More heart /blood

• What region of the brain controls heart rate?

  Medullary chemoreceptors
• What are the two components of the autonomic nervous system?

  Sympathetic and parasympathetic
• What type of actions does the autonomic nervous system involve?

  Unconscious actions
• What part of the nervous system is the autonomic nervous system a part of?

  Peripheral nervous system
• What is the role of the medulla oblongata in heart rate control?

  It controls heart rate via pacemaker cells
• How does the sympathetic nervous system affect heart rate?

  It increases heart rate
• What happens to valves in varicose veins?

  They become faulty and allow blood pooling
• What are the components that make up blood?

  Erythrocytes, lymphocytes, phagocytes, platelets, plasma
• What is the function of erythrocytes?

  Transport oxygen
• What is the function of lymphocytes?

  Produce antibodies
• What do phagocytes do?

  Engulf and digest pathogens
• What are platelets?

  Cell fragments that help blood to clot
• What is the structure of a red blood cell?

  Biconcave shape to increase surface area
• Why do red blood cells lack a nucleus?

  To have more space for hemoglobin
• What is fibrin?

  An insoluble protein that helps blood clot
• How does fibrin assist in the clotting process?

  It forms a mesh that traps cells
• What useful substances are found in blood?

  Oxygen, glucose, hormones, amino acids
• What wasteful substances are found in blood?

  CO2 and waste urea