Histo Lec - M9 Integumentary System

Question 1

is the outer avascular epithelial layer

Answer 1

epidermis

Question 2

epidermis consists of what epith

Answer 2

keratinized stratified squamous epith

Question 3

is the inner layer and consists of a dense irregular connective tissue.

Answer 3

dermis

Question 4

is a transitional layer of loose connective and adipose tissue between the dermis and underlying structures, permitting movement between the two.

Answer 4

hypodermis

Question 5

classified as thick or thin depending upon the thickness of the epidermis

Answer 5

skin

Question 6

The cells of this layer are filled with keratin and devoid of all organelles. Their plasma membranes are coated with an extra-cellular lipid layer. The thickness of this stratum is variable, being thin in thin skin, thicker in thick skin and hypertrophied in calluses.

Answer 6

Stratum corneum

Question 7

Characteristic of only thick skin, this thin layer of consists of flat, eosinophilic, enucleated cells.

Answer 7

Stratum lucidum

Question 8

Usually 1-3 cell layers thick, the keratinocytes in this layer are flattened, nucleated cells containing basophilic keratohyalin granules

Answer 8

Stratum granulosum

Question 9

This stratum is typically several cells thick but does vary with location. Its polygonal cells have a central nucleus and exhibit numerous cytoplasmic processes (spines) which attach to reciprocating processes of adjacent cells by desmosomes.

Answer 9

Stratum spinosum

Question 10

This is the proliferative layer resting on the basement membrane. It consists of a single layer of cuboidal cells with sparse, basophilic cytoplasm and variable amounts of the pigment melanin

Answer 10

Stratum basale

Question 11

thinner, more cellular, and contains small diameter reticular and type I collagen fibers.

Answer 11

The superficial papillary layer

Question 12

lies deep to the papillary layer and is typically thicker and less cellular. It has larger diameter type I collagen and elastic fibers. In the areolae and perineum, this layer contains smooth muscle.

Answer 12

The reticular layer

Question 13

are the most abundant cells of the epidermis. They are attached to one another by desmosomes and to the basal lamina by hemidesmosomes

Answer 13

Keratinocytes

Question 14

are derived from neural crest cells and account for about 5% of the living cells in the epidermis

Answer 14

Melanocytes

Question 15

account for 2-3 % of the living epidermal cells. Unlike melanocytes, these immune system cells can be found throughout the epidermis.

Answer 15

Dendritic cells (or Langerhans’ cells)

Question 16

are slender, keratinous filaments projecting above the surface of the skin.

Answer 16

hair

Question 17

are fine, fetal hairs formed and shed (usually) in utero. They lack a medulla

Answer 17

Lanugo

Question 18

are the short, fine (small diameter without medulla), non-pigmented hairs that cover most of the body. These are visible only upon close examination.

Answer 18

Vellus

Question 19

are the long, coarse (large diameter with medulla), pigmented hairs that are easily observed.

Answer 19

Terminal

Question 20

are intermediate in morphology between vellus and terminal forms.

Answer 20

Intermediate hairs

Question 21

is the epithelial organ responsible for production and growth of hair. It is divisible into three longitudinal segments: infundibulum, isthmus and inferior segment.

Answer 21

Hair follicle