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Flashcards in this deck (261)

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  • What is blood primarily composed of?


    • Cells
    • Plasma (extracellular fluid)
  • What are the formed elements in blood?


    • Erythrocytes (red blood cells)
    • Leukocytes (white blood cells)
    • Platelets
  • What happens when blood leaves the circulatory system?


    Plasma proteins react to form a clot including formed elements and serum.

  • What is serum?


    A pale yellow liquid containing growth factors and proteins released during clot formation.

  • What is the hematocrit?


    The volume of erythrocytes in blood, normally about 44% in healthy adults.

  • What is the composition of plasma?


    An aqueous solution with a pH of 7.4, containing proteins, nutrients, gases, waste products, hormones, and electrolytes.

  • What are the main plasma proteins?


    • Albumin
    • Globulins (α- and β-globulins)
  • What is the role of albumin in blood?


    Maintains the osmotic pressure of the blood.

  • What is the role of globulins?


    Includes transport factors like transferrin and plays a role in coagulation.

  • What is the primary function of leukocytes?


    Act as the body's chief defense against infection.

  • How do leukocytes respond to infection?


    They become motile, cross venule walls, and migrate into tissues.

  • What substances does blood transport?


    • O2
    • CO2
    • Nutrients
    • Hormones
  • What is the significance of blood in body temperature regulation?


    Blood participates in heat distribution and maintaining body temperature.

  • What is the role of blood in acid-base balance?


    Helps maintain the acid-base and osmotic balance in the body.

  • What is the composition of plasma?


    • 7% of plasma volume is made up of substances.
    • Includes plasma proteins, nutrients, gases, waste, hormones, and electrolytes.
  • What is the normal hematocrit in healthy adults?


    About 44% of total blood volume is erythrocytes.

  • What is the function of blood?


    • Transports O2, CO2, hormones, and nutrients.
    • Participates in heat distribution and acid-base balance.
  • What are the major plasma proteins?


    • Albumin: maintains osmotic pressure.
    • Globulins: transport factors and coagulation proteins.
  • What is the role of leukocytes?


    Leukocytes are the body's defense against infection, migrating to sites of infection when activated.

  • What happens to blood when it leaves the circulatory system?


    Plasma proteins react to form a clot, including formed elements and serum.

  • What is the pH of plasma?


    The pH of plasma is approximately 7.4.

  • How is blood separated by centrifugation?


    Blood can be separated into layers: erythrocytes, plasma, and a buffy coat of leukocytes and platelets.

  • What is the composition of whole blood?


    • Erythrocytes: 44%
    • Plasma: 55%
    • Proteins: 7%
    • Water: 92%
    • Other solutes: 1%
  • What are the main components of plasma?


    • Albumins: 58%
    • Globulins: 37%
    • Fibrinogen: 4%
    • Regulatory proteins: <1%
  • What is the normal range of erythrocytes in blood?


    4.2-6.2 million per cubic mm

  • What is the normal range of leukocytes in blood?


    4.5-11 thousand per cubic mm

  • What is the normal range of platelets in blood?


    150-400 thousand per cubic mm

  • What is the buffy coat?


    A thin layer of leukocytes and platelets between erythrocytes and plasma.

  • What happens to blood after centrifugation?


    Erythrocytes settle at the bottom, forming hematocrit; plasma remains on top.

  • What is the O2 pressure in blood?


    Highest in arteries and lung capillaries; decreases in tissue capillaries.

  • What is fibrinogen?


    A plasma protein that polymerizes during clotting to form fibrin, blocking blood loss.

  • What are the types of leukocytes?


    • Neutrophils: 50%-70%
    • Lymphocytes: 20%-40%
    • Monocytes: 2%-8%
    • Eosinophils: 1%-4%
    • Basophils: 0.5%-1%
  • What is the function of fibrin in blood?


    • Forms insoluble, cross-linked fibers
    • Blocks blood loss from small vessels
  • What role do complement proteins play in the body?


    • Important in inflammation
    • Help destroy microorganisms
  • How are blood cells observed histologically?


    • Spread a drop of blood on a slide
    • Stained with acidic (eosin) and basic (methylene blue) dyes
  • What are azurophilic granules?


