Chapter 19: Blood
● Cardiovascular system components
○ Blood, heart and blood vessels
○ Hermatology: study of blood, tissues and blood disorders
○ Two fluids that obtain Oxygen and eliminate CO2
■ Blood: liquid CT that consists of cells surrounded by a liquid extracellular
matrix
■ Interstititial fluid: bathes body cells
● Functions:
○ Transportation: O2 to the lungs to cells of the body and CO2 from body cells to
the lungs
■ Transports heat and waste products to various organs
■ Transport respiratory gases, nutrients, hormones to and from body cells
○ Regulate body pH and temperature, provide protection to maintain homeostasis
■ Use buffers to convert strong acids/bases to weak ones
○ Protection: can clot to protect excessive loss
■ White blood cells can do phagocytosis
● By blood proteins, antibodies, interferons, and complements
● Characteristics:
○ More viscous than water
○ Temperature: 38 degree Celsius
○ pH; 7.35-7.45
○ 20% of extracellular fluid
○ Volume: 5 to 6 liters (45% cells 55% plasma)
○ Hormones ensure homeostasis in volume and osmotic pressure (e.g.:
aldosterone, antidiuretic hormone, atrial natriuretic peptide)
● Components:
, ○ If seated for a long period of time, cellular portion will precipitate out of the
solution and form a heavy sediment below the liquid plasma.
○ RBC (40-45% in volume) - hematocrit -> 4-6 x 10^5/mm^3
■ Females: 42%, Males: 47% due to testosterone)
■ Anemia: low RBCs count
■ Polycthemia: rly high count -> raises viscosity of blood -> increase
resistance to flow -> high blood pressure and risk of stroke
● Causes: increase in RBC production, tissue hypoxia, blood
doping, use of EPO.
○ Megakaryocytes are cells that splinter into 2000-3000 fragments while still in the
red bone marrow
■ These fragments are platelets (irregularly shaped disc with many vesicles
but no nucleus)
○ Blood proteins are usually confined in plasma proteins that are synthesized by
hepatocytes
● Hemopoeisis: process by which formed elements of blood is developed
○ Occurs in yolk sac -> liver, spleen, thymus, lymph nodes -> red bone marrow
■ Red bone marrow is a highly vascularized CT
■ 0.05-0.1% of red bone marrow cells are pluripotent stem cells
(hemocytoblasts)
■ Formed elements do not divide like lymphocytes once they leave the red
bone marrow
○ Process:
■ Stem cells can differentiate into cells that can be used as a source of
bone, cartilage, organ replacements…
■ It starts with a cell called a proerythroblast -> divides to produce cells that
synthesize hemoglobin until it becomes a reticulocyte
● Loss of the nucleus causes the center to indent -> dat shape!
● Reticulocytes retain some mitochondria, ribosomes, and ER
■ Reticular cells produce reticular fibers that form the stroma to support red
bone marrow cells
■ Blood from nutrient and metaphyseal arteries enters a bone and passes
into sinuses
■ After blood cells form, hey enter the sinuses and other blood vessels and
leave the bone through nutrient and periosteal veins
○ Stem cells:
■ Myeloid stem cells: give rise to red blood cells, platelets, monocytes…
Sometimes differentiate into progenitor cells, some known as colony-
forming units.
■ Lymphoid stem cells: give rise to lymphocytes, NK
■ Blast cells are precursor cells (monoblasts -> monocytes)
○ Hemopoietic growth factors
■ Erynthropoietin: RBCs
● Produced by cells in kidneys
, ■ Thrombopoietin: formation of platelets and megakaryocytes
● Produced by liver
■ Cytokines: small glycoproteins that act as local hormones that stimulate
proliferation of progenitor cells
● Produced by red bone marrow cells, leukocytes, macrophages,
fibroblasts
● Two families that stimulate white blood cell formation are colony-
stimulating factors (CSFs) and interleukins
● WHY RBC?
