SSN Session
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Transcript of SSN Session
SSN Session
SkinJennifer Chang (jtc2109)
Bram Welch-Horan (tbw5)October 19, 2005
• Protection - barrier to outside environmentabrasion, moisture, UV light, microorganisms
• Homeostasis - maintenance of internal environmenttemperature, water and salts
• Sensation touch, temperature, pain, pressure, vibration
• Immune surveillance Langerhans’ cells – type of macrophage
• Endocrine function synthesizes vitamin D
Functions
Hairy Glabrous
Types of SkinThick – covers palms of hands and soles of feet, glabrousvs.Thin – covers rest of body, mostly hairy
3 layers
• Epidermis
stratified squamous keratinizing epithelium
• Dermis
papillary layer of loose connective tissue underlain by dense irregularly arranged CT
• Hypodermis
aka subcutaneous tissue, loose CT, contains adipose tissue
Epidermis – stratified squamous keratinized epithelium
5 Layers
1. Stratum corneum
2. Stratum lucidum
3. Stratum granulosum
4. Stratum spinosum
5. Stratum basalis
Stratum corneum
• Superficial keratinized layer• Cells have no nuclei or
organelles• Sealed extracellular space• Most superficial cells are
sloughed off
Stratum granulosum
• Basophilic granules of keratohyalin – Promotes aggregation of
keratin filaments into tonofibrils• Lamellar bodies – water barrier
Stratum corneum
Stratum Spinosum
• several cell layers thick• attached by intercellular bridges (desmosomes)• cells artificially pulled apart, the attachment sites give spiny appearance• Langerhans’ cells found here
desmosomes
Stratum Basalis
mitotic cellcells with melanin
• Mitotic cell layer, attaches to basement membrane via hemidesmosomes
• Cells containing melanin may be either melanocytes or keratinocytes
• Melanin
- pigment - protection from UV rays
- synthesized in melanocytes using tyrosinase - taken up by keratinocytes
Question 1
In the stratum basalis, ______ are found. They attach keratinocytes to ______.
a. Hemidesmosomes, basal lamina
b. Desmosomes, basal lamina
c. Hemidesmosomes, other keratinocytes
d. Desmosomes, Langerhans cells Lab 8, slide 2
Question 1
In the stratum basalis, ______ are found. They attach keratinocytes to ______.
a. Hemidesmosomes, basal lamina
b. Desmosomes, basal lamina
c. Hemidesmosomes, other keratinocytes
d. Desmosomes, Langerhans cells Lab 8, slide 2
Question 2
Which of the following regarding these cells is true?
a) They are mitoticb) They do not have
organellesc) They contain
keratohyalin granulesd) They synthesize
melanin
Question 2
Which of the following regarding these cells is true?
a) They are mitoticb) They do not have
organellesc) They contain
keratohyalin granulesd) They synthesize
melanin
Question 3
This brown substance is synthesized in which cell layer?
a)Stratum corneumb)Stratum
granulosumc)Stratum spinosumd)Stratum basalis
Question 3
This brown substance is synthesized in which cell layer?
a)Stratum corneumb)Stratum
granulosumc)Stratum spinosumd)Stratum basalis
Specialized Structures in Skin
• Nerve supply
• Hair follicles
• Sweat glands
• Sebaceous glands
• (Nails)
• (Mammary glands)
(http://www.columbia.edu/~johan/images/arm.jpg)
The Dermis• Papillary layer
– loose CT– bv’s, nerves,
lymphatics– papillae into
epidermis– Meissner’s
corpuscles
• Reticular layer– dense CT (less
cellular)– eccrine sweat glands– Pacinian corpuscles– anatomy: Langer’s
lines
(Ross, 4/e, p. 425)
Cutaneous Nerve Endings
• (Free nerve endings)– pain & temperature
• (Merkel’s cells)– high-res. tactile sensation (in stratum basale)
• Meissner’s Corpuscles– touch
• Pacinian Corpuscles– vibration & pressure
(Skin lab, slide 16; Cajal stain)
Meissner’s Corpuscles
• in dermal papillae (papillary layer of dermis)
• mechanoreceptors• 2-point
discrimination• encapsulated
• CT capsule• contrast w/ free
nerve endings (Ross, 4/e, p. 412)
Pacinian Corpuscles
(Ross, 4/e, p. 431)
Pacinian Corpuscles
• in deeper dermis & hypodermis– reticular layer
• vibration & pressure• encapsulated• characteristic appearance
– “onion” / “bull’s eye”
• diagnostic for dermis– or hypodermis
• hypodermis – loose CT, bv’s, fat, etc.– a.k.a., subcutaneous tissue,
superficial fascia(Skin lab, slide 18)
Hair Follicles
• epithelially derived– epidermal invagination– matrix of follicle equiv.
to stratum basale
• most of body surface• body temp. regulation• sebaceous glands
– secrete into follicle
• arrector pili– smooth muscle – “goosebumps”– assists gland secretion
(Ross, 4/e, p. 414)
Sebaceous Glands
• associated w/ hair follicle• secrete sebum between
shaft & follicle• holocrine secretion
– oil-filled cells apoptose– secretory product & cell
debris discharged from gland
• sebum may be protective– but is involved in acne
(Skin lab, slide 21)
• coiled tubular glands in dermis (reticular layer)– not associated with hair follicles; widely distributed
• secretory portion (w/ basal lamina)• myoepithelial cells
– contract expel sweat
• ducts – cuboidal cells– stratified (2 layers)– corkscrew path
– reabsorb H2O, salt
• sweat is hypotonic– contains H2O, salt, IgA
• temp. regulation
Eccrine Sweat Glands
(Skin lab, slide 13)
Sweat Ducts
(Skin lab, slide 12)
Question 4
• What is the function of this nerve ending, and which skin layer is it in?
a) pain; hypodermisb) temp.; reticular layerc) two-pt.
discrimination; papillary layer
d) itch; epidermis
(Skin lab, slide 15)
Question 4
• What is the function of this nerve ending, and which skin layer is it in?
a) pain; hypodermisb) temp.; reticular layerc) two-pt.
discrimination; papillary layer
d) itch; epidermis
(Skin lab, slide 15)
Question 5
• The product of the gland in this image would most likely be:
a) attractive to a potential mate
b) hypotonicc) mainly waterd) oily and associated
with cell debris (Skin lab, slide 23)
Question 5
• The product of the gland in this image would most likely be:
a) attractive to a potential mate
b) hypotonicc) mainly waterd) oily and associated
with cell debris (Skin lab, slide 23)