Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

week 1 > Skin Structure And Function > Flashcards

Skin Structure And Function Flashcards

(117 cards)

Start Studying
1
Q

What are the 3 main layers of the skin

A

Epidermis
Dermis and
Subcutis/hypodermis

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

Briefly explain the epidermis ?

A

Self regenerating
Stratified squamous epithelium
Produces non living surface layer of the protein keratin
Direct contact with external environment

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

Is the epidermis water resistant ?

A

Yes

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

The main cells involved in the epidermis are called what ?

A

Keratinocytes

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

What are the different layers of the epidermis starting from deepest

A

Stratum basale -> stratum Spinosum -> stratum granulosum -> stratum Corneum

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

Explain thee basement membrane ?

A

Separates the epidermis from the dermis
Stratum basale attached to it by hemidesmosomes

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

What does the stratum basale layer look like

A

Cuboidal/low columnar cells
Attached to the basement membrane by hemidesmosomes
Basal cells have highly indented+ folded basal cell membrane with numerous hemidesmosomes

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

What is the function of the stratum basale ?

A

Contain stem cells
Mitotically active/ proliferates continuously
Allows maturation to renew/regenerate other layers
Basal cells -> mature into stratum spinosum

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

Explain the stratum spinosum

A

Prickle cell layer
Multilayered
Contains polyhedral shaped keratinocytes - these synthesise cytokeratins

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

What are cytokeratins ?

A

Cytoplasmic intermediate filaments which accumulate to form tonofibrils

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

What are tonofibrils ?

A

Bundles of tonofilaments
Tonofibrils bind to desmosomes to form strong contact between adjacent keratinocytes

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

Why is the stratum spinosum called the prickle cell layer

A

Due to the desmosome junctions which are seen as prickles or spines

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

What do the keratinocytes mature into from the stratum spinosum ?

A

The stratum granulosom - granular layer

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

What occurs to the keratinocytes in the granular layer ?

A

Cells become flattened
Contain basophillic keratohyalin granules

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

What is the function of keratohyalin granules ?

A

Contain amino acids and protein that interact with tonofibrils which produces keratin -> keratinisation

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

What happens with cells in the stratum granulosum

A

Cells start to lose their nucleus and cytoplasm and become the stratum corneum

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

Explain the stratum corneum ?

A

Keratin squames -> large flat plate like envelopes filled with cross linked keratin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why is the stratum corneum water resistant

A

Due to lipids
Lipid containing anti wetting agents synthesised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where is stratum lucidum found ?

A

Only in thick skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What can the epidermis do ?

A

Self renew

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where does skin regeneration start ?

A

Stem cells in the basal layer continuously divide and differentiate migrating upwards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Explain the maturation of keratinocytes ?

A

1.Cells start process of differentiation in basal layer
2. Differentiating cells pushed upwards into stratum spinosum (produce prickle cells)
3.cell shape changes as this occurs and desmosomes become more pronounced
4.prickle cells continue to be pushed upwards and reach granular layer
5.cells degraded - loses nucleas and cytoplasm
6. Highly keratinised flattened cell
7.corneocytes - eventually shed off and die

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the thickness of skin related to ?

A

The dermis and subcutis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the dermis composed of ?

