Lecture 2: Flashcards by Leo Robin Mwape

Define a mole

Cluster of melanocytes
Over-proliferation can be caused by sun exposure

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Define a freckle

Melanocytes overproducing melanosomes
Over-production triggered by sun exposure

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What are the accessory structures of skin

Hair, Sweat glands, receptors and nails

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What are the two types of sweat glands

Eccrine glands and Apocrine glands

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Where are eccrine glands found and what is their function

Found in most areas of the skin
They pour out watery secretions onto the skin surface.
Secretory cells release vesicles that break open on the skin surface. Some antibacterial properties

Important in thermoregulation and excretion

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Where are Apocrine glands found and what is their function

Found in armpit, groin and around nipples
Secrete sticky/oily and sometimes odorous secretions into the base of the hair follicle

Influenced by hormones

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What causes a thin dermis

Reduced collagen. This reflects as sagging or wrinkling of the skin

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What causes a drier epidermis

Less sebum

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What are the two types of adult hair. Describe them

Terminal hairs
Large, thick. darkly pigmented. Found on scalp and armpits

Vellus hairs
Smaller shorter and more delicate hairs found on the body surface

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Describe Terminal hairs

Large, thick. darkly pigmented. Found on scalp and armpits

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Describe Vellus hairs

Smaller shorter and more delicate hairs found on the body surface

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What is hair made up of

Sabaceous gland
Hair Shaft
Hair root
Hair follicle
Arrector Pili muscle
Root hair plexus

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What is the root hair plexus

network of sensory nerves at the
base of each hair follicle. Heightens sensation.

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What is the role of the arrector pili muscle

Contraction produces goosebumps. Improves insulation.

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What is the role of the sebaceous gland

Produces sebum. Nourishes the hair shaft naturally and moisturizes the skin

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How does acne form

Bloked hair follicles and infection due to increased sebum production

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What is lanolin

Sheep sebum which is purified and used commercially in skin care products.

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What are eccrine glands important for

Thermoregulation and excretion

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What is the nail made up of

Nail body
Nail bed
Nail root
Lunula
Eponychium
Hyponychium

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Define the nail body

visible portion of the nail made of dead,
tightly compressed keratinocytes.

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Define the nail bed

Portion of the epidermis covered by the
nail body.

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Define the nail root

An epidermal fold not visible from the
surface. Site of nail production.

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Define the lanula

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A thickened portion of the stratum basale that conceals dermal blood vessels formaing a pale cresent moon shape

Define the eponychium

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Thickened layer of skin at the base of
the nail.

Define the hyponychium

Thickened skin located under the free edge of the nail body. Protective seal against pathogens and debris.

What gives the nail its pink colour

Underlying blood vessels

What are the functions of the nail (4)

Protects the dorsal surfaces of fingertips and toes from injury/infection Limits distortion of digits when exposed to mechanical stress Enhances sensation and fine motor skills Indicative of overall health as certain medical conditions cause nails to change colour/appearance

What causes skin to become paler with aging

Fewer melanocytes. Leads to pale skin and grey hair

How does tobacco smoke cause premature ageing

Contains agents that accelerate aging Damages collagen and elastin in the skin Linked with poor wound healing, acne, skin and oral cancers

How does the skin protect from UV damage

Via the melanin pigment which obsorbs UV light

What are melanosomes

Vesicles containing melanin

What are melanocytes

melanin-producing cells

Where do melanosomes transfer melanin to

To epidermal cells

Where are melanocytes found

ONLY in the stratum basale

Where are melanosomes found

Throughout the epidermis They shed with keratinocytes

What is cholecalciferol

Vitamin D

What is the most common type of skin cancer

Basal cell carcinoma Often seen in areas overexposed to the sun (UV) Metastatic (spread) virtually never occurs

Where does basal cell carcinoma originate

Stratum Basale (affects basal cells)

What is Malignant Melanoma

A less common but extremely dangerous skin cancer originating in the stratum Basale and affects melanocytes Mole or skin lesion (tumor) that changes colour, shape or size. Highly metastatic

Sebum is an oily secretion produced by ___________

Sebaceous glands

Melanocytes are found in the ___________

Stratum Basale

Moles are caused due to over-proliferation of ___________

Melanocytes

The two types of sweat glands are: ________ and ________

Eccrine and Apocrine

Vitamin D is essential for _______ metabolism and its deficiency causes _________

Calcium, Rickets (weaker bones)

What does 'metastatic' mean

Tumor breaks off and spreads through the blood and lymphatic system

What are the effects of reduced blood supply in the skin

Reduced blood supply leads to slower healing wounds This is because a reduce of blood supply there will be a reduced number of dendritic cells and thus a much reduced and slower immune response

What is the advantage of having melanocytes in the stratum Basale

Because cells in the Stratum Basale do not shed, therefore the melanocytes dont shed away. Melanosomes shed away with keratinocytes

Explain holocrine secretion

When cells release by going to the surface and then bursting

What type of glands are sebaceous glands. Explain the mechanism

Holocrine glands. This means each cell produces sebum but then travels to the surface level It has to burst to release it. Helpful to get moisture on the hair shaft and skin around

What gives nails their characteristic hard structure

Tight pressing of keratinocytes that form the nail body

Where does Malignant Melonoma originate, and what does it affect

In the Stratum Basale, however it affects the melanocytes

What causes the formation of the Lunula

Because of the nail root, skin with blood vessels are pressing up against the nail, causing the stratum Basale to be thickened and push up against the nail

What is the function of the Hyponychium

Protection from Foreign organisms, especially pathogens

What is dermatitis

skin inflammation

What happens when melanocytes overproduce melanosomes. What triggers this?

Melanocytes rise to the top of the skin and form freckles. Melanosome overproduction is triggered by sun exposure

What happens when adults get vitamin D defficiency

They do not get rickets, however they can have symptoms including reduced mood. This can be countered with supplementary Vitamin D tablets

Why is Malignant Melanoma metastatic while Basal Cell Carcinoma is not?

Basal cells are programmed to grow upwards and so rises to the skin surface Malignant Melanoma targets melanocytes which are not programmed to grow upwards and so it grows downwards towards the vascular dermis. The vascularity of the dermis is what means the tumour can enter the blood stream, making it more metastatic. Deeper melanoma means closer to the blood system, which means higher chances of mortality

Lecture 2: Flashcards

(57 cards)