• 2. Molting of the insect cuticle
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    2. Molting of the insect cuticle

    The molting process begins when cuticular epidermal cells are stimulated by exposure to 20-hydroxyecdysone – the insect molting hormone. The hormone enters the epidermal cells where it stimulates genes related to molting and the formation of new cuticle. The activated epidermal cells undergo mitosis or grow by cellular enlargement. This is the period of growth to form a new, larger cuticle for the next instar. The existing structural cuticle separates from the epidermal cells. This is termed apolysis. The resulting ecdysial space between the endocuticle and the epidermal cells is filled with a gel that contains inactive chitinase and protease enzymes. A new outer epicuticle layer of cuticulin is secreted.…

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    1. Structure and functions of the insect cuticle

    In most insects, the integument forms a rigid exoskeleton that surrounds the outer surface of the animal. The exoskeleton serves a variety of functions: it gives the insect structure, prevents chemical and mechanical damage, protects against invasion by parasites and infection by microorganisms, inhibits water loss and serves as the attachment point of muscles for locomotion. It also forms the trachea of the respiratory system, forms a lining for the foregut and hindgut regions of the digestive system. and forms the wings in adult insects This cutaway view shows that the integument consists of a series of layers. The integument is separated from the hemolymph by the basement membrane the…

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    Introduction to Skin

    A car has a bonnet and a phone has a cover to protect the internal important machineries from damage from rain or dust. Similarly, we have many important dedicate organs in our body like the lungs, the heart, the liver which needs to be protected from the dust and the germs. So we have a continuous sheet of tissue known as the skin which forms a protective layer and protects the internal delicate organs from germs and dust. Now germs and dusts are airborne. It is present everywhere. So the skin is present to protect the internal organs from them. But what about the skin itself? It does not get…

  • Four Unusual uses for Feathers – Feather Function #2
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    Four Unusual uses for Feathers – Feather Function #2

    Hi, my name is Steve Bush. There are about 10,000 species of birds in the world, and about 10,000 different uses for feathers. Today we’re talking about four uncommon uses for feathers. Four uncommon uses for feathers #1 Bristle Feathers See the whiskers on this nightjar? They’re not whiskers. They’re feathers! They’re formed by growing a feather without all the feathery parts. In function, they probably do a lot of the same work as whiskers. Scientists found that there are nerves to detect vibration connected to each bristle. So they probably help the bird feel around in the dark. Quick note: scientists are not totally sure on this one, but…

  • 7.  Pigment Transfer in Skin Cells
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    7.  Pigment Transfer in Skin Cells

    The preservation of the Developmental Biology Film Series was made possible by generous contributions from Publisher of “The Biggest Picture” Producer of the documentary, “Symbiotic Earth” Mammalian skin consists of a superficial epidermis and an underlying dermis. In the epidermis dead keratinocytes make up the outer layer. Immediately below them are differentiating keratinocytes which arise from actively dividing stem cells that lie closest to the dermis. Other cells, the melanocytes, are found among the dividing keratinocytes. These cells manufacture granules of the pigment melanin and transfer them to the keratinocytes. This diagram shows the structure of this epidermal system. The melanocyte extends long processes called dendrites between the closely packed…

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    What makes tattoos permanent? | #aumsum

    What makes tattoos permanent? Glue sticks. No. Our skin has three layers, epidermis, dermis and hypodermis. Epidermis sheds thousands of skin cells every day. Hence, when we get a tattoo. The tattoo needles which are coated with colored pigment. Are inserted through the epidermis into the dermis. Thus, preventing the tattoo pigment from getting shed away. However, it is mainly our body’s immune response which makes tattoos permanent. What? But how? The tattoo needles create wounds in the skin, activating the immune response. Immune cells like macrophages. Reach the wounded site and start to eat the small particles of colored pigment and clean the area. Bigger pigment particles that cannot…

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    Epigenetics – our bodies’ way to change the destiny written in our DNA | Moshe Szyf | TEDxBratislava

    Translator: Rhonda Jacobs Reviewer: Ellen Maloney So, it all came to life in a dark bar in Madrid, and as I was stepping into the bar, I encountered my colleague from McGill, Michael Meaney. And we’re drinking a few beers, and like scientists do, he told me about his work. He told me that he is interested in how mother rats lick their pups after they are born. And I was sitting there and saying, “This is where my tax dollars are wasted, (Laughter) on this kind of soft science.” But as the beer got more intense and the alcohol gets into the brain, you become more receptive, and he…

  • The amazing brains and morphing skin of octopuses and other cephalopods | Roger Hanlon
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    The amazing brains and morphing skin of octopuses and other cephalopods | Roger Hanlon

    This is a strange and wonderful brain, one that gives rise to an idea of a kind of alternative intelligence on this planet. This is a brain that is formed in a very strange body, one that has the equivalent of small satellite brains distributed throughout that body. How different is it from the human brain? Very different, so it seems, so much so that my colleagues and I are struggling to understand how that brain works. But what I can tell you for certain is that this brain is capable of some amazing things. So, who does this brain belong to? Well, join me for a little bit of…

  • Types of Immunity | Human Health & Disease Part 1 | Biology Class 12 | HINDI
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    Types of Immunity | Human Health & Disease Part 1 | Biology Class 12 | HINDI

    Topic of this presentation is Types of Immunity First of all we will discuss some important terms Ability of our body to fight against disease causing pathogens is called immunity And Body system which is engaged in providing immunity to the organism is called immune system This system develops immunity and fights against pathogens we broadly divide immunity into two categories innate immunity and acquired immunity Innate means from birth The immunity which present in our body from birth is called innate immunity The immunity which acquired after birth on exposure to different pathogens accordingly our body develops immunity against those pathogens that immunity is called acquired immunity acquired immunity…

  • Cockroaches, Alligators & Other Weird Sources of New Drugs
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    Cockroaches, Alligators & Other Weird Sources of New Drugs

    Antibiotics are one of humankind’s most amazing discoveries. Ever since that fateful day in 1928 when Scottish physician Alexander Fleming noticed a funny mold growing in one of his petri dishes, antibiotics have been kicking bacterial butt. That famous mold, of course, was producing penicillin, the founding antibiotic superstar, which has since extended the average human life by at least a decade. It fundamentally changed the face of medicine. Antibiotics, or antimicrobials, are basically selective poisons designed to either kill or slow the growth of bacteria to the point where your body’s own immune system can clean up. These drugs target a specific part of bacteria or some important stage…