Trichology Flashcards
Follicle
A sock-like depression in the skin. Between 0.15 -2mm deep. Hair grows from it. the down growth of skin
Sebaceous Gland
Oil gland secretes oil Protects and lubricates the hair and skin. Makes skin soft Attached to the follicle More on scalp and face Mixes with sweat to form Acid-Mantle
Sudoriferous Gland
Sweat gland. Makes Sweat.
Mixes with oil to form acid-mantle
Has an opening called a pore.
Used to cool the area down
Arrector Pili Muscle
Attached to the follicle.
Contracts with fear and cold,
holds the follicle in place.
Also causes goosebumps
Outer Root Sheath
Lines the inside wall of the follicle.
Is the Outer Protective Layer.
Between the Inner root sheath and the follicle
Inner Root Sheath
Protective inner sheath for growing hair.
Only reaches 2/3 of the way up the shaft.
Between the hair and the outer root sheath.
Dermal Papilla
Transfers nourishment to the matrix via Osmosis. Removes waste from hair. Contains a network of blood vessels Found at the base of the follicle. VITAL for hair growth
Hair Root
Portion of hair under skin surface
Responsible for hairgrowth via keratinisation
Hardening of the hair
Matrix
Where cell division takes place for hairshaft / inner root sheath (mitosis)
Hair starts growing here
Receives nourishment from dermal papilla
Contains melanin (colour pigment)
Blood Vessels
Veins / Arteries / Capilleries
Nourishes the Dermal Papilla
Takes away waste
Bulb
Bulbous shape at bottom of follicle
Living part of the hair root
Contains matrix, dermal papilla, blood vessels
Starts keratinisation process
Trychology (WASP)
Function of the hair is: W - armth A - dornment S - ensation P - rotection
W (WASP)
Warmth:
Stops body heat from being lost
80% of body heat is lost through head / feet
Acts like insulation
Keeps our body temperature even and body warm
A (WASP)
Adornment:
Makes us look destinctive, and feeeel good
And attractive! Especially you ;)
S (WASP)
Sensation:
Acts as a sensory device - feel touch / pulls on hair
Nerves surround the follicle / inner-root
P (WASP)
Protection:
- From sun rays
- Cold
- Scalp injuries
- Head covering acting as a buffer
Hair Type: Vellus
Baby pine hair, soft downy hair found over the whole body. Replaces ‘lanugu’. Usually no pigment due to no medulla (Means its blonde). Shorter length / life cycle
Hair Type: Terminal
Hair over scalp. Grows for 2-7 years. Has colour due to a medulla. Coarser than vellus.
Hair Type: Pubic
Yep this one you were missing but I’ve got your back :) Has a medulla and therefore has pigment. Curly due to flattened (oval crossection) shape.
What is hair made from?
Proteins - called ‘Keratin’
What are the types of bonds?
Hydrogen bond - broken by water
Sulphur / disulphide - broken by perm solution chemical straight
Salt - broken by water
Van Der Waals - Broken by water
What is Porosity?
Ability to absorb moisture. The amount is determined by the cuticle.
What is Elasticity?
Ability of the hair to return to its original shape without breaking.
What is Texture?
The fineness / coarsness of the hair. Determined by the size / diameter of the cortex.
What is Density?
The amount or number of hair follicles per cm^2 (square centimeter)
Hair Growth Cycle
Hair grows 1.25cm average a month, 15cm a year. Human hair lasts between 1-7 years. People with longer hair cycles can have longer hair. (that’s me, by the way. My hair grows like 4cm every month)
3 Stages of the Hair Life Cycle
- Anagen - growing stage
- Catagen - Changing from one stage to another
- Telogen - Resting hair.
Hair Life Cycle: Anagen
First stage. Period of active growth - continuously for 2-7 years. Approx 90% of the hair is in the active stage. The bulb has a bell like shape.
Hair Life Cycle: Catagen
Second stage. Period of change. Dermal papilla stops providing nourishment to matrix. No new cels are being formed. Club hair is formed.
Lasts 2 weeks
Hair Life Cycle: Telogen
Last stage. Hair is not growing at all. 8-10% of hair is in rest stage. Telogen bulbs has a clubbed shape
Keratinisation
Hardening process of the hair shaft. Keratin proteins are carried to dermal papilla and the matrix. As keratin cells are produced, they are pushed up from the matrix to form the cuticle, cortex, medulla and inner root sheath. Once cells are pushed up, they harden and dry.
Hair roots / shaft
Roots are below the skin, shaft is above
3 layers of hair
Cuticle, Cortex and Medulla
Cuticle
- Overlapping scales, pointing downward
- Translucent
- 4-10 layers
- Protects the inside of hair like gladwrap
- Determines porosity
- Outer protective layer
Cortex
- Bulkiest part of the hair
- 70-80% of hair shaft
- Determines elasticity, texture
- Contains chemical bonds (sulphur, hydrogen)
- Most hairdressing services take place in this layer
Medulla
- Inner part of the hair
- No idea what it does
- Can be absent in fine hjair
- Continuous or fragmented
