Blood

• Connective Tissue - mostly nonliving

  This is because blood has to stay fluid and connect tissue have a multitude of fibers
• Blood pH level is around 7.35 - 7.45
• Blood is 8 % of our body weight

  5 - 6 L in males

  4 - 5 L in females
• Blood has many Functions including :

  Transport : Examples include Oxygen, nutrients, proteins, CO2, Hormones, waste, electrolytes, etc.
• Blood has many Functions including :

  Regulation : Body temperature, Fluid Balance, pH balance
• For Fluid Balance, if cells get dehydrated, they can pull water from blood
• Blood has many Functions including :

  Protection : Infections and Blood Loss
• Blood Composition :

  Our whole blood is made of 55 % plasma, 45 % Erythocytes and a <1% Buffy Coat
• Plasma is the liquid part of blood that contains dissolved substances and carries oxygen and nutrients
• The Buffy coat consist of leukocytes and platlets.
• Leukocytes are also known as white blood cells
• White blood cells are reactive cells that fight infection and disease
• Erythrocytes are also known as red blood cells
• red blood cells function is to transport oxygen from the lungs to the body cells
• The Buffy coat and Erythrocytes are known as the formed elements

  This is because they are technically not living cells. They come from living cells
• Hematocrit : how much (in percentages) erythrocytes make up whole blood

  Males : 45 %

  Females : 40 %
• Blood Plasma is 90 % water and 10 % solutes
• The solutes in blood plasma include

  proteins, Hormones, Ions, Dissolved gases, Nutrients, and waste
• Plasma Proteins

  Albumin : carriers
• Plasma Proteins

  a and b Globulins : bulding blocks of hemogloblin
• Plasma Proteins

  Fibrinogen : Fiber bulding blocks (These are important for clotting)
• Plasma Proteins

  y Globulins : Antibodies
• Formed Elements

  Leukocytes : Living cells

  Erythrocytes and Platelets : Remnants of living cells
• Multipotent stem cells can differentiate into many different types of cells, but not all of them.
• Hemocytoblast are found in red bone marrow
• Erythropoiesis is when Erythrocytes form
• Hemocytoblast are stem cells
• When Hemocytoblast are signalled by a hormone (Erythropoietin) The become Proerythroblast
• Committed cell - are unipotent

  Unipotent Stem cell : only become one type of cell
• When signalled, Proerythoblast become a erythroblast and goes through 3 phases on the developmental pathway
• Erythroblast Developmental Pathway

  1. Ribosome synthesis
• Erythroblast Developmental Pathway

  2. Hemoglobin and spectrin accumulation
• Erythroblast Developmental Pathway

  3. Ejection of nucleus and organelle degradation
• In the developmental pathway, after the ejection of the nucleus and organelle degradation, the erythroblast becomes a reticulocyte
• Finally, the Reticulocyte goes through cytoskeletal rearrangement and becomes a erythrocyte
• We are constantly making red blood cells and they are constantly degrading
• Erythropoietin and Oxygen Homeostasis

  1. Stimulus : Hypoxia ( inadequate oxygen delivery )

  this can be due to :

  Decreased red blood cell count

  Decreased amount of hemoglobin

  Decreased availability of oxygen
• Erythropoietin and Oxygen Homeostasis

  2. Kidney releases erythropoietin
• Erythropoietin and Oxygen Homeostasis

  3. erythropoietin enters bloodstream and stimulates red bone marrow
• Erythropoietin and Oxygen Homeostasis

  4. Enhanced erythropoiesis increases red blood cell count