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Introduction to Erectile Dysfunction

By: Administrator, Views: 292

Erectile dysfunction (ED), also known as impotence, is a type of sexual dysfunction characterized by the inability to develop or maintain an erection of the penis during sexual activity. Erectile dysfunction can have psychological consequences as it can be tied to relationship difficulties and se...

Role of the respiratory system - effect of altered ventilation rates

By: HWC, Views: 7600

• Dissociation of the chemical substances in the body fluids can result in the production of free hydrogen ions. • The pH scale is used to measure the concentration of hydrogen ions in solution. • Normal blood pH values vary around 7.4. • When hydrogen ion concentration increases, t...

Types of synapses - electrical & chemical

By: HWC, Views: 7850

• Neurons communicate with one another or effector cells via synapses that allow information to be filtered and integrated. • The two types of synapses are: • electrical • chemical. • Electrical synapses, also known as gap junctions, contain many ion channels (connexons) conne...

DNA close up Animation

By: HWC, Views: 1675

A section from a DNA double helix The backbone of each DNA strand consists of alternating deoxyribose sugars and phosphate groups. The two strands run in opposite directions. One runs from the 5' to 3' direction, the other in the 3' to 5' direction. Think of the deoxyribose units o...

Conduction of action potentials

By: HWC, Views: 7900

• 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 ...

Labor and Delivery - Infant Cord Apgar

By: Administrator, Views: 367

As soon as your baby is born, a delivery nurse will set one timer for one minute and another for five minutes. When each of these time periods is up, a nurse or physician will give your baby her first "tests," called Apgars. This scoring system (named after its creator, Virginia Apgar) helps t...

Calvin cycle (The light-independent reactions )

By: HWC, Views: 7490

The light-independent reactions of photosynthesis occur in the stroma of the chloroplast. Carbon dioxide enters the leaf through tiny pores or stomata and diffuses into the chloroplast. The first stage of the Calvin cycle is the attachment of a carbon dioxide molecule to a 5-carbon ribulose bi...

Gas exchange - driving force

By: HWC, Views: 7809

• The respiratory system is responsible for the movement of gases involved in cellular metabolism. • Oxygen is used up and carbon dioxide is generated during the aerobic breakdown of glucose and other fuel molecules in order to produce ATP. • Three important continuous physiological pro...

Muscle Twitch and Muscle Tension - Motor unit size and force

By: HWC, Views: 7982

• A motor unit is a group of muscle cells controlled by a single neuron. • A stimulus of sufficient intensity will cause all the cells in the motor unit to contract. • A single contraction, caused by a single action potential, is called a muscle twitch. • Latent period: A brief per...