Search Results

Mechanisms of capillary exchange

By: HWC, Views: 6775

■ 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...

Urinary System Animation

By: Administrator, Views: 999

The urinary system: kidneys, ureters, bladder, and urethra with expanded view of a nephron and the urine-filled space within a bladder. Urinary system: two kidneys, two ureters, one bladder, one urethra. Also called the excretory, genitourinary (GU), or urogenital (UG) system. Produces, stor...

Junction Types - Tight and Adherens Junctions

By: HWC, Views: 7000

Many tissues contain in tercellular junctions between cells. 1. Tight junction 2. Adherens junction 3. Desmosome 4. Hemidesrnosome 5. Gap junction 1. Tight junction • Web-like strips of proteins fuse together adjacent plasma membranes. • Tight junctions prevent the transport...

The Pressure Flow Model in a Plant

By: HWC, Views: 6028

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...

Requirements for nervous signals

By: HWC, Views: 6638

• The function of neurons is to allow communication between cells, thereby maintaining homeostasis. • Electrical signals, called membrane potentials, travel along the membranes of the neurons. • Voltage variability and distance traveled determine the type of nervous signal. 1. Graded...

The Lac Operon in E. Coli

By: Administrator, Views: 10709

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...

Pressure Flow Model Animation

By: HWC, Views: 5870

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...

Mechanisms of capillary exchange (transcytosis & bulk flow)

By: HWC, Views: 6303

■ 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...

Lipid absorption - end products & transport mechanism

By: HWC, Views: 6196

• The end products, fatty acids and monoglycerides, depend on bile salts for absorption. • Bile salts form micelles (tiny spheres), which ferry fatty acids and monoglycerides to epithelial cells. • Free fatty acids, monoglycerides, and some phospholipids and cholesterol molecules, dif...