Složení vlasů
Složení vlasů
- Extremely stable structure
- Can resist breakdown thousands of years after a person’s death
- 50–100 microns in diameter
- 3 main layers
- Cuticle
- Cortex
- Medulla
Biochemické složení vlasu
- C-O-N-H-S
- C - Carbon - 49.6%
- O - Oxygen - 23.2%
- N - Nitrogen - 16.8%
- H - Hydrogen - 6.4%
- S - Sulfur - 4.0%
- 3 % voda
- 97 % keratin
- Iron, copper, zinc, chromium, permanganate, sulfur
- Vitamins A, B, C, T and P
- magnesia, arsenic, iron, phosphorus, chromium
- Healthy hair require to get enough protein with food
Cortex
- Majority of hair fiber mass
- Responsible for its strength
- Elongated cells, tightly packed together
- Cells from long filaments, or microfibrils
- Rods of keratin embedded in an amorphous matrix
- High level of the intermolecular cross-linked amino acid
- Cystine
- Disulfide bonds
- Salt bonds
- Hydrogen bonds
Hair cortex fiber (fibril)
Hair cortex fiber's mikrofiber (microfibril) bundle
Hair cortex fibers starting mikrofiber (microfibril)
Hair cortex mikrofiber initial fiber (protofibril)
Original protein spiral fibril
Cortical proteins
- Insoluble in neutral buffers
- Extractable with a minimum of degradation by using alkaline denaturing solvents
- Containing a disulfide-reducing agent
Denaturing agent
- Urea
- Commonly used
Reducing agent
- Mercaptoethanol
- Dithiothreitol
Keep the proteins from aggregating
- Iodoacetic acid
- Cysteine residues were converted to S-carboxymethyl groups
External cuticle hair cuticula (scales)
- 10% of the hair fiber’s weight
- Overlapping layers of scales
- 0.5 micron thick
- Up to 10 scales can overlap in one cross-section
- Protect the underlying cortex
- Act as a barrier
- Intact scales
- Smooth surface reflects light
- Hair looks shiny and healthy
Medulla
- Consists of specialized cells
- Contain air spaces
- Only thick terminal hairs have a medulla, which may be discontinuous
Hair keratin
- Highly viscous and elastic protein
- Stimulates the hair cell hardening
- Formed of resistant to wear long compressed protein molecules
- Regular structure which is sufficiently strong and flexible
- Large protein molecules
- Consists of nineteen amino acids
- Polypeptide chain
- Cysteine - 17.5%
- Cross-linked with disulfide
- Space for the structure (shape)
- Hair elasticity
- Disulphide link disruptions
- Reduce hair elasticity and allow hair to change their shape
- Chemical hair alterations
- Perming
- Straightening
- Coloring, etc.
- Serine - 11.7%
- Glutamic acid - 11.1%
- Threonine - 6.9%
- Glycine - 6.5%
- Leucine - 6.1 %
- Valine - 5.9%
- Arginine - 5.6%
- Aspartic acid - 5.0%
- Alamine - 4.8%
- Proline - 3.6%
- Isoleucine - 2.7%
- Tyrosine - 1.9 %
- Phenylanine - 1.4%
- Histidine - 0.8%
- Methionine - 0.5%
- Fatty substances
- cholesterol
- Mineral compounds
- arsenic
- Hair molecules
- To the zigzag chains of molecules
- Molecular chains form tiny fibers called miceles
- Inter-connect with micels due to the sulfur bridges
- Create fibrous elongated form cells
- Create "keratin" and "protein"
