Skin Flashcards

1
Q

Skin is said to be a combination of which tissues?

A

All four, epithelial, connective, muscle and nerve

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2
Q

Why are epidermal cells classed as kertainocytes?

A

They make keratin

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3
Q

What does the epidermis do?

A

Prevents water loss by evaporation
Epithelium
Separates internal and external compartments

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4
Q

What is the function of the dermis?

A
Reduces risk of external injury
Maintains the epidermis by its blood flow
Permits body cooling
Immune surveillance
UV protection
Energy storage 
Sensory information
Connective tissue - gives structural strength
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5
Q

What is the hypodermis?

A

Adipose layer below the dermis, anchors the skin to the underlying structures

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6
Q

What does the epidermis consist of?

A

5 strata (layers) of stratified squamous epithelium

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7
Q

What are the 4 types of epidermal cells?

A

Keratinocytes
Melanocytes
Langerhans cells
Merkell cells

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8
Q

Describe the structure of Keratinocytes

A

Contains keratin, hard, resistant to abrasion, most abundant cell type?
Extrudes lipids providing waterproofing
Constantly dividing - protecting from trauma and other damage

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9
Q

What are melanocytes responsible for?

A

Pigment formation

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10
Q

What are langerhans cells responsible for?

A

Immune surveillance

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11
Q

What are Merkell cells responsible for?

A

Touch receptors

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12
Q

What are the five layers of epidermis made by?

A

Maturing keratinocytes

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13
Q

Where does the epidermis span to and from?

A

From the basement membrane to the skin layer

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14
Q

What are the names of the five layers in descending order?

A
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale
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15
Q

Describe the cell arrangement in the stratum basale

A

Tall collumnar cells with melanocytes and merkel cells interspersed
Cells linked to the basal membrane by hemisdesmosomes
Cells linked to each other by desmosomes

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16
Q

What is the stratum basale predominantly composed of?

A

Basal keratinocyte stem cells, irregular interface with dermis, forms dermal papillae

17
Q

When is the stratum spinosum created?

A

After cell death

18
Q

How are the spines created in the stratum spinosum?

A

Cell shrinks but the desmosome junctions create spines

19
Q

What does the stratum granulosum contain?

A

Granules of keratohyalin (possible precursors of keratin)

20
Q

Where is keratohyalin converted into keratin?

A

In the stratum corneum

21
Q

How are cells bound together in the stratum corneum?

A

By desmosomes, disulphide linkage gives strength

22
Q

What is keratinization?

A

The process whereby keratin hardens

23
Q

Which layer of skin varies in thickness most around the body?

A

Stratum corneum

24
Q

What are the two layers of dermis?

A

The papillary layer, forming papillae
AND
The reticular layer, forming a network of fibres

25
Q

Describe the tissue of the papillary layer

A

Loose connective, cellular

26
Q

Describe the tissue of the reticular layer

A

Dense irregular connective, fibrous

27
Q

What is the dermis protective against?

A

Pathogens

28
Q

What are the blood vessels in the dermis responsible for?

A

Thermoregulation and nutrition

29
Q

What type of structural proteins exist in the reticular dermis?

A

Densely packed collagen fibers in three planes. It is the primary location of dermal elastic fibers.

30
Q

What gives the dermis its properties of strength, extensibility and elasticity?

A

Collagenous, elastic and reticular fibres

31
Q

What deteriorates in old age within the reticular dermis?

A

Elasticity

32
Q

What can you find in the reticular layer?

A

Roots of the hair, sebaceous gland, sweat glands, receptors, nails, and blood vessels

33
Q

As cells approach the surface how do they become waterproof?

A

The cytoplasm is replaced with a tough waterproof protein called keratin. Intercellular glycolipid exists between cells which are waterproof

34
Q

What protects the skin from UV?

A

Melanin

35
Q

How does a hair stand on end?

A

When the arrector pili muscle contracts

36
Q

What does the sebaceous gland secrete?

A

Sebum

37
Q

What types of sweat glands exist?

A

Apocrine (armpits)(secretes into the hair follicle) and eccrine

38
Q

What type of glands are eccrine sweat glands?

A

Simple tubular glands

39
Q

What type of secretion leaves both types of sweat gland?

A

Apocrine - protein rich

Eccrine - watery thermoregulatory secretion