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The Pressure Flow Model in a Plant

By: HWC, Views: 7103

The vascular system of plants has two transport tissues, called xylem and phloem. Xylem transports water and minerals, while phloem transports a variety of dissolved substances, including sugars and amino acids, throughout the plant. Water in the xylem always moves up, in the direction from th...

Stroke volume - afterload definition & hypertension

By: HWC, Views: 7189

• Pressure (or other resisting force) that ventricles must overcome to push open semilunar valves and eject blood. ▪ Normally, the left ventricle blood pressure must overcome arterial pressure in the aorta. ▪ Abnormally high blood pressure, or hypertension, increases aortic pressure w...

Pressure Flow Model Animation

By: HWC, Views: 6993

This apparatus of beakers A and funnels simulates the flow of a sucrose solution in the phloem of a plant. The funnels and connecting tube represent a sieve tube of the phloem. Differentially permeable membranes cap the funnels at the source and sink ends, allowing water, but not sucrose, to cros...

Monohybrid crosses

By: HWC, Views: 5581

A monohybrid cross is a cross between two parents that breed true for different versions of a single trait. In this example, that trait is flower color. The allele that specifies purple flowers is dominant over the allele that specifies white flowers. The purple-flowered plant has two domin...

Mechanisms of capillary exchange (transcytosis & bulk flow)

By: HWC, Views: 7399

■ This method of capillary exchange is mainly used to transport small amounts of large, lipid-insoluble (water soluble) molecules, such as large proteins. ■ Substances, packaged in vesicles, move through endothelial cells via endocytosis and exocytosis. ■ This method of exchange is th...

Mechanisms of capillary exchange

By: HWC, Views: 7876

■ The primary role of capillaries is to permit the exchange of nutrients and wastes between the blood and tissue cells (via interstitial fluid). ■ Oxygen and nutrients move from the blood to the cells. ■ Carbon dioxide and other wastes move from the cells to the blood. The three ba...

Hemodynamics Animation

By: Administrator, Views: 11478

Hemodynamics is the dynamics of blood flow. The circulatory system is controlled by homeostatic mechanisms, such as hydraulic circuits are controlled by control systems. Hemodynamic response continuously monitors and adjusts to conditions in the body and its environment.

Primary and secondary response to infection

By: HWC, Views: 7470

• 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...

Mechanisms for chromosome movement Animation

By: HWC, Views: 4727

At mitotic metaphase, the fully-formed spindle is composed of many microtubules that extend from the poles. Some of these, the kinetochore microtubules, are attached to the kinetochores of each chromosome. Kinetochores are located at the centromeres. At anaphase, sister chromatids separate and...