Exam 2

• blood is the only liquid tissue in our body
• Blood is the only connective tissue in our body, with about 45% formed elements and 54% plasma

  
• Blood is a type of liquid connective tissue with a background matrix
• About 8% of body weight is blood, with around 5 liters in the body
• Blood temperature is about 100°F and plays a role in heat exchange
• Blood pH is between 7.35-7.45, slightly alkaline, which helps neutralize the slightly acidic foods we consume
• Functions of blood include delivering oxygen and nutrients, transporting metabolic wastes and hormones, maintaining body temperature, pH, fluid volume, preventing blood loss, and infection
• Blood components consist of formed elements (erythrocytes, leukocytes, platelets) and plasma
• Erythrocytes are non-living cells that carry oxygen and nutrients, with about 90% of blood being erythrocytes
• Hemoglobin, found in red blood cells, is composed of globin protein bound to heme pigment, with each hemoglobin carrying about 1 billion oxygen molecules
• Hemoglobin can shift between oxyhemoglobin (bright red) and deoxyhemoglobin (dark red) to transport oxygen throughout the body
• Hemoglobin can also carry carbaminohemoglobin, with only about 20% of carbon dioxide in blood bound as carbaminohemoglobin
• Hematopoiesis is the production of blood cells, an ongoing process that occurs in the bone marrow
• Erythropoiesis, the production of red blood cells, starts with a pluripotent stem cell stimulated to divide, leading to the formation of erythrocytes
• Regulation of erythropoiesis involves erythropoietin stimulating the production of red blood cells when blood oxygen is low
• Blood is made up of red blood cells, white blood cells, platelets, and plasma

  
• Red blood cells are the most common type of blood cell and carry oxygen from the lungs to the body
• White blood cells help fight infection, platelets help stop bleeding, and plasma is the liquid part of blood that carries cells and other substances throughout the body
• Hemoglobin is a protein found in red blood cells responsible for carrying oxygen; it's made up of four protein subunits, each bound to an iron atom

  
• The oxygen dissociation curve shows the relationship between oxygen partial pressure and hemoglobin saturation; it's sigmoid-shaped due to cooperative oxygen binding and allosteric inhibitors

  
• Blood cell development starts with a stem cell, which can become a myeloid or lymphoid stem cell; myeloid stem cells develop into red blood cells, white blood cells, or platelets, while lymphoid stem cells develop into B or T cells

  
• Testosterone stimulates bone marrow to release erythropoietin, leading to increased red blood cell production
• B Vitamins, especially B12 and folate, are essential for red blood cell production
• Iron is crucial for creating hemoglobin and is obtained from the diet, stored as ferritin and hemosiderin, and transported in the blood as transferrin
• If we're making any cells, we need nutrients like B vitamins, iron, and oxygen
• Erythrocytes last 100-120 days before macrophages break them down in the spleen, recycling their parts like heme, proteins, and iron
• Anemias result from low red blood cell count, while polycythemias involve overproduction of red blood cells, causing blood to thicken
• Leukocytes can leave blood vessels and enter tissue fluid through diapedesis; they have granules and a nucleus, display positive chemotaxis, and are crucial for immune responses
• Granulocytes like neutrophils, basophils, and eosinophils have specific functions and characteristics, while agranulocytes like lymphocytes and monocytes play different roles in immunity
• Leukopoiesis involves the production of white blood cells from hemocytoblasts, leading to myeloid and lymphoid stem cells that differentiate into various types of white blood cells
• Regulation of leukopoiesis involves cytokines and colony-stimulating factors that control white blood cell production; disorders like leukemia and infectious mononucleosis can affect white blood cell count and function