MICROSCOPIC ANATOMY Flashcards
components of plasma
- albumin (maintains osmotic P and helps transport water insoluble substances)
- gamma globulins (antibodies)
- fibrinogen (for clotting)
- complement proteins (important for inflammation and destruction of microorganisms)
- other solutes (electrolytes, nutrients, gases, hormones, enzymes)
buffy coat
1% of blood volume and consists of leukocytes and platelets
leukocytes (with percentages and numbers)
total= 6,000-10,000/microliters (approximately 7,500)
neutrophils (60-70%)--> 4,500-5,250 lymphocytes (20-30%)--> 1,500-2,250 monocyte (3-8%)--> 225-600 eosinophil (2-4%)--> 150-300 basophil (0-1%)--> 0-75
what is the shape of a RBC and what does it imply?
biconcave disc without a nucleus maximizing surface area to volume ratio for efficient gas exchange
what is the membrane skeleton of an erythrocyte made out of?
spectrin, actin and protein 4.1
major and minor forms of adult hemoglobin:
major: HBA1 (95%) in which there are 2 alpha and 2 beta polypeptide chains
minor: HbA2 (5%) in which there are 2 alpha and 2 delta polypeptide chains
what are the consequences of sickled erythrocytes?
they are inflexible, have a reduced life span leading to anemia and they increase blood viscosity leading to ischemia
what removes senescent RBCs?
macrophages which are located in the spleen, liver and bone marrow
*RBCs survive for approximately 120 days
reticulocytes
1% of circulating RBCs containing a small amount of rRNA (lost after 1 day of circulation) and are recently released giving a rough estimate of the rate of erythropoiesis
*stains with brilliant cresyl blue
2 classes of leukocytes and how leukocytes function
function as the main line of defense against bacteria, viruses and parasites outside of the blood vessels, leaving by means of diapedesis (between/paracellular or through/transcellular cells)
granulocytes: neutrophils, eosinophils and basophils
agranulocytes: lymphocytes and monocytes
diapedesis
the leaving of blood cells (leukocytes) through capillary walls
neutrophil
- nucleus is heterochromatic and not metabolically active with 2-5 lobes (polymorphonuclear- variable sized) each connected by a thin strand of chromatin
- SPECIFIC granules (makes up 80% of granules and responsible for staining qualities) AND AZUROPHILIC granules (makes up 20% of granules and is large and stained with Azure B with many hydrolytic enzymes to kill bacteria) are present
- few cellular components but a considerable amount of glycogen
- functions: motile, chemotaxis (movement in response to chemical stimulus), and phagocytosis
what are lysozyme and lactoferrin’s functions?
lysozyme: hydrolyzes glycosidases in bacterial cell wall
lactoferrin: iron binding protein
describe the process of phagocytosis by a neutrophil:
- pseudopodia surround bacteria forming phagosomes which then fuse with granules causing hydrolysis of the bacteria
- superoxide (O2-) anions form and netosis occurs (the release of a net-like structure capable of trapping microbes)
- microvesicles that have antibacterial activity are released along with cytokines
- neutrophils die and form pus
eosinophils
bilobed nucleus with SPECIFIC cytoplasmic granules (which have hydrolytic enzymes and a crystalline core) and functions to kill larvae of parasitic worms with EBP, dispose of antigen-antibody complexes and release granule contents (histamine and anaphylaxis substance SRS-A)
*can lead to asthma due to bronchoconstriction, mucus hypersecretion, inflammation and airway remodeling (increased SM, collagen and GC metaplasia)
basophil
less segmented nuclei with many SPECIFIC granules containing heparin, histamine and SRS-A that stain with Azure B
-IgE will bind to its surface stimulating degranulation of it along with mast cells leading to a localized or widespread reaction since they play a role in inflammation and hypersensitivity reactions (could be delayed)
- *shares many cytochemical and pharmacological characteristics with mast cells
- *produces eosinophilic chemotactic factor
lymphocyte types
3 types: small-medium, large agranular and large granular (some have large AZUROPHILIC granules) (large- less heterochromatic) which are all activated by specific antigens
lymphocyte functions
function as: B-cells and T-cells
- B-cells/humoral immunity: (10-15%) differentiate into plasma cells which produce antibodies/immunoglobulins that serve as antigen-receptors on the surface initiating mitosis when stimulated by an antigen (production of plasma cells which make antibodies or memory B-cells which help the cell respond more rapidly to subsequent exposure)
- T-cells/cell-mediated immunity: (70-80%) require APC in order to facilitate the binding of T-cells to foreign antigens stimulating mitosis leading to the production of memory T-cells, cytotoxic T lymphocytes (perforin lyses target cells while granzymes induce apoptosis -FAS-FAS ligand), helper T-cells (which assist B-cells) or suppressor/regulator T-cells (suppresses immune response to self molecules preventing autoimmune diseases)
natural killer cells
large granular lymphocytes which represent 5% of circulating lymphocytes containing azurophilic granules but lacking in B or T-cell surface molecules
