Blood = specialized connective Blood = specialized connective tissuetissue
Cells = 45% of bloodCells = 45% of blood– Erythrocytes (red blood cells, RBCs)Erythrocytes (red blood cells, RBCs)– Leukocytes (white blood cells, WBCs)Leukocytes (white blood cells, WBCs)– Platelets (cell fragments)Platelets (cell fragments)
Plasma = 55% of bloodPlasma = 55% of blood
- extracellular matrix of blood;- extracellular matrix of blood;
5-6 Liters total blood volume in adult 5-6 Liters total blood volume in adult
Functions of BloodFunctions of Blood
Gaseous transport – RBCs carry Gaseous transport – RBCs carry oxygen and carbon dioxideoxygen and carbon dioxide
Transport of metabolites and Transport of metabolites and regulatory molecules (hormones)regulatory molecules (hormones)
Homeostatic regulation of body Homeostatic regulation of body temperature, osmotic balancetemperature, osmotic balance
Transport of cells and antibodies for Transport of cells and antibodies for defense and immunitydefense and immunity
Erythrocytes (red blood cells)Erythrocytes (red blood cells)
- Most numerous blood cells
-Transport O2 and CO2 via hemoglobin
- No nucleus, mitochondria, ER, ribosomes in mature RBCs. All expelled during development.
120-day life span; destroyed by macrophages in spleen and bone marrow.
- The only cell in blood stream that remains in blood stream
ErythrocytesErythrocytes
Biconcave disk shape provides large Biconcave disk shape provides large surface area relative to volume; good for surface area relative to volume; good for gas exchangegas exchange
Shape maintained by bendable Shape maintained by bendable cytoskeletoncytoskeleton
Normal adult RBC
Sickle cell anemia
No mitochondria.Energy needs met by anaerobic fermentation
Red Blood Cell Physiology
Hematocrit - % of whole blood volume that is RBCs
men: 42 – 52%women: 37 – 48%
Typical RBC count:men: 4.6 – 6.2 million/mm3
women: 4.2 – 5.4 million/mm3
Erythrocyte Membrane Organization
Antiporter: Cl- in;HCO3- out
Structure of Hemoglobin (HbA)
Typical Hb concentrations:
men: 13 - 18 g/dLwomen: 12 – 16 g/dL
The Life and Death ofEryhrocytes
Correction of Hypoxemia by a Negative Feedback Loop
Sickle Cell Anemia (HbS)Inherited
Point mutation in gene for Hb -chain
Deoxygenated HbS rigid, fragile RBCs anemia
Increases blood viscosity
RelativeRelative Sizes of Blood Cells Compared Sizes of Blood Cells Compared to RBCs (7-8 to RBCs (7-8 m diameter)m diameter)
Leukocytes (White Blood Leukocytes (White Blood Cells)Cells)
Neutrophil Eosinophil Basophil Monocyte Lymphocyte
Granulocytes Agranulocytes
- Numerous secretory vesicles in Numerous secretory vesicles in cytoplasmcytoplasm
- Nucleus has 2 or more lobes- Nucleus has 2 or more lobes
- Do NOT have Do NOT have abundant abundant secretory vesiclessecretory vesicles
- Single-lobed Single-lobed nucleusnucleus
Neutrophils: 60-70% of circulating Neutrophils: 60-70% of circulating leukocytesleukocytes
Nucleus has 3-5 lobesNucleus has 3-5 lobes
Phagocytosis & destruction of bacteriaPhagocytosis & destruction of bacteria
Motile: exit the blood stream early Motile: exit the blood stream early in response to bacterial infections.in response to bacterial infections.
Granules contain lysozyme and other antimicrobial Granules contain lysozyme and other antimicrobial enzymes, collagenase plus others.enzymes, collagenase plus others.
In females, the nucleus has a drumstick (Barr body), In females, the nucleus has a drumstick (Barr body), contains the condensed, inactivated second X contains the condensed, inactivated second X chromosome.chromosome.
Eosinophils: 2-4% of circulating Eosinophils: 2-4% of circulating leukocytesleukocytes
bi-lobed nucleusbi-lobed nucleus
Eosinophilic granules (red/pink)Eosinophilic granules (red/pink) contain histaminasecontain histaminase
AllergicAllergic & inflammatory reactions & inflammatory reactions and and parasitic infectionsparasitic infections
Counteract the effects of basophils in allergic reactionsCounteract the effects of basophils in allergic reactions
Often found at sites of chronic inflammation, Often found at sites of chronic inflammation, commonly in respiratory or digestives tractscommonly in respiratory or digestives tracts
Basophils: <1% of circulating Basophils: <1% of circulating leukocytesleukocytes
Bilobed nucleusBilobed nucleus
Basophilic granules (blue/black) Basophilic granules (blue/black) obscure the nucleusobscure the nucleus
Secrete Secrete histaminehistamine (vasodilation) (vasodilation) and and heparinheparin (anti-coagulant) (anti-coagulant)
Involved in allergic and inflammatory reactionsInvolved in allergic and inflammatory reactions
Lymphocytes: 20-25% of circulating Lymphocytes: 20-25% of circulating leukoctyesleukoctyes
Agranulocyte Agranulocyte
Variable in size, 6-18 Variable in size, 6-18 m in diameterm in diameter
Single, round, heterochromatic nucleusSingle, round, heterochromatic nucleus
Function in immunityFunction in immunity 2 classes, indistinguishable morphologically2 classes, indistinguishable morphologically
– B cells: produce antibodiesB cells: produce antibodies– T cells: mature in thymus, cell-mediated immune T cells: mature in thymus, cell-mediated immune
responseresponse
Monocytes: 3-8% of circulating Monocytes: 3-8% of circulating leukocytesleukocytes
Agranulocyte Agranulocyte
Largest circulating WBCLargest circulating WBC
Large indented nucleusLarge indented nucleus
Stay in circulation a few daysStay in circulation a few days then migrate into the tissues and differentiate into then migrate into the tissues and differentiate into
macrophagesmacrophages
As macrophages, phagocytize and destroy dead As macrophages, phagocytize and destroy dead cellscells
Platelets (Thrombocytes)Platelets (Thrombocytes) Anucleated cell fragmentsAnucleated cell fragments 2 2 m diameter m diameter 10-day life span10-day life span Main function: blood Main function: blood
clottingclotting
Produced by Produced by megakaryocytes megakaryocytes
in bone marrow: bud off in bone marrow: bud off
cytoplasm to form platelets.cytoplasm to form platelets.Bone marrow capillary
Platelets
Differential White Blood Cell Differential White Blood Cell Count:Count:
Neutrophils > Eosinophils > Basophils Monocytes >Lymphocytes >
Never Let Monkeys Eat Bananas