Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Bioscience > Human skin biology > Flashcards

Human skin biology Flashcards

1
Q

Human Skin Structure

A
  • Epidermis
  • Dermis
  • Hypodermis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Human Skin Structure - Epidermis

A
  • Top layer of skin
  • Provides a barrier and continued renewal
  • No structural strength
  • Mainly consists of layers of keratinocytes
  • Thin skin has 4 layers
  • Thick skin – fingertips, palms, soles
  • Thick skin has 5 layers, 5thlayer is Stratum lucidum
  • No vasculature – all nutrient supply and waste removal through the dermis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Epidermis - Stratification

A

Crucial for barrier function and continued renewal of the epidermis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Stratification – Stratum Basale

A
  • The bottom layer of the epidermis
  • Keratinocyte stem cells are the reservoirs of cells for a lifetime of renewal
  • Transit amplifying keratinocytes proliferate a lot to provide cells for all the top layers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Stratification – Stratum Spinosum

A
  • 8-10 layers of cells
  • Keratinocytes start to flatten out
  • Keratin intermediate filaments and desmosomes hold cells together
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Stratification – Stratum Granulosum

A
  • Flattened keratinocytes undergoing apoptosis
  • Lamellar granules -fuse to plasma membrane and release lipid rich secretions to help form the barrier.
  • Keratohyalin- dark granules, help form keratin intermediate filaments into keratin.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Stratification – Stratum Lucidum

A
  • Only present in thick skin

* Fingertips, palms, soles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Stratification – Stratum Corneum

A
  • 25-30 layers of flattened, dead keratinocytes
  • Keratinocytes overlap like scales of snake
  • Barrier formed to keep moisture in and the outside world out
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Stratification - Process

A
  • Proliferating keratinocytes on the bottom of the epidermis push cells up and away from the dermis.
  • Undergo programmed cell death
  • Complete epidermal turnover approximately once a month
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Basement Membrane

A
  • Interface between the dermis and epidermis
  • Collagen IV, Perlecan, Nidogen, Laminin 332
  • Important for epidermal attachment to the dermis
  • Mutation in basement membrane proteins can result in Epidermolysis Bullosa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Rete Ridges

A
  • Dermal papillae/Rete ridges

* Contour provides resistance to shear forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Pigmentation - Melanocytes

A
  • reside at the basement membrane, on the epidermal side
  • Make melanosomes, which contain the pigment melanin - Melanosomes are transferred to keratinocytes- Contacts on average 36 keratinocytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Pigmentation - Melanin

A
  • pigment that gives skin its colour
  • Pheomelanin is yellow-red, eumelanin is brown-black
  • Melanin protects from UV
  • Nuclear cap protects keratinocyte DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Epidermis – Langerhan’sCells

A

• Langerhan’scells surveil the epidermis for foreign organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Human Skin Structure - Dermis

A
  • Dense matrix made up of collagen and elastin fibres
  • Strong and supple
  • Thickness varies, again thickest on soles and palms
  • Unlike epidermis, dermis is very stable, turnover is minimal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Dermis - Fibroblasts

A
  • Fibroblasts produce collagen and elastin
  • Collagens - strength
  • Elastin - elasticity
17
Q

Dermis - Papillary and Reticular

A
  • Transverse section of human skin
  • Papillary dermis – high cell density, loose connective tissue
  • Reticular dermis – low cell density, dense connective tissue
18
Q

Dermis – Vasculature

A

• Vasculature –- supply nutrients and remove waste for both dermis and epidermis

19
Q

Wound Types

A
  • Superficial
  • Partial-thickness
  • Full-thickness
20
Q

Superficial Wounds

A

Damage to the epidermis only

21
Q

Superficial Wound Healing

A

Healing occurs by migration of keratinocyte from the wound edges and dermal appendages (sweat glands, hair follicles, sebaceous glands)

22
Q

Superficial Wound Healing

A

Once all keratinocytes are in contact on all sides, then stratification can occur to reform the epidermis

23
Q

Partial Thickness Wounds

A

All of the epidermis and some of the dermis is destroyed

24
Q

Partial Thickness Wound Healing

A

• Four phases of healing –
- Inflammatory phase - immune cells come in and clean up the wound.

  • Migratory phase-keratinocytes migrate from the wound edge and appendages, fibroblasts migrate into the clot make collagen fibres
  • Proliferative phase -keratinocytes proliferate
  • Maturation phase - epidermal stratification then scab falls off.
25
Q

Full Thickness Wounds

A
  • All of the epidermis and dermis is destroyed

* Hypodermis can be destroyed too, exposing bone and muscle

26
Q

Full Thickness Wounds

A
  • Wound repair is very difficult because all of the reservoirs of epidermal stem cells have been destroyed.
  • Keratinocytes have to migrate from the wound edges
  • Heals as scar tissue
  • Intervention is required to improve patient outcomes
27
Q

Full Thickness Wound Treatment

A
  • Split thickness skin graft is the gold standard
  • Split thickness skin graft - all of the epidermis, part of the dermis
  • Donor site – undamaged skin
  • Split thickness skin graft covers the wound
  • Donor site will heal in 10-14 days

Bioscience (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions