Skin 1-3 Flashcards
1
Q
What is the largest organ in the human body?
A
Skin
2
Q
How much total surface area is the skin?
A
1.5-2 m2
3
Q
Our ability to what makes us unique?
A
Sweat
4
Q
What is the integumentary system?
A
Skin + all of the accessory structures.
5
Q
WHat are the functions of the integumentary system? (8)
A
Protection
Excretions using glands
Temperature regulation
Production of melanin
Production of keratin
Synthesis of Vitamin D3 to calcitriol.
Lipid storage
Detect sensory
6
Q
What are the 4 types of tissue?
A
Epithelial, connective, muscle, nervous
7
Q
What is epithelial tissue?
A
Covers exposed surfaces, forms secratory glands
8
Q
What is connective tissue?
A
Fills internal spaces, provides structural support, stores energy.
9
Q
What is muscle tissue?
A
Contracts to produce movement
10
Q
What is nervous tissue?
A
Conducts electrical impulses. Carries information
11
Q
What is cutis?
A
Latin for skin
12
Q
What are the 3 primary layer of the skin?
A
Epidermis, dermis, hypodermis.
13
Q
What are the cutaneous layers of the skin composed of?
A
Epidermis and the dermis
14
Q
WHat is the subcutaneous layer of the skin composed of?
A
Adipose tissue
15
Q
Describe the composition of the epidermis?
A
Mostly keratinocytes. Avascular.
16
Q
What is a keratinocyte?
A
Keratin containing cell.
16
Q
What is the function of the epidermis?
A
Stratified barrier, stacked and used to stop things from passing through it.
17
Q
What is the composition of the dermis?
A
Protein fibres, vascular.
18
Q
What are protein fibres composed of?
A
Collagen and elastin
19
Q
What is the purpose of the dermis?
A
Holds accessory structures as well as nerve endings.
20
Q
What is the hypodermis composed of?
A
Adipose tissue
21
Q
What is the purpose of rhe hypodermis?
A
Store adipose tissues and fat which is mobilised during times of fasting.
22
Q
What are the two layers of the dermis?
A
Papillary layer
Reticular layer
23
Q
What is the predominant tissue type in the epidermis?
A
Epithelial tissue
24
What is simple epithelia?
SIngle layer
25
What is stratified epithelia?
Stacked
26
What are the 3 types of epithelia?
Squamous, cuboidal, columnar
27
What are the 4 layers within the epidermis?
Stratum corneum, stratum granulosum, stratum spinosum, stratum basale.
28
What is the desmosome?
Anchors adjacent cells in epidermis.
29
What is a hemidesmosome?
Anchors stratum basale to dermis.
30
What is the function and cell type of stratum corneum?
Spiky layer, contains dead, dried-out cells, wihtout nuclei. Flakes easily. Has the most cells.
31
What is the function and cell type of the stratum granulosum?
Granular layer. Contains granules that promote dehydration of the cell and crosslinking of keratin fibres. Waxy material is secreted into intercellular spaces.
This is where cells die.
32
What is the cell type and function of the stratum spinosum?
Spinous layer.
Desmosomes link cells together.
Cells become increasingly flattened as they move upwards
33
What is the cell type and function of the stratum basale?
Columnar regenerative cells.
Basal cells will divide and will be pushed into the layer above.
34
What will happen to the body without the hemidesmosomes?
The skin will slide off the body.
35
Where is thick skin located?
On the hands and soles of the feet
36
What is a special function of thick skin?
Extra epidermal layer called the stratum ludidum.
37
What is the purpose of the dermal papilla?
Reaches into the epidermal ridges to provide them with blood and nutrients as the epidermis is avascular.
38
Where does the stratum lucidum sit?
Between the stratum corneum and the stratum lucidum.
39
What is an acronym you can use to remember the layers of epidermis for thick skin?
CLGSB, or CGSB for thin skin
40
Is the dermis shed?
No
41
Describe the papillary layer of the dermis
Consists of highly vascular tissues (nourished)
42
Describe the reticular layer of the dermis
Mesh-like, has lots of collagen and elastin for strength
43
Which layers of the dermis contain blood vessels, lymphatics, and sensory nerves?
