Untitled Quiz

Blood Functions

• Blood transports various substances throughout the body.
• Blood maintains homeostasis, regulating body temperature (heat transported to skin's surface when hot) and pH of bodily fluids (using buffers like ion buffers and hemoglobin).
• Blood defends against infection through various white blood cells and antibodies.
• Clotting, through platelets and fibrinogen proteins, prevents excessive blood loss.

Blood Components

Cellular Portion (45% of volume)

• Red blood cells transport oxygen and some carbon dioxide.
• White blood cells defend against viral, bacterial, protist, and animal invaders, as well as virus-infected and cancerous cells.
• Platelets are crucial for blood clotting.
• Stem cells in red bone marrow are the source of all blood components.

Plasma (55% of volume)

• Water is the primary component (90%), acting as a biological solvent.
• Ions act as pH buffers maintaining cell function and volume, vital for excitable cells like muscles and nerves.
• Hormones, released by endocrine glands, are transported in the blood.
• Gases, including oxygen (small amount) and carbon dioxide (most), are dissolved in the plasma.
• Nutrients, such as amino acids, glucose, and lipids (often bound to globulin transport proteins), are carried in the plasma.
• Wastes, including ammonia, urea, and uric acid, are removed from the blood by the kidneys.

Plasma Proteins

• Albumins, produced by the liver, maintain osmotic balance between blood and extracellular fluid, thus maintaining blood volume.
• Antibodies, produced by white blood cells, bind to foreign substances (bacteria and viruses).
• Fibrinogen, produced by the liver, converts to fibrin, forming a network essential for blood clotting.

Red Blood Cells

• Red blood cells are disc-shaped, lack a nucleus and organelles, offering flexibility.
• Their lifespan averages 120 days.
• Old cells are broken down in the liver and spleen, recycling iron to the red bone marrow and using amino acids.
• The heme groups in red blood cells become part of bile.
• Erythropoietin hormone controls red blood cell production.

Blood Oxygen Carrying Capacity Homeostasis

• Oxygen levels are monitored by kidney cells.
• A decrease in oxygen triggers erythropoietin secretion by the kidneys.
• Erythropoietin stimulates red blood cell production in red bone marrow.
• Increased oxygen levels reduce erythropoietin secretion.

Hemoglobin

• Each red blood cell contains 300 million hemoglobin molecules, carrying 1.2 billion oxygen molecules.
• Hemoglobin comprises four polypeptide chains (alpha and beta), each with a heme group containing iron (Fe), which binds oxygen.
• Each hemoglobin molecule can bind four oxygen molecules.

Hemoglobin and Oxygen Binding

• Hemoglobin binds oxygen in the lungs where pH is high, blood oxygen concentration is high and temperature is low.
• Hemoglobin releases oxygen in active tissues (like exercising muscles) where pH is low, blood oxygen concentration is low and temperature is high.
• Carbon dioxide reacts with water to form carbonic acid, which dissociates into hydrogen ions and bicarbonate ions.

Stopping Blood Loss

• Stages:
  • Vascular spasm: smooth muscles constrict blood vessels to stop or reduce blood flow.
  • Platelet plug formation: Damaged blood vessel collagen triggers platelets to aggregate, become sticky and clump together to seal the breach. Platelets contract, bringing the wound edges closer.
  • Coagulation: Soluble fibrinogen is converted into insoluble fibrin, forming a clot that traps red blood cells and platelets.

First Aid for Bleeding

• Apply constant direct pressure to the wound.
• Elevate the injured limb above the heart.
• Apply pressure to the artery supplying the injured limb to reduce blood flow.

Blood Types and Antibodies

• Antigens: proteins/glycoproteins on cell membranes.
• B lymphocytes produce antibodies.
• Antibodies bind to foreign antigens.
• Incompatible blood types cause agglutination (clumping) of red blood cells.
• Agglutination can block small blood vessels damaging organs and potentially leading to death.

Rh Factor

• Rh antigen: present (positive) or absent (negative).
• Rh negative individuals can receive Rh positive blood once without issue, but subsequent exposure triggers antibody production causing agglutination.
• A-like and B-like antigens occur naturally, triggering antibodies already present.
• Rh-like antigens require prior exposure to trigger antibody production.

Blood Type Compatibility, Steps

• Identifying recipient's antigens
• Determining the recipient's antibodies
• Evaluating if donor antigens and recipient antibodies match; matching prevents agglutination (clumping).

Rh Factor and Pregnancy

• Rh-negative mothers carrying Rh-positive babies for the first time form antibodies.
• Second pregnancies with Rh-positive babies may lead to hemolytic disease of the newborn (HDN) where fetal red blood cells are destroyed causing anemia, jaundice and possible death.
• RhoGAM, administered to Rh-negative mothers before and after pregnancy, can prevent HDN by destroying fetal blood cells preventing the formation of antibodies in the mother.

Blood Disorders: Carbon Monoxide Poisoning

• Carbon Monoxide competes with oxygen for hemoglobin binding sites.
• CO binds with hemoglobin firmly and for a long time, preventing oxygen from binding.
• CO poisoning occurs due to exposure to CO from sources such as burning fuel, wood, charcoal or tobacco , in closed spaces. This results in reduced oxygen transport leading to potentially fatal consequences.

Blood Disorders: Anemia

• Reduced oxygen carrying capacity leads to weakness and fatigue.
• Iron deficiency anemia is due to insufficient iron preventing the formation of heme groups in hemoglobin.
• Aplastic anemia results from bone marrow failing to produce enough red blood cells.
• Hemorrhagic anemia occurs from substantial blood loss due to injuries, or diseases like malaria.
• Sickle cell anemia involves abnormal red blood cell shape leading to early destruction by the body.
• Thalassemia occurs due to inadequate alpha or beta protein chains preventing the formation of functional hemoglobins, causing reduced oxygen-carrying capacity.

Blood Disorders: Leukemia

• Cancer of white blood cells causing uncontrolled division.
• Abnormal white blood cells crowd normal cells interfering with organ function.
• Aplastic anemia and defective clotting may result from leukemia.
• Internal bleeding and infection are possible complications of leukemia.

Blood Disorders: Hemophilia

• Hemophilia leads to uncontrolled bleeding.
• Possibly due to insufficient platelets, liver disease preventing the production of clotting proteins, vitamin K deficiency, or inherited defective clotting proteins.