- helps kill virus-infected or malignant cells (such as transplanted or foreign cells) through the production of cytokines
- T-cell polarization
monocytes
variable shaped euchromatic nucleus and cytosol containing small AZUROPHILIC granules, vacuoles and alpha-naphthyl acetate esterase (useful marker)
*developed from blasts in the red bone marrow (2-3 days) then remain in the peripheral circulation (1-2 days) migrating to tissues when they have transformed into macrophages/histiocytes function for 1-3 months with the ability of phagocytosis, serving as APC, forming osteoclasts, producing cytokines and monitoring endothelial cells
blood platelets/thrombocytes
fragments of megakaryocytes that are produced in the bone marrow and are non-nucleated with a central darkly staining granulomere, mRNAs and peripheral less intensely staining hyalomere appearing in clumps and lasting for approximately 10 days
- N= 250,000/microliter
- function= “platelet plug”- seals off small breaks playing a role in coagulation since it serves as a surface upon which clotting reactions occur
Romanovsky type stains
2 basic dyes and 1 acidic dye (examples of mixtures: Wright’s, Giemsa, May-Grunwald)
basic:
1. azure B- binds to DNA and glycosaminoglycans staining nuclei purple while staining granules of basophils and lysosomes a crimson color
- methylene blue- binds to RNA and stains the cytoplasm of the cell a heavenly blue
acidic:
1. eosin- stains proteins, hemoglobin and granules of eosinophils a red-pink color
regions of a blood smear
beginning/head: overlap
middle: RBCs are separated and leukocytes are intact (area of choice for study)
end/tail: over-stretched, broken and distorted
lymphoid multipotential cells vs. myeloid multipotential cells
lymphoid: migrate to lymphoid organs
myeloid: remain in bone marrow
hematopoiesis, granulopoiesis and erythropoiesis
development of: blood cells, granulocytes and erythrocytes
*hematopoiesis occurs in the bone marrow, lymphoid organs and in the liver (fetuses)
blasts
precursor cell to one type of blood cell in which it signifies the start of morphological differentiation with high mitotic activity but without the ability to self-renew
- large cell with a large euchromatic nucleus, several nucleoi and many ribosomes surrounded by a blue cytoplasm
- NO granules are present
neutrophilic differentiation and stages
myeloblast–> promyeloblast–> myelocyte–> metamyelocyte–> band cell–> mature pmn
- first 4 in bone marrow and last two in peripheral blood
- chromatin becomes heterochromatic, nucleus becomes lobulated, granules appear and basophilia decreases
neutrophilic promyelocyte
slight chromatin condensation and contains AZUROPHILIC granules and lysosomes (hydrolytic enzymes- acid phosphatase +) and is capable of mitosis
neutrophilic myelocyte
nucleus is round/oval and more heterochromatic containing much more SPECIFIC granules (lacoferrin and lysozyme) and less AZUROPHILIC granules and is capable of mitosis even though ability to replicate DNA and synthesize RNA decreases
- cytoplasmic color change
- chromatin= more condensed and basophilia= decreases
neutrophilic metamyelocyte
- is no longer able to sunthesize nucleic acids (DNA and RNA) or undergo mitosis
- chromatin is more condensed (Golgi is reduced) and it has an indented nucleus without basophilia but with many SPECIFIC and a few AZUROPHILIC granules
neutrophilic band
- *percentage in the peripheral blood is a rough estimation of the rate of neutrophil production
- further bending of the nucleus to look like an “S” without the capability of mitosis and chromatin is condensed
how long does it take for neutrophils to be produced and what is their fate?
production of neutrophils takes 9-14 days and then it is circulated in the peripheral blood in 1 of 2 different pools for one day (exchange of cells between the two can occur):
- circulating pool: suspended in plasma and circulating in vessels
- marginating pool: not circulating meaning in constricted capillaries or adhered to endothelium
then diapedesis occurs (paracellular or transcellular) and the cells can live for 5 days in tissues
distribution of granulocytes:
MGR- marrow granulocytic reserve (bone marrow)
TBGP- total blood granulocyte pool (peripheral circulation)
MGR= 10 x TBGP
red bone marrow
RED BLOOD CELLS
in the flat bones (especially the spongy bone) of the body containing cords of hematopoietic cells for blood cells to mature
- nurtures stem cells and facilitates their activity as a hematopoietic stem cell niche
- alterations–> myeloproliferative disease
yellow bone marrow
ENERGY
collection of adipose cells holding energy located in the medullary cavities of bones (all but flat bones) which are not active during hematopoiesis
erythrocyte differentiation including stages:
decrease in volume–> nuclear changes (chromatin becomes heterochromatic, nucleoli disappear, cell gets smaller and extrusion of nucleus)–> cytoplasmic changes (polysomes decrease and hemoglobin increases)
BLAST/ERYTHROBLAST–> BASOPHILIC ERYTHROBLAST–> POLYCHROMATOPHILIC ERYTHROBLAST–> NORMOBLAST–> RETICULOCYTE–> ORTHOCHROMATIC ERYTHROBLAST–> MATURE ERYTHROCYTE (RBC)
