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Primary and secondary response to infection

By: HWC, Views: 6401

• 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...

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

By: HWC, Views: 6580

• 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...

Types of antimicrobial substances (interferons & complement protein)

By: HWC, Views: 6740

• 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...

Inflammation and Fever

By: HWC, Views: 7134

• 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...

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

By: HWC, Views: 7009

• Most cells which have CD8 on their surface become cytotoxic T cells (Tc cells). • CD8 T cells recognize a foreign antigen when it is presented in conjunction with the protein, MHC-I. • Nearly all nucleated cells in the body express MHC-I molecules. • T cells that recognize self-pe...

Cardiac conductile cells

By: HWC, Views: 6906

• In order for the heart to function properly, all of its cells must contract in a specific sequence. This sequence is determined by a pathway known as the conduction system. • Cardiac muscle cells have two attributes that enable the conduction system to work: • Connective. Action pot...

Coaductile pathway, Timing of contraction signal & Conduction system and ECG

By: HWC, Views: 6889

• When the system is healthy, the signal to contract the entire conduction system originates in the SA node - known as the heart's pacemaker. • The SA node triggers contraction because it depolarizes at a faster rate than other parts of the conduction system. • The wave of excitation fr...

Stroke volume

By: HWC, Views: 6664

Preload definition • Preload is the degree of stretch of cardiac muscles cells prior to contraction. • The amount of stretch is related to the end-diastolic volume[EDV]. • Increased return blood flow from the veins increases end-diastolic volume. Cardiac muscle sarcomeres stretch and ...

Homeostasis (range of body conditions, normal limits, mild stresses & severe stresses)

By: HWC, Views: 6616

Homeostasis: • Provides relative stability of the internal environment. • Results from constant adjustments. • Regulated by regulatory processes. • Requires system interplay. • Normal limits. • Temporary stresses. • Disruptions requiring medical intervention. • D...