Innate defences - 1st and 2nd line of defence(2) - Tagged.pdf

The body’s response to injury Part A – (1st and 2nd line of defenses) Mr Bashir Sumar School of Nursing and Midwifery  Important Copyright Notice for Western Sydney University Students The material in this presentation...

The body’s response to injury Part A – (1st and 2nd line of defenses) Mr Bashir Sumar School of Nursing and Midwifery  Important Copyright Notice for Western Sydney University Students The material in this presentation has been made available to you by and on behalf of Western Sydney University for your personal use and study only. The material contained in this recorded lecture is subject to copyright protection. You may not make any further copies and share the recorded lectures in whole or in part by any hardcopy, digital and or online technologies. Objectives of Part A Innate or non-specific defenses Surface Barriers: Skin and Mucosae Describe surface membrane barriers and their protective functions. Internal Innate defenses: Cells and Chemicals Explain the importance of phagocytosis and natural killer cells in innate body defense. Describe the inflammatory process at a basic level. Name some of the body’s antimicrobial substances and state their function.  Overview of the body’s defenses 1st line of defense Or Innate immunity 2nd line of defense Non-Specific Immunity 3rd Line of Defense Specific Immunity Or acquired immunity  Innate defenses Surface barriers-1St Line of defense. Surface barriers ward off invading pathogens – Skin, mucous membranes, and their secretions Physical barrier to most microorganisms Keratin resistant to weak acids and bases, bacterial enzymes, and toxins Mucosae provide similar mechanical barriers Other features include the hairs, mucous lining, skin secretions, gastric juice… etc. Can you think of the role they play in our body’s defenses? Surface barriers -1St Line of defense…cont’d Protective chemicals inhibit or destroy microorganisms – Acidity of skin and secretions – acid mantle – inhibits growth – Enzymes - lysozyme of saliva, respiratory mucus, and lacrimal fluid – kill many microorganisms – Mucin forms thick sticky mucous that traps microorganisms – Defensins – antimicrobial peptides – inhibit growth – Other chemicals - lipids in sebum, dermcidin in sweat – toxic © 2016 Pearson Education, Inc. Surface barriers -1St Line of defense…cont’d Respiratory system modifications – Mucus-coated hairs in nose – Cilia of upper respiratory tract sweep dust- and bacteria-laden mucus toward mouth Surface barriers breached by nicks or cuts - second line of defense must protect deeper tissues © 2016 Pearson Education, Inc.  Reflection Imagine you are a bacteria or a virus trying to enter into a perfectly healthy human body. – Name at least five different possible entry points you could use to enter. – For each entry point identify and discuss at least two obstacles that you will face and what eventually happens to you. – What would you need or what needs to happen so you are successful?  Innate defenses Internal defenses: cells and chemicals -2nd Line of defense. Once the barrier defenses (1st line of defense) are breached, protective tactics that employ and mobilise the inflammatory response are activated. This response enlists macrophages, mast cells, white blood cells, and dozens of chemicals that kill pathogens and help repair tissue. These protective tactics identify and destroy harmful substances but not human cells  Innate defenses Internal defenses: cells and chemicals -2nd Line of defense. Necessary if microorganisms invade deeper tissues – Phagocytes (neutrophils and macrophages) – Natural killer (NK) cells – Antimicrobial proteins (interferons and complement proteins) – Fever – Inflammatory response (macrophages, mast cells, WBCs, and inflammatory chemicals)  Figure 21.2a Phagocytosis. Innate defenses Internal defenses A macrophage (purple) uses its cytoplasmic extensions to pull rod-shaped bacteria (green) toward it. Scanning electron micrograph (4800x). © 2016 Pearson Education, Inc.  Figure 21.2b Phagocytosis. Slide 1 1 Phagocyte adheres to pathogens or debris. 2 Phagocyte forms pseudopods that Phagosome eventually engulf the (phagocytic particles, forming a vesicle) phagosome. Lysosome 3 Lysosome fuses with the phagocytic vesicle, forming a phagolysosome. Acid hydrolase enzymes 4 Lysosomal enzymes digest the particles, leaving a residual body. 5 Exocytosis of the vesicle removes indigestible and residual material. Events of phagocytosis. © 2016 Pearson Education, Inc. Immune system: Innate defenses https://www.youtube.com/watch?v=z3M0vU3Dv8E Please watch the first 4:45 minutes of this video - it introduces the skin as one of the innate defences which are covered in this weeks module.