Chapter 5: Hair and Nails
What is the wall of the hair follicle composed of?
A peripheral connective tissue sheath, derived from the dermis, and an inner epithelial root sheath, from the epidermis
Three functions of hair which contribute to homeostasis.
Alerting the body to the presence of insects, guarding the scalp from physical trauma, and preventing heat loss.
What causes the root hair plexus stimulus?
Bending the hair stimulates the root hair plexus.
Name the three regions of hair. (outer to inner)
Cuticle, Cortex, Medulla (C.C.M)
What does the appearance of gray/white hair signify?
Decreased melanin production; increased air bubbles in the shaft.
the thick proximal nail fold commonly called the cuticle
Eponychium
Why is hair considered an nonliving material?
Hair contains hard keratin that consists of dead keratinized cells
Once hair has advanced from the hair root to the hair shaft what cellular process is marked?
Hair in the hair shaft signifies that keratinization is complete
What creates hair pigment for humans? And where is it created?
Hair pigment is made by melanocytes at the base of the hair follicle and transferred to the cortical cells.
What advantages does hard keratin have over soft keratin?
It is tougher and the individual cells do not flake off.
Hair that is still contained in the hair root marks what ongoing cellular process?
Keratinization is still ongoing.
Accessory organs of the skin originate from which epidermal layer?
Stratum Basale
What type of coarse hair is found on the scalp, axillary, pubic, and eyebrow regions?
Terminal
What type of hair are you cutting if you go to the barber and get a hair cut?
Terminal
What type of hair are you grooming if you have your eyebrows arched?
Terminal
The hair matrix which houses actively dividing cells is located inside of what structure of the hair?
The bulb of the hair follicle.
Why are split ends in healthy hair unavoidable?
The cuticle wears away at the tip of the hair shaft whick allows keratin fibrils in the cortex and medulla to frizz out.
What provides nutrients to growing hair and signals it to grow?
The hair papilla contains a knot of capillaries that supplies nutrients to the growing hair and signals it to grow.
A genetically determined and sex-influenced condition.
True (frank) baldness
Name two types of hair.
Vellus and Terminal
What portion of the hair is considered living?
Within the hair follicle
A smooth muscle attached to hair follicles.
arrector pili
The sensation of goose bumps while watching a movie is produced by what structure?
arrector pili
A bulky layer surrounding the medulla consisting of several layers of flattened cells.
cortex
The outermost portion of hair which is formed from a single layer of cells overlapping on another.
cuticle
The portion of hair that provides strength and keeps the inner layers tightly compacted.
cuticle
What attribute of hair keeps it separate from neighboring hairs so it does not mat?
cuticle
Which portion of the hair is the most heavily keratinized?
cuticle
portion of the nail that grows out away from the body.
free edge
Hard keratin dominated which two appendages of the skin?
hair and nails
The deep end of the hair follicle that expands?
hair bulb
Portion of hair that folds down from he epidermal surface into the dermis.
hair follicles
A nipple like bit of dermal tissue which protrudes into the hair bulb.
hair papilla
Alopecia
hair thinning after age 40 for either sex
the proximal region of the thickened nail which appears as a white crescent.
lunule
What deficiency is a follicular response to DHT?
male pattern baldness
The central core of hair which consist of large cells and air spaces.
medulla
Which part of hairs contains soft kersatin?
medulla
extension of the stratum basale beneth the nail
nail bed
skin folds that overlap the borders of the nail
nail folds
The thickened proximal part of the nail bed containing germinal cells responsible for nail growth.
nail matrix
The portion of the nail that is embedded in the skin and adheres to an epithelial nail bed.
nail root
Flexible strands produced by hair follicles and consist of dead keratinized cells.
pili (hair)
Hair's growth phase is followed by what two phases?
regressive and resting phase lasting 1-3 months
The portion of the hair in which keratinization is still ongoing.
root
A knot of sensory nerve endings.
root hair plexus (hair follicle receptor)
Being alerted to the presence of insects due to tingling hair is produced by what structure?
root hair plexus (hair follicle receptor)
The portion of the hair in which keratinization is complete.
shaft
Where can you find soft keratin on the body?
skin
What type of fine body hair is found on children and female adults?
vellus
What type of hair are you viewing on your arm that has a blond appearance?
vellus