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Neurosynapse Animation

By: Administrator, Views: 10702

In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell. Synapses are essential to neuronal function: neurons are cells that are specialized to pass signals to individual tar...

Rods and Cones Animation

By: Administrator, Views: 11166

A photoreceptor cell is a specialized type of neuroepithelial cell found in the retina that is capable of visual phototransduction. The great biological importance of photoreceptors is that they convert light (visible electromagnetic radiation) into signals that can stimulate biological processes...

Conduction of action potentials

By: HWC, Views: 7899

• Action potentials must be rapidly conducted over long distances in order for the nervous system to communicate with other cells. • Propagation of an action potential uses processes similar to those that generate the potential at the trigger zone. • a When a graded potential reaches ...

The Pressure Flow Model in a Plant

By: HWC, Views: 7121

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...

Cognitive development by Piaget (Preoperational stage or intelligence)

By: HWC, Views: 6949

The next stage of cognitive development proposed by Piaget, is the preoperational stage, roughly between the ages of 2 and 7. At this stage Piaget asserted that a child has what he called preoperational intelligence. hey can mentally representing objects, but do not have a system for organising...

Secretin (inhibiting gastric acid secretion), Cholecystokinin (fat digestion) & Cholecystokinin

By: HWC, Views: 7569

• As chyme approaches the small intestine, secretin also targets acid-producing parietal cells in the gastric mucosa. • Increased secretin inhibits gastric add secretion. • With less gastric acid produced, the chyme going into the intestine is less acidic. • The hormone CCK also reg...

HIV Infection: Viral life cycle

By: HWC, Views: 7092

The series of steps that HIV follows to multiply in the body. The process begins when HIV encounters a CD4 cell. The seven steps in the HIV life cycle are: 1) binding; 2) fusion; 3) reverse transcription; 4) integration; 5) replication; 6) assembly; and 7) budding. Many viruses f...

Types of antimicrobial substances (interferons & complement protein)

By: HWC, Views: 7771

• Found in blood and interstitial fluids. • Discourage microbial growth. • Include interferon and complement proteins. • Produced and released by virus-infected lymphocytes. • Enter new cells and inhibit viral replication. • Act against a large variety of viruses (non-speci...

Role of the urinary system - acidosis and alkalosis

By: HWC, Views: 7966

• Tubular cells of the proximal convoluted tubule and collecting tubules can alter filtrate pH and therefore blood pH. • These cells can affect blood pH with two coupled mechanisms: • Reabsorption of bicarbonate ions. • Secretion of hydrogen ions. • The reabsorption of bicarbonate...