The skin (histology)

Question 1

Layers of the skin

Answer 1

Epidermis = keratinised stratified squamous epith.
Dermis = dense connective tissue (for tensile strength) - contains hair follicles, BVs
Hypodermis = adipose tissue - anchors skin to underlying structures, insulative

Question 2

Epidermis layers

Answer 2

Stratum basale = rests on BM, mitotically active, once cells differentiate they move up
Stratum spinosum
Stratum granulosum
Stratum corneum = keratinised, hardened cellsq

Question 3

Stratum basale

Answer 3

single cell layer on BM
cuboidal, or low columnar epith.
epith. stem cells differentiate into keratinocytes

Question 4

stratum spinosum

Answer 4

have cytoplasmic processes which attach to each other by desmosomes (hence you see a gappy appearance between cells)

cells are maturing - increasing in size and flattening

Question 5

stratum granulosum

Answer 5

one to three layers thick
appears basophillic (darker in colour)

Question 6

stratum corneum

Answer 6

anucleate, very flattened
filled entirely with keratin
the plasma membrane is covered with lipids - this helps form a water barrier to the external

Question 7

fingerprint comprised of

Answer 7

dermal papillae (projections from dermis)
epidermal ridges compliment them (the shape which fits the dermal papillae

mechanically supportive

Question 8

Demis layers

Answer 8

papillary layer = superficial, thin, contains BVs and nerve fibres, function is to feed epidermis

reticular layer = deep, thick, made of dense, irregular CT, elastic and collagen, function is strength and flex

Question 9

Hair follicles structure

Answer 9

Infunibulum = upper portion, above sebaceous gland, to surface
isthmus = middle, includes a bulge and sebaceous gland
inferior segment

arrector pilli muscle - contraction assists sebaceous gland secretion into infundibulum

appocrine sweat glands - also empties into infundibulum

Question 10

sebaceous gland

Answer 10

secrete sebum to coat skin and hair

produce sebum and undergo apoptosis at the same time (so secretion has both cells and sebum)

Question 11

eccrine sweat gland

Answer 11

stratified cuboidal
on surface of entire body except lips and genitals
temperature regulation

Question 12

appocrine sweat glands

Answer 12

associated with hair follicles
found areola, genitalia
pheromone rich secretion

assisted secretion by arrector pilli muscle