Lecture 19: Skin Thermoregulation and wound healing Flashcards

(59 cards)

1
Q

what are the 2 types of skin?

A

Glaborous skin

hair bearing skin

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2
Q

what are glamorous skin?

A

palm and soles

thick epidermis

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3
Q

hear bearing skin _____ depending on site

A

differs

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4
Q

Stratified squamous epithelium is constantly _____

A

growing

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5
Q

Stratified squamous epithelium contains ___…

A

no blood vessels , fed by vessels in the dermis

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6
Q

Stratified squamous epithelium skin turnover is …

A

52-75 days

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7
Q

what cells are in the epidermis ?

A

keratinocytes
Melanocytes
Langerhans Cells

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8
Q

epidermis is a barrier for?

A

water loss and infection

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9
Q

epidermis is colonised by?

A

microorganisms,

e.g. Staphylococcus epidermidis

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10
Q

what does a structure of a dermis contain?

A
blood vessels
Nerves 
hair follicles
smooth muscle
Glands
lymphatic tissue
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11
Q

what loose connective tissue is in the dermis?

A

collagen
elastin
reticular fibers

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12
Q

what do Arrector pili muscles

do in the dermis?

A

attached between hair papilla and epidermis

contract, hair pulled upright – goose bumps

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13
Q

what do sebaceous glands

do in the dermis?

A

sebum (lipids and waxy substances)

lubrication, water-proofing, softening, bactericidal

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14
Q

what glands does the dermis have?

A

sebaceous glands

sweat glands

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15
Q

what is the outermost layer of the dermis?

A

papillary layer

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16
Q

papillary layer ….

A
extends into the epidermis 
supply epidermis with nutrients
papillary ridges ( finger and foot prints)
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17
Q

what’s a dense layer the dermis has?

A

reticular layer

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18
Q

reticular layer facts…

A
continuous with the hypodermis
contains the bulk of the structures 
e.g. sweat glands
irregularly arranged fibres
resists stretching
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19
Q

where is the hypodermis located?

A

below dermis

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20
Q

where is the hypodermis made from?

A

Loose connective tissue and elastin

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21
Q

what does the hypodermis do?

A

Attaches skin to bone and muscle

Supplies skin with blood vessels and sympathetic nerves

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22
Q

what are three cells found in the hypodermis?

A

Fibroblasts, macrophages and adipocyte

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23
Q

How do we get pigment?

A

melanin form melanocytes

melanosomes transfer to keratinocytes

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24
Q

what does melanin protect us from?

25
what can the skin absorb ?
Oxygen, nitrogen and carbon dioxide Drugs can be administered through the skin important site of transport in many other organisms
26
what can the skin store and synthesise?
storage centre for lipids and water | synthesis of vitamin D by action of UV
27
what can the skin excrete?
urea in sweat Sodium chloride in sweat Lactic acid in sweat
28
what's the average body temperature supposed to be ?
36.5 C to 37.5 C
29
what does body temp have to be maintained between ?
+- 0.6 c
30
what is skin temperature dependent on ?
dependent on outside temp
31
what is body temperature controlled by?
regulating the balance between heat production and heat loss
32
what's Basal Metabolic Rate | ?
Rate of metabolism of all cells
33
what extra metabolic rate?
``` Muscle contractions Activity in deep organs Hormone Adrenaline, noradrenaline and sympathetic stimulation of cells Digesion, absorption and storage of food ```
34
How does heat loss happen?
Transfer of heat from core to skin | via blood flow
35
order of skin formation
epidermis papillary loops dermis papillary plexus
36
How does heat from skin go to surroundings?
radiation conduction convection evaporation
37
what percent of heat is lost through radiation and how?
60% (nude) | lost as infrared heat rays
38
where is heat from conduction lost too and what percent?
3% to solids | 15% to air
39
How Is heat lost through convection?
hot air to rises | increases with wind velocity
40
In what ways does our body evaporate heat and how much?
sweating | 600-700ml skin and lungs a day
41
what's lost in sweat ?
sodium chloride 15-30g
42
sweating involved stimulation of the _____
hypothalamus
43
what does the hypothalamus contain?
heat sensitive neurons - anterior | 1/3 cold sensitive
44
when temp increases how does the firing rate of the hypothalamus increase?
2-10 folds
45
where are thermoreceptors found?
skin and deep tissue
46
what thermoreceptors signal to the posterior hypothalamus?
peripheral tissues
47
if its too hot the hypothalamus will start...
Vasodilation Sweating Pilorelaxation Inhibition of shivering Inhibition of chemical thermogenesis
48
if its too cold the hypothalamus will start...
``` Vasoconstriction Piloerection Shivering chemical thermogenesis Increased thyroxine ```
49
what happens when you have a epidermal wound?
Basal epidermal cells leave basal membrane Enlarge and migrate Contact inhibition Other cells divide to replace those moving Continues until wound is resurfaced Occurs within 24-48 hours of injury
50
what are the four phases of wound healing?
inflammation migration poliferation maturation
51
How does a wound heal ?
1. bv dilate, phagocytes invade 2. scab, epithelial cells and fibroblasts migrate, fb synthesis collagen and glycoproteins 3. growth of epithelial cells an bv, deposition of collagen fibres 4. scab gone, cf organised, bv normal
52
what are some problems that can happen when a wound is healing?
Ischaemia Dry wound environment Infection/foreign body poor nutrition
53
what is a scar formed form?
collagen and matrix materials
54
what's the difference between scard skin and normal skin?
vessels than normal skin Lack of hair, sensory neurones or skin glands
55
whats keloid scaring?
Scar extends past the original wound and into surrounding tissues More common in darker skins
56
whats hypertrophic scarring?
Raised scar Remains within original wound boundary
57
what cells does skin cancer involve?
squamous cell, basal cell, melanocyte
58
what skin disorder is Psoriasis?
very rapid skin cell turnover cells build up on the skin forms thick, flaky patches called plaques
59
what does eczema cause?
intense itching | inflammation occurs