    • Produce metachromasia in leukocytes
    • Stain cytoplasmic granules containing charged proteins
  • What are the characteristics of erythrocytes?


    • Terminally differentiated
    • Lack nuclei
    • Filled with hemoglobin
  • What is anemia?


    • Condition of low erythrocyte concentration
    • Symptoms include lethargy, fatigue, shortness of breath
  • What is sickle cell anemia caused by?


    • Homozygous mutation in hemoglobin
    • Causes RBCs to become deformed and rigid
  • What is erythrocytosis?


    • Increased concentration of erythrocytes
    • Can occur in high altitudes due to low O2 tension
  • What is the primary component of plasma?


    • Water (~92% of plasma)
    • Acts as a solvent for formed elements and solutes
  • What is the function of albumin in plasma?


    • Retains fluid in microvasculature
    • Contributes to blood viscosity
  • What do globulins do in the bloodstream?


    • α-Globulins transport lipids
    • β-Globulins transport iron
    • γ-Globulins are antibodies
  • What is the role of fibrinogen?


    • Precursor of fibrin
    • Participates in blood coagulation (clotting)
  • What are the other solutes found in blood plasma?


    • Electrolytes, nutrients, respiratory gases, wastes
  • What is the importance of electrolytes in blood plasma?


    • Establish and maintain membrane potentials
    • Maintain pH balance
  • What is the function of nutrients in blood plasma?


    • Energy source
    • Precursors for synthesizing other molecules
  • How is oxygen transported in the blood?


    • <blockquote>

      2% dissolved in plasma

      </blockquote>
    • 98% bound to hemoglobin in erythrocytes
  • How is carbon dioxide transported in the blood?


    • ~7% dissolved in plasma
    • ~66% converted to bicarbonate (HCO3−)
  • What are wastes in blood plasma?


    • Breakdown products of metabolism
    • Serve no function, just being transported
  • What are waste products in blood plasma?


    • Lactic acid
    • Creatinine
    • Urea
    • Bilirubin
    • Ammonia
  • What is the composition of blood plasma?


    • Water (~92%)
    • Plasma proteins (~7%)
    • Other solutes (~1%)
  • What are the functions of blood plasma?


    • Solvent for formed elements
    • Buffers pH changes
    • Retains fluid in microvasculature
    • Contributes to blood viscosity
  • What are the types of globulins?


    • a-Globulins: transport lipids
    • b-Globulins: transport iron ions
    • y-Globulins: antibodies
  • What is the role of fibrinogen in blood?


    Precursor of fibrin, essential for blood clotting.

  • What is the significance of oxygen in blood?


    Needed for aerobic cellular respiration; 98% is bound to hemoglobin.

  • How are blood cells studied histologically?


    By preparing smears from blood drops on microscope slides.

  • What stains are used for blood smears?


    • Eosin (acidic)
    • Methylene blue (basic)
    • Giemsa
    • Wright stain
  • What are erythrocytes?


    Terminally differentiated red blood cells filled with hemoglobin, lacking nuclei.

  • What are the symptoms of anemia?


    • Lethargy
    • Shortness of breath
    • Fatigue
    • Skin pallor
    • Heart palpitations
  • What causes sickle cell anemia?


    Homozygous mutation causing an amino acid substitution in hemoglobin.

  • What can cause erythrocytosis?


    Physiologic adaptation in high altitudes where O2 tension is low.

  • What is the normal concentration of erythrocytes in women?


    Approximately 3.9-5.5 million per microliter (μL).

  • What is the normal concentration of erythrocytes in men?


    Approximately 4.1-6.0 million per microliter (μL).

  • What is the shape of human erythrocytes?


    Flexible biconcave discs.

  • What is the diameter of a human erythrocyte?


    Approximately 7.5 μm.

  • Why is the biconcave shape of erythrocytes important?


    Provides a large surface-to-volume ratio and facilitates gas exchange.

  • What is the composition of the erythrocyte plasmalemma?


    About 40% lipid, 10% carbohydrate, and 50% protein.

  • What is rouleaux?


    Stacks of erythrocytes that may adhere loosely in larger blood vessels.

  • What is the composition of the erythrocyte plasmalemma?


