The immune system

• What is the main focus of the video discussed in the study material?

  The human body's defense system against pathogens
• What are the two main components of the human body's defense system?

  • Physical and chemical barriers
  • Immune system
• How do physical and chemical barriers function in the body's defense system?

  They stop pathogens from entering the body.
• What is the primary physical barrier that protects the body from pathogens?

  Skin
• What substances does the skin secrete to help kill pathogens?

  Oils and antimicrobial substances
• How do pathogens typically enter the body if they cannot penetrate the skin?

  Through openings like the nose or mouth
• What adaptations do the nose have to prevent pathogens from entering the body?

  Lots of little hairs and mucus
• What are the two tubes that lead from the throat?

  The trachea and the esophagus
• What is the role of mucus in the trachea, bronchi, and bronchioles?

  To trap particles and pathogens
• What structures help move mucus and trapped particles up to the throat?

  Cilia
• What happens to the mucus once it reaches the back of the throat?

  It is swallowed down to the stomach
• What strong acid does the stomach produce to kill pathogens?

  Hydrochloric acid
• What is the approximate pH level of the stomach contents?

  About 2
• What happens to most pathogens in the stomach due to the acid?

  They are killed
• What takes over when pathogens manage to enter the body despite the defenses?

  The immune system
• What is the primary type of cell involved in the immune system?

  White blood cells
• What are the three important functions of white blood cells?

  Phagocytosis, producing antitoxins, and producing antibodies
• What is phagocytosis?

  A process where white blood cells engulf pathogens
• How do white blood cells destroy pathogens during phagocytosis?

  By tracking them down, binding to them, and engulfing them
• What do white blood cells produce to counteract toxins from pathogens?

  Antitoxins
• What are antigens?

  Substances detected by the immune system as foreign
• What are antibodies?

  Small proteins made by white blood cells that bind to antigens
• How do antibodies function in the immune response?

  They signal white blood cells to destroy foreign antigens
• What happens once the immune system identifies effective antibodies?

  It produces many of them and remembers for future attacks
• What does it mean to be immune to a disease?

  The body can quickly produce antibodies to destroy pathogens before they can develop
• How do we survive the millions of pathogens that attack us daily?

  Through our body's defense system
• What is the purpose of the video creator asking for likes at the end of the video?

  To gauge the usefulness of the video
• What is the role of phagocytes?

  digest and destroy bacteria and other microorganisms that have infected our bodies
• What is the role of lymphocytes?

  produce antibodies to destroy microorganisms- some lymphocytes persist in our blood after infection and give us immunity to specific diseases