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Pores and Ion Channels

By: HWC, Views: 6908

Transmembrane channels, also called membrane channels, are pores within a lipid bilayer. The channels can be formed by protein complexes that run across the membrane or by peptides. They may cross the cell membrane, connecting the cytosol, or cytoplasm, to the extracellular matrix. Membrane po...

The Lac Operon in E. Coli

By: Administrator, Views: 11790

The lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria. Although glucose is the preferred carbon source for most bacteria, the lac operon allows for the effective digestion of lactose when glucose is no...

Structures that affect circulation - arterioles and vasomotor responses

By: HWC, Views: 7425

■ Small arteries and arterioles determine SVR. ■ Blood pressure drops significantly as blood passes through arterioles. ■ Decreasing arteriole radius and decreased wall elasticity are the main reasons for increased SVR. ■ Small changes in arteriole radius can cause large changes in ...

Role of complement proteins

By: HWC, Views: 7474

• 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...

Structures that affect circulation - heart and systolic/diastolic BP

By: HWC, Views: 7634

• Heart generates blood pressure. • Arterioles produce resistance thereby regulating blood flow to tissues. • Veins store blood; kidneys regulate blood volume; both affect venous return and cardiac output. ■ Contractions of the ventricles determine blood pressure, which drives th...

Negative Feedback Regulation of Blood Pressure

By: HWC, Views: 7722

stimulus • Blood pressure determines the flow of blood to and from capillaries. • Low blood pressure results in reduced blood flow. • High blood pressure can cause blood vessels to break. Baroreceptors • The aortic arch carries blood to the body. • The common carotids ca...

Otitis Media

By: Administrator, Views: 10802

Otitis media is a group of inflammatory diseases of the middle ear. The two main types are acute otitis media (AOM) and otitis media with effusion (OME). AOM is an infection of rapid onset that usually presents with ear pain. In young children this may result in pulling at the ear, increased cryi...

Gonorrhea

By: Administrator, Views: 294

Gonorrhea, colloquially known as the clap, is a sexually transmitted infection (STI) caused by the bacterium Neisseria gonorrhoeae. Infection may involve the genitals, mouth, or rectum. Infected men may experience pain or burning with urination, discharge from the penis, or testicular pain. Infec...

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

By: HWC, Views: 7813

• 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...