    • 40% lipid
    • 10% carbohydrate
    • 50% protein
  • What types of proteins are predominant in the erythrocyte membrane?


    • Integral membrane proteins
    • Peripheral proteins
  • What is the function of spectrin in erythrocytes?


    Stabilizes the membrane and maintains cell shape.

  • What is the primary function of hemoglobin in erythrocytes?


    Carries O2 and CO2 in the blood.

  • What happens to erythrocytes after 120 days in circulation?


    They are recognized and removed by macrophages due to membrane defects.

  • What are the two major groups of leukocytes?


    • Granulocytes
    • Agranulocytes
  • What characterizes granulocytes?


    Possess abundant cytoplasmic granules and polymorphic nuclei.

  • What are the three types of granulocytes?


    • Neutrophils
    • Eosinophils
    • Basophils
  • What is a key feature of agranulocytes?


    Lack specific granules but contain some azurophilic granules.

  • What are the two types of agranulocytes?


    • Lymphocytes
    • Monocytes
  • What is the role of leukocytes in the body?


    Defense against invading microorganisms.

  • What triggers the loosening of intercellular junctions in endothelial cells?


    Cytokines released from various sources

  • What protein appears on endothelial cells after exocytosis?


    P-selectin

  • How do leukocytes interact with P-selectin?


    They display glycosylated ligands, causing them to slow down and roll

  • What is diapedesis?


    Process where leukocytes migrate out of venules into surrounding tissue

  • What is chemotaxis in relation to neutrophils?


    Chemical mediators attract neutrophils to bacteria, causing rapid accumulation

  • What is the normal range of leukocytes in healthy adults?


    4500-11,000 leukocytes per microliter of blood

  • What percentage of circulating leukocytes do mature neutrophils constitute?


    50%-70%

  • What is the composition of the erythrocyte plasmalemma?


    • 40% lipid
    • 10% carbohydrate
    • 50% protein
  • What proteins are included in the erythrocyte membrane?


    • Integral membrane proteins
    • Ion channels
    • Band 3 protein
    • Glycophorin A
  • How do erythrocytes transport oxygen and carbon dioxide?


    Through hemoglobin forming oxyhemoglobin and carbaminohemoglobin

  • What is the typical lifespan of human erythrocytes?


    About 120 days

  • How do erythrocytes generate energy?


    Through anaerobic glycolysis

  • What happens to erythrocytes before being released into circulation?


    They undergo terminal differentiation, losing nucleus and organelles

  • What is the average lifespan of human erythrocytes in circulation?


    120 days

  • What happens to senescent RBCs?


    They are removed by macrophages in the spleen, liver, and bone marrow.

  • What is the life span of granulocytes?


    Only a few days.

  • What is the primary energy source for granulocytes?


    They depend largely on glycolysis.

  • What distinguishes agranulocytes from granulocytes?


    Agranulocytes lack specific granules but contain some azurophilic granules.

  • What are the two main types of agranulocytes?


    • Lymphocytes
    • Monocytes
  • What triggers the migration of leukocytes to tissues?


    Factors called cytokines are released.

  • What is the process called when leukocytes exit blood vessels?


    Diapedesis.

  • What is chemotaxis?


    It is the attraction of leukocytes to bacteria via chemical mediators.

  • What is the normal range of leukocytes in healthy adults?


    4500-11,000 per microliter of blood.

  • What is the normal range of leukocytes in healthy adults?


    4500-11,000 leukocytes per microliter of blood

  • What percentage of circulating leukocytes are neutrophils?


    50-70%

  • What are the major functions of neutrophils?


    • Kill and phagocytose bacteria
  • What is the life span of mature neutrophils?


    1-4 days

  • How do eosinophils function in the immune response?


    • Kill helminthic and other parasites
    • Modulate local inflammation
  • What is the role of basophils in the immune system?


    • Modulate inflammation
    • Release histamine during allergy
  • What is the primary function of lymphocytes?


    E

  • What is the life span of monocytes?


    Hours to years

  • What are granulocytes?


    • Neutrophils
    • Eosinophils
    • Basophils
  • What are agranulocytes?


    • Lymphocytes
    • Monocytes
  • What are the characteristics of neutrophil nuclei?


    3-5 lobes

  • What is the color of neutrophil granules?


