Hematology Course Introduction 2024 Prof. Waseem AlTameemi

Hematopoiesis

• Haemopoietic stem cells (HSC) make up approximately 0.01% of total bone marrow cells.
• The main function of hematopoiesis is to produce mature blood cells.
• A pluripotential stem cell (HSC) has the ability to differentiate into multiple cell types.

Stem Cell Production

• One stem cell can produce approximately 10^18 (100 trillion) mature blood cells after 20 cell divisions.

Maturation of Bone Marrow Cells

• As bone marrow cells mature, they become more differentiated and specialized.

Granulocyte Production

• The growth factor granulocyte-colony stimulating factor (G-CSF) stimulates the production of granulocytes.

Hematopoietic Stem Cell Circulation

• Inflammation and stress can induce hematopoietic stem cells to circulate.

Reticulocytes in Peripheral Blood

• The normal range of reticulocytes in adults in peripheral blood is 0.5-2.5%.

Erythropoietin (Epo) Production

• Hypoxia stimulates Epo production, which in turn stimulates red blood cell production.

Indication for Erythropoietin Therapy

• Erythropoietin therapy is indicated for patients with chronic kidney disease or anemia.

Granulocyte Development

• The first recognizable granulocyte in the bone marrow is the myeloblast.

Clinical Application of G-CSF

• Granulocyte colony stimulating factor (G-CSF) is used to stimulate the production of neutrophils in patients with neutropenia.

Neutrophil Maturation

• It takes approximately 10-14 days for neutrophils to mature within the bone marrow.

Bone Marrow Cell Distribution

• Immature cells are mostly concentrated in the bone marrow.

Consequences of Malignant Infiltration

• When the bone marrow becomes infiltrated by malignant cells, hematopoiesis can be disrupted.

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Arrhythmias and Cardiac Conduction

Age Group and Arrhythmias

• The elderly may experience arrhythmias.

Mechanisms of Tachycardia

• The three main mechanisms of tachycardia are re-entry, automaticity, and triggered activity.

Heart Rate Classification

• A heart rate > 100/min is classified as tachycardia.

Wide Bizarre QRS Arrhythmias

• Wide bizarre QRS arrhythmias involve the ventricles.

Arrhythmia Classifications

• The classifications of arrhythmias include supraventricular and ventricular arrhythmias.

Type of Tachycardia

• Re-entrant tachycardia is initiated by an ectopic beat and sustained by a re-entry circuit.

After-Depolarizations

• Early after-depolarizations can occur in the early phase 2 of the action potential, while late after-depolarizations can occur in the late phase 3.

Ventricular Arrhythmias

• Ventricular arrhythmias can occur in patients with coronary heart disease, arising from an incompletely repolarized cell membrane.

Respiratory-Dependent Rhythm

• Sinus arrhythmia exhibits phasic alteration of the heart rate during respiration.

Symptoms of Arrhythmia

• Symptoms of arrhythmia include palpitations, dizziness, and chest discomfort or breathlessness.

Anti-Arrhythmic Drugs

• Class III anti-arrhythmic drugs act on the atria, ventricles, and accessory pathways.

Bradycardia

• Bradycardia is often caused by reduced automaticity, which can be due to sinus node dysfunction.

Investigation of Arrhythmias

• Electrophysiological studies are used to assess sinus node function, AV conduction, and inducibility of arrhythmias.

Anatomic Circuit

• Atrial flutter exhibits an anatomic circuit with two pathways joined by a common tissue.