BIO 1300 Lecture Notes - Lecture 3: Hair Follicle, Melanin, Thermoregulation
26 Mar 2015
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Therefore, they counter this by returning back to the water. Capable of breathing through their skin by absorbing air through direct contact. Their skin is permeable to gases and water. Some amphibians have a mucus layer to keep their skin moist, others need to return to water. Shelled eggs (amniotic) are a fundamental aspect of living on land. Keratin is responsible for making our skin impermeable. Bird feet and claws are a modification of keratin. Sub-cutaneous (under the skin) fat gives us insulation. Dead skin cells pushed to the outer surface and is shed. Stratum granulosum: lamellar bodies (proteins and fats) secreted. 2 broad areas: stratum papillare (1/4) and reticulum layer (the rest) Stratum papillare: finger prints, blood capillaries and receptors. Reticulum layer: collagen connective tissue that holds our skin and provides firmness. Sebaceous glands excrete sebum (grease that lubricates the hair) Eccrine sweat: cooling of our body surfaces, green glands (not associated with hair)
