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Action potentials - electrical characteristics and generation

By: HWC, Views: 6567

• An action potential is the nervous impulse or signal for long distance communication. Each action potential is generated at the cell's trigger zone. • Action potentials are considered an all-or-nothing phenomena because they are either generated or not. • The generation of an action...

Darwin's Observation (Fossils, Galapagos Islands & Africa ) and Natural Selection (Adaptive Traits)

By: HWC, Views: 6549

Along Darwin's voyage, he made many observations. Each one added to his understanding of how organisms change over time. Darwin was already familiar with fossils and knew that many fossils were very different from living organisms. But, also there were some fossils that were very similar to li...

Interview with Person who has Schizophrenia

By: Administrator, Views: 10192

Schizophrenia is a mental disorder characterized by abnormal behavior, strange speech, and a decreased ability to understand reality. Other symptoms include false beliefs, unclear or confused thinking, hearing voices that do not exist, reduced social engagement and emotional expression, and lack ...

Major Elements in Biological Molecules: Lipids

By: HWC, Views: 5907

A triglyceride (also called triacylglycerol) is composed of three fatty acid molecules and one glycerol molecule. The fatty acids attach to the glycerol molecule by a covalent ester bond. The long hydrocarbon chain of each fatty acid makes the triglyceride molecule nonpolar and hydrophobic. Pa...

Introduction to Epilepsy

By: Administrator, Views: 9758

Epilepsy is a group of neurological disorders characterized by epileptic seizures. Epileptic seizures are episodes that can vary from brief and nearly undetectable periods to long periods of vigorous shaking. These episodes can result in physical injuries, including occasionally broken bones. In ...

Multiple Sclerosis Animation

By: Administrator, Views: 9895

Multiple sclerosis (MS) is a demyelinating disease in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This damage disrupts the ability of parts of the nervous system to communicate, resulting in a range of signs and symptoms, including physical, mental, and so...

Labor and Delivery - Placenta Cord

By: Administrator, Views: 298

Soon after a baby is conceived, a support system, comprised of the placenta and umbilical cord, begins to develop. These two structures are essential for sustaining a healthy pregnancy, explains Donald Davis, an obstetrician in Medicine Hat, Alta., and past president of the Society of Obstetricia...

Attention Deficit Disorder (ADD)

By: Administrator, Views: 9849

Attention deficit hyperactivity disorder (ADHD) is a mental disorder of the neurodevelopmental type. It is characterized by difficulty paying attention, excessive activity, and behavior without regards to consequences which is not appropriate for a person's age. There are also often problems with...

Hyperglycemia Animation

By: Administrator, Views: 10624

Hyperglycemia means high (hyper) glucose (gly) in the blood (emia). Your body needs glucose to properly function. Your cells rely on glucose for energy. Hyperglycemia is a defining characteristic of diabetes—when the blood glucose level is too high because the body isn't properly using or doesn...