Day 3: Blood Flashcards
1
Q
formed elements of blood
A
- platelets
- RBC
- WBC
- granulocytes:
- neutrophils
- eosinophils
- basophils
- agranulocytes
- lymphocytes
- monocytes
- others (stem cells, mast cell precursors, etc)
- granulocytes:
2
Q
serum
A
no clotting factors present
(clotted blood)
3
Q
plasma
A
- anticoagulant is present in the tube:
- EDTA, heparin, sodium citrate
- mixture of fluids, proteins, and metabolites
- all proteins present, including fibrinogen
- unclotted blood remains at tube bottom
4
Q
neutrophil
A
- polymorphonuclear neutrophils (PMNs)
- most numerous of WBC & granulocytes (60-75% of nucleated cells)
- 3-5 lobes, 9-15 um in diameter
- form first line of defense against infection
-
3 different granules
-
tertiary granules
- facilitate migration through tissue
-
tertiary granules
- Phagocytosis: bacteria engulfed, internalized in phagosome, pH reduced
-
specific granules
- kill bacteria with enzymes & reactive oxygen
-
azurophilic granules (all granulocytes)
- lysosomal enzymes digest bacteria
-
specific granules
- neutrophils secrete interleukin-1 (IL-1), a pyrogen (fever-causing)
- dies, semidigested material and tissue fluid form pus
- condensed chromatin may continue to trap bacteria extracellularly
- born in marrow, marginal pool stored in marrow (or bld vessels?) (mature or precursor band cells)
- the peripheral blood neutrophil count measures only the circulating peripheral blood pool, not the marginal pool
- terminally differentiated cells, die by apoptosis after 1-4 days in connective tissue
5
Q
band cell
A
- immature neutrophil
- non-segmented U-shaped nucleus
- normally present in peripheral blood in small quantities, but over 2% (of circulating leukocytes) can indicate pathology
- released from the bone marrow in response to stress (infection)
6
Q
eosinophils
A
- 1-3% of WBC
- respond to parasitic infections, take part in hypersensitivity and allergic reactions
- 2 lobed nucleus, eosinophilic/acidophilic (pink) granules
- specific granules are anti-inflammatory, anti-helminthic
- terminally differentiated; 2 week lifespan
7
Q
basophils
A
- least frequently encountered granulocyte in the blood (<1%)
-
specific granules (basophilic) stain dark blue to black
- contain histamine (inflammatory responses, capillary dilation + permeability), heparin (prevent coagulation), serotonin, and other mediators of hypersensitivity + allergic reactions
- have a bilobed nucleus
- basophil responsible for vascular disturbances (widespread vasodilation associated with hypersensitivity and anaphylaxis)
- considered to live + function primarily in blood stream, but have been recently discovered in connective tissue
- primary function is in the blood
8
Q
lymphocytes
A
- 20-30% of WBCs, majority of agranulocytes
- predominantly small cells (6-10 um; larger ones 10-18 um)
- in smaller cells, nucleus occupies most of cell
- round to oval nucleus of homogenous heterochromatic condensed chromatin (dark/solid looking)
- primary mediators of immunity; only cells that circulate into and out of the peripheral blood, patrolling and scouting for antigenic stimlation
- 2 primary populations: memory and effector cells, natural killer cells are a 3rd class
- effectors
- B cells: humoral (antibody) immunity
- response to extracellular pathogen
- T cells (over 75% of circulating lymphocytes): cell-mediated immunity
- response to virus (intracellular pathogen)
- B cells: humoral (antibody) immunity
- effectors
- lifespan of several months to years
- predominantly small cells (6-10 um; larger ones 10-18 um)
- in smaller cells, nucleus occupies most of cell
- homogenous condensed chromatin (dark/solid)
9
Q
monocytes
A
- largest of leukocytes (12-20 um)
- nucleus is eccentrically located + indented to varying degrees (sometimes kidney shaped, never lobed)
- nuclear chromatin is more dispersed than lymphocyte (nucleus not as small / darkly stained)
- cytoplasm tends to be gray rather than bright blue of lymphocytes; contains small vacuoles and irregular inclusions
- 3-8% of WBC
- born in marrow; released to circulation; “reserve pool” stored in spleen
- becomes macrophage when enters connective tissue
10
Q
erythrocytes
A
- circular, pale center reflecting its biconcave shape
- eosinophilic
- biconcave shape allows it to deform without stretching the cell membrane
- make up 99% of cells in a blood smear
- function to protect hemoglobin from denaturation and degradation
- functional for 120 days
- after, they display oligosaccharides in membrane that targets them for destruction by macrophages in spleen (mostly) and liver)
- reticulocytes : 2% of circulating RBCs
11
Q
granuloctes
A
cells with a segmented nucleus that also contain cell-specific granules (membrane-bound inclusions) within their cytoplasm
12
Q
CBC components
A
- determination of hemoglobin
- measured colorimetrically after a treatment with dilute HCl
- hematocrit (% RBC)
- WBC counter (#/uL)
- WBC differential count (% of each type)
- reticulocyte count
- estimated platelet count
13
Q
leukocytes
A
- all contain azurophilic (primary, nonspecific) granules, which are small lysosomes containing acid hydrolases
- granulocytes (neutrophils, basophils, eosinophils) have specific granules
14
Q
diapedesis
A
- leave blood vessels by passing between endothelial cells of postcapillary venules and capillaries
- Involves recognition molecules of the WBC surface interacting with ligands (E-selectin and P-selectin) on endothelial cells
- First phase: leukocytes are loosely tethered to endothelial cells, slowing their rate of flow as they roll along the endothelial cell surface
- Second phase: integrins on the blood cell surface tightly bind to adhesion molecules on endothelial cell luminal surface
- Aided by chemokines at injury site, the leukocyte extends a pseudopod to + through the interendothelial junction and migrates into surrounding connective tissue
15
Q
platelets
(thrombocytes)
A
- cytoplasmic fragments of large megakaryocytes that reside in the bone marrow
- smallest cellular elements of the blood
- have a lifespan of about 10 days
- biconvex (non-nucleated cell fragment has 2 parts:
-
outer hyalomere (structural zone)
- contains actin + myosin
- two tubular systems: surface-opening and dense tubular system
- surface is glycocalyx rich in glycosaminoglycans (integral in platelet adhension)
-
inner granulomere (organelle zone; has basic + acidic granules)
- alpha granules (fibrinogen + coagulation factors)
- delta granules (factors that promote the clotting cascade)
- lambda granules (lysosomes)
-
membrane zone (open canalicular system)
- mediates degranulation
-
outer hyalomere (structural zone)