○ Their biconcave shape allows them to have a high oxygen carrying capacity and
allow them to deform and fit in small capillary beds
○ They also lack a mitochondria so they don’t have to use any of the oxygen they
carry
○ Plasma membrane is strong and flexible -> deform
○ Lack nucleus and organelles -> no need for metabolic activities
○ Each RBC contains ~280 million hemoglobin molecules
■ A hemoglobin molecule consists of a globin composed of 4 polypeptide
chains (2 alpha and 2 beta) and a heme
■ Center of each heme is an iron ion that can combine with one oxygen
molecule
● Hemoglobin can bind to 4 O2 molecules
● Also transport 23% of the total CO2
● Hemoglobin:
○ Transports Oxygen and Carbon Dioxide
○ Regulate blood flow and blood pressure
■ Nitric Oxide - a gaseous hormone that line blood vessels - binds to
hemoglobin and gets released -> promotes vasodilation (increase in
blood vessel diameter) -> improve in blood in flo and enhance oxygen
delivery to cells
○ Red blood cells also contain carbonic anhydrase which convert CO2 to H2O to
carbonic acid, which in turn dissociated into H+ and HCO3-.
■ This reaction is good because 1) it allows 70% of CO2 to be transported
in blood plasma from tissue cells to the lungs in the form of HCO2-, 2)
serves an important buffer in extracellular fluid
, ● Hypoxia: occur when little oxygen enters the blood; oxygen delivery may also fall due to
anemia (lack of iron, lack of amino acids, lack of vitamin B)
○ Stimulates the kidneys to release erythropoietin to speed up proerythroblasts ->
reticulocytes.
● White blood cells:
● WBCs and other cells have proteins called major histocompatibility antigens
● Leukocytes: can live for a few days
○ Leukocytosis: increase in the number of WBCs above 10,000/microliter
■ Protective response to stress such as infection, exercise, anesthesia,
surgery
○ Leukopenia: abnormally low WBC counts
■ Can be caused by radiation, shock and other chemotherapeutic agents
○ Emigration of WBCs
■ Also called diapedesis) where they roll around the endothelium, stick to it
and then squeeze between endothelial cells
■ Adhesion molecules help WBCs stick to the endothelium
● E.g.: selectins in endothelial cells that stick to carbohydrates;
● Cardiovascular system components
○ Blood, heart and blood vessels
○ Hermatology: study of blood, tissues and blood disorders
○ Two fluids that obtain Oxygen and eliminate CO2
■ Blood: liquid CT that consists of cells surrounded by a liquid extracellular
matrix
■ Interstititial fluid: bathes body cells
● Functions:
○ Transportation: O2 to the lungs to cells of the body and CO2 from body cells to
the lungs
■ Transports heat and waste products to various organs
■ Transport respiratory gases, nutrients, hormones to and from body cells
○ Regulate body pH and temperature, provide protection to maintain homeostasis
■ Use buffers to convert strong acids/bases to weak ones
○ Protection: can clot to protect excessive loss
■ White blood cells can do phagocytosis
● By blood proteins, antibodies, interferons, and complements
● Characteristics:
○ More viscous than water
○ Temperature: 38 degree Celsius
○ pH; 7.35-7.45
○ 20% of extracellular fluid
○ Volume: 5 to 6 liters (45% cells 55% plasma)
○ Hormones ensure homeostasis in volume and osmotic pressure (e.g.:
aldosterone, antidiuretic hormone, atrial natriuretic peptide)
● Components:
, ○ If seated for a long period of time, cellular portion will precipitate out of the
solution and form a heavy sediment below the liquid plasma.
○ RBC (40-45% in volume) - hematocrit -> 4-6 x 10^5/mm^3
■ Females: 42%, Males: 47% due to testosterone)
■ Anemia: low RBCs count
■ Polycthemia: rly high count -> raises viscosity of blood -> increase
resistance to flow -> high blood pressure and risk of stroke
● Causes: increase in RBC production, tissue hypoxia, blood
doping, use of EPO.
