Brainscape's Knowledge GenomeTM

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


See full index

Dermatology > Structure & Function Of The Skin - Epidermis > Flashcards

Structure & Function Of The Skin - Epidermis Flashcards

1
Q

What are the three layers of the skin

A

Epidermis - stratified cellular epithelium (outer layer)
Dermis - connective tissue under the epidermis
Subcutis - fat layer beneath the dermis

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

Where do the layers of the skin come from embryologically

A

Epidermis - ectoderm
Dermis - mesoderm

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

What are melanocytes

A

Pigment producing cells from neural crest

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

What are blaschko’s lines

A

A pattern of lines that indicate normal cell development in the skin
Usually invisible, but can be seen in people with certain skin conditions

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

Describe the embryological development of the epidermis

A

The ectoderm forms a single layer called the periderm
The periderm gradually increases in layers of cells
This forms the layers of the dermis
The periderm cells then cast off

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the four layers of the skin

A

Keratin layer
Granular layer
Prickle cell layer
Basal layer

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

Describe the keratin layer of the epidermis

A

Non-nucleated, tightly bound together cells
Contain corneocytes (mature keratinocytes)
Is a protective, water proof layer

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

Describe the basal layer of the epidermis

A

Usually one cell thick
Cuboidal, epidermal stem cells
Are highly metabolically active cells & form keratinocytes

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

Describe the granular layer of the epidermis

A

Contain keratohyalin granules, high lipid content & lamellar bodies (secretory organelles)
Secrete lipids, keratin & proteins that create skin barrier
Is where keratinocytes gain keratin & lose their nuclei
Is the origin of the ‘cornfield envelope’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the prickle cell layer of the epidermis

A

Large polyhedral cells with lots of desmosomes,
Contain langerhans cells (immune response)
Provides structural support

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

What is the main cell type found in the epidermis

A

Keratinocytes

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

What other cells, other than keratinocytes, are found in the epidermis & state which layer they are mainly in

A

Melanocytes (basal layer & above),
langerhans cells (prickle cell layer),
merkel cells (basal layer)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What regulates epidermal turnover

A

Growth factors, (programmed) cell death, certain hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the production of keratinocytes in the epidermis

A

Keratinocytes are formed from the differentiation of stem cells in the basal layer. They then migrate up to the more superficial layers. They gain keratin, lose their nucleus and then die in the granular layer

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

Describe the cells of the basal layer

A

Small cuboidal stem cells that are highly metabolically active and contain lots of intermediate filaments (keratin)

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

Describe the cells of the prickle cell layer

A

Large, polyhedral cells with lots of desmosomes. Also contain langerhans cells

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

Describe the cells of the granular layer

A

Cells with high lipid content, large keratohyalin granules & lamellar bodies (secretory organelles)

18
Q

What are corneocytes

A

Mature (dead) keratinocytes found in the keratin layer

19
Q

Describe the embryological development of melanocytes

A

Migrate from the neural crest to the epidermis in first 3 months of foetal development

20
Q

What important organelles do melanocytes contain

A

Melanosomes

21
Q

What do melanosomes do

A

Convert tyrosine to melanin pigment

22
Q

What are the two types of melanin pigment

A

Eumelanin (brown or black)
Phaeomelanin (red, yellow)

23
Q

What is the function of melanin & importance of melanin caps

A

Melanin absorbs light
The melanin cap in melanocytes forms a protective cap over the nucleus

24
Q

How do melanocytes transfer melanin to keratinocytes

A

They transfer the melanosomes (melanin granules) to adjacent keratinocytes via dendrites

25
Q

How does the epidermis change depending on skin types

A

Darker skin
- larger melanosomes containing more melanin
- melanosomes exist throughout the epidermis

Fairer skin
- smaller amounts of melanin & so degrades more quickly
- melanosomes are confined to basal layer (when unexposed)

26
Q

Where do Langerhans cells originate

A

They are mesenchymal in origin
& form from cells in the bone marrow

27
Q

Where are Langerhans cells found

A

Prickle cell layer of epidermis
(& dermis & lymph nodes)

28
Q

What is the role of Langerhans cells

A

Involved in the skin immune system
– Antigen presenting cells
– Pick up antigen in skin and circulate to lymph nodes via lymphatic system

29
Q

What organelle is found in Langerhans cells

A

Racket organelle (Birbeck granules)

30
Q

What are merkel cells & where are they found in the epidermis

A

They are mechanoreceptors
They are found between keratinocytes & nerve fibres in the basal layer

31
Q

Where are mucosal membranes found in the body

A

Eyes, mouth, nose, genito-urinary & GI tracts

32
Q

Describe the oral mucosa

A

Masticatory – keratinised to deal with friction/pressure
Lining mucosa – non-keratinised
Specialised mucosa - tongue papillae – taste

33
Q

Describe the ocular mucosa

A

Lacrimal glands, eye lashes, sebaceous glands

34
Q

What are melanocytes

A

Pigment (melanin) producing dendritic cells

35
Q

What is melanin produced from

A

Tyrosine

36
Q

Where is melanin produced

A

In the melanosomes of melanocytes

37
Q

What three layers of the epidermis are formed from the periderm

A

Keratin layer
Granular layer
Prickle cell layer

38
Q

What provides movement of the epidermis

A

The basement membrane below

39
Q

What is the cornified envelope

A

The cornified envelope replaces the plasma membrane of differentiating keratinocytes
It consists of keratins that are enclosed within an insoluble amalgam of proteins (filaggrin etc), which are crosslinked by transglutaminases and surrounded by a lipid envelope.
It originates in the granular layer.

40
Q

What two proteins are contained in keratohyaline granules & what is their function

A

Filaggrin & Involucrin
- strengthens & flattens the corneocytes
- key component of the cornified envelope,
- help keratin filaments bind together
=> skin barrier

41
Q

Summarise the cells of the epidermis

A
42
Q

Summarise the 4 layers of the epidermis

A

Dermatology (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions