The Integumentary System Flashcards
(116 cards)
1
Q
Cutaneous membrane
A
Consists of two layers:
- Epidermis
- Dermis
2
Q
Accessory structures
A
Hair, hair follicles, exocrine glands and nails
3
Q
2 parts of integumentary system
A
- Cutaneous
2. Accesory
4
Q
Where are the accessory structures embedded?
A
In the dermis
5
Q
Functions of the integumentary system
A
- Protection of organs
- Excretion of salts
- Body temperature
- Melanin, keratin, vitamin D
- Lipid storage
- Sensory detection
- Immune response
6
Q
How does the epidermis get nutrients and oxygen?
A
They are diffused from capillaries within the dermis
7
Q
What kind of epithelial tissue is the epidermis?
A
Stratified squamous
8
Q
Why are the cells with the highest metabolic demands closer to the basement membrane?
A
The diffusion distance is shorter there
9
Q
Keratin
A
Tough, fibrous protein that makes up keratinocytes
10
Q
Thin skin
A
- 4 layers of keratinocytes
- covers most of the body surface
11
Q
Thick skin
A
- 5 layers of keratinocytes
- palms of hand and soles of feet
12
Q
Stratum basale (epidermis)
A
- Attached to the basement membrane
- Epidermal ridges, dermal papillae
- Basal (stems) cells, melanocytes, tactile cells
13
Q
Basal cells
A
Stem cells that divide to replace the more superficial keratinocytes that are shed at the epithelial surface
14
Q
Where are tactile cells found?
A
Skin surfaces lacking hair
15
Q
Tactile cells
A
Sensitive to touch and when compressed, release chemicals that stimulate their associated sensory nerve endings
16
Q
Tactile disc
A
Tactile cell + sensory nerve ending
17
Q
Stratum spinosum (epidermis)
A
Keratinocytes bound together by desmosomes
18
Q
Dendritic cells
A
Cells in the stratum spinosum that stimulate defence against microorganisms and superficial skin cancers
19
Q
Stratum granulosum (epidermis)
A
- Keratinocytes produce lots of keratin and cells die from keratohylin
20
Q
Keratohylin
A
A protein made by keratinocytes which form dense cytoplasmic granules that dehydrate cells
21
Q
Stratum lucidum (epidermis)
A
A glassy layer in thick skin only
22
Q
Stratum corneum (epidermis)
A
- Multiple layers of flattened, dead, interlocking keratinocytes
- Water resistant but not water proof
23
Q
Keratinisation
A
The formation of protective, superficial layers of cells filled with keratin
24
Q
Insensible perspiration
A
Water loss from stratum corneum
25
Sensible perception
Water loss from active sweat glands
26
Where is EGF produced?
- Salivary glands
| - Glands of the duodenum
27
Functions of EGF
Promotes:
1. Division of basal cells in stratum basale and stratum spinosum
2. Keratinisation
3. Epidermal development and repair
4. Secretions of epithelial glands
28
2 layers of the dermis
1. Papillary: nourishes and supports epidermis
| 2. Reticular: detects sensory input and thermoregulates
29
Which layer does dermatitis primarily involve?
Papillary layer
30
What epithelial tissue is the papillary layer made of?
Areolar tissue
31
What epithelial tissue is the reticular layer made of?
Dense irregular connective tissue (collagen and elastic fibers)
32
Tension lines
The pattern made from fiber bundles in the skin
33
Why do surgeons cut parallel to tension lines?
Cuts will heal with little scarring
34
Cutaneous plexus
The deeper network of arteries in the subcutaneous layer
35
Subpapillary plexus
The layer of small arteries in the papillary layer
36
Contusions
(Bruises) When dermal blood vessels are ruptured, blood leaks into the dermis
37
2 pigments of epidermis
Melanin and carotene
38
Melanocytes
Produce melanin
39
What amino acid makes up melanin?
Tyrosine
40
Melanosomes
Intracellular vesicles containing melanin
41
How do melanocytes respond to UV exposure?
