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Chronology of leptin research (A history of leptin research)

By: HWC, Views: 3750

In 1950. researchers at Jackson Laboratories noticed that one of their mice had become extremely obese—it had an insatiable appetite. Intrigued, they bred a strain of mice showing this characteristic. In the late 1960s, researchers surgically connected the bloodstreams of a normal mouse and a...

Introduction to Autism

By: Administrator, Views: 10064

Autism is a developmental disorder characterized by difficulties with social interaction and communication, and by restricted and repetitive behavior. Parents usually notice signs during the first three years of their child's life. These signs often develop gradually, though some children with au...

Second Messengers in the Inositol-lipid Signaling Pathway

By: HWC, Views: 5894

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...

Premenstrual Syndrome

By: Administrator, Views: 9853

Premenstrual syndrome (PMS) refers to physical and emotional symptoms that occur in the one to two weeks before a woman's period. Symptoms often vary between women and resolve around the start of bleeding. Common symptoms include acne, tender breasts, bloating, feeling tired, irritability, and mo...

Sperm Formation Animation

By: Administrator, Views: 370

A man’s reproductive system is specifically designed to produce, store, and transport sperm. Unlike the female genitalia, the male reproductive organs are on both the interior and the exterior of the pelvic cavity. They include: the testes (testicles) the duct system: epididymis and vas def...

Pressure Flow Model Animation

By: HWC, Views: 5865

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...

Embryonic development - week 1 and 2

By: HWC, Views: 6686

The first through eighth weeks after fertilization are called the embryonic. Week 1 • Within a day, the zygote begins mitotic cell division (cleavage) forming blastomeres. By the 4th day, the blastomeres have formed a solid ball called a morula. • The morula enters uterine cavity ar...

Energy Flow - Trophic Levels and Food

By: HWC, Views: 6218

All of these relationships between different species are founded on one thing: energy. Organisms get food in order to get energy, which is used by the organism for growth, maintaining health, and reproduction. We can classify the members of a community according to how they obtain food. Produc...

Renin/Angiotensin (water gain from urine & Na ion and water reabsorption)

By: HWC, Views: 6564

• Sensing declining blood pressure or blood volume, juxtaglomerular cells of the nephron release renin, an enzyme that promotes the formation of angiotensin II. • Angiotensin II targets smooth muscle cells in blood vessels that provide blood to the nephron. • Angiotensin II causes thes...