Search results for: 'antibiotic resistance'

Watch Later 3:14

By: HWC, Views: 6343

The Crisis in Antibiotic Resistance More than 70 years ago, Alexander Fleming discovered penicillin. A few decades later, when this antibiotic was used in World War II, Fleming's discovery had revolutionized medicine. No longer did people have to die from something as trivial as an infected cut.Y...

Watch Later 2:54

Mycobacterium tuberculosis: Drug Resistance and Natural Selection

By: HWC, Views: 5443

The evolution of drug resistance in microorganisms, such as M. tuberculosis, that cause human diseases is of particular concern to biologists. When Mycobacterium tuberculosis infects the lungs of humans, it causes the disease tuberculosis, also called TB. Once infected, the lungs act as a new...

Watch Later 2:09

Natural Selection, Species Isolation and Real World Example

By: HWC, Views: 6086

`Natural selection' is the process in which organisms with adaptive traits survive and breed in greater number than organisms without such traits. Eventually, almost all of the individuals in the population will have the same adaptive trait. This was the concept presented by Charles Darwin in ...

Watch Later 2:58

The primary factors that affect circulation - MABP, CO and SVR

By: HWC, Views: 6949

Introduction Blood flow is determined by the relative intensities of factors that drive and resist moving blood. • Cardiac output (CO) equals the mean arterial blood pressure (MABP, a driving force) divided by systemic vascular resistance (SVR, a resisting force). • Hormones and the cen...

Watch Later 1:10

Types of disease resistance: innate defenses & immunity

By: HWC, Views: 6861

Our immune system protects us and helps fight off disease. Microorganisms, small microscopic organisms, and viruses are everywhere. Ever thought about how many are on that door you just opened? Many microbes and viruses can cause disease and are termed pathogens. Plants and animals have what i...

Watch Later 2:30

Primary and secondary response to infection

By: HWC, Views: 6389

• 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: 6573

• 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 3:10

Plant Defense Mechanisms from Pathogens

By: HWC, Views: 6102

Plants and pathogens have coevolved such that pathogens can recognize plants by the sugars, or other molecules, they produce. Plants, in turn, can recognize pathogens by the molecules they produce. The ability to recognize pathogens allows plants to activate defense systems that can prevent wides...

Watch Later 1:40

Structures that affect circulation - arterioles and vasomotor responses and venous return

By: HWC, Views: 6742

■ 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 ...

Search Results