Integument

Question 1

Hemidesmosomes attach ______ to _______.

Answer 1

Stratum basale to basement membrane

Question 2

Primary hair vs. secondary hair on histology slide

Answer 2

Primary hair is MUCH larger Primary hairs form clusters with secondary hairs (1) primary hair surrounded by multiple secondary hairs

Question 3

Hair

Answer 3

• Derived from matrical cells
• Made of keratin, but different from keratinocytes

Question 4

Where is the stratum lucidum found?

Answer 4

Typically- only found in select regions such as the paw pad and nasal planum

Question 5

Location where keratin begins to be made in the cell

Answer 5

Stratum granulosum Then that cell layer dies, and it becomes a part of the stratum corneum

Question 6

Melanocytes and basal stem cells are attached to ___

Answer 6

Basement Membrane

Question 7

Staining of Melanocytes on Hematoxylin/Eosin Stain

Answer 7

Brown

Question 8

Merkle Cells

Answer 8

• Mechanoreceptors sensitive to light touch
• Research suggest that they are derived from the same primoridum as epithelium
• Once thought to be of neural crest origin

Question 9

Type I Collagen

Answer 9

Predominantly found in the reticular dermis

In muscle, the bundles are separated by “facial planes” which are just type I collagen.

Question 10

Epidermal Layers

Answer 10

Question 11

Dermis

Answer 11

• Has fewer cells than the epidermis
• Majortiy of space is occoupied by connective tissue and collagen bundles
• Papilar dermis (more cells, less fibers)
• Reticular dermis (large amount of collage bundles)- few cells

Question 12

Epidermis

Answer 12

• Thin or thick skin
• 5 cell layers or 20-30 cell layers thick

Question 13

Stratum basale

Answer 13

• Location of skin stem cells
• Attached by hemidesmosomes
• Mitosis abundant - chromosome condensation is easily viewed inside the cell
• 1 layer of cells directly attached to the basement
• Basal layer
• Melanin (brownish) granules associated with this layer

Question 14

Morphology of cells leaving the basement membrane

Answer 14

Changes from round to increasinly more squamous

Question 15

Stratum spinosum

Answer 15

• Layer directly above the stratum basale
• 2-5 cell layers thick
• Cells begin differentiation here
• Cubodial to squamous

Question 16

Stratum granulosum

Answer 16

• Flat polygonal cells with basophillic granules
• Keratohyalin granules –> keratin
• Job is to produce large amounts of keratin proteins
• Cells accumulate keratin granules
• Held together by desmosomes

ex. Animal dehydrated = shrinkage of tissue= spiky projections between cells

Question 17

Kertain protein (function and production location)

Answer 17

• Protect skin
• Stratum granulosum

Question 18

Stratum lucidum

Answer 18

• Directly above the stratunm granulosum
• Translucent, squamous layer
• Organelles absent
• Limited to thick epidermis (footpad, nose, teeth)
• Not always visible
• Pick cytoplasmic staining H&E stain

Question 19

Stratum corneum

Answer 19

• Many layers
• Flat, cornified, dead
• Cells have already gone final stages of differentiation and are undergoing apoptosis
• Tough, protective skin

Question 20

Melanin

Answer 20

• Body’s internal production of sunscreen

Question 21

Soft Keratin

Answer 21

• Outer layer
• Corneum

Question 22

Keratinocytes

Answer 22

• Divide and differentiate into outer protective cell layers
• Form all the layers (basal, spinosum, granulosum, corneum)
• Produce keratin protein

Question 23

Melanocytes

Answer 23

• Responsible for melanin production
• Brownish granules on H&E stain
• Near keratinocytes on slides
• Almost always located in the basal layer (anchored)
• Octopus shape
• Multiple cytoplasmic processes
• Melanin uptake via keratinocytes via cytoplasmic processes