They produce more melanin
42
Where are melanosomes in keratinocytes?
Surrounding the nucleus, preventing damage to the DNA
43
Carotene
Orange yellow pigment that accumulates in epidermal cells
44
Which pigment can be converted to vitamin A?
Carotene
45
Hemoglobin
Binds and transports oxygen in the bloodstream and gives blood its red colour
46
Cyanosis
The bluish coloration of the skin when oxygen levels drop and hemoglobin produces lots of oxygen, turning a much darker red
47
Jaundice
When the liver is unable to excrete bile, a yellowish pigment accumulates in the body fluids
48
Melanocyte-stimulating hormone (MSH)
Some tumours affecting the pituitary gland result in the secretion of large amounts of MSH which causes melanocytes to overproduce melanin
49
Addison's disease
The pituitary gland secretes large quantities of adrenocorticotropic hormone (ACTH) which darkens the skin
50
Vitiligo
Individuals lose melanocytes, causing white patches on the skin
51
What happens when epidermal cells are exposed to a healthy amount of UV radiation?
1. Epidermal cells in the stratum basale and the stratum spinosum convert a cholesterol steroid compound into vitamin D3.
2. The liver converts vitamin D3 into an intermediary product used by the kidneys to synthesis the hormone calcitriol
52
Calcitriol
Essential for the normal absorption of calcium and phosphate ions in the small intestines (important for bone maintenance and growth)
53
Metastasis
When cancer spreads to distance body sites
54
ABCDE melanoma detection
```
Asymmetry
Border
Colour
Diameter
Evolving
```
55
Rickets
Disease caused by vitamin D3 deficiency that results in the bending of abnormally weak and flexible bones
56
Root hair plexus
Sensory nerves surrounding the base of each hair follicle
57
Arrector pili muscle
When stimulated, it contracts, pulling the hair follicle and forcing the hair to stand erect
58
Hair root
The portion that anchors the hair into the skin
59
Hair shaft
Extends from halfway under the skin surface and protrudes out
60
Medulla
Core of the hair contain a flexible soft keratin
61
Cortex
Contains thick layers of hard keratin which gives the hair its stiffness
62
Cuticle
Although thin, is very tough, and it contains hard keratin
63
Hair bulb
The bulging base of the hair follicle
64
Hair papilla
A peg of connective tissue containing capillaries and nerves
65
Hair matrix
Layer of epithelial cells at the base of the hair bulb in contact with the hair papilla
66
How does hair grow?
Basal cells of the hair matrix divide, producing daughter cells that are gradually pushed to the surface
67
Hair growth cycle
As hair grows, the root is firmly attached to the matrix of the follicle. At the end of the growth cycle, the follicle becomes inactive and the hair is termed a club hair. The follicle gets smaller and over time the connections between the hair matrix and the club hair root break down. When another cycle begins, the follicle produces a new hair and the old club hair is pushed to the surface and shed.
68
Internal root sheath
Surrounds the hair root and the deeper portion of the shaft. The cells of this sheath disintegrate quickly.
69
External root sheath
Extends from the skin surface to the hair matrix
70
Glassy membrane
Thickened, clear layer wrapped in the dense connective tissue sheath of the follicle as a whole
71
Lanugo hairs
Hairs that appear after 3 months of embryonic development:
- Extremely fine
- Unpigmented
- Shed before birth
72
Vellus hairs
Peach fuzz
73
Terminal hairs
Heavy, deeply pigmented hairs e.g. head hair, eyebrows, eyelashes
74
Type of hair before and after puberty
Before: vellus
After: Terminal
75
Sebaceous glands
Holocrine glands that discharge sebum into hair follicles
76
Holocrine secretion
A process that involves the rupture of secretory cells
77
Release of sebum
1. The sebum released from gland cells enters the lumen of the gland
2. The arrector pili muscles that erect the hair then contract, squeezing the sebaceous gland and forcing the sebum into the hair follicle and onto the surface on the skin
78
Composition of sebum
Triglycerides, cholesterol, proteins and electrolytes
79
Functions of sebum
1. Inhibits growth of bacteria
2. Lubricates and protects the hair shaft
3. Conditions the surrounding skin
80
Sebaceous follicles
Large sebaceous glands that are not associated with hair follicles. Instead, their ducts discharge directly onto the epidermis
81
Where are sebaceous follicles located?
