The Immune System Overview, Animation
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- Опубліковано 10 гру 2018
- (USMLE topics) What happens during an infection? Surface barriers, innate and adaptive immune response. Purchase PDF (script of this video + images) here: www.alilamedicalmedia.com/-/g...
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Voice by: Ashley Fleming
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The immune system is the body’s defense system. It protects the body from disease-causing organisms, called pathogens. Surface barriers: physical, chemical, and biological obstacles. The primary physical barrier is the skin. Body systems that are open to outside environment, such as the respiratory, digestive, urinary and reproductive system, each have their own mechanisms to prevent entrance of microbes: mucous membranes trap them, sneezing or coughing reflex expels them, while urine mechanically flushes them out. Chemical barriers include stomach acid and various antimicrobial substances in sweat, saliva, tears. The body’s normal flora competes with pathogens for nutrition and space, providing biological barriers.
If an organism manages to get past the surface barriers, it will meet with the innate component of the immune system, which mounts an immediate, but non-specific response. If this fails to contain the infection, another layer of defense, called the adaptive, or acquired, immune response comes into play. The adaptive response takes longer to be activated, but is more effective as it specifically targets the invading pathogen. It also leaves the body with a “memory” of the pathogen, so it can react faster the next time the same pathogen attacks.
The major players of the immune system are the white blood cells, or leukocytes. All leukocytes derive from hematopoietic stem cells in the bone marrow. Each of them has different roles in the immune response.
The first response of the innate immune system is inflammation. Resident macrophages, which constantly patrol body tissues, ingest the pathogen and release inflammatory chemicals, called cytokines, which attract other immune cells to the site of injury. Basophils, eosinophils and mast cells release their own cytokines, amplifying inflammation. Cytokines dilate blood vessels, increasing blood flow and are responsible for clinical signs of inflammation such as redness and swelling. They act on endothelial cells of blood vessels and serve as chemical cues for migration of neutrophils - the major phagocytes involved in first-line defense. Activated endothelial cells attach to neutrophils in the flow, slowing them down, before getting them to squeeze through the vessel wall. Neutrophils engulf bacteria and destroy them with enzymes or toxic peroxides. They may also release highly reactive oxygen species in a phenomenon known as oxidative burst, which kills pathogens faster and more efficiently. The neutrophils themselves, however, also die in the process, their debris forming pus on the injury site.
The adaptive immune response starts with the so-called “antigen-presenting cells”, of which dendritic cells are most effective. Resident dendritic cells on the site of infection swallow up pathogens, cut them into pieces, called antigens, and display them on their surface. These dendritic cells are then picked up by lymphatic capillaries and travel to lymph nodes, where they present the antigens to a matching T-cell. The pathogen itself may also travel to a lymph node where it may encounter a matching B-cell. The match-finding process underlies the specificity of adaptive immune response. T-cells and B-cells exist in billions of variations, each carries a unique surface protein, which acts like a key. Among these billions of keys, only the ones that can bind to, or unlock, the invading pathogen, are activated. Activated T-cells and B-cells undergo differentiation and proliferation, called clonal expansion. This process produces memory cells, ready for future infections by the same pathogen; and effector cells, which include activated cytotoxic T-cells and plasma B cells producing antibodies; both of these are specific to the pathogen. Antibodies and cytotoxic T-cells then leave the lymph node for the bloodstream to be delivered to the site of infection.
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Best overview video on immunity ever! Keep up the good work!!
I saw this video 2 years ago and understood evrything , spent all day searching for it today
Good clear animation and narration. Excellent!
Thanks for all these videos! Very useful.
Great. The best video I watched in immunity. Keep going
Thank you for this video. It was of great help.
Immune system explained as good as I’ve seen. ✌️
Great and simple clearance and understand of immune system
Great video.. thanks alot!
Keep posting. You are amazing
Mam your video is clear about immunity,
I had seen many but I liked yours .
Wow, so interesting inmunology
after watching cells at work, this video becomes the best explanation of immune system
You are AMAZING!!!!!
Did not expect to hear that coughing noise in the background lmao
I am a medstudent and I found it very clear. Amazing job guys!
This is so amazing and fascinating 😆🤩
good job.thanks
Excellent !!
This was great.
Well presented.
Nice lecture
Excellent
very nice
Please make a video on hypersensitivity reactions
wow ❤❤ best overview video ,
Amazing
very nice video
tq
Can you do the immune videos in further detail please? Like immense extreme detail and go over all the cells and mechanisms and aspects of the human immune system please
that's like the basic principles of a whole semester of immunology...
Love it
Great vdo Mam!!
Thanks!
Welcome! Thanks for the Super thanks!
Keep it up !
Great
i love u guys
Could you make a immune system vs parasites please I'm a kid and training to become a Immunologist so tell me more thanks! 😊
The best
سبحان الله وبحمده سبحان الله العظيم ❤️❤️
Good job
Your videos are the best! Really helpful! Can you, please, also do the reproductive system?
video: immün sistem özet
immün sistemin efektör mekanizmaları
It’s very amazing that our body immune system fight the invaders. I wish scientists can invent something that using our own T Cells and B Cells to fight cancers or different diseases. Instead of administering toxic chemo or bad radiation in our body. I believe our immune system is the most important role for us to live in the 🌍 earth.
Why is that germ so cute?
❤❤💐💐👌👌👍👍🙏🙏
2 B
*2 braincells*
k?
What I like about the original Alila are the videos and the voice. This one sounds different and I don't like it.
Which ones did you like?
@@Alilamedicalmedia I liked the soothing, professional, more of automated type of voice from the original ones. The voice on this one is way opposite of it. Thanks for responding.