Integumentary System Flashcards Preview

Human Organs and Tissues > Integumentary System > Flashcards

Flashcards in Integumentary System Deck (76):
1

2 layers of skin

Epidermis
Dermis

2

Is the hypodermis part of the skin?

No

3

Main functions of the skin

Protective
Immunological (has APCs)
Sensory
Exocrine (sweat, apocrine, sebum, mammary glands)
Endocrine (vitamin D synthesis)
Homeostasis (thermoregulation, water conservation, gas exchange, excretion)
Communication

4

Eccrine sweat glands

Throughout skin
Excrete water, salt, urea
Critical for cooling the body
Soles of feet and palms of hands - also underarms, groin, and forehead

5

Apocrine sweat glands

Axilla and groin only
Develop during puberty
Secrete water and lipids (glycoproteins)
Break down the organic compounds in sweat causing body odor
Pheromones for signalling

6

Sebaceous glands

Associated with hair follicles
Secrete oils that coat the hair and skin
Protective film
Sebum composed of lipids, triglycerides, waxes, squalene, cholesterol and cell remnants
Secretion controlled by testosterone/androgens

7

Langerhans cells

Immune cells responsible for picking up pathogens

8

Merkel cells

Nerve cells responsible for sensation

9

What are the only type of nerve endings in the epidermis?

Unencapsulated (free) nerve endings

10

5 layers of the skin

Stratum corneum
S lucidum
S granulosum
S spinosum
S basale

11

Thick skin

Made up of all 5 layers
Restricted to palms of hands and soles of feet
Lacks hairs and has abundant sweat glands
S spinosum is also thick

12

Thin skin

No stratum lucidum
Has hairs
Covers the rest of your body
S granulosum and corneum are pretty thin

13

Turnover of skin involves..

Cell renewal (mitosis)
Differentiation
Cell death
Exfoliation (sloughing off)

14

Stratum basale

Also called stratum germinativum
Basal cell layer of epithelia
Rests on basal lamina
Single layer of columnar cells
Has mitotically active keratinocytes, melanocytes, and Merkel cells

15

Melanocytes do not have..

Desmosomes
But they do have hemidesmosomes

16

Desmosome Structure

Adaptor proteins attach keratin filaments to the cytoplasmic plaque
Transmembrane linkers connect adjacent cells

17

Keratin filaments are also known as... (2 names)

Tonafilaments
Intermediate filaments

18

Stratum spinosum

Cuboidal to squamous cells with central nuclei
Contains aggregates of keratin called tonafilaments
Responsible for mechanical strength of epidermis
Variable number of cell layers depending on location

19

Malpighian layer

Includes the stratum basale and stratum spinosum
Nearly all the mitotic activity in the epidermis occurs here and cell division occurs only at night

20

Stratum granulosum

Keratinocytes mostly squamous
Contain membraneless keratohyalin granules in this layer

21

2 types of granules

Keratohyalin granules (membraneless)
Lamellar granules (membrane)

22

Lamellar granules

Fuse with the plasma membrane and release their GAGs and phospholipids into intercellular spaces
May be important in sealing the deeper layers of the skin

23

Stratum lucidum

Only in thick skin
Narrow, acidophilic translucent band of flattened keratinocytes whose nuclei, organelles, and intercellular borders are not visible

24

Stratum corneum

Many layers of dead, plate-like keratinocytes with thickened plasma membranes
No nuclei
Filled with mature keratin
Permeability barrier

25

What layer do the nuclei begin to disintegrate in?

The outer layer of the stratum granulosum

26

Where are melanocytes found?

Stratum basale
Their dendrites go into the spinosum
Attached to basal lamina by hemidesmosomes
No desmosome attachment to keratinocytes

27

Highest concentration is found where?

In the cells that are more deeply localized because those are the cells that divide more rapidly

28

What has an impact on skin colour

Melanin and carotene
Thickness of the epidermis
Number of dermal blood vessels
Color of the blood (hemoglobin) in those vessels

29

Melanin

Brown-black pigment formed in cells called melanocytes
Amount of melanin is based on inheritance

30

Hemoglobin

Molecules found in RBC that gives blood its red coloraton
It is made of non-protein (heme which contains iron)
and the protein (globin)

31

Carotene

Yellowish pigment found in corneum and dermis
Plant pigment that enters the body via foood
Helps yield the yellow and red skin colors

32

Albinism

Condition where skin does not produce melanin

33

2 step process of tanning

1. Physiochemical reaction darkens preexisiting melanin and releases it rapidly into the keratinocytes
2. Higher rate of melanin synthesis by melanocytes, increases the amount of melanin

34

UVB vs UVA

UVA penetrates deeper into the dermis and damages dermal components
Promotes skin aging

35

Aging skin has...

