A is correct.

Lecture Overview

• Subject: Blood Typing and Respiratory Anatomy

• Topics Covered:

  • Respiratory Anatomy

  • Respiratory Regulation

  • Neural control of breathing and chemoreceptors

  • Carbon dioxide transport and the carbonic acid equation

  • Blood physiology and blood typing

  • Non-specific and specific immunity

Respiratory System Review

• Lung Pleura:

  • Stick together, causing lung volume to change with thoracic cavity volume changes.

  • Muscle contractions are responsible for pressure and volume changes.

Carbon Dioxide Transport

• Carbonic Acid Equation:

  • CO₂ + H₂O ⇌ H₂CO₃ ⇌ HCO₃⁻ + H⁺

  • The reversible nature means CO₂ can increase or decrease pH levels in blood.

• Effects of CO₂ on pH:

  • Hypercapnia (high CO₂):

  • Produces protons, leading to acidosis (pH < 7.35).

  • Body's response: increased respiratory and heart rates to expel CO₂.

  • Hypocapnia (low CO₂):

  • Decreased protons, leads to alkalosis (pH > 7.45).

  • Body's response: decreased respiratory rate.

Chemoreceptor Response

• Arterial PCO₂ Levels:

  • High Level: Stimulates chemoreceptors, accelerates respiration, lowers PCO₂.

  • Low Level: Inhibition of chemoreceptors leads to decreased respiration.

Blood Composition

• Total Blood Composition:

  • Formed Elements (~45%): Red/white blood cells, platelets.

  • Plasma (about 55%): Water, proteins, nutrients, electrolytes, wastes.

  • Proteins include albumin (water balance), globulins (immunity), fibrinogen (clotting).

Red Blood Cells (RBC)

• Characteristics:

  • High surface area for gas exchange. Biconcave shape aids flexibility to pass through capillaries.

  • RBCs do not have organelles, cannot synthesize proteins, divide, or repair themselves.

• Production: Erythropoiesis is stimulated by erythropoietin (EPO), particularly when O₂ levels are low.

• Hematocrit measures RBC proportion in blood.

Blood Types and Immunology

• Blood Typing:

  • Antigens present on RBCs determine blood type (30+ types, 4 major: A, B, AB, O).

  • Rh factor presence (+ or -) is crucial.

• Antibody Production:

  • Antibodies produced against antigens not present on the individual's RBCs.

  • Example: Type B blood produces anti-A antibodies.

Agglutination Process

• Interaction: Occurs between antigens (on cells) and antibodies (in serum).

• Outcome: Clumping (agglutination) can lead to removal of pathogens or a negative reaction in mast cells during transfusion.

Transfusion Science

• Compatibility:

  • Donor blood must not have antigens matching recipient antibodies to prevent agglutination, which can be fatal.

Testing Blood Type

• Blood Typing Test: Determines antigens via agglutination.

• Understanding antigens helps to infer the antibodies present and what blood type is needed for transfusions.

Specific Scenario Problems

Problem 1: Blood Type Determination

• If a test shows anti-Rh agglutination, what does it mean?

  • The blood contains Rh antigens corresponding to the antibodies present.

Problem 2: Safety of Blood Transfusion

• If a patient has anti-A and anti-B antibodies, what blood types can they safely receive?

  • They can only accept O- blood.

Conclusion

• Proper understanding of blood types and physiological interactions is essential for safe medical practices, especially in transfusions.

• Review upcoming lectures on immunology and blood physiology as it connects with this topic.