09.13 Hematopoietic System and Lymphoid System Flashcards
- Bone marrow biopsy shows the architecture of the system
- Bone marrow aspiration shows morphology of the cells
- Proerythroblast
- Early erythroblast
- Intermediate erythroblast
- Late erythroblast
- polychromatic erythrocyte
- Mature erythrocyte
erythroid precursors in BM
They get smaller and the cytoplasm becomes less basophilic.
Nucleus becomes smaller
- *A. Proerythroblast**
1. Divides through mitosis to produce subsequent cells
2. Very large nucleus with large, round nuclear chromatin.
3. The cytoplasm is deep basophilic (dyes purple) due to polyribosomes with pale peri-nuclear zone.
B. subsequently, they get smaller and cytoplasm becomes less basophilic.
erythroid island in BM
myelopoiesis
- Myeloblast
- Promyelocyte
- Myelocyte
- Metamyelocyte
- Band cell
- PMN leukocyte (neutrophil in picture)
PMN leucocytes have multi-lobulated nucleus connected with strings of chromatin
- three types of myelocyte develop into 3 different PMN leukocytes.
- when body is infected, the number of band cells in the blood circulation increases.
- nucleus gets indented from promyelocyte to completely lobulated in PMN leukocytes
- Myelo(mono-)poeisis produces macrophages.
- macrophage has many names
- Very large cell with irregular shape with very low nucleus/cytoplasm ratio (small nucleus)
- Cytoplasm is voluminous and weakly basophilic
X. Megakaryopoiesis – platelet developing cells
- Group I (immature)
- Cytoplasm is strongly basophilic with very high N/C ratio
- Group II
- Less basophilic cytoplasm with some azurophilic granules
- Lower N/C ratio
- Group III (mature)
- Plentiful cytoplasm which is weakly basophilic and contains abundant azurophilic granules
- Very low N/C ratio
Neutrophil: lilac colored cytoplasm
eosinophil: red cytoplasm
basophil: blue all over
lymphocytes: high N/C ratio
- Encapsulated spherical or kidney-shaped organs composed of lymphoid tissue
- Contains an outer cortex, inner cortex, and medulla
Lymph node architecture
fibers in the foreground; macrophage in the background
lymph node x-section
lymph node follicle
follicle with germinal center in the outer and inner cortex.
No follicle in the medulla
Medullary cords are branched extensions of the inner cortex that contain B lymphocytes and plasma cells
Medullary lymphoid sinuses are dilated capillary like structures that separate the medullary cords
B-cell in the outer cortex and medulla.
T-cell in the inner cortex.
tingible-body macrophages within a reactive follicle
thymus cortex and medulla
Thymus cortex. lymphocytes on upper left, reticular cells on the lower center.
Extensive population of T-cells and many macrophages
- normal structure in thymus medulla
- Concentric arrays of epithelial cells which contain keratohyaline and bundles of cytoplasmic fibers
- Comprised of multiple layers of epitheloid cells
Hassall’s corpuscles
- In infancy, thymus actively produces lymphocytes
- T-cell differentiation and maturation
- Post-pubescent thymus involutes and is characterized by areas of adipose tissue.
- Adults should not have active thymic tissue
spleen red and white pulp
White pulp:
- Thick sheath of cylinder of mainly t-lymphocytes surrounding a central artery or arterioles
- Round mass of bluish-staining maninly B-lymphocytes, the peri-arteriolar lymphatic sheath (PALS)
Round mass of bluish-staining maninly B-lymphocytes, the peri-arteriolar lymphatic sheath (PALS)
spleen red/white pulps and artery
- Contains splenic cords and sinuses (aka sinusoids)
- Splenic cords: reticular cells supported by reticular fibers, macrophages
- Elongated endothelial cells line the sinusoids and filter blood.
thymus and spleen comparison
A. Mucosa Associated Lymphoid Tissue (MALT)
a. Encapsulated lymphoid tissue
b. Depending on their locations, called palatine, pharyngeal or lingual tonsils
a. Encapsulated lymphoid tissue
b. Depending on their locations, called palatine, pharyngeal or lingual tonsils
a. Encapsulated lymphoid tissue
b. Depending on their locations, called palatine, pharyngeal or lingual tonsils
a. Located in the lamina propria and submucosa of the ileum
b. Consists of nodules composed of T-lymphocytes and a germinal center containing B-cells and macrophages
c. M cells take up antigen and present them to antigen-presenting cells
b. Contains lymphoid aggregates in the mucosa and submucosa
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