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ESA 1 - Body Logistics > Session 5.1c - Pre-Reading - Melanocyte to Melanoma > Flashcards

Session 5.1c - Pre-Reading - Melanocyte to Melanoma Flashcards

https://www.youtube.com/embed/aiARvdeXdKM?autoplay=1 From Melanocyte to Melanoma

1
Q

What are melanocytes?

A

Cells that produce melanin

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2
Q

What are cells that produce melanin called?

A

Melanocytes

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3
Q

What is melanin?

A

A brown, black pigment

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4
Q

What is the brown, black pigment in the skin called?

A

Melanin

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5
Q

What does melanin determine?

A

The colour of the skin, hair and eyes in human

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6
Q

What determines the colour of the skin, hair and eyes in humans?

A

Melanin

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7
Q

What does melanin protect against?

A

Helps to guard against the damaging effects of the Sun.

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8
Q

What molecule in our body helps to guard against the damaging effects of the Sun?

A

Melanin

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9
Q

Where are melanocytes found?

A

In the skin, positioned at the epidermal-dermal junction

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10
Q

What do melanocytes look like?

A

Appearing as round at cell bodies with long irregular extensions called dendrites

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11
Q

Where are melanocytes round?

A

At the cell body

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12
Q

What is the shape of the melanocyte cell body?

A

Round

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13
Q

What are the long irregular extensions on melanocytes?

A

Dendrites

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14
Q

What is the structure of the dendrites on the melanocyte?

A

Long irregular extensions off the cell body.

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15
Q

Where in the melanocyte does melanin formation occur?

A

In the cell body in an intra-cytoplasmic membrane-bound organelle called the melanosome

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16
Q

Melanin formation occurs in the ____ of the melanocyte.

Choose ONE:

  • Cell body
  • Dendrite
A

Cell body

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17
Q

What organelle does melanin formation occur in?

A

Melanosome

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18
Q

What is a melanosome?

A

An intra-cytoplasmic membrane-bound organelle which produces melanin.

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19
Q

What transports the melanosome to the keratinocyte?

A

Microtubules

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20
Q

Where do microtubules transport the melanosome to?

A

The surface of the melanocyte, to a neighbouring keratinocyte

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21
Q

Where does the melanosome go next, after melanin formation?

A

To a neighbouring keratinocyte.

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22
Q

Where are melanosomes released in the keratinocyte?

A

Into the matrix of the cytoplasm

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23
Q

Where do melanosomes accumulate, once released into the keratinocyte?

A

In the supranuclear region of the cytoplasm

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24
Q

Why do melanosomes accumulate in the supranuclear region of the cytoplasm?

A

Thereby protecting the nuclei of dividing cells from the damaging effects of the Sun

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25
Q

Give two factors which increase the risk of malignant melanoma.

A
  • Heritable predisposition
  • Genetic mutations
  • Ultraviolet (UV) radiation, e.g. emitted by the Sun
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26
Q

Where can you get ultraviolet UV radiation?

A

By the Sun

27
Q

What does the sun emit?

A

Ultraviolet (UV) radiation

28
Q

What does UV radiation do that’s damaging to the body?

A

It is directly absorbed by DNA

29
Q

What is UV radiation a major risk factor for?

A

All types of skin cancer, including malignant melanoma

30
Q

What is a major risk factor for all types of skin cancer, including malignant melanoma?

A

Ultraviolet (UV) radiation.

31
Q

What specifically absorbs UV radiation in DNA?

A

A double bond in a thymine base

32
Q

What happens to DNA when UV radiation is absorbed?

A

When UV radiation is absorbed by a double bond in a thymine base, the double bond opens, allowing the base to react with nearby molecules

33
Q

What can thymine double bonds absorb?

A

UV radiation

34
Q

What allows a double bond in thymine to absorb and open up?

A

UV radiation

35
Q

What consequence does a thymine double bond opening have?

A

It can react with nearby molecules

36
Q

What can a UV-modified thymine base (opened double bond) react with?

A

If a UV-modified thymine base is adjacent to another thymine base on the same DNA strand, the two molecules can form a thymine dimer, as a result of covalent bonding

37
Q

What needs to happen for two thymines to react?

