परिक्रामी प्रणाली

CIRCULATION SYSTEM

• Angiology is the study of the circulatory system
• William Harvey is considered the father of angiology
• Vertebrates have a closed circulatory system
• Earthworms also have a closed circulatory system
• Animals with a spine are called vertebrates, examples include fish, amphibians, reptiles, birds, and mammals
• Blood is red in color due to the presence of hemoglobin
• Blood is a fluid connective tissue, connecting all body parts
• pH of blood is 7.4, slightly alkaline
• Blood is about 4-5 times thicker than water
• Blood makes up about 7% of a person's body weight
• Blood is a colloid solution (solute + solvent)
• Blood size ranges from 1-1000 nanometers

BLOOD COMPOSITION

• Plasma (liquid portion, 55%):
  • Color: Yellowish
  • Contains water (90-92%), proteins (7%), minerals/ions (0.9%), amino acids, glucose (0.1%)
  • Plasma proteins include albumin, globulin, fibrinogen/prothrombin, involved in blood clotting
• Solid portion (45%):
  • Red Blood Cells (RBCs/Erythrocytes):
    • Red color due to hemoglobin, which carries oxygen
    • Biconcave shape
    • Produced in bone marrow
    • Life span: 120 days
    • Destroyed in the liver and spleen
    • Contains 4 iron atoms that bind to oxygen
  • White Blood Cells (WBCs/Leukocytes):
    • Crucial in the immune system
  • Platelets (Thrombocytes):
    • Crucial in blood clotting
• Hemoglobin:
  • Protein containing iron, responsible for oxygen transportation in blood
• Bilirubin:
  • Yellow pigment produced by the liver
• Biliverdin:
  • Green pigment produced during hemoglobin breakdown

RBC (Red Blood Cell)

• RBC count: 4.5-5.5 million/mm³ (men), 4-5 million/mm³ (women)
• Low RBC count causes anemia
• High RBC count is called polycythemia
• RBCs do not have a nucleus in most mammals
• RBCs contain 4 chains of haemoglobin for carrying oxygen
• RBCs formation depends on Vitamins B6, B9 , B12
• Height at which humans live affects RBCs count