Biology Chapter 10 Blood PDF

Biology Fall 2024/2025 Chapter 10 Blood  Chapter 10 Blood Major Objectives Upon completion of this chapter, students should be able to: Describe the composition, function, and general characteristics of blood Explain what the terms: anemia, polycythemia, leukopenia, leukemia,...

Biology Fall 2024/2025 Chapter 10 Blood  Chapter 10 Blood Major Objectives Upon completion of this chapter, students should be able to: Describe the composition, function, and general characteristics of blood Explain what the terms: anemia, polycythemia, leukopenia, leukemia, and leukocytosis stand for and describe the causes of each condition Discuss blood cell formation (hematopoiesis) in terms of sites, precursors, growth factors involved, etc. Describe the purpose and the process of blood clotting: triggers, mediators, function, clotting abnormalities, thrombosis, embolism, thrombocytopenia Describe the ABO and Rh blood grouping systems in humans Discuss the basis of blood transfusion and blood transfusion reactions  Physical characteristics of blood A type of connective tissue: part solution (plasma) and part suspension (formed elements) Has metallic taste Color varies from scarlet red (rich in oxygen) to pale blue (poor in oxygen) Density is higher than that of water (blood is heavier than water) Highly viscous (X5) as compared to water due to presence of formed elements especially RBCs Alkaline; pH = 7.35-7.45 at physiologic temperature pH < 7.35: Acidosis; pH > 7.45: Alkalosis Average volume per adult = 5-6L; blood generally makes up about 8% of body weight Figure 10.1 The composition of blood. Plasma 55% Constituent Major Functions Formed elements (cells) 45% Water 90% of plasma volume; solvent Cell Type Number Functions for carrying other substances; (per mm3 of blood) absorbs heat Erythrocytes Salts (electrolytes) (red blood cells) 4–6 million Transport oxygen Sodium Osmotic balance, pH buffering, and help transport Potassium regulation of membrane carbon dioxide Calcium permeability Magnesium Chloride Leukocytes (white blood cells) 4,800–10,800 Defense and Bicarbonate immunity Plasma proteins Albumin Osmotic balance, pH buffering Lymphocyte Fibrinogen Clotting of blood Basophil Globulins Defense (antibodies) and lipid transport Eosinophil Substances transported by blood Nutrients (glucose, fatty acids, amino acids, vitamins) Neutrophil Monocyte Waste products of metabolism (urea, uric acid) Platelets Respiratory gases (O2 and CO2) 250,000–400,000 Blood clotting Hormones (steroids and thyroid hormone are carried by plasma proteins)  Composition of blood Whole Blood: Formed elements + Plasma Buffy Coat: White layer composed of leukocytes and platelets. Hematocrit: % of erythrocytes of whole blood (about 45%) 11/12/11 Blood Film (smear) To study the cellular constitution of blood, a drop of blood is applied to a glass slide, spread evenly, dried, fixed with methanol and stained with specific chemical stains (e.g. Giemsa stain). The end result is what is called a blood film Below is an example of blood film showing various types of blood cells including: ― Disc-shaped, anucleated, small, Red Blood cells with an empty center (Pallor) ― Lymphocytes (T cells & B cells) = (mononuclear cells) ― Neutrophils  Erythrocytes (red blood cells) Carry oxygen to all parts of body Anuclear (lack nucleus) Contain mainly hemoglobin (Hb) Biconcave discs (depressed center on both sides); doughnuts shape A single RBC contains about 250 million hemoglobin molecules, each can bind 4 molecules of oxygen Low hemoglobin or low RBC count: Anemia High RBC count: Polycythemia ‒ Polycythemia vera: cancer of bone marrow leading to increased RBC ‒ Secondary polycythemia: smoking or living in high altitude Table 10.1 Types of Anemia. Sickle cell Anemia: – A hereditary disease resulting from a point mutation in the Hb gene which replaces the amino acid at position 6 (glutamine → valine). – The mutation is recessive; individuals carrying it at both alleles (homozygous recessive) develop SCA; heterozygous individuals have SCT (sickle cell trait). – In SCA, Hb that releases oxygen deforms and become spiky causing cells to deform – Oxygen carrying capacity or [Hb] of blood decreases → anemia – deformed (sickled) RBCs become stiff and inflexible → cannot carry oxygen and tend to block capillaries → tissue infarction (tissue death). – Most common in people of African descent – Oddly enough, the SCA trait is protective against infection by parasite the malaria → deformed RBCs stick to walls and loose potassium, a badly needed element for malarial to grow inside the host Table 10.2 Characteristics of Formed Elements of