Search results for: 'El'

Watch Later 1:42

By: HWC, Views: 7497

• Non-specific and specific defense mechanisms work through the functions of complement proteins. • As soon as pathogens penetrate the physical barrier of the skin, other resistance mechanisms begin. • Cells, such as macrophages, phagocytize pathogens. • These cells increase exposu...

Watch Later 2:30

Primary and secondary response to infection

By: HWC, Views: 7489

• Pathogens enter the body by penetrating the non-specific barriers in the skin and mucus membranes. • Pathogens first encounter macrophages and natural killer cells that carry out phagocytosis and cytolysis respectively. • A pathogen's first encounter with the immune system can promo...

Watch Later 2:08

Non-specific disease resistance mechanisms & Skin's defense barriers

By: HWC, Views: 7734

• Non-specific disease resistance acts quickly to fight a wide variety of invaders. • Mechanisms include: • Barriers • Antimicrobial substances • Cellular defenses • Inflammation • Fever Barriers - types • Physical and chemical bathers prevent invasion by micro...

Watch Later 3:45

Barriers - eye structures, digestive mucosa, respiratory mucosa & genitourinary mucosa

By: HWC, Views: 8046

• Eyebrows, eyelids, eyelashes and conjunctiva serve to trap microbes preventing their invasion. • Tearing (lacrimation) is a protective mechanism that washes away microbes that attempt to enter the eyes. • Salts, mucus, and lysozymes in tears neutralize substances and bacteria. �...

Watch Later 2:19

Types of antimicrobial substances (interferons & complement protein)

By: HWC, Views: 7774

• Found in blood and interstitial fluids. • Discourage microbial growth. • Include interferon and complement proteins. • Produced and released by virus-infected lymphocytes. • Enter new cells and inhibit viral replication. • Act against a large variety of viruses (non-speci...

Watch Later 2:58

Cellular defenses (natural killer cells, phagocyte types & process of phagocytosis)

By: HWC, Views: 7480

• Lymphocytes that rapidly defend against abnormal (cancer) or virus-infected cells. • Found in blood, spleen, lymph nodes, and red bone marrow. • Lack receptors for binding with specific antigens. • Act upon cells displaying abnormal MHC antigens. • NK cells destroy cells in ...

Watch Later 3:05

Inflammation and Fever

By: HWC, Views: 8232

• Inflammation is an immune response that can occur anywhere in the body, but is observed most frequently on the skin. • It provides early protection by preventing infection from spreading to other parts of the body. • Inflammation also promotes repair of damaged tissues. Inflammat...

Watch Later 1:10

T cell receptors

By: HWC, Views: 7432

• T cells are responsible for cell-mediated immunity. • Each T cell contains a unique form of T cell receptor (TCR) on its membrane. • These T cell receptors are produced through a process of genetic recombination which is able to produce millions of different variations. • Each T ce...

Watch Later 2:51

Helper T cell receptors, activation, proliferation, differentiation & action

By: HWC, Views: 7837

• Most cells which have CD4 on their surface become Helper T cells (TN cells). • The CD4 1 cells only recognize a foreign antigen when it is presented with an antigen presenting immune cell (APC) that includes MHC-II protein. • The Helper T cell antigen receptor must match the presented...

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