Face, back, chest, nipples and external genitalia
82
Vernix caseosa
A protective superficial layer made of sebaceous gland secretions and shed epidermal cells that coats the skin surface in fetuses
83
Seborrheic dermatitis
Inflammation around abnormally active sebaceous glands, most often in the scalp
84
Cradle cap
Mild cases of seborrheic dermatitis in infants
85
Location of apocrine sweat glands
In the armpits, around the nipples and in the pubic region
86
What method of secretion do apocrine sweat glands use?
Merocrine (despite the name)
87
Secretions of apocrine glands
Sticky, cloudy, and potentially odorous secretion
88
Where do apocrine sweat glands secrete?
Into hair follicles
89
Where do eccrine sweat glands secrete?
Directly onto the surface of the skin
90
Secretions of apocrine glands
Sweat (99% water and sodium chloride)
91
Functions of eccrine sweat glands
1. Cooling surface of the skin to reduce body temp.
2. Excreting water and electrolytes
3. Providing protection from environmental hazards (flushing from surface or dermicidin)
92
2 other integumentary glands
1. Mammary glands
| 2. Ceruminous glands
93
Where are ceruminous glands found?
In the passageway of the external ear
94
Cerumen
Earwax
95
What controls the activation of sebaceous glands and apocrine sweat glands?
Automatic nervous system
96
Function of nails
1. Protect exposed dorsal surfaces of the tips of fingers and toes
2. Limit distortion of the digits from mechanical stress
97
Nail body
Visible portion of the nail
98
Nail bed
Epidermis under nail body
99
Lateral nail grooves
Depression on side of nail body
100
Lateral nail folds
Folded over skin at border of nail body
101
Free edge
Distal portion of nails that continues past nail bed
102
Hyponchium
Area of thickened stratum corneum
103
Nail root
Epidermal fold where nail production takes place
104
Eponychium
Cuticle
105
Lunula
Obscured blood vessels forming a pale crescent
106
Composition of the body of the nail
Dead, tightly compressed cells packed with keratin
107
Repair to injury to the intehument
1. Inflammation phase (immediately): bleeding, mast cells trigger inflammatory response
2. Migration phase (after several hours): scab forms, stratum basale cells migrate along edges of wound, phagocytes remove debris, and clotting isolates region
3. Proliferation phase (after a week): scab undermined by epidermal cells migrating over collagen fibre meshwork produced by fibroblasts, phagocytic activity has stopped and fibrin clot is dissolving
4. Scarring phase (after several weeks): scab shed, shallow depression and scar tissue
108
Composition of blood clot
Mainly insoluble network of fibrin
109
Granulation tissue
Combination of blood clot, fibroblasts, and an extensive capillary network at the base of the wound
110
Keloid
Thick, raised area of scar tissue
111
First degree burn
- Only the surface of the epidermis is damaged
- Most sunburns
- Erythema (red and painful skin)
112
Second degree burn
- The entire epidermis and perhaps some of the dermis are damaged
- Blistering, pain and swelling
113
Third degree burn
- Epidermis and dermis are destroyed, extending into subcutaneous layer
- Sensory nerves destroyed = less painful than 2nd
- Skin grafting necessary
114
Estimation of burn surface area
Rule of nines
115
Why are burns that cover more than 20% of the skin surface life threatening?
They affect:
1. Fluid and electrolyte balance
2. Thermoregulation
3. Protection from infection
116
Effects of ageing on the skin
- Integument thins
- Blood flow decreases
- Cellular activity decreases
- Repair takes place more slowly
