Biology

• The function of the epidermis is to protect against water loss, UV radiation, pathogens, and mechanical damage.
• The dermal layer contains blood vessels, nerves, hair follicles, sweat glands, sebaceous glands, and collagen fibers that support the skin.
• Skin color is determined by melanin pigmentation, with darker colors indicating more melanin production.
• Skin coloration can be due to melanin pigment or carotenoid pigments from dietary sources.
• Melanocytes produce melanin, which absorbs ultraviolet light and provides protection against sunburn.
• Melanocytes produce melanin, which absorbs light energy and prevents it from damaging cells.
• Melanocytes produce melanin, which absorbs ultraviolet light and prevents it from damaging cells.
• Catagen phase lasts only two weeks and involves the shortening of the hair root.
• Hair is made up of keratinized cells arranged into three layers: medulla (central core), cortex (middle layer), and cuticle (outermost layer).
• During anagen phase, hair grows at a rate of about 1 cm per month.
• Hair growth occurs in three phases - anagen (growth), catagen (regression), and telogen (resting).
• Eumelanin produces black/dark brown coloration, while pheomelanin produces yellow/reddish-brown coloration.
• Both carotene and xanthophyll are precursors to vitamin A.
• Telogen phase lasts three months and involves the shedding of old hairs.
• Eumelanin produces black/dark brown coloration, while pheomelanin produces yellow/reddish-brown coloration.
• Melanocytes are specialized cells found in the epidermis that synthesize and store melanin granules.
• Stratum basale - contains stem cells that divide mitotically to replace dead skin cells.
• Hair growth occurs through mitosis at the base of the follicle.
• The skin has four layers: epidermis (outermost), dermis (middle layer), hypodermis/subcutaneous tissue (deepest).
• The epidermis consists of four types of epithelial tissue: stratified squamous non-keratinized, stratified squamous keratinized, cuboidal, and columnar.
• Stratum spinosum - contains living cells with intercellular bridges called desmosomes.
• Telogen phase is also known as resting or shedding phase where old hairs are pushed out to make room for new ones.
• The epidermis consists of four main types of tissue: stratified squamous epithelium, connective tissue, adipose tissue, and muscle tissue.
• Catagen phase is characterized by the shortening of dermal papillae and the shrinking of the hair bulb.
• The skin is composed of two layers: epidermis and dermis.
• Stratum corneum is composed of dead cells that form a waterproof barrier on the surface of the skin.
• Anagen phase begins with the formation of new follicles from epidermal tissue.
• Skin consists of two major components: epidermis and dermis.
• Skin consists of two major types of tissue: connective tissue and epithelial tissue.
• The skin has four main functions: protection against physical damage, temperature regulation, excretion of waste products, and synthesis of Vitamin D3.
• Sebaceous glands secrete oil called sebum onto the surface of the skin.
• The skin has four main functions: protection against physical damage, temperature regulation, excretion of waste products, and synthesis of vitamin D3.
• Anagen phase begins with the formation of new follicles from epidermal tissue.
• The catagen phase is characterized by the shortening of the hair root as the follicle shrinks and detaches from its blood supply.
• The hair shaft is made up of keratinized epithelial cells arranged in layers called cuticle, cortex, and medulla.
• Melanocytes produce melanin pigments that protect the skin from UV radiation damage.
• Anagen is the active growing stage where new hair grows from the root at a rate of about 1 cm per month.
• Anagen is the active growing stage where new hair grows from the root at a rate of about 1 cm per month.
• The stratum corneum is made up of keratinized squamous epithelial cells with no nuclei or organelles.
• The hair cycle consists of three stages: Anagen (active growing stage), Catagen (transition stage), and Telogen (resting stage).