A

It is connective tissue
Composed of collagen I
and elastin fibres and ground substance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are the main cells found in the dermis ?
Fibroblasts
26
What are the main functions of the dermis ?
Immune role Provides a blood supply Tensile strength -> collagen Allows stretch -> elastin
27
What are the to layers of the dermis ?
Superficial papillary dermis Deep reticular dermis
28
Explain the structure of papillary dermis ?
Contain fine, interlacing collagen and elastic fibres Also contain blood vessels and nerve endings
29
Explain the structure of the reticular dermis ?
Thicker layer -> collagen binds much more strongly Elastin fibres much thicker too ad longer
30
What is the dermis epidermal junction ?
Attachment of epidermis to dermis through hemidesmosomes It aligns cells of the epidermis
31
What is function of the dermo-epidermal junction
Serves as a base for repithelialisation in wound healing Barrier function -> from and into epidermis
32
Explain the subcutis
Mostly composed of adipose tissue Compartmentalised by vertical fibrous septa
33
What is the use of subcutis
Fatty layer of the skin Acts as energy source Shock absorption and insulation
34
How does the skin act as a sensory organ
It has free nerve endings in the skin
35
What is the function of the free nerve endings ?
Occupy the papillary dermis and extend into epidermis where they associate with Merle cells and act as mechanoreceptors
36
What are meisnners corpuscles
Rapidly acting mechnoreceptors which are responsible for touch Prominent in papillary dermis of hands and feet
37
What are pacinian corpuscles ?
Detect deep pressure and vibration
38
Where are pacinian corpuscles found ?
Deep into subcutis
39
What are examples of adnexal structures ?
Hair and nails and glands
40
What is hair
Long thin cylinderal shafts composed of keratin
41
What is the function of hair and fur?
Providing colour and shape but particularly thermoregulation -> heat conservation
42
What is the hair follicle ?
Tubular structure of specialised connective tissue and epithelium
43
How is a hair follicle reduced ?
During active hair growth the epithelial cells around the hair papilla proliferate to form layers of the follicle
44
What gives hair their colour ?
Melanocytes As melanin is incorporated in cells that form hair shaft
45
What causes hair to stand up ?
Contraction of the arrest or pili smooth muscle -> thermoregulated response
46
Explain the structure of the nail briefly
Dense keratinised plate which rests on stratified squamous epithelium - ‘the nail bed’
47
How do nails grow ?
Proliferation and differentiation of the epithelium underlying the nail root
48
What is the role of the eccrine glands ?
Temperature control glands -> excrete sweat and therefore lower body temperature
49
Where are eccrine glands found ?
Everywhere on human skin part from nail beds, lips, external auditory canal and some parts of the genitalia Most abundant -> palms, soles and axillae
50
What are the role of the apocrine glands ?
Scent glands - role unclear in humans
51
Where can the apocrine glands be found ?
Axillae and genitals
52
What are sebaceous glands and their function
Formed from hair follicle Produce sebum- lipid which can lubricator the skin Greatly enlarge at puberty in response to androgens
53
Where can sebaceous glands be found ?
Everywhere except palms and soles
54
Label the skin
55
What are the cells in the dermis ?
Fibroblasts Lymphocytes Dermal dendritic cells Mast cells
56
What are common cells in the epidermis ?
Keratinocytes Stem cell Merkel cell Langerhans cell Melanocytes
57
Where can keratinocytes be found ?
Keratinised stratified squamous epithelium
58
Where can keratinocyte be found ?
Protection and barrier Involved with melanocytes in vitamin d function
59
Where can stem cells be found ?
Stratum basale
60
What is the function of stem cells ?
Self renewal and repopulation of epidermal layers Allow skin regeneration and cell turnover
61
Where can merkel cells be found ?
Epidermis
62
What is the function of touch cells ?
Touch cells Relay touch related information
63
Where can Langerhan cells be found ?
Epidermis Stratum spinosum and upper dermal layer
64
What is the function of langerhans cell
Antigen presenting cells Allow phagocytosis
65
Where can melanocytes be found ?
Basal layer
66
What is the function of melanocytes
Protection from radiation For example ultraviolet light Provide colour to skin and hair
67
How do melanocytes protect from uv radiation ?
Melanin produced from tyrosine within melanosomes -> transferred to keratinocytes Form cap over nucleas protecting the dna
68
What is uv radiation implicated in ?
Development of melanoma and non melanoma skin cancers
69
What can chronic uv exposure in humans lead to ?
Loss of skin Abnormal pigmentation Haemorrhage of blood vessels Wrinkles + premature ageing
70
What is vitamin d useful for ?
Vitamin d synthesis
71
How is vitamin d produced
255-330nm UVB converts 7-dehydrocholesterol in the plasma membrane of keratinocytes to pre vitamin D3
72
How do melanocytes and keratinocytes work together to protect cells from UV damage
1. Melanin in synthesised by melanocytes within organelles called melanosomes 2. Melanosomes transferred into neighbouring keratinocytes By melanocytes cytoplasmic processes 3. Melanosomes with keratinocyte -> a cap is formed over nucleus which forms protective layer over the dna
