Brainscape's Knowledge GenomeTM

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


See full index

Tissue Biology > SKIN > Flashcards

SKIN Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What did Virchow describe skin as?

A

Protective covering

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

What functions does the skin have?

A
  • Resists bacterial and fungal invasion
  • It’s rich in antigen-presenting cells (Langerhans cells) for immune response
  • Pigmentation from melanin provides protection from UV
  • Facilitate synthesis of vitamin D3
  • Skin helps thermoregulate via blood circulation in extremities and sweat
  • Receptors for touch, pressure, pain and temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the layers of the skin?

A

3 main layers,

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

What does the epidermis do?

A

Continuously multiplying stratified squamous epithelium which produces a non-living layer of keratin

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

What types of cells does the epidermis contain?

A
  • The epidermis contains
  • keratinocytes (90%)
  • melanocytes, which protect against sunlight
  • Langerhans cells which recognise external antigens (immune response)
  • Merkel cells which are sensory receptor cells
  • inflammatory cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why is keratinisation of the skin important?

A

its integral to skin renewal and healing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does the epidermis function?

A
  • The layers of the epidermis continually move upward, flatten, build up at the surface and then slough off to make room for the cells behind them
  • The epidermis is adapted to withstand constant abrasion and desiccation due to tough non-living surface layer composed of protein keratin wrapped in plasma membrane.
  • the epidermis is avascular (it doesn’t contain any blood vessels) so its nourished by diffusion from the dermis.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

the dermoepidermal junction

A

is an area of tissue that joins the epidermis and the dermal layers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what does the dermorpidermal juction contain?

A
  • rete ridges: highly corrugated and many downward ridge like extensions of the epidermis
  • dermal papillae: alternating, upward projections of dermis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are rete ridges?

A

Finger like projections in the junction that increase the surface area of the epidermis that is exposed to the blood vessels and the needed nutrients.
It is responsible for the change of nutrients from th epidermis to the dermis and without it the skin would suffer premature ageing and damage.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the layers of the epidermis?

A
  • keratin layer (stratum corneum)
  • granular layer (stratum granulosum)
  • prickle cell layer (stratum spinosum)
  • basal layer (stratum basale)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What layer does thick skin have that thin skin doesn’t have and what does it do?

A
  • stratum lucindum, between stratum cornea and stratum granulosum
  • its comprised of a few layers of tightly packed squamous cells that lack organelles and nuclei. Its translucent
  • it reduces friction and shear forces between the surrounding layers of the epidermis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Basal Layer (Stratum Basale)

A
  • deepest layer of epidermis
  • single layer of of closely packed basophilic cuboidal to columnar epithelial cells (kertainocytes) attached to the basement membrane on their dermal surface.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does the basal layer function?

A

Every hour, between 30,000 and 40,000 dead skin cells are shed. At the basal surface the cells in this layer are attached to the underlying basement membrane - the dermoepidermal junction.

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

Prickle Cell Layer ( Stratum Spinosum)

A

Superficial to the stratum basale and forms the majority of the epidermis.
It consists of several layers of irregular, polyhedral cells that become flattened in the outermost layers.
The stratum spinosum made of:
- polyhedral-shaped keratinocytes
- round-oval nuclei
- prominent nucleoli and cytoplasm, forming a pavement-like pattern.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Granular Layer (Stratum Granulosum)

A

3 to 5 layers of flattened cells, contain numerous basophilc granules (keratohyalin)
Begin to lose their polyhedral shape and become more flattened near the surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does the granular layer function?

A

They acquire dense basophilic,keratohyaline, they undergo kertinisation as they progressing towards the surface, the cells lose their nuclei and cytoplasm, becoming flattened interconnectedkeratin squareswhich form the surface of the skin thestratum corneumC.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Keratin layer (Stratum Cornuem)

A
  • Outermost layer of the epidermis with the vital barrier function.
  • Dead anucleate cornified cells, keratin replaces cytoplasm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Whats the Malpighian layer?

A

the stratum basale and stratum spinosum layer are collectively known as the Malpighian layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What determines the colour of skin and hair?

A

Melanocytes are cells that produce melanin, however it is not the number of melanocytes but the activity that is affected by corticotropin from the pituitary.

21
Q

How many melanocytes occur per 1mm2 of epidermis?

A

1000-2000

22
Q

Where is melanin produced?

A

melanosomes = membrane-bound organelles

23
Q

What 2 major forms of melanin are found in humans?

A
  • Eumelanin = brown to black

- Phenomelanin = yellow to red

24
Q

What is the purpose of melanin?

A

protection against damaging effects of UV radiation on DNA

25
Q

Where does a melanoma form from?

A

Mainly from frequent exposure to the sun

They develop from melanocytes in the skin and some in the mucous membranes, urea of the eye and meninges.

26
Q

How does a melanoma form?

