23 Questions
What is the primary function of hair according to the text?
To regulate body temperature
Which part of the hair structure is biologically inactive?
Hair shaft
What is the function of a hair follicle?
To house the hair root
What is the difference between vellus hair and terminal hair?
Thickness and length
From where does hair actually grow?
Hair root
How many follicles do people have on their head on average?
100,000 to 150,000
What is the secondary purpose of hair according to the text?
For adornment
Which type of hair is typically finer and without a medulla?
Vellus hair
In which region of the body can vellus hair typically not be found?
Palms of hands
What is the main difference between vellus hair and terminal hair?
Presence of medulla
Which type of follicle generally creates wavy to straight hair and is typically seen in European hair types?
Oval
Where is the hair root protected within the skin?
Dermis
Which structure at the very bottom of the hair root is essential to the health and growth of the hair shaft?
Hair bulb
What is the function of the dermal papilla in relation to the hair follicle?
Encloses the base of the hair bulb
What is the role of the dermal papilla in hair growth?
Supplying oxygen-rich blood and keratin cells
During which phase of the hair growth cycle is the dermal papilla totally inactive?
Telogen phase
What do sebaceous glands provide to the hair follicle?
Natural oils
What substance do sebaceous glands secrete to add luster and pliability to the hair and scalp?
Sebum
What effect does overproduction of sebum by sebaceous glands have on the scalp?
Oily dandruff
What is the role of the arrector pili muscle?
Contracting to make the hair stand up straight
Which type of hair does not possess arrector pili muscles?
Eyelash hair
How does the arrector pili muscle give skin the appearance of 'goose bumps'?
By contracting and making the hair stand up straight
What is the primary function of sebum produced by sebaceous glands?
To provide natural oils for conditioning hair
Study Notes
Hair Functions and Structure
- Primary function of hair is protection, temperature regulation, and sensory perception.
- The part of the hair structure that is biologically inactive is the hair shaft.
- Hair follicles serve to anchor each hair in place and facilitate hair growth by nourishing them.
Types of Hair
- Vellus hair is fine and lacks a medulla.
- Terminal hair is coarser, thicker, and typically has a medulla.
- Vellus hair is usually not found on the palms of hands and soles of feet.
Hair Growth and Follicles
- Hair grows from the hair follicle located within the dermis layer of the skin.
- On average, people have about 100,000 to 150,000 hair follicles on their scalp.
- Secondary purpose of hair includes providing a sense of touch and aiding in biological signaling.
Hair Characteristics
- Straight to wavy hair is produced by oval-shaped follicles, common in European hair.
- The hair root is protected within the hair follicle.
- The structure at the very bottom of the hair root crucial for hair health is the hair bulb.
Dermal Papilla and Hair Growth
- The dermal papilla supplies nutrients to the hair follicle and regulates hair growth.
- The dermal papilla is inactive during the telogen (resting) phase of the hair growth cycle.
Sebaceous Glands Function
- Sebaceous glands provide oil to the hair follicle, which helps in moisturizing.
- They secrete sebum, a substance that adds luster and pliability to hair and scalp.
- Overproduction of sebum can lead to an oily scalp, potentially causing dandruff or other scalp issues.
Muscle Involvement
- The arrector pili muscle is responsible for causing hair to stand erect, creating 'goose bumps' when stimulated.
- Vellus hair does not have arrector pili muscles attached.
- Arrector pili contraction results in the skin's appearance of goose bumps due to pulling on the hair follicles.
Sebum's Role
- The primary function of sebum is to lubricate hair and skin, preventing dryness and providing a barrier against external elements.
Explore the structure and primary functions of hair, including insulation and protection, as well as its secondary function for adornment. Learn about the significance of hair as a symbol of pride, self-care, and esteem. Dive into topics like hair growth, hair typing, and hair care.
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