Functions and Types of Glands in Hair

Hair Function and Types

• The primary function of hair is to protect the body from external damage.
• Lanugo is the type of hair that appears during the last trimester of fetal development.
• Vellus hair is the fine, light-colored short hair found on the body.
• Terminal hair is the main type of hair that grows to a certain length and then ceases to grow.

Glands

• Sebaceous glands, which produce sebum, an oily substance rich in lipids, are typically found in the dermis.
• Apocrine sweat glands open into hair follicles.
• Eccrine sweat glands are the most numerous type of sweat gland in the palms and soles.

Epidermis Layers

• The Stratum corneum, the outermost layer of the epidermis, is strong due to the presence of multiple layers of dead cells.
• The Stratum lucidum, a translucent layer of the epidermis, contains a substance called eleidin.
• The Stratum granulosum, also known as the 'granular layer', contains keratohyaline granules.
• The Stratum spinosum layer of the epidermis contains predominantly prickle cells.
• Desquamation, or shedding of dead skin cells, occurs in the Stratum corneum.
• The Stratum corneum is primarily composed of dead squamous cells filled with keratin.

Hair Growth and Development

• The growth cycle of hair is influenced by testosterone in men and is involved in hair growth in both men and women.
• The difference in hair length between the back of the hand and pubic hair is due to the variation in hair growth rates.

Skin Types

• Palmar skin, found on palms, soles, and flexor surfaces of digits, is thick and hairless.

Genetic Disorders

• Albinism is caused by a lack of the enzyme tyrosinase, which affects the production of melanin.

Explore the primary functions of hair, such as protection, touch sensation, and warmth. Learn about major glands like sebaceous glands and sweat glands, including eccrine and apocrine glands.