    Faint/light pink

  • What happens to neutrophils in an anaerobic environment?


    They can kill bacteria and help clean up debris

  • What is the half-life of neutrophils in blood?


    6-8 hours

  • How do neutrophils engulf bacteria?


    By pseudopodia and internalizing them in phagosomes

  • What is a key role of activated neutrophils in the inflammatory response?


    Release chemokines to attract other leukocytes

  • What is the role of specific secondary granules in neutrophils?


    Secretion of ECM-degrading enzymes and bactericidal proteins

  • What is the lifespan of neutrophils in connective tissues?


    1-4 days before undergoing apoptosis

  • What do neutrophils do to bacteria?


    Engulf bacteria using pseudopodia and internalize them in phagosomes

  • What happens to phagosomes after bacteria are engulfed?


    Specific granules fuse and discharge contents into phagosomes, which are then acidified

  • What is produced during the burst of O2 consumption in neutrophils?


    Superoxide anions (O2–) and hydrogen peroxide (H2O2)

  • What is the role of myeloperoxidase (MPO) in neutrophils?


    Generates hypochlorite and other toxic agents to bacteria

  • What is the function of lysozyme in neutrophils?


    Degrades components of bacterial cell walls

  • What are defensins?


    Small cysteine-rich proteins that disrupt cell membranes of bacteria

  • What is the diameter of neutrophils in blood smears?


    12-15 μm

  • What is a characteristic of neutrophil nuclei?


    Two to five lobes linked by thin nuclear extensions

  • What happens to neutrophils during diapedesis?


    Become amoeboid and highly active

  • What are azurophilic granules?


    Large dense vesicles in neutrophils that kill and degrade microorganisms

  • What can a single nucleotide substitution in the hemoglobin gene cause?


    Sickle cell disease due to polymerization of hemoglobin

  • What are features of sickle cell disease?


    Greater blood viscosity and poor microvascular circulation

  • What is the role of neutrophils during diapedesis?


    Neutrophils become amoeboid and highly active, adhering to ECM substrates like collagen.

  • What is chemotaxis in neutrophils?


    It is the process by which neutrophils actively pursue bacterial cells at infection sites.

  • What are the two main types of granules in neutrophils?


    • Azurophilic primary granules (lysosomes)
    • Specific secondary granules
  • What is the function of azurophilic granules?


    They kill and degrade engulfed microorganisms using proteases and antibacterial proteins.

  • What does myeloperoxidase (MPO) do?


    Generates hypochlorite and other toxic agents to bacteria.

  • What is the function of lysozyme?


    Degrades components of bacterial cell walls.

  • What are defensins?


    Small cysteine-rich proteins that disrupt cell membranes of bacteria and other microorganisms.

  • What can result from neutrophil defects?


    Increased frequency and persistence of bacterial infections.

  • What do specific secondary granules secrete?


    ECM-degrading enzymes like collagenases and bactericidal proteins.

  • How do activated neutrophils contribute to inflammation?


    They release chemokines and cytokines, attracting other leukocytes and directing tissue activities.

  • What is the significance of glycogen in neutrophils?


    It is broken down into glucose for energy via the glycolytic pathway.

  • What is the half-life of neutrophils in blood?


    6-8 hours.

  • What happens to neutrophils after they die?


    They undergo apoptosis after 1-4 days in connective tissues.

  • What is the process of phagocytosis in neutrophils?


    Neutrophils engulf bacteria using pseudopodia and internalize them in phagosomes.

  • What happens during the burst of O2 consumption in neutrophils?


    Forms superoxide anions and hydrogen peroxide for microbial killing.

  • What role does lactoferrin play in neutrophils?


    Binds iron, limiting its availability to bacteria and causing their death.

  • What forms a viscous fluid during the immune response?


    Apoptotic neutrophils, bacteria, semidigested material, and tissue fluid.

  • What forms a viscous yellow fluid known as pus?


    • Apoptotic neutrophils
    • Bacteria
    • Semidigested material
    • Tissue fluid
  • What is a neutrophil dysfunction associated with actin?


    Reduced neutrophil motility due to abnormal actin polymerization.

  • What happens with NADPH oxidase deficiency in neutrophils?


    Failure to produce H2O2 and hypochlorite, reducing microbial killing power.

