November 5, 2014 Objective: To describe the structure and function of the hair and nails To make a...
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Transcript of November 5, 2014 Objective: To describe the structure and function of the hair and nails To make a...
November 5, 2014
Objective: To describe the structure and function of the hair and
nails To make a model of the skin
Journal: What are two accessory organs that can be found in the dermis?
Hair Functions
- Helps regulate body temperature- Helps detect things on your skin- Eyelashes and nose hairs are for protection
Hair Anatomy
Made up of dead keratinized epithelial cells
Hair Shaft: the part that protrudes above the skin
Hair Follicle: Tube-like hole in the skin from which the hair develops
Hair Anatomy Continued…
Hair Bulb: Expanded base of the root
Hair Papilla: when the dermis of the skin projects into the base of the hair to supply it with nutrients from blood vessels
Two Stages of Hair Growth
Growth Stage: Stem cells reproduce and differentiate to form
epithelial cells, which are then keratinized and die The hair grows longer as cells are added to the base
Resting Stage: No hair growth Hair is held within the hair follicle
Duration of each cycle depends on the hair.
Hair Lifespan
Eyelashes lasts around 3 to 4 monthsHair on your head lasts about 3 to 4 yearsIt is normal to lose about 100 hairs a day. Baldness occurs when the hair follicles are
lost due to genetic factors or testosterone
** Ingested substances can become part of a hair’s composition, so the longer the length of the hair the longer the record of what was consumed by the individual.
Hair Color and Style
Dependent on the amount and type of melanin you produce in the hair bulb
The more melanin, the darker the hairWhite hair occurs in the absence of melaninRed hair occurs when the melanin is altered
and has iron it inFlat hair shafts = curly hairRound hair shafts = straight hair
Nail Structure
Nails are thin plates made up of layers of keratinized stratum corneum cells.
Nail body: visible part of the nailNail root: part of the nail covered by skinNail fold: the fold of skin that holds the nail
in place
Nail Structure Continued…
Cuticle: stratum corneum cells from the nail fold that extends on to the nail body
Nail Bed and Matrix: Stratum basale that produce the cells that make up the nail body
Lunula: crescent shaped part of the nail matrix
Nail Growth
Nails grow continuouslyProduction of cells within the nail matrix
results in growth of the nail
What your nails can tell your about your health
Nail Shape and Texture: Horizontal ridges - stress Vertical ridges - arthritis Vertical grooves - kidney disorders, aging, and iron deficiency
Markings: Blue nail beds – not enough oxygen in the blood Small white patches – zinc or calcium deficiency or parasites Receded lunulae - poor circulation, shallow breathing habits,
or thyroid problems Large lunulae (more than 25% of the thumb nail) - high blood
pressure.