Hypersensitivity, Overview of the 4 Types, Animation.

Share this & earn $10
Alila Medical Media
Published at : 25 Sep 2021
81179 views
1710
31

(USMLE topics) Basics of hypersensitivity, symptoms, causes, summary of mechanisms of action the 4 types. This video is available for instant download licensing here https://www.alilamedicalmedia.com/-/galleries/images-videos-by-medical-specialties/allergy-immunology/-/medias/f9b07c9d-3dd9-4e20-8ded-6c73ee636e4d-hypersensitivity-narrated-animation
Voice by: Ashley Fleming
©Alila Medical Media. All rights reserved.
Support us on Patreon and get early access to videos and free image downloads: patreon.com/AlilaMedicalMedia
All images/videos by Alila Medical Media are for information purposes ONLY and are NOT intended to replace professional medical advice, diagnosis or treatment. Always seek the advice of a qualified healthcare provider with any questions you may have regarding a medical condition.
Hypersensitivity refers to abnormal reactions of the immune system against certain antigens. It includes exaggerated reactions to otherwise harmless environmental antigens, commonly known as allergies; and inappropriate reactions against the body’s own antigens, or autoimmune diseases.
Reactions can range from a mild rash, to damaged organs, to fatal anaphylactic shock.
There are 2 principal groups of factors contributing to hypersensitivity:
- Imbalance between effectors and regulators of immune response: in some people, mechanisms that normally moderate the immune system are compromised, causing it to overreact to harmless, non-infectious antigens.
- Self-reactivity of immune cells: during their development in the thymus and bone marrow, T-cells and B-cells learn to not react to the body’s own antigens; self-reactive cells are normally eliminated; but in some people, some of these cells escape and may attack their own tissues once activated.
Hypersensitivity reactions only occur in pre-sensitized individuals. Patients must have had a previous contact with the antigen, which produced no symptoms, but during which the body had started making antibodies or activated immune cells that may cause symptoms in subsequent exposures to the same antigen.
Hypersensitivity is classified into 4 types based on mechanisms of action:
In type I hypersensitivity, a previous exposure to the antigen results in production of a class of antibodies called IgE. IgE molecules bind to their receptors on the surface of mast cells and basophils. Upon re-exposure to the same antigen, or sometimes a similar antigen, the antigen binds to adjacent IgE molecules, bringing their receptors together, triggering a signaling cascade that induces the release of histamine and other inflammatory chemicals. These chemicals cause dilation of blood vessels, smooth muscle spasms, and are responsible for symptoms such as edema, rash, difficulty breathing due to bronchospasm, abdominal cramping, vomiting and diarrhea. The reactions are immediate, within minutes of contact with the antigen, and can range from mild to severe. Severe reactions may lead to anaphylactic shock, a life-threatening condition in which blood pressure drops and airways narrow to a dangerous level. Most allergies are type I hypersensitivity reactions.
In type II hypersensitivity, previously formed IgG or IgM antibodies bind to antigens on the surface of a particular cell type. Antibody binding marks the cells for destruction, either by the complement system or phagocytosis. The antibodies may also interfere with normal functions of the cells without killing them. Type II is at the basis of many autoimmune diseases, where the body produces antibodies to destroy its own cells. Another example is hemolytic disease of the newborn, where maternal antibodies bind to D-antigen on the surface of fetal red blood cells and destroy them.
Type III hypersensitivity reactions are also mediated by IgM or IgG, but in this case, the antibodies bind to free-floating antigens, forming antibody-antigen complexes. The complement system is activated and inflammation results, causing damage to the affected tissue. A typical example is serum sickness, induced by a large amount of antigens in the blood. Immune complexes are deposited in the walls of blood vessels, triggering their inflammation, or vasculitis.
Type IV hypersensitivity is a delayed reaction, mediated by T-cells. Pre-sensitized T-cells are produced during a previous contact with the antigen. Upon re-exposure to the same antigen, T-helper cells release inflammatory cytokines, while T-killers induce cytotoxic reactions. Typical examples are allergic reactions to substances that come into direct contact with the skin, known as contact dermatitis. Type IV is also the basis of the tuberculosis skin test.

yt:quality=highhypersensitivityimmune system

🔥 Fireplace (10 HOURS) Ultra HD 4K 🔥 Relaxing Fire Burning with Crackling Fire Sounds (NO MUSIC) UHD

🔥 Fireplace (10 HOURS) Ultra HD 4K 🔥 Relaxing Fire Burning with Crackling Fire Sounds (NO MUSIC) UHD

ITEM # 4 WILL SEND SHOCKWAVES THROUGH AMERICA

ITEM # 4 WILL SEND SHOCKWAVES THROUGH AMERICA

The card payment industry explained | emerchantpay

The card payment industry explained | emerchantpay

Would have & Wouldn't have |. English grammar lesson

Would have & Wouldn't have |. English grammar lesson

Maps - Vintage 1970s Soul Maroon 5 Cover ft. Morgan James

Maps - Vintage 1970s Soul Maroon 5 Cover ft. Morgan James

Bobby Vee  - Take Good Care Of My Baby  - 1961

Bobby Vee - Take Good Care Of My Baby - 1961

Incredible: How to make wine glass in marble

Incredible: How to make wine glass in marble

Damian "Jr. Gong" Marley - Medication ft. Stephen Marley

Damian "Jr. Gong" Marley - Medication ft. Stephen Marley

*NeW* ARTiSAN Made me Pop Off! - Valorant

*NeW* ARTiSAN Made me Pop Off! - Valorant

Lil Peep - worlds away (Official Audio)