  • What are the major events of neutrophil migration during inflammation?


    1. Local macrophages release proinflammatory cytokines.
    2. Neutrophils bind selectins and roll on endothelium.
    3. New integrins expressed, and ICAM-1 appears on endothelium.
    4. Firm adhesion occurs via integrins.
    5. Neutrophils migrate through the endothelium by diapedesis.
  • What do eosinophils primarily combat?


    Eosinophils primarily target parasitic worms or helminths.

  • What is the percentage of eosinophils in leukocytes?


    Eosinophils constitute 1%-4% of leukocytes.

  • What are the characteristics of eosinophils?


    • Bilobed nucleus
    • Abundant acidophilic specific granules
    • Granules stain pink or red
  • What proteins do eosinophilic granules contain?


    Major basic proteins (MBP) and eosinophilic peroxidase.

  • What role do eosinophils play in inflammation?


    They modulate inflammatory responses by releasing chemokines, cytokines, and lipid mediators.

  • Where are eosinophils particularly abundant?


    In connective tissue of the intestinal lining and sites of chronic inflammation.

  • What do eosinophils remove from interstitial fluid?


    Antigen-antibody complexes

  • Where are eosinophils particularly abundant?


    Connective tissue of the intestinal lining and sites of chronic inflammation

  • What triggers the rapid immigration of leukocytes?


    Cytokines and cell binding proteins

  • What do local macrophages release during inflammation?


    Proinflammatory cytokines like IL-1 and TNF-a

  • What is the role of selectins in neutrophil migration?


    They cause neutrophils to adhere loosely to the endothelium

  • What is pus primarily composed of?


    Semidigested material and tissue fluid

  • What is a common dysfunction of neutrophils?


    Failure of actin polymerization, reducing motility

  • What percentage of leukocytes do eosinophils constitute?


    1%-4%

  • What is a key characteristic of eosinophils?


    Bilobed nucleus and large acidophilic granules

  • What do major basic proteins (MBP) in eosinophils do?


    They help kill parasitic worms or helminths

  • What do eosinophils release to modulate inflammatory responses?


    Chemokines, cytokines, and lipid mediators

  • What facilitates the migration of neutrophils through the endothelium?


    Integrins and their ligands provide firm adhesion

  • What is the process called when neutrophils migrate between endothelial cells?


    Diapedesis

  • What role do eosinophils play in the body?


    • Modulate inflammatory responses
    • Release chemokines, cytokines, and lipid mediators
    • Increase during helminthic infections and allergies
    • Remove antigen-antibody complexes by phagocytosis
  • Where are eosinophils typically abundant?


    • Connective tissue of intestinal lining
    • Sites of chronic inflammation (e.g., lung tissues in asthma)
  • What is eosinophilia?


    An increase in eosinophils in blood associated with allergic reactions and helminthic infections.

  • What substances do eosinophils produce?


    • Modulate inflammation
    • Inactivate leukotrienes and histamine
  • What effect do corticosteroids have on eosinophils?


    They rapidly decrease the number of blood eosinophils by interfering with their release from bone marrow.

  • What are the characteristics of basophils?


    • Diameter: 12-15 μm
    • Less than 1% of circulating leukocytes
    • Nucleus divided into two lobes
  • What do basophils contain in their granules?


    • Heparin
    • Histamine
    • Platelet activating factor
    • Eosinophil chemotactic factor
  • How do basophils contribute to inflammation?


    They supplement mast cells and secrete granules in response to antigens and allergens.

  • What is anaphylaxis?


    A severe systemic response to allergens, leading to vasodilation and a drop in blood pressure due to rapid degranulation of basophils and mast cells.

  • What are the effects of immediate hypersensitivity?


    Can result in bronchial asthma, hives, rhinitis, conjunctivitis, or allergic gastroenteritis.

  • What are lymphocytes?


    The most numerous agranulocytes with spherical nuclei, constituting about one-third of leukocytes.

  • How can mature lymphocytes be subdivided?


    By distinctive surface molecules called CD markers

  • What are the major classes of lymphocytes?


    • B lymphocytes
    • Helper T lymphocytes
  • What are neutrophils characterized by?


