PowerPoint Summary

Unit Overview

• Focus: White Blood Cell (Leukocyte) structure and function.

Functions of Leukocytes

• Defense Mechanism:

  • Protects against bacteria, fungi, viruses, and parasites.

  • Shields the body from trauma and abnormal cells.

Leukocyte Production & Development

• Two Groups Based on Granule Development:

  1. Granulocytes (Polymorphonuclear):

     • Contain granules in cytoplasm.

     • Types: Neutrophils, Eosinophils, Basophils.

  2. Agranulocytes (Mononuclear):

     • Few or no visible granules.

     • Types: Lymphocytes, Monocytes.

Bone Anatomy and Hematopoiesis

• Bone Structures:

  • Yellow Marrow: Spongy bone contains red marrow.

  • Blood Vessels: Located in bone marrow.

• Leukopoiesis: Formation of white blood cells from stem cells.

Granulocyte Development Stages

• Stages of Granulocyte Maturation:

  1. Myeloblast: Large cell, prominent nucleoli, light to medium blue cytoplasm.

  2. Promyelocyte: Slightly larger, small reddish-purple granules, nucleus round/oval.

  3. Myelocyte: Smaller, few specific granules, denser nucleus.

  4. Metamyelocyte: Kidney-bean shaped nucleus, specific granules present.

  5. Band Cells: U or S-shaped nucleus, no constriction less than 2/3 diameter.

  6. Segmented Granulocyte: Lobulated nucleus, 2-5 lobes, obvious specific granules.

Agranulocyte Development

• Monocyte Production:

  • Stages: Monoblast, Promonocyte, mature Monocyte.

  • Mature Monocyte: C-shaped nucleus, no visible granules, becomes Macrophage in tissues.

• Lymphocyte Production:

  • Stages: Lymphoblast, Prolymphocyte, mature Lymphocyte.

  • B-Lymphocytes = Bone marrow maturation; T-Lymphocytes = Thymus maturation.

Normal Leukocyte Characteristics in Canines

• Neutrophil: Most common, segmented nucleus, pale pink cytoplasm.

• Lymphocyte: High nuclear-to-cytoplasm ratio.

• Monocyte: Large, pale blue, vacuolated cytoplasm.

• Eosinophil: Reddish/orange granules.

• Basophil: Less segmented nuclei, purple granules.

Feline, Bovine, Equine and Avian Leukocytes

• Feline: Similar to canine; notable features include Dohle bodies in cytoplasm.

• Bovine: Variable size; prominent vacuoles in Monocytes.

• Equine: Majority of lymphocytes are small; kidney-shaped Monocytes.

• Avian: Heterophils possess bilobed/nultilobed nucleus, colorless cytoplasm with eosinophilic granules.