Human Anatomy: Blood and Heart Study Notes

Human Anatomy: Blood and Heart Study Notes

• Blood Function:
  • Transportation of gases, nutrients, hormones, and waste products.
  • Regulation of pH, body temperature, and osmotic pressure.
  • Protection through clotting, white blood cells, and proteins.
• Blood Characteristics:
  • Volume: 8% of body weight (females: 4-5L, males: 5-6L)
  • pH: 7.35 to 7.45
  • Temperature: 38°C
• Blood Components:
  • Plasma (55%): Water, liquid extracellular matrix, proteins (albumins, globulins, fibrinogen), other solutes (electrolytes, nutrients, hormones, gases, waste).
  • Formed Elements (45%): Cells and cell fragments (red blood cells, white blood cells, platelets).
• Blood Cell Formation (Hematopoiesis):
  • Red bone marrow is the primary site.
  • Stem cells in red bone marrow reproduce and differentiate, forming all blood cells.
  • Pluripotent stem cells differentiate into myeloid and lymphoid stem cells.
  • Formed elements do not divide once they leave red bone marrow, except for lymphocytes.
  • Cells enter the bloodstream through sinusoids.
• Blood Cell Formation Regulation:
  • Hematopoietic growth factors regulate differentiation and proliferation.
  • Erythropoietin (EPO) from the kidney stimulates RBC production.
  • Thrombopoietin (TPO) from the liver stimulates platelet production.
  • Colony-stimulating factors (CSFs) and interleukins help with the formation of WBCs and other blood cells.
• Red Blood Cells (RBCs/Erythrocytes):
  • Structure: Biconcave, anucleate (no nucleus).
  • Components: Hemoglobin (transports oxygen and carbon dioxide), lipids, ATP, carbonic anhydrase.
  • Function: Transport oxygen and carbon dioxide.
  • Normal Count: 4.8 x 10⁶/µL (female), 5.4 x 10⁶/µL (male).
  • Disorders: Anemia
  • Life cycle: Live for about 120 days, destroyed by macrophages in spleen and liver, broken down components are recycled.
• Hemoglobin:
  • Protein in RBCs.
  • Composed of 4 globin molecules and 4 heme molecules.
  • Transports oxygen and carbon dioxide.
  • Iron is necessary for oxygen transport.
• Erythropoiesis:
  • RBC production begins in red bone marrow with proerythroblasts.
  • Proerythroblasts develop into mature RBCs within 1-2 days.
  • Regulation of erythropoiesis through negative feedback, controlled by the amount of oxygen delivery to tissues (low oxygen level causes release of EPO to produce more RBCs).
• White Blood Cells (WBCs/Leukocytes):
  • Types: Granular (neutrophils, eosinophils, basophils) and agranular (lymphocytes, monocytes).
  • Functions: Combat invaders through phagocytosis and immune responses.
• Platelets/Thrombocytes:
  • Cell fragments from megakaryocytes in red bone marrow.
  • Disc-shaped and contain vesicles, but no nucleus.
  • Important in preventing blood loss by forming platelet plugs and promoting clot formation.
• Blood Groups:
  • Determined by antigens (agglutinogens) on RBC surface.
  • Antibodies (agglutinins) in plasma can bind to antigens, causing agglutination or hemolysis.
  • ABO and Rh blood groups are common examples.
• Heart Location and Pericardium:
  • Located in the mediastinum, between the lungs, about 2/3 to the left of the midsternal line and 1/3 to the right.
  • Pericardium is a membrane around the heart, protecting and confining it while allowing free movement. The two main parts are the fibrous pericardium and the serous pericardium, which consists of a parietal and visceral layers.
• Heart Walls:
  • Three layers: Epicardium (outermost, visceral layer of serous pericardium). Myocardium (middle, cardiac muscle). Endocardium (innermost, endothelium).
• Heart Chambers:
  • Two atria (receiving chambers) and two ventricles (pumping chambers). Right atrium and ventricle handle deoxygenated blood and left atrium and ventricle handle oxygenated blood.
  • Blood moves between atria and ventricles through atrioventricular valves. Blood moves between ventricles and arteries through semilunar valves.
• Heart Valves:
  • AV (atrioventricular) valves (tricuspid, bicuspid/mitral) control blood flow between atria and ventricles. Regulate blood flow and prevent backflow from ventricles to atria.
  • Semilunar valves (aortic, pulmonary) control blood flow from ventricles into arteries. Prevent backflow from arteries into ventricles.
• Circulation: - Two main circuits: Pulmonary circulation moves blood between the heart and lungs for gas exchange. Systemic circulation moves blood between the heart and the rest of the body.
• Coronary Circulation:
  • Network of blood vessels that supply blood to the heart muscle, originating from the ascending aorta.
  • Main coronary arteries branch off into smaller branches (including posterior interventricular branch, marginal branch, anterior interventricular branch, circumflex branch).
  • Coronary veins empty into the coronary sinus and then into the right atrium for drainage.

Explore the critical functions, characteristics, and components of blood in the human body. This quiz covers the essential aspects of blood transportation, regulation, and cell formation, helping you understand the heart's role in circulation. Perfect for students studying human anatomy.