Blood Coagulation and Platelets

Platelets Coagulation

• Platelets (thrombocytes) are small, irregularly-shaped blood cells involved in blood coagulation
• Functions:
  • Form blood clots to stop bleeding
  • Release chemicals that attract white blood cells to fight infection
• Coagulation process:
  1. Injury to blood vessel
  2. Platelets aggregate to form a platelet plug
  3. Coagulation factors (e.g., thrombin) are activated
  4. Fibrin clot forms, trapping platelets and blood cells
  5. Clot retraction and dissolution

Red Blood Cells Oxygen Transport

• Red blood cells (erythrocytes) are biconcave disk-shaped cells that carry oxygen
• Functions:
  • Transport oxygen from lungs to tissues
  • Transport carbon dioxide from tissues to lungs
• Structure:
  • Flexible cell membrane
  • Hemoglobin protein binds to oxygen
  • No nucleus or organelles to maximize space for hemoglobin

White Blood Cells Immunity

• White blood cells (leukocytes) are part of the immune system
• Functions:
  • Phagocytosis: engulf and digest foreign particles and bacteria
  • Antibody production: produce antibodies to fight infection
  • Activation of immune responses
• Types of white blood cells:
  • Neutrophils: phagocytosis
  • Lymphocytes: antibody production
  • Monocytes: mature into macrophages for phagocytosis
  • Eosinophils: combat parasites and play a role in allergic reactions
  • Basophils: involved in inflammation and allergic reactions

Plasma Protein Functions

• Plasma is the liquid portion of blood, comprising 92% water and 8% proteins and nutrients
• Protein functions:
  • Albumin: maintains blood pressure, transports hormones and fatty acids
  • Globulins: transport lipids, hormones, and vitamins
  • Fibrinogen: converts to fibrin in blood coagulation
  • Immunoglobulins: antibodies produced by B cells

Blood Type Compatibility

• ABO blood group system:
  • A and B antigens on red blood cells
  • Corresponding antibodies in plasma (A and B)
• Compatibility rules:
  • Type A: can receive A or O blood, but only donate to A
  • Type B: can receive B or O blood, but only donate to B
  • Type AB: can receive AB, A, B, or O blood, but only donate to AB
  • Type O: can receive O blood, but can donate to all types
• Rh factor:
  • Rh+ (Rh positive): has Rh antigen on red blood cells
  • Rh- (Rh negative): lacks Rh antigen on red blood cells

Blood Component Functions

• Platelets:
  • Involved in blood coagulation
  • Form blood clots to stop bleeding
  • Release chemicals to attract white blood cells to fight infection
• Red Blood Cells:
  • Carry oxygen from lungs to tissues
  • Carry carbon dioxide from tissues to lungs
  • Have flexible cell membrane and hemoglobin protein to bind oxygen
  • Lack nucleus and organelles to maximize space for hemoglobin
• White Blood Cells:
  • Part of immune system
  • Engulf and digest foreign particles and bacteria through phagocytosis
  • Produce antibodies to fight infection
  • Activate immune responses
  • Types: neutrophils, lymphocytes, monocytes, eosinophils, basophils

Blood Coagulation Process

• Injury to blood vessel
• Platelets aggregate to form platelet plug
• Coagulation factors (e.g., thrombin) are activated
• Fibrin clot forms, trapping platelets and blood cells
• Clot retraction and dissolution

Plasma Functions

• Comprises 92% water and 8% proteins and nutrients
• Albumin:
  • Maintains blood pressure
  • Transports hormones and fatty acids
• Globulins:
  • Transport lipids, hormones, and vitamins
• Fibrinogen:
  • Converts to fibrin in blood coagulation
• Immunoglobulins:
  • Antibodies produced by B cells

Blood Type Compatibility

• ABO blood group system:
  • A and B antigens on red blood cells
  • Corresponding antibodies in plasma (A and B)
• Compatibility rules:
  • Type A: can receive A or O blood, but only donate to A
  • Type B: can receive B or O blood, but only donate to B
  • Type AB: can receive AB, A, B, or O blood, but only donate to AB
  • Type O: can receive O blood, but can donate to all types
• Rh factor:
  • Rh+ (Rh positive): has Rh antigen on red blood cells
  • Rh- (Rh negative): lacks Rh antigen on red blood cells

Blood Components

Platelets and Coagulation

• Platelets are small, irregularly-shaped blood cells that play a vital role in blood clotting
• Platelets are produced in the bone marrow through thrombopoiesis
• Platelets form a platelet plug when a blood vessel is injured, which is the initial step in the coagulation cascade
• Coagulation is the process of forming a blood clot to prevent excessive bleeding
• Platelets release chemicals that attract more platelets and facilitate the formation of a fibrin clot

Red Blood Cells and Oxygen Transport

• Red blood cells (RBCs) carry oxygen from the lungs to the body's tissues
• RBCs contain hemoglobin, which binds to oxygen and gives blood its red color
• Hemoglobin is composed of four polypeptide chains (globins) and four heme groups
• Oxygen binds to the iron atom in the heme group, allowing RBCs to transport oxygen to the body's tissues
• RBCs are flexible, disk-shaped cells that can change shape to fit through narrow blood vessels

White Blood Cells and Immunity

• White blood cells (WBCs) are a key component of the immune system
• There are several types of WBCs, including neutrophils, lymphocytes, monocytes, and eosinophils
• WBCs fight infection and disease by phagocytosing foreign particles and bacteria, producing antibodies, and activating the immune response
• WBCs also destroy infected cells or foreign substances

Plasma and Protein Functions

• Plasma is the liquid portion of blood that carries proteins, nutrients, and waste products
• Plasma proteins, such as albumin, globulins, and fibrinogen, have several important functions:
  • Maintaining blood pressure and volume
  • Regulating blood pH and electrolyte balance
  • Transporting hormones, vitamins, and nutrients
  • Supporting the immune response
  • Helping to form blood clots

Blood Type Compatibility

• Blood type is determined by the presence or absence of specific antigens on the surface of RBCs
• There are four main blood types: A, B, AB, and O
• Each blood type has specific antibodies that react with incompatible antigens, leading to an immune response
• Type O negative blood is considered the "universal donor" type, as it can be transfused to anyone without triggering an immune response