Both the papillary and reticular layers
44
What are the two plexuses of the dermis?
Cutaneous plexus
Subpapillary plexus.
45
What is a plexus?
Branching network of nerves or blood vessels.
46
What is the makeup and function of the cutaneous plexus?
Network of blood vessels that supply the hypodermis and deeper dermis inc capillaries for hair follicles and sweat glands.
47
What is the makeup and function of the subpapillary plexus?
Branches from the cutaneous plexus, network of blood vessels providing O2 and nutrients to the upper dermis and epidermis
48
Describe the hypodermis
Subcutaneous layer.
Not part of the skin.
Lots of adipocytes and fat for energy and insulation.
49
Describe a first degree burn?
Superficial
Red, dry, painful
No blisters
Skin is still a waterproof barrier
Heals 3-10 days
50
Describe a normal second degree burn
Damages epidermis and varying amounts of dermis.
Painful, red, moist, blistered.
Heals in 1-2 weeks with appropriate dressing
51
Describe a deeper 2nd degree burn
May be white and waxy.
hair follicles and sweat glands may remain intact.
Usually heal in a month
May have some loss of sensation and scarring.
52
Does second degree burn damage secondary structures?
Not often
53
Describe a 3rd degree burn
Full thickness, extends into subcutaneous and involve muscle and bone.
Varies in colour from waxy white to red or black
Hard, leathery skin
No pain as sensory nerves are destroyed
Skin grafts and weeks to regenerate
54
What are the 3 accessory structures of skin?
Hair, sweat glands, nail, receptors.
55
What is hair made up of?
Karatinized cells produced inside of a hair follicle.
56
How does the arrector pili muscle stop heat from escaping the body?
Seals the pore of the skin shut, resulting in goosebumps.
57
What is the function of the root hair plexus?
Collection of sensory nerves at the base of each hair follicle leading to heightened sensation
58
What do the sebaceous glands produce??
Sebum
59
What is the purpose of sebum?
Nourishes hair shaft and makes it water repellent
60
What leads to the production of acne?
Blocked hair follicules and increased sebum production
61
What is lanolin>
Sheep sebum
62
What is the purpose of an eccrine sweat gland?
Sweating to evaporate to cool the core temperature
63
What are the two types of sweat glands?
Eccrine and Apocrine
64
What is the function of the apocrine gland?
Secrete sticky/oily secreations to the base of the hair follicule
65
What stimulates the apocrine glands?
Hormones
66
Where are apocrine glands found?
Armpit, groin, around the nipples.
67
What are the 3 types of skin receptors?
Tactile, lamellar, bulbous
68
What is the purpose of the nails?
Protect fingertips
Enhance sensation
Sensory receptors requiring deformation
69
What are the 6 signs of skin aging?
Thin epidermis
THis dermis
Slower skin repair
Drier epidermis
Impaired cooling
Less pigmentation
70
What leads to a thin epidermis with aging?
When the stem cells in the stratum basal are no longer able to multiply as effectively
71
What leads to sagging and wrinkling of the skin?
Reduced collagen which leads to a then dermis
72
What leads to slow skin repair in aging?
Reduced blood flow in the capillaries
73
How does smoking contribute to skin aging?
Tobacco contains agents that accelerate aging, damage collagen
74
WHat is the purpose of melanin pigment?
Protects cells from UV damaged
75
What is the lifecycle of melanin pigment?
Produced in melanocytes and transferred to epidermal cells via melanosomes
76
What layer are melanocytes found in?
Stratum basale ( meaning they are not shed)
77
Are melanosomes shed?
Yes, with keratinocytes
78
Where are melanosomes found?
All throughout the epidermis
79
What is the difference between a mole and a freckle?
A mole is a cluster of melanocytes caused by the overproliferation caused by sun exposure, whereas a freckle is caused by melanocytes overproducing melanosomes
80
What is vitamin D used for?
Essential for normal calcium metabolism and strong bones
81
What causes rickets?
Vitamin D deficiency
82
What is requires for vitamin D synthesis?
UV exposure
83
describe Basal Cell Carcinoma
Skin cancer, common but bengin.
84
Where does basal cell carcinoma originate and where does it spread?
