Peripheral Blood Flashcards
major components of blood
Formed elements (erythrocytes, leukocytes, platelets) Blood plasma (PRO-rich liquid, electrolytes)
Blood proteins
In blood plasma; albumin, globulins, fibrinogen, complement proteins
albumin
blood plasma PRO that maintains osmotic pressure of blood and transports water-insoluble substances
globulin
blood plasma PRO; usually gamma globulins that are antibodies
fibrinogen
blood plasma PRO necessary for blood coagulation via formation of fibrin
complement PRO
blood plasma PRO important in inflammation and destruction of microorganisms
hematocrit tube contents
Hematocrit (bottom): % of blood volume made of RBCs (41% females, 45% males)
Buffy coat (middle): leukocytes and platelets (1%)
Plasma (top): leftover PRO and electrolytes (>50%)
What does low hematocrit tell you?
Anemia
What does high buffy coat value tell you?
since more leukocytes/platelets:
- localized/systemic infection
- blood malignancy
Erythrocyte size/color
- 5 to 8 microns in diameter
- deeper pink (eosin) at periphery
fetal RBC
do have nuclei, but after birth they are made without nuclei, and the old fetal cells just die out
purpose of RBC biconcave shape
provides large SA:V ratio (40% greater surface area than sphere)
- facilitates gas exchange
- can change shape to pass thru capillaries
rouleaux
aggregate stack of RBCs in small blood vessels
purpose of RBC cytoplasmic viscosity
higher intracellular hemoglobin concentration
RBC membrane skeleton
influences deformability and stability against shearing
spectrin - creates tracks between the different PRO on skeleton
actin - different from muscle actin; stabilizes some glycoPRO
protein 4.1 - connects spectrin to actin
ankyrin - connects spectrin to band 3 transport PRO
hemoglobin
about 1/3 of RBC weight, globular chromoprotein
globular PRO that is responsible for cytoplasmic viscosity and eosinophilia of RBC
Sickle cell anemia mutation
changes glu –> val in DNA coding for B-chain of adult Hb
HbS
hemoglobin in sickle cell anemia
-insoluble at low O2 tension and crystallizes out
RBC of sickle cell anemia
inflexibility and reduced life span can lead to anemia (low Hb)
increased blood viscosity can lead to ischemia (reduced blood supply)
RBC life span
120 days, removed from circulation by macrophages in spleen, liver, bone marrow
reticulocytes
NOT RETICULAR CELLS (those make collagen III)
young RBCs with some rRNA in cytoplasm, stained by brilliant cresyl blue
- about 1% of circulating RBC, so can be used as rough estimate of rate of erythropoiesis
- help monitor anemia, bone marrow regeneration, and hematopoetic restoration after therapy
percentages of leukocytes in a normal person
neutrophils: 60-70%
euosinophils: 2-4%
basophils: <1%
lymphocytes: 20-30%
monocyte/macrophages: 3-8%
diapedesis
used to think was paracellular movement (between cells), but found to be transcellular (through cells)
neutrophils (structure/contents)
2-5 lobes of same nucleus, connected by bridges, all heterochromatic
- no nucleoli
- salmon pink cytoplasm due to 80% specific granules (small), with few mitochondria, small Golgi, poorly developed RER, few ribosomes, some glycogen
- 20% azurophilic granules (large, from primary lysosomes)
neutrophil specific granule contents
work together for phagocytosis
lysozyme - hydrolyzes glycosides in bacterial cell wall
lactoferrin - binds Fe
alkaline phosphatase, collagenase
neutrophil azurophilic granule contents
menu of hydrolytic enzymes (from primary lysosomes) to hydrolyze dead bacteria
- myeloperoxidase and lactoferrin - within microvesicles, have antibacterial activity
- create cytokines
neutrophil respiratory burst
uses up O2 to form superoxide anions to kill bacteria
neutrophil netosis
release of mesh-like structure capable of trapping microbes
eosinophil
bilobed nucleus with only large specific (eosinophilic) granules w/ crystalline core (w/ major basic PRO)
-same size as neutrophils
eosinophil specific granule contents
acid phosphatase, arylsulfatase, B-glucuronidase, cathespin, phospholipase, RNAase, eosinophilic peroxidase, major basic PRO, histaminase, eosinophil cationic PRO, eosinophil-derived neurotoxin
eosinophil function
- kill parasitic worm larvae (major basic PRO)
- phagocytosis of Ag-Ab complexes (via hydrolytic enzymes)
- inactive mediators of inflammation (histamine, SRS-A)
- make lipid mediators of inflammation (leukotrienes)
- -do one or the other depending on situation
- produce cytokines (ILs) to promote self-survival, enhance activity, and act on immune system
