Toad Skin – Frogs use their skin as the first line of defense against pathogens in the environment. Their skin is composed of epidermal and dermal layers, in which each layer highly consists of epithelial and fibroblastic cells, respectively.
Cat Skin – The largest organ in a cat’s body is the skin. It could take up about 12-24% of their body weight, depending on the specie and age. The skin provides protection to cats against the environment. It helps in regulating temperature and give cats a sense of touch. Cat skin is composed of three main layers: the epidermis or outer layer, dermis or middle layer, and subcutis or the innermost layer. Along with these layers are hair and claws which serves as skin appendages of cats.
Human Hair – Humans develop different types of hairs. The first hair to develop that started from the third to fourth month of fetal life is called the lanugo. This type of hair is downy and slender. It is followed by down hair or vellus, which is fine, short, and unpigmented. It develops during the first few months of infancy. During puberty, this is supplemented by the terminal hair which is longer, coarser, and more heavily pigmented. Terminal hair develops in the armpits, genital regions, and for males, on the face or sometimes on the trunk and limbs. Hairs on the scalp which are the densest and longest, usually have an average total number between 100,000-150,000. The rate of hair growth in humans is about 0.5 in (13mm) per month.
Toad Skin – Frogs use their skin as the first line of defense against pathogens in the environment. Their skin is composed of epidermal and dermal layers, in which each layer highly consists of epithelial and fibroblastic cells, respectively.
Cat Skin – The largest organ in a cat’s body is the skin. It could take up about 12-24% of their body weight, depending on the specie and age. The skin provides protection to cats against the environment. It helps in regulating temperature and give cats a sense of touch. Cat skin is composed of three main layers: the epidermis or outer layer, dermis or middle layer, and subcutis or the innermost layer. Along with these layers are hair and claws which serves as skin appendages of cats.
Human Hair – Humans develop different types of hairs. The first hair to develop that started from the third to fourth month of fetal life is called the lanugo. This type of hair is downy and slender. It is followed by down hair or vellus, which is fine, short, and unpigmented. It develops during the first few months of infancy. During puberty, this is supplemented by the terminal hair which is longer, coarser, and more heavily pigmented. Terminal hair develops in the armpits, genital regions, and for males, on the face or sometimes on the trunk and limbs. Hairs on the scalp which are the densest and longest, usually have an average total number between 100,000-150,000. The rate of hair growth in humans is about 0.5 in (13mm) per month.
References:
Kim, J. & Dao, H. (2021). Physiology, Integument. NCBI. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK554386/#:~:text=The%20integumentary%20system%20includes%20the,D%2C%20and%20detection%20of%20stimuli
Moriello, K. (2018). Structure of the Skin in Cats. MSD Manual: Veterinary Manual. Retrieved from https://www.msdvetmanual.com/cat-owners/skin-disorders-of-cats/structure-of-the-skin-in-cats#:~:text=The%20skin%20has%203%20main,and%20subcutaneous%20muscles%20and%20fat.
Schreiber, B. (n.d.). hair: anatomy. Britannica. Retrieved from https://www.britannica.com/science/hair-anatom
Varga, J., Bui-Marinos, M. & Katzenback, B. (2019). Frog Skin Innate Immune Defenses: Sensing and Surviving Pathogens. frontiers. Retrieved from https://www.frontiersin.org/articles/10.3389/fimmu.2018.03128/full