histology 6- integumentary system

Question 1

List the components of the integumentary system.

Integumentary System

Answer 1

• Skin

- Accessory structures/Epidermal derivatives

Question 2

Accessory structures/Epidermal derivatives

Answer 2

• Sebaceous (oil) glands
• Sudoriferous (sweat) glands
• Hair
• Nails

Question 3

List and describe the major functions of the integumentary system. Functions of Integument

Answer 3

• Protection
• Sensation
• Temperature Regulation
• Metabolic Waste Elimination

Question 4

two layers of the skin

Answer 4

epidermis

dermis

Question 5

epidermis

Answer 5

• superficial
• ectoderm derived
• keratinized stratified squamous epithelium

Question 6

dermis

Answer 6

• deep
• mesoderm derived
• CT

Question 7

deep to the dermis is what

Answer 7

• Hypodermis/Subcutaneous Layer/Superficial fascia

- Adipose Tissue

Question 8

thicker skin has a thicker layer of what compared to thin skin

Answer 8

superficial keratin

Question 9

process of keratinizatoin

Answer 9

• Cell flattens, dies
• keratohyalin granules appear in granular cells
• water barrier separates keratinized cells from precursors
• New keratinized cells pH = 6.8-7.5
• Most superficial keratinized cells pH = 4.5-5.3

Question 10

List, identify, and describe the different layers of keratinocytes in the epidermis.

Answer 10

-Basal Cell → Spinous Cell → Granular cell → Keratinized cell

Question 11

4 cells found in epidermis

Answer 11

• Keratinocytes
• Melanocytes
• Langerhans cells
• Merkel cells

Question 12

Keratinocytes

Answer 12

• provide a mechanical and chemical barrier against environmental damage
• pathogens, heat, UV radiation, water loss

Question 13

Melanocytes

Answer 13

-melanin-producing cells in stratum basale

Question 14

Langerhans cells

Answer 14

• dendritic cells (antigen-presenting immune cells) most prominent in s. spinosum (found in all layers)
• take up and process microbial antigens during skin infections

Question 15

Merkel cells

Answer 15

-touch receptors, fine spatial details (exact function is still unsure)

Question 16

5 layers of the epidermis

Answer 16

supferficial->Deep

1. stratum cornea
2. stratum lucidum
3. stratum granulosum
4. stratum spinosum
5. stratum basale

Question 17

stratum cornea

Answer 17

-25-30 rows of dead, flat keratinocytes (just bags o’ keratin at this point)

Question 18

stratum lucidum

Answer 18

• present only in fingertips, palms, and soles of feet (thick skin)
• 3-5 rows of clear, flat, dead keratinocytes with large amounts of keratin

Question 19

stratum granulosum

Answer 19

• 3-5 rows of flattened keratinocytes
• organelles begin disintegrating
• Contains:
  
  • Keratohyalin (converts tonofilaments to keratin)
  • Lamellar granules (releases a lipid-rich, water-repellent secretion)

Question 20

stratum spinosum

Answer 20

• 8-10 rows of many-sided keratinocytes with bundles of tonofilaments
• includes projections of melanocytes and Langerhans cells

Question 21

stratum basale

Answer 21

• single row of cuboidal or columnar keratinocytes with scattered tonofilaments
• stem cells that differentiate into keratinocytes, melanocytes, Langerhans cells, and Merkel cells.

Question 22

layers of the dermis

Answer 22

papillary layer

reticular layer

Question 23

papillary layer…type of CT

Answer 23

• superficial, loose (areolar) CT
• contains dermal papillae that house capillaries, corpuscles, and free nerve endings
• also provides mechanical stability to epidermis (no sliding between layers)

Question 24

reticular layer….type of CT…consists of what kinds of fibers

Answer 24

• deep 4/5 of dermis, dense irregular CT
• bundles of collagen & coarse elastin fibers
• spaces between fibers house adipose cells, hair follicles, sebaceous & sudoriferous glands

Question 25

Describe and identify Meissner and Pacinian corpuscles. What type of stimulus activates each?

Answer 25

1. Meissner (tactile) Corpuscles - light touch, tactile, sensitive (feather grazing skin) - superficial - horizontal layers in a papilla 2. Pacinian (lamellar) Corpuscles - heavy touch (pressure) - deep - ovoid rings around concentric central cavity

Question 26

parts of hair and follicle

Answer 26

hair - medulla - cortex - cuticle of hair (pigment follicle - internal root sheath in contact with hair - external root sheath - glassy sheah most superficial in contact with epidermis/dermis

Question 27

Hair follicle anchored by _______ of root and _______ in middle of bottom

Answer 27

bulbous shape, dermal papilla

Question 28

sections of the nails

Answer 28

nail plate lunula nail bed free margin

Question 29

nail plate

Answer 29

toughened keratin "nail"

Question 30

lunula

Answer 30

white half-moon near nail root, most visible on thumb

Question 31

nail bed

Answer 31

-skin beneath nail plate

Question 32

free margin

Answer 32

nail at fingertip not attached to nail bed

Question 33

arrector pili muscles. What type of muscle tissue? What innervates these? What is their function?

Answer 33

- smooth muscle - innervated by autonomic nervous system - function in hairy mammals: elevate hair follicles and provide air space between hairs for insulation - function in humans: goosebumps (kind of vestigial/useless)

Question 34

Sebaceous glands (oil)

Answer 34

- branched acinar gland - found everywhere except palms of hands and soles of feet - lubricates hair follicles with oils/waxes/cell fragment secretion called sebum

Question 35

Sudoriferous glands (sweat)

Answer 35

-exocytosis of sweat -two types eccrine sweat gland apocrine sweat gland

Question 36

eccrine sweat gland

Answer 36

- found throughout skin in deep dermis to surface of epidermis from birth - less viscous secretion - water - electrolytes, nitrogenous wastes, amino acids, glucose, lactic acid - regulates body temperature and removes wastes

Question 37

apocrine sweat gland

Answer 37

- found in subcutaneous layer - located in skin of axilla, groin, bearded regions of face, labia (secondary hair growth in puberty) - more viscous than eccrine secretion (eccrine + lipids and proteins) - stimulated during emotional stress and sexual excitement