Secrets of Skin episode 2 – Moving: What makes sharks built for speed? How do snakes move without limbs? How do sugar gliders fly without feathers? The answer all lies in their skin. Professor Ben Garrod uncovers the secrets of how skin has evolved to enable animals to solve some of the most remarkable challenges on Earth.
To do this, Ben heads to the specialist flight centre at the Royal Veterinary College to analyse the way a sugar glider uses its skin flaps to stay aloft. He goes diving with sharks at the Blue Planet Aquarium and discovers that, far from being smooth, sharkskin is incredibly rough. It is covered with thousands of tiny teeth that make a shark hydrodynamic. Ben also finds out how the keratinised scales on snakes’ bellies are the perfect configuration to allow them to move over virtually any surface they encounter.
Featuring groundbreaking new science, experiments and leading scientists from a variety of disciplines, the series unravels the natural history of the body’s largest organ.
Secrets of Skin episode 2 – Moving
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different developmental origin, structure and chemical composition. The adjective cutaneous means “of the skin” (from Latin cutis ‘skin’). In mammals, the skin is an organ of the integumentary system made up of multiple layers of ectodermal tissue and guards the underlying muscles, bones, ligaments, and internal organs.
Skin of a different nature exists in amphibians, reptiles, and birds. Skin (including cutaneous and subcutaneous tissues) plays crucial roles in formation, structure, and function of extraskeletal apparatus such as horns of bovids (e.g., cattle) and rhinos, cervids’ antlers, giraffids’ ossicones, armadillos’ osteoderm, and os penis/os clitoris.
All mammals have some hair on their skin, even marine mammals like whales, dolphins, and porpoises that appear to be hairless. The skin interfaces with the environment and is the first line of defense from external factors. For example, the skin plays a key role in protecting the body against pathogens and excessive water loss. Its other functions are insulation, temperature regulation, sensation, and the production of vitamin D folates. Severely damaged skin may heal by forming scar tissue. This is sometimes discoloured and depigmented. The thickness of skin also varies from location to location on an organism. In humans, for example, the skin located under the eyes and around the eyelids is the thinnest skin on the body at 0.5 mm thick and is one of the first areas to show signs of aging such as “crows feet” and wrinkles. The skin on the palms and the soles of the feet is the thickest skin on the body as 4 mm thick. The speed and quality of wound healing in skin is promoted by the reception of estrogen.
