Skin And Breast Flashcards
(149 cards)
1
Q
How many layers of epidermis are there
A
4
2
Q
4 layers of epidermis
A
Germinative (stratum basale) layer
Spinous layer (stratum spinosum)
Narrow granular layer (stratum granulosum)
Dead keratinised squames (stratum corneum)
3
Q
Germinative layer (stratum basale)
A
Base
Composed of a single row of cells
4
Q
Spinous layer (stratum spinosum)
A
Thickest layer
5
Q
Narrow granular layer (stratum granulosum)
A
Cells contain keratohyaline granules - the precursor of keratin
6
Q
Dead keratinised squames (stratum corneum)
A
Overall thickness varies from site to site in the body to reflect the amount of abrasion occurring at the site
7
Q
What layer is deep to the epidermis
A
Dermis
8
Q
2 layers of dermis
A
On rich in glycosaminoglycan close to the epidermis
A deeper collagenous layer below
9
Q
What other structures are found in the dermis
A
Roots of hairs and sweat glands that have grown down from the epidermis
Sensory nerve endings of skin- sensory transducers
Plexuses of blood vessels
10
Q
Where is the keratinised layer thick
A
Soles of feet
Parts of hands
11
Q
What is the keratinised layer thin
A
On parts of the abdomen and thorax
On the lips
Over some part of the external genitalia
12
Q
Why is the skin on the palms of feet and hands thick
A
due to significant compression and abrasion
Hairless skim
13
Q
Living epidermis below keratin
A
Generally compact
Its boundary with the underlying dermis is very ‘wavy’ creating very many dermal papillae
14
Q
What are the precursors of keratin
A
Keratohyaline granules
15
Q
Is the granular layer dark or light staining
A
Very dark staining
16
Q
What is the most superficial living layer of the epidermis
A
Granular layer
17
Q
What are the majority of cells in the epidermis
A
Keratinocytes
18
Q
Keratinocytes
A
Derived from stem cells within the germinal layer of the epidermis that rests on a basement membrane adjacent to the dermis of the skin
19
Q
Melanocytes origin
A
Derived from the neural crest of the embryo and migrate into the epidermis during development
20
Q
Melanocytes function
A
Produce melanin pigment granules that are transferred to the keratinocytes of the basal and prickle cell layers of the skin
21
Q
Where is melanin stored
A
Keratinocytes
-amount stored = proportional to colour of skin
22
Q
Where is melanin produced
A
Melanocytes
23
Q
How to identify dividing cells
A
Pale staining of cytoplasm
Compact nature of nuclear chromatin
24
Q
Cells of spinous layer (prickle cell)
A
Cells are joined tightly by desmosomes that prevent the skin from splitting when stretch
If the cells shrink during processing the desmosomes connections become more evident and the cells appear spiny
25
What prevents the skin from splitting when stretch
Desmosomes in spinous (prickle cell) layer
26
Where are langerhan’s cells found
Epidermis- particularly in spinous (prickle cell) layer
27
Langerhan’s cells structure
Pale cytoplasm
Ovoid or irregular shaped nucleus
28
Langerhan’s cells function
Antigen-detecting cells, part of the immune system of the skin
Increases dramatically in number in inflammatory situatins
29
Where are merkel cells present
Basal layer of epidermis
30
Merkel cell function
Form synapses with nerve fibres in the dermis and convey the sensation of fine touch
31
Where does hair arise from
Germinative epithelium within the hair bulb that also contains melanocytes responsible for the pigmentation of the haur
32
What cells are responsible for the pigmentation of hair
Melanocytes
33
Where does hair lengthen
Within a root sheath composed of epidermis with the same layer of the rest of the skin but a thickened basement membrane (glassy membrane)
34
Glassy membrane
Thickened basement membrane of root sheath
35
What surrounds each hair
A collagenous follicle sheath into which is inserted an erector pili muscle (smooth muscle) that is autonomically jnnervated
36
Sympathetic stimulation of erector pili muscle
Causes the muscle to contact and hairs to stand on end
37
What opens into the hair shaft
One or more sebaceous glands that lubricate the emerging hair
38
Hairless follicles
Provide surface lubrication to the skin
Eg face and groin
39
What surrounds a hair bulb
Fatty connective tissue
40
What forms the nails of fingers and toes
Compacted keratin
41
Where do nails arise from
Nail matrix cells that are located under a fold of skin (eponychium or cuticle) at proximal end of nail
42
Lunula
A pale crescent of nail matrix cells seen through the semi-transparent nail near the cuticle
43
Hyponychium
Nail lengthens across the epidermal nail bed to which it remains firmly attached except at the distal end where it underlain by a fold of skin (hyponychium)
44
Result of destruction of the nail matrix
Permanent loss of the nail
45
Outer layer of dermis
Closest to epidermis
Contains collagen and elastic fibres (fibrous layer)
46
Deeper layer of dermis
Contains much adipose tissue (fatty layer)
47
What is the most common sweat gland