A
  • UV damage opening a thymine double bond
  • This can react with another thymine base
  • Other thymine base must be on the same DNA strand.
38
Q

What is a thymine dimer?

A

Two thymine molecules that have reacted as a result of UV damage.

39
Q

What bonds produce a thymine dimer?

A

Covalent bonds

40
Q

What does the thymine dimer reaction most typically involve?

A

The reaction most often involves the formation of two new bonds between neighbouring bases yielding a four-membered ring.

41
Q

How many ‘members’ are typically involved in the thymine dimer reaction?

A

Four

42
Q

What are the structural consequences of a UV-induced reaction?

A
  • Local distortions in the helix

- ‘Taking’ in the DNA strand(?)

43
Q

What are the functional consequences of a UV-induced reaction?

A

If UV-related damage is not corrected by molecular repair mechanisms, DNA transcription and replication are blocked, and genetic information may be permanently mutated.

44
Q

What are the consequences of histological changes from a UV-induced reaction?

A

Genetic mutations in melanocytes are associated with histologic changes along a continuum that may culminate in invasive malignancy.

45
Q

Describe the most benign and most malignant melanoma stages (including no disease)

A

The transition from a normal melanocyte to metastatic melanoma

46
Q

The transition from a normal melanocyte to metastatic melanoma can be visualised how?

A

By several histologic intermediates

47
Q

What are the histological intermediates seen in the transition from normal melanocyte to metastatic melanoma?

A
  • Atypical/dysplastic nevus of varying stages of severity
  • Melanoma in situ
  • Invasive melanoma
48
Q

What is atypical nevus?

A

Also known as dysplastic nevus

Atypical moles

49
Q

What is dysplastic nevus?

A

Also known as atypical nevus

Atypical moles

50
Q

What are atypical moles known as?

A

Dysplastic nevus (atypical nevus)

51
Q

What does nevus mean?

A

‘Birthmark’ (mole)

52
Q

What is melanoma in situ?

A

Stage 0 melanoma

Melanoma in situ is also called stage 0 melanoma. It means there are cancer cells in the top layer of skin (the epidermis). The melanoma cells are all contained in the area in which they started to develop and have not grown into deeper layers of the skin.

Some doctors call in situ cancers pre cancer. In a way, they are. Although the cells are cancerous, they cannot spread to other parts of the body, so in situ cancers are not a cancer in the true sense. But if they are not treated, in situ cancers can develop into invasive cancer.

53
Q

What is Stage 0 melanoma also known as?

A

Melanoma in situ

54
Q

Cancerous melanoma cells that are contained in the epidermis and not grown into any deeper layers is staged as what?

A

Stage 0 melanoma (melanome in situ)

55
Q

During which period if melanomas are diagnosed and treated by are they shown to have an excellent prognosis?

A

Radial growth phase

56
Q

What is the radial growth phase of melanoma?

A

In the radial growth phase, melanoma appears as an irregular plaque; cells may invade the dermis, but do not form a nodule

57
Q

Radial growth phase is important in melanomas because …?

A

Melanomas diagnosed and treated during the radial growth phase have been shown to have an excellent prognosis

58
Q

What is the treatment for late stage melanoma?

A

Currently, there is no cure for late stage melanoma

59
Q

How is melanoma morbidity and mortality reduced?

A

By early detection

60
Q

What does early detection of melanoma do?

A

Reduces morbidity & mortality.

61
Q

Why is early detection critical in melanoma?

A

Currently, there is no cure for late stage melanoma. As a result, early detection plays a critical role in reducing melanoma morbidity & mortality.

62
Q

What could significantly enhance the detection process of melanoma?

A

New diagnostic tools to complement the visual examination of lesions

63
Q

What could new diagnostic tools detect to complement the visual examination of lesions?

A
  • Early-stage melanoma
  • Borderline lesions
  • Those lacking the classical appearance of melanoma
64
Q

What does new diagnostic tools to complement the visual examination of lesions do for melanoma?

A

Could significantly enhance the detection process.

ESA 1 - Body Logistics (18 decks)

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