Basic Blood Flashcards
Blood
- Fluid connective tissue, circulates through cardiovascular system
- Consists of cells & a protein-rich fluid, plasma • Erythrocytes (red blood cells, RBCs)
- Leukocytes (white blood cells, WBCs)
- Thrombocytes (platelets)
- Functions:
- Delivery of nutrients & oxygen AND transport of wastes & CO2
- Delivery of hormones, regulatory substances, immune system cells
- Maintenance of homeostasis: acts as a buffer, participates in coagulation, thermoregulation
Hematocrit
-volume of RBCs in a sample of blood
Blood Plasma
- liquid extracellular material (90% water by weight)
- solvent for a variety of solutes (proteins, regulatory substance, nutrients, electrolytes, dissolved gases, wastes)
Interstitial fluid
-fluid found surrounding tissue cells, derived from blood plasma
• Electrolyte composition reflects that of blood plasma, from which it is derived
Albumin
-main protein constituent (~50%), made in the liver
• Responsible for exerting the concentration gradient btwn blood & EC
tissue fluid
• Source of major colloid osmotic pressure, osmotic pressure on vessel walls
• Carrier protein for thyroxine, bilirubin, barbiturates
Serum
-blood plasma without clotting factors
Globulins
- Immunoglobulins (γ-globulins): largest component, functional immune- system molecules
- Non-immune globulins (α-globulin & β-globulin):
- Maintain the osmotic pressure within the vascular system & serve as carrier proteins • Includes fibronectin, lipoproteins, & coagulation factors
Fibrinogen
-largest plasma protein (340 kDa), is made in the liver
• Soluble fibrinogen → insoluble protein fibrin (323 kDa)
• In conversion, fibrinogen chains → monomers → polymerize forming long fibers
• Become cross-linked → form an impermeable net preventing further blood loss
Blood cells
- Formed elements suspended in plasma • All formed in bone marrow
- Plays a significant role in diagnosis of disease
- Functional components: • Erythrocytes
- Leukocytes
- Platelets
Erythrocytes
• Anucleate cells devoid of typical organelles
• Biconcave disc, extremely flexible
• Bind O2 for delivery to tissues & bind CO2 for removal from tissues
-Lifespan: 120 days
Reticulocytes
- Immature RBCs released into circulation from bone marrow
- Have not yet shed all of their nuclear material & still have organelles
- Will mature into erythrocytes in 24-48hrs
Glycophorin C
- integral membrane proteins of erythrocyte cytoskeleton
- attaches underlying cytoskeletal protein network to cell membrane
Band 3 protein
- integral membrane proteins of erythrocyte cytoskeleton
- binds hemoglobin & acts as an anchoring site for the cytoskeletal proteins (most abundant)
Peripheral membrane proteins
-integral membrane proteins of erythrocyte cytoskeleton
• 2-D hexagonal lattice network
• Laminates inner layer of membrane
Lattice is composed α-spectrin & β- spectrin molecules
• Heterodimer that forms long, flexible
tetramers
Spectrin filaments are anchored by:
• Band 4.1 protein complex → interacts
with glycophorin C
• Ankyrin protein complex (ankyrin &
band 4.2 protein) → interacts with band 3
Anemia
- Decreased Hb levels
- Most anemias are caused by a reduction in the number of RBCs
- Hemorrhage, insufficient production or
- Hemolytic anemia: accelerated destruction of RBCs
- Insufficient dietary Fe, vitamin B12, or folic acid can lead to decreased RBC production
- Clinical symptoms vary, depending on the type
- Weakness, fatigue, & loss of energy
- Frequent headaches, difficulty concentrating, dizziness, pale skin
Hereditary spherocytosis
- Autosomal dominant mutation
- Affects ankyrin complex (band 3, band 4.2, spectrin, and other erythrocyte-integral membrane proteins)
- Defective anchor points, causing membrane to detach & peel off → spherical erythrocytes
Hereditary Elliptocytosis
- Autosomal dominant mutation
- Spectrin-to-spectrin lateral bonds & spectrin-ankyrin-band 4.1 protein junctions are defective
- Membrane fails to rebound & progressively elongates → elliptical erythrocytes
Jaundice
- yellow appearance of the sclera of the eye & skin
- Can be caused by the destruction of circulating erythrocytes
Sickle-Cell Anemia
- Single-point mutation β-globin chain of hemoglobin A (HbA)
- Sickle hemoglobin (HbS) • Valine → glutamic acid
- HbS molecules aggregate & grow in length • Sickle-shaped at ↓O2sat
- 85% in homozygotes; <40% in heterozygotes
- Sickled RBCs:
- Blood is more viscous, sickled RBCs are more fragile
- Break down after ~20 days
- Pile up in the smallest capillaries, large-vessel obstruction may also occur
Leukocytes
- Two general groups based on presence or absence of prominent granules
- Granulocytes give me all the ‘feels’ → neutrophils, eosinophils, basophils
- Agranulocytes → lymphocytes, monocytes
Neutrophil
• Multi-lobed nucleus,
polymorphonuclear neutrophils or polymorphs
• General lack of cytoplasmic staining
• Function in acute inflammation & tissue injury
• Secrete enzymes, ingest damaged tissue, kill invading microorganisms
• Recognize & bind to bacteria, foreign organisms, & other infectious agents
Neutrophil Granules
• Reflect the various phagocytotic functions
1. Azurophilic granules (primary granules): lysosomes containing myeloperoxidase (MPO)
2. Specific granules (secondary granules): various enzymes, complement activators, & antimicrobial peptides
3. Tertiary granules (two types):
• Phosphatases
• Metalloproteinases - facilitate migration of through CT
Eosinophils
• About same size as neutrophils
• Nuclei are typically bi-lobed
• Contain large & elongated specific & azurophilic granules
•Release arylsulfatase&histaminase
• Phagocytoseantigen–Abcomplexes
• Increase counts w/ allergies and/or parasitic
infections (worms) → eosinophilia
•Maymediate chronic inflammation(i.e.,lung
tissues in asthmatics)
Basophils
- About the same size as neutrophils
- Least numerous < 0.5%
- Lobed nucleus is usually obscured by the granules
- Functionally related to mast cells (connective tissue)
- Bind an antigen-IgE antibody complex (plasma cells) triggers activation
- Release of vasoactive agents from granules
- Responsible for the severe vascular disturbances associated with hypersensitivity reactions & anaphylaxis
