Structure and Function of the Skin Flashcards Preview

Dermatology > Structure and Function of the Skin > Flashcards

Flashcards in Structure and Function of the Skin Deck (70)
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1
Q

Which part of the skin is comprised of stratified squamous epithelium?

A

Epidermis

2
Q

Merkel cells reside in which layer of the epidermis?

A

Basal cell layer

3
Q

Where do langerhans cells in the skin originate?

A

Bone marrow

4
Q

Basic skin atomy develops after how many weeks of gestation?

A

16 weeks

5
Q

Which parts of the skin have developed by 4 weeks of gestation?

A
  1. Periderm
  2. Basal layer
  3. Dermis
6
Q

After how many weeks of gestation is the skin considered fully formed?

A

26 weeks

7
Q

Which structures within the skin are hairs always associated with?

A
  1. Arrector pili muscles
  2. Hair bulbs
  3. Sebaceous sweat glands
8
Q

What causes albinism?

A

Absence of genes which allow melanin to be formed

9
Q

Which hormone is required for melanosomes to be produced to allow for melanin production?

A

Melanocyte stimulating hormone

(derived from ACTH from the pituitary)

10
Q

What are Blaschko’s lines?

A

Lines which show developmental growth patterns of skin

(related to different cell groups which grow, divide and migrate over time - the lines are the separations between such populations)

11
Q

The dermis is comprised mostly of what?

A

Connective tissue

12
Q

In which cell can mechanoreceptors be found?

A

Merkel cells

13
Q

What causes vitiligo?

A

Autoimmune condition causing a relative lack of melanocytes

14
Q

What are the layers of the epidermis from superficial to deep?

A
  1. Keratin layer (stratum corneum)
  2. Clear layer (Stratum lucidum)*
  3. Granular layer (Stratum granulosum)
  4. Prickle layer (Stratum spinosum)
  5. Basal layer (Stratum basale)

*Not considered a major layer

15
Q

Why is it important the cells in the basal layer are protected most by melanin?

A

Stem cells reside here

DNA must be capped by melanin as this cannot be replaced

16
Q

Which cell type of most prominent in the epidermis?

A

Keratinocytes (95%)

17
Q

Which two major conditions involves increased epidermal turnover?

A
  1. Psoriasis
  2. Skin cancer
18
Q

What induces merkel cell cancer?

A

Infection from viruses

(Rare and high mortality cancer)

19
Q

In which cell may Birbeck granules be found?

A

Langerhans cells

(they look like tennis rackets)

20
Q

What is the name given to melanin that is black/brown in colour?

A

Eumelanin

21
Q

What is the name given to melanin that is red/yellow in colour?

A

Pheomelanin

22
Q

What is the correct order for the stages of hair growth?

A
  1. Anagen (Growing)
  2. Catagen (Involuting)
  3. Telogen (resting
23
Q

Where do melanocytes originate?

A

Neural crest

(in ectoderm during embryogenesis)

24
Q

What may increase within the skin in reponse to mechanical pressures?

A

Keratin

(for increased strength)

25
Q

The epidermis arises from whcih embryological tissue?

A

Ectoderm

26
Q

Which cells within the skin are the outermost cells able to detect microbes?

A

Langerhans cells

27
Q

What is the treatment for vitiligo?

A

Phototherapy

(filtered phototherapy can control the autoimmune response)

28
Q

Which layer of the epidermis contains filaggrin and involucrin?

A

Granular layer

(provides such substances to maintain water barrier of skin)

29
Q

Which type of granules will release filaggrin and involucrin?

A

Lamellar

(within the granular layer)

30
Q

What is the term given to the remnant of granular cells which now have no nucleus?

A

Corneocytes

(cells of the granular layer are flattened, lose thier nucleus, release contents of lamellar granules (filaggrin and involucrin) and create 2-3 layers to become the keratin layer)

31
Q

How many days does it take for cells to migrate from the basement membrane to the keratin layer?

A

28 days

32
Q

What is the most common cause of hair loss?

A

Telogen effluvium

33
Q

For which reason do humans not go bald during the telogen phase?

A

The telogen phase is asynchronous

(all hairs reach this stage at different times)

34
Q

What marks the boundary between the epidermis and dermis?

A

Papillae

(folded for mechanical stability)

35
Q

What happens when the nail matrix is damaged during mechanical trauma?

A
  1. Stem cells undergo trauma
  2. Normal nail still grows
  3. Areas of opacities and crumbly regions may be present where the process of differentiation has been disrupted
36
Q

Which amino acid is converted to melanin within melanosomes?

