week 7- WBCs Flashcards
• What non-RBC info is in a CBC?
o WBC info: number of WBCs, WBC differential (WBC populations)
o PLT info: number of platelets, platelet volume (MPV)
• What is non-RBC composition of whole blood? Absolute #?
o Plasma: 46-63% o Formed elements: 0.1% platelets and WBCs o N: 55-70%, 2500-8000 o E: 1-4%, 50-500 o B: 0-2%, 25-100 o L: 20-40%, 1000-4000 o Monocytes: 2-8%, 100-700
• What is basic function of WBCs?
o defense system against infectious foreign invaders and non-infectious challenge. 2 separate events:
o Phagocytosis: Involves granulocytes and monocytes
o Development of a specific immune response: Involves monocytes (macrophages) and lymphocytes
• How do WBCs travel in body?
o vascular system is only a temporary residence
o main function of vasculature with respect to WBCs is to transport to body tissues.
• Where is bone marrow? Function? Types?
o production site for all hematopoiesis
o primarily in hollow parts of long flat bones like the sternum and hips
o red and yellow: Majority of RBCs, WBCs and platelets formed in red marrow.
• What are blood stem cells?
o Pluripotent: pluri = more + potential = power
o Refers to the ability of a cell to become many different types of cells
o 2 types of stem cells in bone marrow:
o Mesenchymal: connective tissue, blood vessels and lymphatic tissue
o Hematopoietic: blood cells: RBCs, WBCs, platelets
• How are WBCs differentiated from each other?
o by nuclear and cytoplasmic characteristics
o granulocytes, agranulocytes
• what are granulocytes
o The granules in eosinophils have affinity for the acid part of the Wright’s stain and they stain orange-pink
o Basophils, for the basic part of the stain, bluish-black.
o Neutrophils, for both acid and basic parts, pinkish-blue (purple)
• What are agranuloctes?
o Monocytes: usually large with a horseshoe shaped nucleus
o Lymphocytes may be small (non-reactive) with a large N:C or large (reactive) with a smaller N:C. The nucleus is usually round (small lymphs) or may be slightly indented (large lymphs).
• What stimulates production/maturation of all the different WBCs?
o All different types of cytokines
• What is the general morphologic maturation scheme of WBC/RBCs?
o First 4, for both WBC and RBC o Cytoplasm: more basophilia -> less o Large nucleus -> smaller o Larger nucleoli -> small -> absent o Large cell size -> smaller o 5th: WBC granulocytes only: o Nucleus large and round -> smaller and segments
• What are the 6 general stages of maturation following commitment of stem cell in bone marrow?
o Myeloblast: non-granular cytoplasm and red nucleus
o Promyelocyte: distinct granules
o Myelocyte: cell division possible through this stage, identified as n/e/b
o Metamyelocyte: slightly indented nucleus
o Band/ stab cell: indentation > ½ distance from farthest nucleus margin
o mature n/e/b: Segmented nucleus
• What precursor cells are not seen in normal blood smear? Seen?
o Not: Myeloblast, promyelocytes, myelocyte, metamyelocyte
o Seen: band cell; mature granulocyte
• What does a WBC count tell you?
o total WBC count and differential are measured in an automated counter
o reflects the circulating pool of myeloid and lymphoid cells
o WBC in each microliter (ml;mm3) is reported
• What are normal and bad WBC levels?
o > 2 yrs: 4500-10,000/mL
o 30,000
• What are low/high WBC counts called?
o High= >11,000; leukocytosis
o Low= <4000; leukopenia
• What causes leukocytosis?
o Infections o Leukemic neoplasia o Other malignancy o Trauma, stress, hemorrhage o Tissue necrosis o Inflammation o Dehydration o Thyroid storm o Steroid drugs o Post Splenectomy
• What causes leukopenia?
o Drug toxicity o Bone marrow depression/failure o Severe infections o Dietary deficiencies o Marrow aplasia o Marrow infiltration o Autoimmune disease o Hypersplenism o Chemotherapy
• Where do mature cells go?
o Normally only mature cells go into peripheral blood
o May also remain in storage in marrow
• What may be reason for increase/decrease in WBC count? How do you tell?