Eccrine sweat glands
48
Eccrine sweat glands
Consist of a tightly coiled knot of fluid-secreting cells and a straight duct lined by simple cuboidal epithelium
Duct extends to the surface of the skin
Coiled secretory portion is surrounded by flattened myoepithelia cells
49
Myoepithelial cells
Contractile cells that surround the coiled part of the eccrine sweat glands and help to expel sweat
50
Lining of duct of eccrine sweat glands
Simple cuboidal epithelium
51
Apocrine sweat glands
Produce pheromone
Found in armpits, around the anus and on external genitalka
52
Which cells produce pheromone
Apocrine sweat glands
53
Which 2 types of sensory transducers can be easily detected
Pacinian corpuscle
Meissner’s corpuscle
54
Pacinian corpuscle
Large structure with a nerve ending at its core
55
Meissner’s corpuscle
Numerous and have a spiral appearance
Located mainly in the dermal papillae
56
What stain is used to stain nerves black
Osmium tetroxide
57
Function of a Pacinian corpuscle
Pressure sensor mostly in dermis of skin
Can be found in other organs eg pancreas
58
What does a Pacinian corpuscle look like
Oniom
59
Eyelids
Covered on the outside by thin hairy skin with a row of prominent eyelashes at its margin
Sweat glands discharge on to the outside surface
Inside of the eyelid is lined by a moist conjunctiva consisting of a stratified columnar epithelium composed of 2 layers of cells
60
Inside lining of eyelid
lined by a moist conjunctiva consisting of a stratified columnar epithelium composed of 2 layers of cells
61
What is contained within the substance of the eyelid
Eyelashes
Striated muscle fibres of the orbicularis oculi muscle
Several glands to keep the surface of the eye moist and protected from infection or dehydration
62
Largest gland in eyelid
Meibomian gland
63
Meibomian gland
A modified sebaceous gland that secretes a lipid rich secretion that reduces evaporation from the cornea of the ehe
64
Smaller sweat glands in eyelid
Moll
65
Smaller sebaceous glands in eyelid
Zeis
66
Smaller accessory lacrimal glands in eyelid
Kraus
Wolfring
67
Function of orbicularis oculi muscle
Allows you to screw up your eyes
68
Formation of the breast
Paired epithelial rudiments derived from sweat glands are present from birth.
They begin to enlarge 1 to 2 years before menarche. The process starts between the ages of 9 and 11 years under the influence of oestrogen
69
What causes the enlargement of the breasts
Oestrogen
70
At what age do the breasts start to enlarge
9-11
71
What are the breast composed of at first
Mostly adipose tissue
Into this grow solid cords of epithelial cells from the nipple which branch, hollow out and form lactiferous ducts
72
Differentiation into adult (inactive) breasts continues up to what age
15-18
73
How is the breast divided
Into 15-20 segments separated by fibrous septa that radiate from the nipple
74
What attaches the breast to the chest wall and overlying skin
Thickened fibrous strands (suspensory ligaments of Cooper)
75
Lactiferous ducts
Open onto surface of nipple via lactiferous sinuses but remain blind ended with little or no development of secretory alveoli before pregnancy
76
What causes tenderness or discomfort in breasts
Adult inactive breasts are however responsive to fluctuating hormone levels. In the second half of each menstrual cycle progesterone-promoted oedema often leads to distension of the segments. This may cause tenderness or discomfort.
77
What causes oedema of breast
Progesterone
78
Nipple
A raised area of skin with a fibro-muscular core containing between 12-20 small openings of lactiferous ducts
Surrounded by a more flattened Stella
79
Number of lactiferous ducts per nipple
12-20
80
Areola
Hairless more flattened area surrounding nipple
Contains numerous raised sebaceous glands - Montgomery’s tubercles
81
Montgomery’s tubercles
Sebaceous glands in areola
82
Why do the nipple and areola undergo heavy pigmentation
After first pregnancy
83
Smooth Muscles fibres of breast
Able to change shape and protuberance of nipple and areola
84
What type of epithelium lines the lactiferous duct
Stratified cuboidal epithelium (roughly circular nucleus)
85
What causes the epithelial tissues to enter a proliferation phase in the first trimester of pregnancy
Oestrogen
Growth hormone
Cortisol
86
Proliferation phase of epithelial tissue in first trimester
Ducts divide and secretory alveoli develop at their ends
87
Secretory alveoli
Consist of clusters of columnar epithelial cells surrounded by a mesh work of flattened myoepithelial cells
88
What is full development of lactating breasts dependent on
Prolactin
Progesterone
Human chorionic somatomammotropin (hCS or human placental lactogen hPL)
Adrenal corticosteroids
Insulin
89
What happens after the proliferative phase
Alveolar cells mature and secretory material builds up within them and in the lumina
Storms becomes depleted of adipose tissue
90
Breasts in later stages of pregnancy
Lymphocytes and plasma cells accumulate in the stoma
