Questions and Answers
What does the pilosebaceous unit consist of?
Hair follicles and sebaceous glands
What does the sebaceous gland produce?
Sebum
What is the hair root represented by?
The bottom of the sock
What are the three main parts of the hair shaft?
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What is the innermost part of the hair shaft called?
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What does the cortex of the hair contain?
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What is the outermost layer of the hair called?
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What type of hair is vellus hair?
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What characterizes terminal hair?
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What is the resting phase of the hair growth cycle called?
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What phase of the hair growth cycle is called anagen?
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What is the transition phase of the hair growth cycle called?
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Study Notes
Pilosebaceous Unit
- Composed of hair follicles and sebaceous glands that produce sebum.
- Sebaceous glands discharge sebum through the pilosebaceous duct, which also serves as the pathway for hair growth.
- Size of sebaceous glands varies based on body location.
- Contains arrector pili muscle, which contracts to pull hair upright in response to cold or fright.
Hair Root
- Resembles the bottom of a sock; the papilla is located at the base.
- Surrounding the papilla is the matrix or hair bulb, where cells divide and form hair.
Hair Follicle
- Functions as a "sock" in the skin that encases the hair.
Hair Shaft
- Visible part of hair that grows above the skin.
- Consists of three main parts: medulla, cortex, and cuticle.
Medulla
- Innermost component of the hair shaft, formed by rows of polyhedral cells.
- Contains eleiden (an early form of keratin) and air spaces.
Cortex
- Middle and primary section of hair, comprised of elongated cells.
- Contains pigment in dark hair; air-filled in white hair, contributing to hair color.
Cuticle
- Outermost layer of hair, made of a single layer of thin, flat, keratinized cells.
Vellus Hair
- Fine, soft hair that covers most of the body.
Terminal Hair
- Longer, coarser, and pigmented hair; varies in diameter, texture, and shape.
Hair Growth Cycle Phases
- Telogen: Resting phase of the hair growth cycle.
- Anagen: Active growing phase of hair.
- Catagen: Transition phase lasting 2-3 weeks, where scalp and body hair shift between growth and rest.
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Description
Test your knowledge on the pilosebaceous unit with these flashcards. This quiz focuses on the components, functions, and biochemical processes involved in hair follicle structure and related glands. Perfect for students or anyone interested in dermatology.
