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Structures that affect circulation - arterioles and vasomotor responses

By: HWC, Views: 7450

■ 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 ...

The Lac Operon in E. Coli

By: Administrator, Views: 11808

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...

Role of complement proteins

By: HWC, Views: 7496

• 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...

Inflammatory response Animation

By: HWC, Views: 4290

Any tissue damage or bacterial invasion can bring about inflammation. The inflammatory response can be triggered by an invasion of bacteria, or by a cut or other physical damage to cells. Chemicals, such as histamine, released by the bacteria or damaged cells. accumulate in the tissue. Thes...

Structures that affect circulation - heart and systolic/diastolic BP

By: HWC, Views: 7665

• 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: 7737

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...

Evolutionary tree of life Animation

By: HWC, Views: 1404

An evolutionary tree of life that reflects mainstream thinking about the connections among major lineages (bya = billions of years ago, mya = millions of years ago). By about 3.8 billion years ago, chemical and molecular evolution had produced the first living cells. The first major divergenc...

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: 7835

• 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...