Blood Cells and Hemoglobin Clinical Overview

Flashcards covering key vocabulary terms, structural components, ranges, and functions of red blood cells, hemoglobin types, white blood cell subsets, and platelets.

Erythrocytes (Red Blood Cells)

Flexible, oval biconcave disks lacking a cell nucleus that transport oxygen from the lungs to tissues and circulate for about $100 - 120\,\text{days}$.

Adenosine 5'-triphosphate (ATP) in RBCs

A major energy source in erythrocytes essential for maintaining their biconcave shape and deformability, without which RBCs flatten out.

Hemoglobin (Hb)

An iron-containing metalloprotein that constitutes $96\%$ of the dry weight of a red blood cell and is responsible for oxygen transport throughout the body.

Normal Male Adult Hemoglobin Level

$13.8 - 17.2\,\text{g/dL}$.

Normal Non-Pregnant Female Hemoglobin Level

$12.1 - 15.1\,\text{g/dL}$.

Heme

An organic compound structure composed of a porphyrin attached to an iron ion ($Fe^{2+}$), synthesized within the mitochondria.

Hemoglobin A

The most common adult hemoglobin type, composed of two $\alpha$ and two $\beta$ subunits ($\alpha_2\beta_2$), encoded by the HBA1, HBA2, and HBB genes.

Hemoglobin A2

A rare adult hemoglobin variant composed of two $\alpha$ and two $\delta$ subunits ($\alpha_2\delta_2$).

Hemoglobin F

Fetal hemoglobin predominant in infants, composed of two $\alpha$ and two $\gamma$ subunits ($\alpha_2\gamma_2$).

Leucocytes (White Blood Cells)

Cells of the immune system derived from multipotent hematopoietic stem cells in the bone marrow that defend the body against pathogens and foreign materials.

Normal White Blood Cell Count

$4,500$ to $11,000\,\text{WBCs per microliter}$ of blood.

Granulocytes

Phagocytic white blood cells characterized by visible cytoplasmic granules and lobed nuclei, comprising neutrophils, basophils, and eosinophils.

Band Neutrophils

Immature neutrophils characterized by a nucleus shaped like a 'U' or a curled rod prior to nuclear segmentation.

Neutrophils

Phagocytic granulocytes with a multi-lobed nucleus (3 to 4 lobes) that form an essential defense against bacteria and make up $1\% - 3\%$ of peripheral WBCs.

Basophils

The smallest circulating granulocytes ($10 - 15\,\mu\text{m}$ in diameter) containing large, masking granules that release histamine and heparin to mediate allergic responses.

Eosinophils

Granulocytes measuring $9 - 15\,\mu\text{m}$ in diameter with two nuclear lobes, accounting for $1\% - 4\%$ of peripheral WBCs and releasing toxins to target parasites and worms.

Agranulocytes

White blood cells without visible cytoplasmic granules, consisting of lymphocytes and monocytes.

Monocytes

The largest type of white blood cell ($10 - 30\,\mu\text{m}$ in diameter) featuring a single kidney-shaped nucleus, which migrate into tissues to form macrophages or dendritic cells.

Macrophages

Large, long-lived phagocytes derived from monocytes that ingest dead cells and function as antigen-presenting cells.

Dendritic Cells

Cells derived from monocytes that support antigen immunity and develop irregular star-shaped nuclear structures with cytoplasmic protrusions as they mature.

Lymphocytes

Spherical agranulocytes with large nuclei and minimal cytoplasm, classified into T cells, B cells, and natural killer cells.

B Lymphocytes (B-cells)

Bone marrow-produced cells that synthesize antibodies and differentiate into plasma cells.

T Lymphocytes (T-cells)

Lymphocytes that secrete cytokine proteins to coordinate and direct the response of other immune cells.

Platelets (Thrombocytes)

Small, non-nucleated cell fragments ($2 - 4\,\mu\text{m}$ in diameter) with a circulation lifespan of $8 - 14\,\text{days}$ that play a key role in hemostasis.

Megakaryocytes

Large cells located in the bone marrow that produce and release platelets into blood circulation.