Lesson 4 - Biological Aspects of Friction Ridge Skin

Epidermis, dermis, hypodermis

Name the three layers of the skin.

Structure

Permanence of friction ridge skin is due to the _____ of the skin.

Formation

Discriminability of friction ridge skin is due to the _____ of the skin.

Keratinocytes

The epidermis is composed of cells called _____.

a) Stratum corneum

b) Stratum lucidum

c) Stratum granulosum

d) Stratum spinosum

e) Stratum basale

Label the layers of the epidermis.

~10.5 weeks

The “critical stage” of fingerprint development begins at how many weeks?

Ridges, furrows

Primary ridges form _____ on the surface; secondary ridges form _____ on the surface.

Regression, size (height)

Volar pad _____ and _____ determines pattern ridge count.

Symmetry

Volar pad _____ determines pattern type.

~16 weeks

Secondary ridge formation begins at how many weeks?

True

True/False: Eccrine glands are the only type of glands found on volar skin.

Stratum basale

What is the name of the layer of the epidermis known as the “blueprint”? 

~6 weeks

Volar pad formation begins at how many weeks?

False

True/False: The stratum lucidum or “hyalin” layer is the outermost layer of the epidermis and contains the cells that “slough” off.

Basal

Damage to the _____ layer of the epidermis will cause permanent scarring.

True

True/False: High/asymmetrical volar pads will likely result in a high ridge count loop.

Desmosomes, hemidesmosomes

Basal cells are joined to each other by cell junctions called _____ and are joined to the basement membrane zone by another type of junction called _____.

Generate new cells

Which is NOT a function of the basement membrane zone?

30 days

It takes approximately _____ for skin cells to complete all stages of differentiation and be sloughed off.

True

True/False: Ridges grow perpendicular to stress forces.

Dependent

Is minutia formation a dependent or independent event?

False

True/False: Ridges form before flexion creases.

True

True/False: Friction ridge skin is thicker than the rest of the skin on the body.