Stratum basale and does not spread
85
Where does maligant melanoma originate?
Melanocytes
86
What layer of skin is a tattoo on?
Dermal layer
87
What are the 5 types pf touch receptors on the skin?
Free nerve endings
Tactile discs
Tactile corpuscles
Lamellar Corpuscules
Bulbous Corpuscles
88
Where are free nerve endings found?
Distal ends of axons
89
Describe the structure of a free nerve ending
Unmyelinated and small diameter (C-fibres), but some are small diameter myelinated (A delta)
90
What kinds of stimuli do free nerve endings respond to?
Temperature
Painful
Movement and pressure
Itch
Hair follicules
91
What kind of pathways do sensory terminals have?
Cation channels (TRP)
CHemical (H1 (GPCRs))
APs in afferent sensory axons in somatosensory cortex
92
Where are Tactile (Merkel) discs located?
Free nerve ends in deepest layer of epidermis. They are abundant in fingertips and small receptive fields
93
How does the Tactile disc function?
Communicates with epidermal (Merkel) cells and nerve endings via seratonin (5HT)
94
What are Merkel discs sensitive to?
Touch and light pressure
Texture, shape, and edges
Low frequency vibration
95
Where are Tactile (Meissner) Copuscles located?
Papillary layer of the dermis, particularly in hairless areas
96
What is the structure of the Meissner Corpuscles?
Encapsulated,
Surrounded by Schwann cells and thin oval FCT capsule
Deformation of capsule causes Na ions to enter nerve terminal and cause an AP
97
What can Meissner Corpuscles detect?
Fine or discriminative touch
Light pressure
Low frequency vibrations
98
Where are the Lamellar (Pacinian) Corpuscles found?
Deep in dermis and hypodermis
99
Describe the structure of a Pacinian Corpuscle
Single seonsory axon terminal with concentric layers of collagen fibres and specialized fibroclasts. They are then separated by jelly-like interstitial fluid. They are isolated from most things
100
Describe how a Pacinian Corpuscle functions
Deformation of capsule opens Na+ channels in the sensory axon causing an AP to propagate.
They are stimulated by deep pressure and also vibrations
101
Where is a Bulbous (Ruffini) corpuscles located?
In the dermis and subcutaneous tissue
102
Describe the structure of a Ruffini Corpuscle
Network of nerve endings intertwined within a core continuous with those of the surrounding dermis. Capsule
103
What is the function of a Ruffini Corpuscle?
Sensitive to deep pressure and distortion of the skin, so is important for signalling heavy prolonged touch as well as proprioception.
104
What is the function of arteries in the skin?
Constrict and decrease blood flow for temperature regulation
105
What system controls the walls of the arteries an the pre-capillary sphincters?
SNS
106
What hormone is a trigger for skin blood flow?
Noradrenaline acting on adrenergic receptors on the smooth muscle in the skin
107
Does reducing or increasing the activation of the alpha-1 receptors cause reduction in skin bloodflow?
Increase as it causes the arteries to constrict
108
What is vasomotor tone?
Relaxation and contraction of the blood vessels
109
What are the 4 primary mechanisms of heat transfer?
Radiation
Conduction
Convection
Evaporation
110
Describe radiation heat transfer
Any objects not at absolute 0 radiate heat to the environment
111
Describe conduction heat transfer
When heat is lost to air and surfaces around you
112
Describe the process of convection heat transfer
Wind taking away heat from around our body and replacing it with cool air
113
What are the eccrine swear glands innervated by?
Sympathetic nervous system
114
Which hormone are eccrine sweat glands activated by?
ACh
115
What does the preoptic area of the hypothalamus do?
Detects temperature via central thermoreceptors
116
What happens if the detected temperature is too high?
SNS activation causes vasodialation and cholinegergic activation of mAChR causes sweating.
Increase in respiratory rate
117
What happens when the detected temperature is below the set point?
Shivering
Non-shivering thermogenesis (cellular metabolism - glycogenolysis)
Increase in Thyoxine which increases the basal metabolic rate
118
What is the rule of 9s?
Head - 9
Upper limb (each) - 9
Trunk and back - 36
Lower limb - 18
Percentage of body coverage for burns victims