- play role in asthma (infiltrate bronchial mucosa for bronchoconstriction, excess mucus secretion, inflammation, and airway remodeling (hyper-responsiveness)
basophils
less nuclear segmentation, and obscured by azurophilic granules
- same size as neutrophils
- lamellar/spherical substructure
basophil specific granule contents
eosinophilic chemotactic factor, heparin, histamine, peroxidase, slow-reacting substance of anaphylaxis (SRS-A)
basophil function
- inflammation (generalized response)
- immediate hypersensitivity reactions (localized/wide spread, mediated by IgE)
- delayed hypersensitivity reactions (take 12-18 hours to develop, if chemicals or ticks)
relationship between basophils and mast cells
they are different, but share characteristics
-rapid degranulation of basophils and mast cells may occur at the same type (localized or widepsread/anaphylactic shock)
relationship between basophils and eosinophils
accumulate at same site
granular leukocytes
have specific cytoplasmic granules, and sometimes azurophilic granules
-neutrophils, eosinophils, basophils
agranular leukocytes
lack specific cytoplasmic granules, but may have others
-lymphocytes, monocytes
lymphocyte sizes
small, large agranular, large granular (natural killers)
small/medium lymphocytes
the same size as RBC
- round heterochromatic nucleus
- pale blue cytoplasm
- most frequent size class in peripheral blood
large agranular lymphocytes
larger than RBC
- larger, less heterochromatic nucleus
- cytoplasm has more organelles
- have been activated by specific antigens
large granular lymphocytes
Natural Killer cells - have large azurophilic cytoplasmic granules
5-10% circulating lymphocytes
-no B/T cell surface molecules
3 functional classes of lymphocytes
T lymphocytes
B lymphocytes
Null cells (NK cells)
B lymphocytes
10-15% of circulating lymphocytes
- Ag receptors are Igs
- differentiate into plasma cells (via mitosis) to make Ab (humoral immunity), or memory cells (adaptive immunity)
T lymphocytes
70-80% of circulating lymphocytes
- receptors are not Igs, but require APCs to activate
- activated T cells differentiate into CD8, CD4, or regulator T cells
CD8
cytotoxic T cells
-involved in cell mediated immunity via perforin (lyse target cells) and granzymes (induce apoptosis)
CD4
helper T cells
regulator T cells
suppress response of other leukocytes to foreign antigens and self antigens (if autoimmune)
-may block antitumor responses of CD8
functions of natural killer cells
killing of virus-infected cells or malignant cells (without prior sensitization)
produce cytokines (like IFN-y) to influence host’s immune response
-T-cell polarization, maturation of dendritic cells
monocyte
largest leukocyte with variably shaped nuclei (more euchromatic)
- abundant cytoplasm w/ full complement of organelles, small azurophilic granules, vacuoles
- nucleolus present
lifespan of monocyte
circulate for about 3 days, leave blood, and transform into histiocytes
monocyte functions
- phagocytosis of bacteria/tissue debris
- Ag presentation
- fusion to form osteoclasts
- formation of giant cells if chronic inflammation
- produce cytokines for hematopoisis regulation
- immune surveillance of endothelial cells (patrolling)
platelets
small, non-nucleated cytoplasmic fragments
- made by megakaryocytes, so has functional mRNAs
- usually 250,000/ul, and live for 10 days before apoptosis
functions of blood platelets
- seal off breaks in blood vessels
- role in blood coagulation (provide surface and make factors 8/9)
- maintain competence (integrity) of endothelium
- may be related to arthritis, and inhibition of angiogenesis
non-PRO plasma components
electrolytes N-substances (urea, uric acid, creatine, creatinine, ammonium salts) nutrients (GLU, lipids, AA) blood gases (O2, CO2, N2) regulatory substances (hormones/enzymes)
HbA1
major form of Hb in adults (95%)
-2 alpha chains + 2 beta chains
HbA2
minor form of Hb in adults (5%)
-2 alpha chains + 2 delta chains
HbF
made in intrauterine period
-2 alpha chains + 2 gamma chains
oxyhemoglobin
RBC carrying O2 from pulmonary alveoli to tissues
carbaminohemoglobin
RBC carrying CO2 from tissues to pulmonary alveoli
neutrophil functions
- main function is phagocytosis and bacterial killing via cell motility and chemotaxis
- specific granules fuse with phagosome, so lysozome/lactoferrin can kill bacterium
- azurophilic granules fuse with phagosome to make secondary lysosome, so enzymes hydrolyze dead bacterium