    • Multi-lobulated nuclei
    • Dynamic nuclear shape
    • Diameter of 12-15 μm
  • What do eosinophils indicate when increased in blood?


    • Eosinophilia
    • Associated with allergic reactions
    • Linked to helminthic infections
  • Where are eosinophils typically found in patients with eosinophilia?


    • Connective tissues under epithelia of:
    • Bronchi
    • Gastrointestinal tract
    • Uterus
    • Vagina
  • What hormone decreases the number of blood eosinophils?


    Corticosteroids

  • What are basophils?


    • Diameter of 12-15 μm
    • Less than 1% of leukocytes
    • Nucleus divided into two lobes
  • What do basophilic granules contain?


    • Heparin
    • Histamine
    • Various mediators of inflammation
  • What role do basophils play in inflammation?


    They supplement the functions of mast cells

  • What do basophils catalyze in the immune response?


    Production of lipid-derived proinflammatory factors called leukotrienes.

  • What do basophils and mast cells have in common?


    • Metachromatic granules containing heparin and histamine
    • Surface receptors for immunoglobulin E (IgE)
    • Secrete granular components in response to antigens and allergens
  • What triggers the release of inflammatory mediators in basophils and mast cells?


    Allergen binds to receptor-bound IgE molecules, causing cross-linking and rapid exocytosis of cytoplasmic granules.

  • What are the major classes of lymphocytes?


    • B lymphocytes
    • Helper T lymphocytes (CD4+)
    • Cytotoxic T lymphocytes (CD8+)
    • Natural killer (NK) cells
  • Where do T lymphocytes differentiate?


    In the thymus, unlike B cells and other circulating leukocytes which mature in the bone marrow.

  • What is the size range of lymphocytes?


    Small lymphocytes: similar to RBCs; Medium/Large lymphocytes: 9-18 μm in diameter.

  • What are lymphomas?


    Disorders involving neoplastic proliferation of lymphocytes or failure to undergo apoptosis, considered malignant.

  • What characterizes small lymphocytes?


    Spherical nuclei with highly condensed chromatin and a thin rim of scant cytoplasm.

  • How long do lymphocytes typically survive?


    Varies by function; some live a few days, others for many years in circulation or tissues.

  • What are lymphomas considered?


    Malignant

  • What is the function of specific granules in neutrophils?


    Undergo exocytosis to release enzymes and bactericidal factors

  • What do azurophilic granules contain?


    Components to kill engulfed bacteria

  • What is the nucleus structure of a neutrophil?


    Lobulated

  • What are monocytes precursors to?


    Macrophages, osteoclasts, microglia

  • What is the diameter of circulating monocytes?


    12-15 μm

  • What is the cytoplasm color of monocytes in stained smears?


    Bluish-gray

  • What occurs during extravasation?


    Accumulation of immigrating monocytes in inflammation

  • What are platelets also known as?


    Thrombocytes

  • What is the size of blood platelets?


    2-4 μm in diameter

  • How do platelets originate?


    From cytoplasmic processes of giant polyploid bone marrow cells

  • What is the role of macrophages in inflammation?


    Immune defense and tissue repair

  • What characterizes chronic inflammation?


    Continuous recruitment of monocytes and macrophages

  • What are eosinophils characterized by?


    • Bilobed nuclei
    • Coarse cytoplasmic granules
    • Brightly eosinophilic specific granules
    • Azurophilic granules
  • What is the size range of monocytes?


    12-15 um in diameter

  • What do monocytes develop into?


    • Macrophages
    • Osteoclasts
    • Microglia
  • What is the significance of monocytes in the immune system?


    They are antigen-presenting cells involved in immune defense and tissue repair.

  • What is the lifespan of circulating platelets?


    About 10 days

  • What is the normal range of platelet counts in blood?


    150,000 to 400,000/μL

  • What are the two zones of a platelet?


    • Hyalomere (lightly stained peripheral zone)
    • Granulomere (darker central zone rich in granules)
  • What occurs during extravasation of monocytes?


    Accumulation of immigrating monocytes during early inflammation.

  • What happens to macrophages during acute inflammation?


    They usually undergo apoptosis or leave the site.

  • What is the role of platelets in the body?


    They promote blood clotting and help repair minor tears in blood vessels.

