Integumentary System 1

Question 0

Which layer of skin is CT layers derived from mesoderm?

Answer 0

Dermis

Question 1

Which layer of skin is keratinizing stratified squamous epithelium derived from ectoderm?

Answer 1

Epidermis

Question 2

What type of cell transforms into protective flat scales of keratin?

Answer 2

Keratinocytes

Question 3

What cells are derived from lympoid progenitor cells, enter the epidermis, where they phagocytize and process antigens entering through the skin?

Answer 3

Langerhan’s cells

Question 4

What type of cells produce melanin?

Answer 4

Melanocytes

Question 5

What cells are associated with sensory nerve endings?

Answer 5

Merkel’s cells

Question 6

Epidermis consists of several layers of keratinocytes that represent stages of a specialized form of apoptosis. Cells continously grow maintaining a consistent thickness of skin. Proliferation is driven mainly by what, which is locally produced by dermal fibroblasts in response to what hormone?

Answer 6

IGF, GH

Question 7

Skin cells eventually undergo apoptosis by what two mechanisms?

Answer 7

DNA fragmentation, being filled with keratin

Question 8

Which layer of skin is a simple layer of stem cells that differentiate into keratinocytes?

Answer 8

Stratum basale

Question 9

Which layer of skin is a stratified layer of cells that enlarge and form processes and flatten as they progress toward the surface?

Answer 9

Stratum spinosum

Question 10

Which layer of skin is made of cells that develop granules with precursors of filaggrin, a protein that aggregates keratin filaments?

Answer 10

Stratum granulosum

Question 11

Which layer of skin consist of cells that flatten, lose their nuclei and organelles and become filled with keratin filaments?

Answer 11

Stratum corneum and lucidum

Question 12

Keratinocytes in the basal layer proliferate and synthesize keratin proteins, as they enter what layer?

Answer 12

Stratum spinosum

Question 13

In what layer does keratin granules form and release filaggrin and trichohyalin into the cytoplasm?

Answer 13

Stratum granulosum

Question 14

What is the effect of filaggrin aggregating keratin into bundles of intermediate filaments called tonofibrils?

Answer 14

Flattens and cornifies the cell with soft keratin

Question 15

What are the four most prominent functions of keratin and its various forms of intermediate filaments.

Answer 15

Mechanical support - to strengthen and maintain integrity of epidermis
Cytoarchitectural functions - i.e. regulate desmosomal attachment to other cells, cell migration
Organelle/vesicle distribution - especially transport of melanin-filled melanosomes
Regulation of signaling pathways affecting apoptosis - oxidative stress responses and protein synthesis

Question 16

Desquamation (exfoliation) of cells depends on what?

Answer 16

pH gradient

Question 17

All nucleated cells are linked by what, which imparts physical strength to the epidermis?

Answer 17

Desmosomes

Question 18

What exfoliates the cells by breaking down the desmosomes, in a pH dependent manner?

Answer 18

Peptidases

Question 19

In the deeper epidermal layers where pH in neutral what prevents peptidase actions on desmosomes and inhibits exfoliation?

Answer 19

Protease inhibitors, LETKI

Question 20

As pH drops in the superficial layers (epidermis), what is permitted to release keratinocytes?

Answer 20

KLK - kallikrein related serine peptidases