the Blood (1 of 3). Table 10.2 Characteristics of Formed Elements of the Blood (2 of 3). Table 10.2 Characteristics of Formed Elements of the Blood (3 of 3). Figure 10.4 The development of blood cells. Hemocytoblast Hematopoie stem cells sis Lymphoid Myeloid stem cells stem cells Secondary stem cells Basophils Erythrocytes Platelets Eosinophils Lymphocytes Monocytes Neutrophils  Figure 10.5 Mechanism for regulating the rate of RBC production. IMB ALA NC E Homeostasis: Normal blood oxygen levels 1 Stimulus 5 O2–carrying IMB Low blood O2–carrying ALA ability of blood NC E ability due to increases. Decreased RBC count Decreased amount of hemoglobin Decreased availability of O2 4 Enhanced erythropoiesis 2 Kidney (and liver, increases RBC count. to a smaller extent) releases erythropoietin. 3 Erythropoietin stimulates red bone marrow. eticulocyte is a young RBC that still contain some rough endoplasmic reticulum emocytoblast till formation of mature RBC takes 3 to 5 days  Formation of White Blood Cells and WBC and platelet Platelets formation stimulated by colony stimulating factors (CSFs) and interleukins. These substances enhances the production of WBC to fight disease as well The hormone thrombopoietin accelerate platelet production by megakaryocytes Bone marrow biopsy is a procedure to take bone marrow sample for testing leukemia or aplastic anemia. Important Glossary: Myelopoiesis, lymphopoiesis, erythropoiesis Leukocytosis & Leukopenia Thrombocytosis & Thrombocytopenia  Hemostasis Hemostasis is a process by which blood is prevented from loss by injured blood vessel. Three major phases: ― Vascular spasm ― Platelet plug formation ― Coagulation (blood clotting) Figure 10.6 Events of hemostasis. Step 1 Vascular spasms occur. Smooth muscle contracts, causing vasoconstriction. Step 2 Platelet plug forms. Injury to lining of vessel exposes collagen fibers; platelets adhere. (platelets become sticky) Collagen fibers Platelets release chemicals that make nearby platelets sticky; platelet plug forms. Platelets Step 3 Coagulation events occur. Clotting factors present in plasma and released by injured tissue cells interact with Ca 2+ to form thrombin, the enzyme that catalyzes joining of Fibrin fibrinogen molecules in plasma to fibrin. Fibrin forms a mesh that traps red blood cells and platelets, forming the clot. Figure 10.7 Fibrin clot. Homeostatic Imbalance 10.3 A thrombus occluding a small pulmonary blood vessel in a human lung. Hemostatic Imbalance Clotting 1.Formation of blood clots inside blood vessels; they develop as stationary [thrombus] or moving [embolus] Thrombus may cause coronary thrombosis. Embolus may move to brain causing stroke. Bleeding 1.Poor/no clot formation due to decrease number of platelets (thrombocytopenia) or deficiency in one or more of the coagulation factors (hemophilia) Focus On Careers, Phlebotomy Technician Phlebotomy sics of Blood groups and Blood grouping syste Genetically-determined glycoproteins known as blood group antigens (e.g. ABO and Rh antigens) are expressed on the surface of RBCs Different individuals express different types of antigens; in the ABO system, an individual could be A, B, AB, or O. For Rh, the individual is either Rh+ = have the antigen or Rh- = does not have it Type A individuals have anti-B antibodies in their blood; Type B individuals has anti-A antibodies, Type O individuals has both anti-A and anti-B antibodies Type AB individuals do not have anti-A or anti-B antibodies. Rh does not associate with circulating antibodies. Table 10.3 ABO Blood Groups (1 of 2). Table 10.3 ABO Blood Groups (2 of 2). Figure 10.8 Blood typing of ABO blood groups. Serum Blood being tested Anti-A Anti-B Type AB (contains antigens A and B; agglutinates with both sera) Agglutinated RBCs Type B (contains antigen B; agglutinates with anti-B serum) Type A (contains antigen A; agglutinates with anti-A serum) Type O (contains no antigens; does not agglutinate with either serum)  Blood Transfusion Reactions Transfer of blood from an A to a B individual causes the anti-A antibodies in B individual to recognize, bind and destroy (hemolyse) transfused RBCs from A individual (hemolytic anemia) → blood grouping and donor/recipient matching is very important for blood transfusion to be safe. Rh is of concern during blood transfusion (Rh+ gives only Rh+ while Rh- gives both Rh+ and Rh-) and pregnancy especially if the mother is Rh-. An Rh- female who delivers an Rh+ baby is given anti- Rh antibodies (RhoGAM) right after birth to neutralize/remove Rh antigens → will not produce anti-Rh antibodies that may cause hemolytic disease of the newborn in a future Rh+ baby; done after each