Histology Flashcards
What are the steps (intermediates) in maturation of the RBC?
Proerythroblast –> Basophilic Erythroblast –> Polychromatic erythroblast –> Normoblast –> Reticulocyte (goes out to peripheral blood) –> mature RBC
What causes the blue colour in the early development of the RBC?
polyribosomes and RNA
What causes the more red colour later in the development of the RBC?
hemoglobin and proteins
What happens to the nucleus of the normoblast after it is extruded?
Gets phagocytosed by macrophages
What is left in the cell to differentiate it from a mature RBC after the nucleus is extruded from the normoblast?
polyribosomes in the cytoplasm
What are the first granules to develop in WBCs?
- what do they contain?
Azurophilic (non-specific)
- contain lysosomes
What are the second granules to form in WBCs?
- what do they contain?
Specific granules - (different in each of the different cell types)
- contain protein
What is the order of cell intermediates in the development of granulocytes?
- at which point are signs of differentiation into a specific granulocyte present?
Myeloblast –> Promyelocyte –> Myelocyte –> Metamyelocyte
The Myelocyte is the first step which shows signs of differentiation
What granules are contained in the cytoplasm of myelocytes?
both azurophilic and specific granules
What granules are contained in the myeloblast?
only azurophilic (there is no specification for differentiation yet)
What is the main differentiating feature of a metamyelocyte compared to a myelocyte?
Metamyelocytes have an indented nucleus (beginning to form the multi-lobed nucleus seen in mature granulocytes)
What are contained in the granules of mature monocytes?
Lysosomal enzymes
What histological features help to identify a monocyte?
- Granules in cytoplasm (although this cannot always be noticed)
- eccentrically located nucleus
- indentation in nucleus (similar to metamyelocyte - except that metamyelocytes are found in bone marrow smear whereas monocytes are found in peripheral blood smear)
What histological features help to identify a lymphocyte?
- large nucleus
- thin pale-staining rim of cytoplasm
(size of the cells will vary depending on activity of cell)
List the order for differential WBC count (starting with the most common WBC)
Neutrophils Lymphocytes Monocytes Eosinophils Basophils
“Never Let Monkeys Eat Bananas”
What type of collagen is found in the spleen?
- what secretes it?
Type III collagen
- synthesized by reticular cells (specialized type of fibroblast)
What type of collagen is secreted by osteoblasts?
Type I collagen
What are the two outer layers that surround hyaline/articular cartilage?
Perichondrium (outermost fibrous layer) Chondrogenic layer (inner layer with chondroblasts)
What is found in the interterritorial matrix of hyaline cartilage?
Type II collagen
What is found in the territorial matrix of hyaline cartilage? (ie the dark colour or isogenous nests around chondrocytes).
GAGs
What type of cartilage is found in the epiglottis?
Elastic cartilage
What type of collagen is found in the annulus fibrosis?
Type I collagen
What type of collagen is found in tendons?
Type I collagen
What are the cells in tendons for which you can see elongated dark nuclei?
Fibroblasts