A

Tyrosine

37
Q

Which do children with phenylketonuria (PKU) often have pale skin, blond hair and blue eyes?

A
  1. The process of converting phenylalanine to tyrosine is disrupted
  2. Tyrosine is required to be converted to melanin within melanosomes
  3. Less melanin is produced
38
Q

What are nails comprised of?

A

Specialised keratins

39
Q

What causes Nelson’s syndrome?

A

Excess ACTH release from the pituitary

(leads to excess MSH production causing increased melanin)

It is common in people who have had adrenal glands removed after suffering from Cushing’s syndrome/disease

40
Q

The dermis arises from which embyological tissue?

A

Mesoderm

41
Q

Which three main factors control epidermal turnover?

A
  1. Growth factors
  2. Cell death
  3. Hormones
42
Q

How is melanin transferred to other cells after production?

A

Via dendritic like processes of melanocytes

43
Q

Which skin gland is mainly found in the axillae and perineum, is androgen dependent and produces oily fluid responsible for body odour as bacteria decompose it?

A

Apocrine

44
Q

How many types of glands can be found in the skin?

A

3

45
Q

What are the different types of glands which can be found in the skin?

A
  1. Eccrine
  2. Sebaceous
  3. Apocrine
46
Q

Fow which reason do the blood vessels in the dermis supply blood surplus to metabolic demands?

A

Thermoregulation

47
Q

Which glands are most commonly found on the face and chest?

A

Sebaceous

48
Q

What is bullous pemphigoid?

A

Autoimmune condition

Involves blister formation at dermo-epidermal junction

49
Q

What is epidermolysis bullosa?

A

Inherited condition

Blisters form from slightest tough or mechanical pressure

Children with the condition are referred to as buttery children due to their skin delicacy

50
Q

Which condition may also be referred to as Hansen’s disease?

A

Leprosy

51
Q

Which skin gland is the most common overall?

A

Eccrine

52
Q

Which three layers comprise the dermo-epidermal junction from superficial to deep?

A
  1. Lamina lucida
  2. Lamina densa
  3. Sub-lamina zone
53
Q

How does neurofibromatosis affect the nerve endings?

A

Causes overgrowth of nerve endings

54
Q

In which layer of the skin is the papilla of a hair follicle found?

A

Dermis

55
Q

The dermo-epidermal junction has which roles?

A
  1. Semi-permeable membrane acting as a filter and barrier
  2. Support and anchorage of basal cells
56
Q

Why does skin sag with age?

A
  1. Less collagen is produced
  2. Collagen becomes disordered
57
Q

What is a haemangioma?

A

Collection of dilated blood vessels giving dark red/purple appearance

58
Q

Which receptors in the skin are specialised for

a) Only light pressure
b) Deep pressure and vibration

A

a) Meissners corpuscles
b) Pacinian corpuscles

59
Q

Eccrine glands are prompted by which stimuli?

A
  1. Temperature
  2. Mental (concious thought)
  3. Gustatory (taste)
60
Q

For which reasons is vitamin D useful?

A
  1. Increases calcium absorption from the bowel
  2. Promotes mineralisation of bone
  3. Contributes to normal immune cell functioning
61
Q

For which reasons is vitamin A useful?

A
  1. Promoting good vision
  2. Contributing to normal immune cell function
62
Q

Name the autoimmune condition which attacks papilla of hair follicles

A

Alopecia areata

63
Q

In which layer of the skin are immune cells most abundant?

A

Dermis

(Macrophages, mast cells, lymphocytes and Langerhans cells)

64
Q

What is the difference in the amount of mites on an individual’s skin if they have regular scabies versus crusted (Norweigen) scabies?

A

12 vs 100,000+

65
Q

Which gland is not part of the pilosebaceous unit?

A

Eccrine

(Unit includes apocrine and sebaceous)

66
Q

What is the most abdundant protein in the dermis?

A

Collagen

67
Q

UV light is required for vitamin D metabolism. Which wavelength of UV is required and what does it do to produce vitamin D?

A

Required wavelength - 290-320nm

Converts 7-dehydrocholesterol to vitamin D3

68
Q

Where does most thyroxine convert to triiodothyronine within the body?

A

Skin and peripheral tissues

(Only around 20% in the thyroid gland)

69
Q

What do Pacinian corpuscles look under a microscope?

A

Half onions

70
Q

In which two ways is vitamin D obtained by the body?

A
  1. Synthesised in the skin via UV light exposure
  2. Diet