73
Where are keratins found
All epidermal layers
74
What is the function of keratins ?
Major structural protein Intermediate filaments
75
What molecules are found in keratohyalin molecules ?
Profilaggrin Involucrin Loricrin
76
What is the function of profilaggrin
Converted to fillaggrin -> aggregates keratin filaments into tight bundles
77
What is the function of involucrin?
Formation of cell envelope around cells in the stratum corneum
78
Where is the function of loricrin
Cross links to involucrin
79
What molecules form the lamellar granules
Polysaccharides Glycoproteins Lipids
80
What is the function of the polysaccharides+ glycoproteins and lipids in the lamellar granules
Form the cement that holds together the stratum corneum cells -> impermeable intracellular lipid layer
81
What is the function of fibroblast
Synthesis of collagen,elastin + other extra cellular matrix compounds -> involved in sending and receiving signals from other molecules
82
What is the function of lymphocytes
Immunosurveillance -> detecting foreign antigens
83
What is the function of dermal dendritic cells
Phagocytosis Antigen presentation
84
What is the function of mast cells
Produce inflammatory mediators such as histamine or heparin For eosinophils and neutrophils Important in wound healing - immediately released after injury
85
What is collagen type 1
Major structural fibrous protein - provide tensile strength
86
What is the function of elastin
Confer elasticity and recoil -> allow stretch and recoil in response to movement
87
What do proteoglycans and glycosaminoglycans provide
Hydration
88
What are the key molecules in the dermis
Collagen type I - stronger than type III Elastin Proteoglycans Glycosaminoglycans
89
What is a wound
The breakdown in the protective function of the skin
90
A wound causes the loss of what thing ?
The loss of continuity of epithelium
91
What is the depth of injury related to ?
The ability to heal
92
Describe what would mean by erosion wound
Only epidermis lost - healing faster
93
What would mean by ulceration ?
Wound deep into epidermis
94
What is partial thickness wound
Epidermis and varying parts of dermis are damaged
95
In a partial thickness wound what acts as a reservoir of epithelial cells
Adnexal structures because they allow repopulation of the wound
96
What is a full thickness wound ?
Epidermis All of dermis Deeper structures affected Wound edge cells only
97
What are the three phases of wound healing
Inflammatory Proliferation Remodelling
98
Explain the inflammation phase ?
1.Platelets initiate haemostasis/blood clot and healing cascade 2. Attracts other cells to. The wound to fight infection and transition from inflammation to repair 3. Neutrophils and macrophages phagocytose dead tissue and bacteria/pathogens
99
What are the characteristic of inflammation ?
Red/swelling
100
Explain the proliferative phase
1.Reepithelialisation 2. Formation of granulation tissue mainly type III collagen 3. Neovascularisation occurs : proliferation and migration of endothelial cells occur
101
Explain what reepithelisation is
1-2 days of wounding Epithelial cells loosen cell to cell adhesions and migrate to the wound site, cover the granulation tissue and then meet in the middle 2. Once wound is covered in keratinocytes - keratinocytes start to proliferate
102
Explain simply what reepithelisaton is
Cells dividing to replace damaged or loss of cells
103
What are the two methods of keratinocyte migration
Leapfrog method Train method
104
How is collagen type III formed when granulation tissue is formed
Underneath cells fibroblasts are recruited that replace collagen
105
What is the remodelling phase
When granulation tissue becomes mature tissue
106
How does remodelling phase occur
Collagen is organised into thick bundles Cross linked -> forms mature scar Switch in type of collagen
107
What is the switch in collagen in te remodelling phase
Type III to type I
108
Compare type I collagen to type III collagen
Type I collagen is much more organised and stronger
109
Explain the strength of the skin
Final -> only 70-80% of preinjured skin And after 1 year Strength is 5% at 1 week 20% at 3 weeks
110
How do cells in wound healing know what to do ?
They respond to signalling molecules
111
What is the function of epidermal growth factor
Allows reepithelialisation -> proliferation and maturation of keratinocytes
112
What is the function of platelet derived growth factor
Matrix formation -> activates increased numbers and activity of fibroblasts Also important in remodelling due its role in production of proteases
113
What is the function of vascular endothelial growth factor
Angiogenesis which is endothelial cell proliferation and migration
114
Which 3 signalling molecules are involved in inflammation
Interleukin -1 (II-1) Interleukin-6 (II-6) Tumour necrosis factor
115
What do epidermal growth factors do in terms of keratinocytes
Signal to the keratinocytes to divide and migrate to close over the wound
116
What are local factors that’s affect wound healing
Infection Foreign body Oxygenation - cells highly active need o2 for respiration Vascular supply
117
What are systemic factors that’s defect wound healing
Age Diseases Alcohol and smoking Immunocomprimised conditions Obesity - affects vascular flow Medications

week 1 (6 decks)

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