o May be d/t alteration of all WBC cell lines
o More commonly results from alteration of only one type of WBC
o Need differential=absolute values of each type, %
o *most variation in WBC count are due to inc/dec in # neutrophils, since by % they are most numerous
• How do you do a differential WBC count?
o Place one drop of blood onto glass slide, spread the drop & air dry.
o Wright’s Stain: A mixture of Methylene Blue basic dye and Eosin red-orange acidic dye.
o Phosphate buffer applied directly on top of stain, rinse, dry & examine.
o Oil immersion [100x] lens: count 100 WBCs
o This gives the RELATIVE # of each type of WBC, expressed as a percentage of the 100 cells counted.
• What are results of a Wright stain? Cell types?
o Cell structures with acidic groups bind the basic dye & appear blue.
o Cell structures with basic groups bind the acidic dye & appear various shades of pink or red-orange.
o Lymphocytes: scant cytoplasm
o Monocytes: ground glass cytoplasm
o Neutrophils: lavender
o Eosinophils: orange/red
o Basophils: blue/black
• What does a normal wright stained blood smear look like?
o Lots of purple RBCs, a few purple neutrophils with segmented purple nuclei
• What is normal WBC differential in newborn?
o WBC: 6-3000 o PMN: 42-80% o Band: 2% o L: 26-36% o Mono: 3-8% o E: 0-5% o B: 0-2%
• Differential in infant, 1-12 mos?
o WBC: 6-18,000 o PMN: 18-44% o Band: 3% o L: 46-76% o M: 3-8% o E: 0-5% o B: 0-2%
• Differential in child, 1-16 yrs?
o WBC: 5-14,000 o PMN: 37-75% o Band: 3% o L: 25-57% o M: 3-8% o E: 0-5% o B: 0-2%
• Differential in adult?
o WBC: 4-10,000 o PMN: 36-75% o Band: 2% o L: 20-50% o M: 3-8% o E: 0-5% o B: 0-2%
• What is the absolute number of WBC cell types?
o =(Total WBC) x Relative % of each cell type
o Important to determine if pt has a sufficient # cells of a specific type
• Give an example of absolute vs relative WBC counts:
o Adult w/ total WBC= 15,000 (ref: 4500-10,000)
o 30% Ns (ref: 55-70%); 70% Ls
o Abs # Ns: 15,000 x 0.3 = 4500 (ref: 2500-8000)
o NORMAL absolute N count; only RELATIVE neutropenia (NOT absolute neutropenia)
• What can PMNs do? Most common?
o =polymorphonuclear leukocytes
o All are capable of phagocytosis
o Neutrophils most common; primary defense against microbial invasion
• What happens to neutrophils? Purpose? Granules?
o Stored in bone marrow 5-7 days (mature neutrophil reserve).
o Circulate in blood ~7 hrs.
o live in tissue for 2 hrs before they apoptose
o Acute bacterial infection, inflammation, & trauma stimulate neutrophil production leading to increased total WBC count
o Granules contain leukocyte alkaline phosphatase (LAP)
• What are pathologic neutrophil stains?
o Cytoplasm may show vacuoles during active phagocytosis
o Toxic granulation: Dark purple granules in cytoplasm due to severe infections, burn pts.
o Shift to the left: inc Band neutrophils in peripheral circulation: response to bacterial infection
o Nucleus becomes hypersegmented with vitamin B12 or folic acid deficiency
• What is neutrophilic toxic granulation? Hypersegmentation?
o found in severe inflammatory states.
o toxic granules are azurophilic, thought to be due to impaired cytoplasmic maturation in the effort to rapidly generate large numbers of granulocytes.
o Hyper: More that 3 cells (per 100) with 5 lobes or one with 6 lobes is evidence
• What are causes of neutrophilia (increased)?
o Acute infection o Trauma o Physical/emotional stress o Inflammatory disorders o Metabolic disorders o Myelocytic leukemia o Cushing’s syndrome
• What are causes of neutropenia (decrease)?
o Overwhelming bacterial infection o Viral infections o Aplastic anemia o Radiation therapy o Addison’s disease o Chemotherapy o Dietary deficiency