Lil Peep - worlds away (Official Audio)

Linius ft. Kordas - Standard

Linius ft. Kordas - Standard

Proof - Kurt Kobain

Proof - Kurt Kobain

Typically Tropical - Barbados

Typically Tropical - Barbados

Pink VS Blue VS Black Food Color Challenge | Eating Everything Only in One Color by RATATA CHALLENGE

Pink VS Blue VS Black Food Color Challenge | Eating Everything Only in One Color by RATATA CHALLENGE

Don Moen - I Offer My Life | Praise & Worship Music

Don Moen - I Offer My Life | Praise & Worship Music

NICK YOUNG MONEY  X  RINA SAINYAKIT - ISSUE

NICK YOUNG MONEY X RINA SAINYAKIT - ISSUE

James Blake - Coming Back (Lyric Video) ft. SZA

James Blake - Coming Back (Lyric Video) ft. SZA

The Twins Who’ve Spent £140K To Make Themselves Even More Identical | This Morning

The Twins Who’ve Spent £140K To Make Themselves Even More Identical | This Morning

Selena Gomez - Lose You To Love Me (Official Music Video)

Selena Gomez - Lose You To Love Me (Official Music Video)

You've Already Got It! - Week 1, Day 1 - The Gospel Truth

You've Already Got It! - Week 1, Day 1 - The Gospel Truth

The Corporation - Documentary

The Corporation - Documentary

Come out of that bathroom young lady

Come out of that bathroom young lady

Understanding Types of Links |  Internal, Inbound & Outbound Links | (in Hindi)

Understanding Types of Links | Internal, Inbound & Outbound Links | (in Hindi)

Learn English Words: NOTWITHSTANDING - Meaning, Vocabulary with Pictures and Examples

Learn English Words: NOTWITHSTANDING - Meaning, Vocabulary with Pictures and Examples

remember me when summer ends

remember me when summer ends

M. Zubair's Alleged Video Scandal: When, Where and How | Media channel mentioned | Mansoor Ali Khan

M. Zubair's Alleged Video Scandal: When, Where and How | Media channel mentioned | Mansoor Ali Khan

How To Enroll in IFCU's Online Banking

How To Enroll in IFCU's Online Banking

Brownstone - 5 Miles To Empty (Official Video)

Brownstone - 5 Miles To Empty (Official Video)

An Entire Day with Freddie Benson 📹 iCarly | NickRewind

An Entire Day with Freddie Benson 📹 iCarly | NickRewind

NSW got 45 per cent of the Pfizer vaccines allocated to GPs last month, data shows | 7.30

NSW got 45 per cent of the Pfizer vaccines allocated to GPs last month, data shows | 7.30

Armin van Buuren & Avalan - Should I Wait (Official Video)

Armin van Buuren & Avalan - Should I Wait (Official Video)

Best Google Drive Add-Ons

Best Google Drive Add-Ons

Yungen ft. Dappy - Comfortable (Official Video)

Yungen ft. Dappy - Comfortable (Official Video)

Making Sure

Making Sure

Code Black & Atmozfears - Accelerate (Official XXlerator Anthem 2014)

Code Black & Atmozfears - Accelerate (Official XXlerator Anthem 2014)

Ne-Yo - Because Of You (Official Music Video)

Ne-Yo - Because Of You (Official Music Video)

Anybody can be good in the country The Most Popular Collection of OriginalSolo jazz

Anybody can be good in the country The Most Popular Collection of OriginalSolo jazz

Origin of the Genetic Code: What we do and do not know

Origin of the Genetic Code: What we do and do not know

Did we all FORGET how good Man City are? Only Pep Guardiola’s team could dominate Chelsea | ESPN FC

Did we all FORGET how good Man City are? Only Pep Guardiola’s team could dominate Chelsea | ESPN FC

Marketing Audit: It May Not Sound Exciting But It Can Be Crucial For Your Budget

Marketing Audit: It May Not Sound Exciting But It Can Be Crucial For Your Budget

Tallest Buildings by Country Ranking 2017

Tallest Buildings by Country Ranking 2017

Markets may see more volatility but it can be absorbed: Strategist

Markets may see more volatility but it can be absorbed: Strategist

DIRT TO MYSTIC BOW IN 1 VIDEO 2021 | GROWTOPIA PROFIT

DIRT TO MYSTIC BOW IN 1 VIDEO 2021 | GROWTOPIA PROFIT

Elderbrook - Could [Official Video]

Elderbrook - Could [Official Video]

Adopted By Evil DARK FAIRIES In Roblox!

Adopted By Evil DARK FAIRIES In Roblox!

Quixotic - Palms

Quixotic - Palms

Zubi - No Need (feat. Anatu & Rusalka)

Zubi - No Need (feat. Anatu & Rusalka)

Why There's Almost Certainly No Such Thing As Free Will

Why There's Almost Certainly No Such Thing As Free Will

I Am Determined

I Am Determined