Cells produce antibodies that appear in the colostrum and confer passive immunity of the newborn
91
What happens as suckling commences
Myoepithelial cells that surround the terminal acini contract and the milk is expressed
92
What suppresses lactation
High levels of oestrogen and progesterone
93
How are milk proteins released
Merocrine process
94
How are milk fats released from the cell
Apocrine process
95
What makes up a large part of the stroma of the breast in its lactating state
Dense fibrous connective tissue- mostly collagen fibes
96
What are moles
Formed from a dense aggregation of melanocytes and their attendant keratinocytes
97
Where in the skin do blisters caused by abrasion most commonly form
Dermal/epidermal interface
98
Where in the skin do blisters caused by heat most commonly form
May occur at any depth and may involve deep layers of dermis
99
Which hormone induces the expression of milk during breast feeding
Oxytocin
100
Where is oxytocin released from
Anterior pituitary
101
Action of oxytocin
Causes Myoepithelial cells surrounding the secretory alveoli of the breast to contract and help expel the milk
102
What stimulates oxytocin secretion
Tactile stimulation of the nipple
103
Function of skin
Barrier to infection
Waterproofing
Thermoregulation
Protection against trauma
Protection against UV light
Vitamin D synthesis
Sensation
104
What cells are found in the stratum basale
Basal epithelial cells (stem cells)
Melanocytes
105
Function of melanin
Absorbs UV light protecting us from non-ionising radiation damage
106
Density of melanocytes in basal layer
1000-2000 per mm^2
107
How is melanin transferred from melanocytes to keratinocytes
Melanosomes
108
What hormones stimulate the synthesis of melanin
MSH
ACTH
109
Shape of keratinocytes
Polygonal
110
Function of merkel cells
Sensory
111
Function of langerhan’s cells
Antigen recognition
112
Flattened squames of stratum granulosum
Eosinophilic cytoplasm
Haematoxophilic kerato-hyaline granules
113
Stratum lucidum
only present in the thicker skin of the palms and soles. Its main function is to reduce friction between the stratum corneum and stratum granulosum
114
Epidermal adnexae
Down-growths of epidermis into dermis and subcutis eg hair follicles, sebaceous glands
115
Mechanism of sebaceous glands
Holocrine secretion- entire cells lost
116
Where are apocrine glands found
Axillae
Groins
Cerminous glands in the ear
117
Apocrine glands
Surface budding
Eosinophilic cytoplasm
118
Eccrine glands
Coiled tubes
2 cell layers thick- inner secretory and outer Myoepithelial
Merocrine secretion- exocytosis
119
Length of Meissner’s corpus
30-140 um long
120
Function of Meissner’s corpuscle
Fine touch
121
Length of Pacinian corpuscle
1-4 mm long
122
Function of Pacinian corpuscle
Vibration and tickle
123
Where are Pacinian corpuscles found
Deep dermis
124
Where are Meissner’s corpuscles found
Dermal papillae especially in hairless skin
125
Subcutis
White adipose tissue and fibrovascular septa
126
Subcutis function
Insulation
Shock absorber
Food store
127
Terminal duct lobular units of breast
Lobules arranged around a terminal duct
Set in loose fibrous connective tissue
128
Two layers of cells of ducts and lobules
Outer Myoepithelial layer
Inner columnar epithelium
129
How to recognise breast is lactating
Inner layer of secretory cells become vacuolated
130
3 histological layers of skin
Epidermis
Dermis
Subcutis
131
Which layer of the epidermis is acellular
Stratum corneum
132
What layer of the epidermis contains visible desmosomes
Stratum spinosum
133
Which is the outermost layer of the epidermis
Stratum corneum
134
Which layer of the epidermis contains melanocytes
Stratum basale
135
Keratin is synthesised in which layer of the epidermis
Stratum granulosum
136
What do melanocytes synthesise melanin from
Tyrosine
137
What does melanin protect us from
Effects of UV light
138
What is a hair bulb
A downward extension of the epidermis into the dermis
139
What is a hair papilla
A specialised part of the dermis that is richly innervated and vascularised
140
Where are apocrine sweat glands found
Axillae
Groins
Perianal skin
External ear canals
Breast areolae
Eyelids
141
Where are sebaceous glands found
Associated with hair follicles on the face, scalp, ears, nostrils and vulva
142
What type of secretion do sebaceous glands use
Holocrine secretion (whole dead cells) to produce a lipid rich secretion
143
What does a pacinian corpuscle detect
Pressure (and maybe vibration)
144
What detects pain, temperature and itch
Free nerve endings
145
What detects light touch
Meissner’s corpuscle
146
What does the pacinian corpuscle comprise of
A central axon surrounded by layers of modified Schwann cells
147
Where are pacinian corpuscles found
Subcutis
148
Where are meissner’s corpuscles found
Papillary dermis
149
How to tell lactating breast tissue
Comprises secretory lobules lined by an outer layer of myoepithelial cells and inner layer of vacuolated secretory cells
