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Coaductile pathway, Timing of contraction signal & Conduction system and ECG

By: HWC, Views: 7941

• When the system is healthy, the signal to contract the entire conduction system originates in the SA node - known as the heart's pacemaker. • The SA node triggers contraction because it depolarizes at a faster rate than other parts of the conduction system. • The wave of excitation fr...

Second Messengers in the Inositol-lipid Signaling Pathway

By: HWC, Views: 7014

Extracellular signals produce specific responses in target cells through the action of intracellular second messengers. Here, we focus on three second messengers, IP3, DAG, and Ca2+, all involved in the inositol-lipid signaling pathway. A hormone-receptor signal on the cell surface leads to the a...

Cellular Respiration & Glucose Mobilization (Glucose transport & Phosphorylation of Glucose)

By: HWC, Views: 7540

Glucose is completely broken down into CO2 and H2O during the process of cellular respiration, which includes 3 stages: 1) glycolysis; 2) the Krebs Cycle; and 3) the electron transport chain. Glucose enters this energy yielding pathway of cellular respiration in the first stage known as...

Fermentation - When Oxygen Is Absent, Pyruvate to Lactate & Pyruvate to Ethanol

By: HWC, Views: 7301

Pyruvate is the end product of glycolysis. If oxygen is present, pyruvate enters the mitochondrion where further energy yielding reactions of the Krebs cycle will take place. However, if oxygen is not present, pyruvate will enter a pathway called fermentation. This pathway regenerates NAD+ fro...

Neural Reflex Arc Animation

By: Administrator, Views: 10945

A reflex arc is a neural pathway that controls a reflex. In vertebrates, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. This allows for faster reflex actions to occur by activating spinal motor neurons without the delay of routing signals through the bra...

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...

Alternative Energy Sources

By: HWC, Views: 1985

Points at which organic compounds enter the reaction stages of aerobic respiration. Complex carbohydrates are broken down into simple sugars, such as glucose. They become the substrates for glycolysis. If your body doesn't need to burn glucose for energy, glucose-6-phosphate can be co...

Evolutionary tree of life Animation

By: HWC, Views: 1404

An evolutionary tree of life that reflects mainstream thinking about the connections among major lineages (bya = billions of years ago, mya = millions of years ago). By about 3.8 billion years ago, chemical and molecular evolution had produced the first living cells. The first major divergenc...

Language Areas Animation

By: Administrator, Views: 10907

Specific language areas of the brain. Many cortical (and non-cortical!) regions are involved in language processing. The primary language pathway begins in Wernicke’s area (posterior temporal lobe), which receives information from the auditory and visual cortices and assigns meaning (= lang...