○ Megakaryocytes are cells that splinter into 2000-3000 fragments while still in the
red bone marrow
■ These fragments are platelets (irregularly shaped disc with many vesicles
but no nucleus)
○ Blood proteins are usually confined in plasma proteins that are synthesized by
hepatocytes
● Hemopoeisis: process by which formed elements of blood is developed
○ Occurs in yolk sac -> liver, spleen, thymus, lymph nodes -> red bone marrow
■ Red bone marrow is a highly vascularized CT
■ 0.05-0.1% of red bone marrow cells are pluripotent stem cells
(hemocytoblasts)
■ Formed elements do not divide like lymphocytes once they leave the red
bone marrow
○ Process:
■ Stem cells can differentiate into cells that can be used as a source of
bone, cartilage, organ replacements…
■ It starts with a cell called a proerythroblast -> divides to produce cells that
synthesize hemoglobin until it becomes a reticulocyte
● Loss of the nucleus causes the center to indent -> dat shape!
● Reticulocytes retain some mitochondria, ribosomes, and ER
■ Reticular cells produce reticular fibers that form the stroma to support red
bone marrow cells
■ Blood from nutrient and metaphyseal arteries enters a bone and passes
into sinuses
■ After blood cells form, hey enter the sinuses and other blood vessels and
leave the bone through nutrient and periosteal veins
○ Stem cells:
■ Myeloid stem cells: give rise to red blood cells, platelets, monocytes…
Sometimes differentiate into progenitor cells, some known as colony-
forming units.
■ Lymphoid stem cells: give rise to lymphocytes, NK
■ Blast cells are precursor cells (monoblasts -> monocytes)
○ Hemopoietic growth factors
■ Erynthropoietin: RBCs
● Produced by cells in kidneys
, ■ Thrombopoietin: formation of platelets and megakaryocytes
● Produced by liver
■ Cytokines: small glycoproteins that act as local hormones that stimulate
proliferation of progenitor cells
● Produced by red bone marrow cells, leukocytes, macrophages,
fibroblasts
● Two families that stimulate white blood cell formation are colony-
stimulating factors (CSFs) and interleukins
● WHY RBC?
○ Their biconcave shape allows them to have a high oxygen carrying capacity and
allow them to deform and fit in small capillary beds
○ They also lack a mitochondria so they don’t have to use any of the oxygen they
carry
○ Plasma membrane is strong and flexible -> deform
○ Lack nucleus and organelles -> no need for metabolic activities
○ Each RBC contains ~280 million hemoglobin molecules
■ A hemoglobin molecule consists of a globin composed of 4 polypeptide
chains (2 alpha and 2 beta) and a heme
■ Center of each heme is an iron ion that can combine with one oxygen
molecule
● Hemoglobin can bind to 4 O2 molecules
● Also transport 23% of the total CO2
● Hemoglobin:
○ Transports Oxygen and Carbon Dioxide
○ Regulate blood flow and blood pressure
■ Nitric Oxide - a gaseous hormone that line blood vessels - binds to
hemoglobin and gets released -> promotes vasodilation (increase in
blood vessel diameter) -> improve in blood in flo and enhance oxygen
delivery to cells
○ Red blood cells also contain carbonic anhydrase which convert CO2 to H2O to
carbonic acid, which in turn dissociated into H+ and HCO3-.
■ This reaction is good because 1) it allows 70% of CO2 to be transported
in blood plasma from tissue cells to the lungs in the form of HCO2-, 2)
serves an important buffer in extracellular fluid
, ● Hypoxia: occur when little oxygen enters the blood; oxygen delivery may also fall due to
anemia (lack of iron, lack of amino acids, lack of vitamin B)
○ Stimulates the kidneys to release erythropoietin to speed up proerythroblasts ->
reticulocytes.
● White blood cells:
● WBCs and other cells have proteins called major histocompatibility antigens
● Leukocytes: can live for a few days
○ Leukocytosis: increase in the number of WBCs above 10,000/microliter
■ Protective response to stress such as infection, exercise, anesthesia,
surgery
○ Leukopenia: abnormally low WBC counts
■ Can be caused by radiation, shock and other chemotherapeutic agents
○ Emigration of WBCs
■ Also called diapedesis) where they roll around the endothelium, stick to it
and then squeeze between endothelial cells
■ Adhesion molecules help WBCs stick to the endothelium
● E.g.: selectins in endothelial cells that stick to carbohydrates;
