(6) The Composition and Function of Blood

Chapter 1: Introduction to Blood

  • Blood is a familiar substance in the human body

  • Blood's function was not well-understood in the past

  • Blood is critical for human life

Chapter 2: Components of Blood

Blood as a connective tissue

  • Blood is considered a connective tissue

  • Blood is the only fluid tissue in the body

  • Blood is full of fibrous proteins

Formed elements of blood

  • Blood cells are suspended in plasma

  • Blood separates into components when placed in a centrifuge

  • Densest section: erythrocytes (red blood cells)

  • Least dense section: yellowish plasma

  • Buffy coat: white layer containing platelets and leukocytes (white blood cells)

Functions of blood

  • Distributes substances around the body

  • Carries oxygen, nutrients, hormones, and waste products

  • Regulates pH and body temperature

  • Prevents infection

Chapter 3: Plasma

  • Plasma is a sticky fluid made mostly of water

  • Contains proteins, nutrients, ions, gases, and hormones

  • Most abundant plasma protein: albumin

  • Other proteins include globulins for transport

Chapter 4: Red Blood Cells

  • Red blood cells don't possess typical organelles and don't divide

  • Shaped like flattened discs with depressed centers

  • No nucleus, mostly hemoglobin inside

  • Hemoglobin transports oxygen throughout the bloodstream

  • Hemoglobin structure: globin protein with four polypeptides and heme group with iron

  • Each hemoglobin can bind four oxygen molecules

  • Red blood cells are produced through erythropoiesis in the red bone marrow

  • Red blood cells function for about three months before being destroyed by macrophages

Chapter 5: White Blood Cells

  • White blood cells are complete cells with nuclei and organelles

  • Part of the immune system

  • Defend against pathogens and harmful substances

  • Two types: granulocytes and agranulocytes

  • Granulocytes: neutrophils, eosinophils, basophils

  • Agranulocytes: lymphocytes and monocytes

  • Leukocytes are produced through leukopoiesis

Chapter 6: Platelets

  • Platelets are fragments of megakaryocytes

  • Essential for blood clotting

  • Flow through the bloodstream in an inactive state

  • Platelets are regenerated every ten days

  • Megakaryocytes form due to repeated mitotic cycles without cytokinesis

  • Platelets are released when megakaryocyte extensions burst

  • Platelets are important for hemostasis and blood clotting

Chapter 7: Blood Types

  • Humans can exhibit blood types A, B, AB, and O

  • Blood types are determined by glycoproteins and glycolipids in red blood cell membranes

  • A and B refer to different agglutinogens

  • AB blood has both agglutinogens, O blood has neither

  • Blood transfusions must match blood types to avoid complications

  • Rh blood groups refer to Rh factors and are reported along with ABO blood group

Chapter 8: Conclusion

  • Understanding the structure and function of blood is important to examine the circulatory system as a whole