A

Melanocyte transformation to melanoma is via radial and vertical growth phases: Melanocyte proliferation forming nevi with subsequent dysplasia, hyperplasia, invasion and metastasis

27
Q

How can we diagnose melanoma?

A

Skin biopsydetermines diagnosis and disease severity.Melan-Aandhuman melanoma black(HMB) immunohistochemistry is used to detect melanoma cells.

28
Q

What are Langerhans cells ?

A

They are monocyte-derived dendritic cells that reside in the epidermis

29
Q

What is the function of Langerhans cells?

A
  • Phagocytic and antigen-processing and presenting cells.
  • They monitor and capture invading surface antigens, then migrate to regional lymph nodes.
  • Induce an immune response via antigen presentation to CD4+ and CD8+ T lymphocytes
30
Q

Where are Langerhans cells found?

A

Stratum spinosum and stratum granulosum

31
Q

What are Merkel cells? and what to they do?

A

They are intra-epidermal touch receptors and contain membrane-bound vesicles in their cytoplasm.
Make synaptic junctions with their sensory nerves in the upper dermis.

32
Q

What are some epidermal skin appendages?

A
  • Hair Follicles
  • Sebaceous glands
  • Eccrine (sweat) glands
  • Apocrine glands
33
Q

Hair Follicles

A
  • produced in follicles, cylindrical shafts composed of keratin; hair shafts have a surface cuticle composed of a single layer of flattened keratin scales
34
Q

What are the function of hair follicles?

A 
Thermoregulation
Hair growth is cyclical w/ 3 phases:
- long phase of active growth (anagen)
- short phase of involution (catagen)
- short inactive involuted phase (telogen)
35
Q

Where are sebaceous glands located?

A

Between a hair follicle and its arre ctor pili muscle in the dermis

36
Q

What is holocrine secretion?

A

Sebaceous glands produce sebum made of lipid-rich decomposed cells. They empty their secretions via duct into the upper part of the hair follicle near the hair shaft.

37
Q

What does each gland contain?

A

a peripheral layer of cuboidal cells with spherical nuclei resting on a thin basement membrane

38
Q

How does each gland function?

A

Active cells give rise to the larger sebum-producing cells. The larger cells are polyhedral with large amounts of lipid in the cytoplasm. Nuclei become pyknotic and cells gradually disintegrate, to the secretory product.

39
Q

What is an arrestor pili?

A

Sebaceous glands have a small bundle of obliquely arrangedsmooth muscleknown as thearrector pili muscle. Contraction of this muscle compresses the gland and helps expel sebum into the follicle.

40
Q

Eccrine (sweat) glands

A

Eccrine sweat glands are simple, coiled tubular glands consisting ofsecretoryand narrowerexcretory ductportions.

41
Q

What types of eccrine gland cells are there?

A

The tightly convoluted secretory part of a gland deep in the dermis consists of two types of cuboidal to pyramidalsecretory cells—clear cellsanddark cells.

42
Q

What do these cells do?

A
  • Clear cells primarily secrete water and electrolytes
  • Dark cells secrete macromolecules.
  • Smaller, intensely eosinophilicmyoepithelial cells, border the secretory cells.
  • Myoepithelial cells are mainly contractile and help expel sweat into the lumen
43
Q

What is the excretory duct?

A

The excretory duct is made of two layers of dark-stainingcuboidal epithelial cells and has a smaller diameter than the secretory acinus and lacks myoepithelial cells.

44
Q

Where are apocrine glands found?

A

Apocrine glands are confined to a few localised areas, mainly in the axilla and groin.
The secretory component is located in deep reticular dermis or subcutis

45
Q

What do apocrine glands look like and do?

A

Apocrine gland secretions in humans have no defined function.
A duct system carries the secretion into the upper part of the hair follicle above the sebaceous duct.
The secretory gland isa coiled tubular type with a widely dilated lumen.
The secretory cells are usually low cuboidal with eosinophilic cytoplasm.
They have a discontinuous layer of myoepithelial cellsbetween the secretory cells and the basement membrane.
The ductis histologically similar to that of eccrine sweat glands.

46
Q

What is the dermis?

A

The dermis is composed of bundles of collagen fibres and strands of elastic fibres embedded a small amount of acellular ground substance,
There are a few fibroblasts which synthesise the collagen, elastic fibres and matrix.

47
Q

How many layer does the dermis have and what are they called?

A

2 layers:

  • Superficial papillary dermis (beneath the epidermis)
  • Deeper reticular dermis (borders the subcutis)
48
Q

What does the papillary dermis contain?

A

The papillary dermis is loose and contains very fine, interlacing collagen (red) and elastic fibres (black) in the EVG (elastin- Verhoeff Van Gieson) stain. It contains arterioles, capillary loops and venules, as well as lymphatics

49
Q

What is the reticular dermis?

A

The reticular dermisR, generally a much thicker layer. The interface may be poorly defined.

Tissue Biology (7 decks)

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