  • What is the function of platelets in blood loss control?


    • Form a platelet plug through primary aggregation
    • Release adhesive glycoprotein and ADP for secondary aggregation
  • What are the two systems of membrane channels in platelets?


    • Open canalicular system
    • Dense tubular system
  • What do delta granules in platelets contain?


    • ADP
    • ATP
    • Serotonin (5-hydroxytryptamine)
  • What do alpha granules in platelets contain?


    • Platelet-derived growth factor (PDGF)
    • Platelet factor 4
    • Other platelet-specific proteins
  • What is the normal platelet count range in blood?


    150,000 to 400,000/uL

  • What is the lifespan of circulating platelets?


    About 10 days

  • What are the two types of platelet aggregation?


    • Primary aggregation
    • Secondary aggregation
  • What is the appearance of platelets in stained blood smears?


    Often appear in clumps, discoid shape with a hyalomere and granulomere

  • What is the role of the glycocalyx in platelets?


    Involved in adhesion and activation during blood coagulation

  • What is the structure of a platelet?


    • Peripheral marginal bundle of microtubules and microfilaments
    • Central granulomere rich in granules
  • What is the function of the open canalicular system in platelets?


    Facilitates uptake of factors from plasma.

  • What do dense tubular system vesicles in platelets store?


    Ca ext{**} ions.

  • What is the process of degranulation in platelets?


    Rapid exocytosis of proteins upon activation.

  • What do basophils contain that modulates immune response?


    Specific basophilic granules.

  • What is the diameter range of delta granules in platelets?


    250-300 nm.

  • What is the role of platelets in primary aggregation?


    Adhere to collagen in the vascular wall to form a platelet plug.

  • What induces secondary aggregation in platelets?


    Release of adhesive glycoprotein and ADP.

  • What proteins promote blood coagulation during platelet aggregation?


    Fibrinogen, von Willebrand factor, and platelet factor 4.

  • What is the role of platelet factor 4?


    Acts as a chemokine for monocytes, neutrophils, and fibroblasts.

  • What causes clot retraction?


    Activity of platelet-derived actin and myosin.

  • What enzyme dissolves the clot during clot removal?


    Plasmin.

  • How do aspirin and NSAIDs affect platelet function?


    They inhibit prostaglandin synthesis needed for aggregation.

  • What is a common bleeding disorder related to platelets?


    Autosomal recessive glycoprotein Ib deficiency.

  • What are lymphocytes classified as?


    Agranulocytes without specific granules.

  • What is the size range of lymphocytes in blood?


    6 to 15 μm in diameter.

  • What are the characteristics of lymphocytes?


    • Agranulocytes
    • Lack specific granules
    • Size ranges from 6 to 15 μm
    • Classified as small, medium, and large
  • How do small lymphocytes compare to erythrocytes?


    Slightly larger than erythrocytes with a thin rim of cytoplasm around a spherical nucleus.

  • What distinguishes medium lymphocytes from erythrocytes?


    Medium lymphocytes are distinctly larger than erythrocytes.

  • What are the features of large lymphocytes?


    Much larger than erythrocytes; may represent activated cells returning to circulation.

  • What does a medium-sized lymphocyte contain?


    • Euchromatic nucleus (N)
    • Cytoplasm with mitochondria (M)
    • Free polysomes
    • Few dark lysosomes (azurophilic granules)
  • What is the process of blood coagulation?


    Involves platelet aggregation and cascade of plasma proteins forming a fibrin polymer, creating a thrombus.

  • What role does platelet factor 4 play?


    Acts as a chemokine for monocytes, neutrophils, and fibroblasts; stimulates fibroblast proliferation by PDGF.

  • What is clot retraction?


    The clot bulges into the vessel lumen and then contracts due to platelet-derived actin and myosin.

  • How is a clot removed from the body?


    The clot is dissolved by proteolytic enzymes after new tissue restores the endothelium.

  • What effect do Aspirin and NSAIDs have on blood coagulation?


    They inhibit platelet function and blood coagulation by blocking prostaglandin synthesis needed for aggregation.

  • What is a bleeding disorder related to platelets?


    A rare autosomal recessive glycoprotein Ib deficiency affecting platelet binding to collagen.