AnatomyLesson 2 of 3 in the course The Integumentary System

Hair Structure, Growth, and Functions

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

Save course
Lesson progress
0 / 5

Your progress is kept in this browser only.Sign up to save it

Summary

Hair is a keratinous filament made primarily of dead, keratinized cells. The hair follicle is an epidermal penetration into the dermis from which a hair strand grows. The exposed portion is the hair shaft; the portion anchored below the skin surface is the hair root.

At the base of the root, the hair bulb contains the hair matrix, a region of mitotically active basal cells. These cells divide and push older cells outward, forming the growing hair. The bulb surrounds the hair papilla, connective tissue containing blood capillaries and nerve endings.

All flashcards

What are the hair shaft and hair root?
The shaft is the exposed portion of a hair; the root is anchored below the skin surface.
Which features help determine whether hair is straight or curly?
The shape of the follicle and the structure of the cortex and, when present, the medulla.
What are the layers of a hair strand?
From the center outward: the medulla when present, the cortex, and the cuticle.
How does hair help protect the body?
Scalp hair shields the skull from sunlight; nose and ear hairs and eyelashes help trap particles.
What are the three layers of the hair follicle wall?
The internal root sheath, external root sheath, and glassy membrane.

Quiz questions

  1. Which hair structure contains the dividing cells that form new hair?Answer: The hair matrix within the bulb
  2. What is the hair papilla, and what does it contain?Answer: Connective tissue in the bulb containing capillaries and nerve endings
  3. Which sequence gives the hair-growth phases in their correct order?Answer: Anagen, catagen, telogen
  4. Why can the exposed hair shaft be cut without causing pain?Answer: It consists of dead keratinized cells and lacks sensation
  5. Which structure detects movement of a hair before it presses on the skin?Answer: The hair root plexus surrounding the follicle

Based on Anatomy and Physiology 2e by J. Gordon Betts, Kelly A. Young, James A. Wise, Eddie Johnson, Brandon Poe, Dean H. Kruse, Oksana Korol, Jody E. Johnson, Mark Womble, Peter DeSaix (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

More in Anatomy

All Anatomy lessons
AnatomyAnterolateral Abdominal Wall, Respiratory Muscles, and Pelvic Floor5 flashcards · 5 quiz questions · 4 gamesPlay free →AnatomyPeripheral Nervous System: Ganglia, Nerves, and Neural Pathways5 flashcards · 5 quiz questions · 4 gamesPlay free →AnatomyPectoral Girdle Anatomy: Clavicle, Scapula, and Shoulder Joints5 flashcards · 5 quiz questions · 4 gamesPlay free →AnatomySkeletal Muscle Roles, Fascicle Arrangements, and Lever Systems5 flashcards · 5 quiz questions · 4 gamesPlay free →AnatomyMuscles of the Pelvic Girdle, Thigh, Leg, and Foot5 flashcards · 5 quiz questions · 4 gamesPlay free →AnatomyPericardial Structure, Anatomical Relationships, and Common Disorders5 flashcards · 5 quiz questions · 4 gamesPlay free →