Thinner epidermis and dermis
Disorganization
Loss of collagen
Reduced vascularization

36

Vitamin D synthesis

UVB required to activate 7-dehydrocholesterol in the epidermis to form pre-vitamin D

37

Langerhans cells

Star shaped immune cells
Occur mainly in the stratum spinosum
APCs that process and present to the lymphocytes any antigenic material that penetrates the skin's surface

38

SALT

Skin associated lymphoid tissue

39

Merkel cells

Few in number
Found in basal layer of epidermis
Form macula adherens junctions with keratinocytes
Cells contain small dense granules similar to neuroendocrine cells
Function thought to be sensory or neuroendocrine in nature

40

Glabrous skin

Thick skin
Merkel cell is in close apposition to a plate like nerve ending from a neuron

41

Interpapillary peg

Narrow downgrowth of the epidermis
Divides dermal ridge into 2 secondary dermal ridges

42

Dermis

Vascular connective tissue
Variable thickness over different regions
Much thicker than the overlying epidermis

43

4 cell types found in the dermis

Fibroblasts
Lymphocytes
Macrophages
Mast cells

44

3 typical structures found in the dermis

Sweat glands
Sebaceous glands
Hair follicles
Most arise from the epidermis

45

2 dermal layers

Papillary layer
Reticular layer

46

Papillary dermal layer

Uneven and forms dermal papillae which increases contact area with the epidermis
Composed of loose CT
Mainly collagen type 3
Smally immature elastic fibers
Contains capillary loops and Meissner corpuscles which are fine touch receptors

47

Reticular dermal layer

Dense irregular connective tissue
Gives skin overall strength and elasticity
Mainly collagen type 1
Larger elastic fibers
Houses glands and hair follicles
Rich supply of nerves in both free and encapsulated endings
Shunts to control blood flow

48

Arteriovenous anastomoses

In reticular dermal layer
Control the amount of blood reaching the papillary capillaries, aiding in regulating heat loos and blood pressure

49

Hypodermis

Subcutaneous layer or fascia
Not a true layer of skin
Links skin to body proper
Variable thickness in different regions of the body
Allows for movement of skin over body
Full of adipocytes
More nerve endings
Contains the lymphatics

50

Hair follicle

Invagination of the epidermis extending into the dermis

51

Hair shaft

In the center of the follicle
Extends above the surface of the epidermis
Consists of an inner medulla, cortex, and outer cuticle of the hair

52

Hair bulb

Terminal expanded region of the hair follicle in which the hair is rooted

53

Internal vs external root sheath

Internal: lies deep to the entrance of the sebaceous gland
External: direct continuation of the surrounding malpighan layer of the epidermis

54

Glassy membrane

Noncellular layer
Thickening of the basement membrane
Separates the hair follicle from the surrounding dermal sheath

55

4 types of hair

Lanugo: neonatal, fine, soft hair with no medulla
Vellus: post-natal, short, fine shaft, no medulla
Intermediate: post natal to 2 years
Terminal: post natal and on, long, course shaft, medullated (pigmentated), most common

56

Nail root

Stratum basale and spinosum of epidermis
Forms nail matrix whose cells synthesize the nail plate or body

57

Nail bed

Stratum basale and spinosum of nail
Does not contribute to nail synthesis

58

Nail plate

Closely compacted, keratin enriched with hard interfibrillar material
Stratum corneum of the nail

59

Eponychium

Cuticle
Junction between skin and stratum corneum and base of the nail plate

60

3 glands in the skin

Eccrine sweat glands
Apocrine sweat glands
Sebaceous glands

61

Mammary gland

Modified apocrine sweat glands
Milk producing glands that develop during pregnancy and lactation

62

Functional unit of breast tissue

Terminal duct lobular unit

63

Meissner's corpuscle

Encapsulated unmyelinated nerve ending in the dermal papilla of skin
Senses deformation of skin
Rapidly adapting
Throughout skin, but concentrated in areas sensitive to light tough

64

Pacinian Corpuscle

Lie deep in the dermis, and hypodermis
Present in some mucous membranes and joints
Mechanoreceptors
Respond to pressure or any kind of mechanical stimulus

65

Contact hypersensitivity

Due to allergic reaction to chemical or compound
Hapten specific T cell recognizes the hapten in the skin and causes cell injury = inflammation

66

Psoriasis

Chronic, reoccuring skin disease
Produces red, scaly, well defined, patches affecting any part of the skin on your body
Areas in inflammation and excessive skin production

67

1. Hyperkeratosis
2. Parakeratosis

1. Thickening of the stratum corneum
2. Retained nuclei in the stratum corneum

68

Ehlers-Danlos syndrome

Rare genetic disorder
Caused by defective collagen synthesis
Fragile skin
Hyperextensible joints
Can affect organs

69

Bullous pemphigoid

Chronic blistering of the skin
Generally in the elderly
Autoimmune disorder
Caused by loss of attachment of basal keratinocytes to the underlying basement membrane
Associated with deposition of immunoreactants at the dermal-epidermal junction

70

Vitiligo

Loss of skin colour
Melanocytes are being destroyed or not functioning properly

71

ABCDEs of skin cancer

A: asymmetry
B: border
C: colour
D: diameter
E: evolving

72

Skin cancer is caused/associated with chronic inflammation of the skin from things such as... (3)

1. Sunburn or excessive sun damage, especially early in life (both UVA/B)
2. Chronic non healing wounds, especially burns
3. Genetic predisposition, including Congenital Melanocytic Nevi Syndrome

73

3 most common types of skin cancer and where the originate from

Basal cell carcinoma: stratum basale keratinocytes
Squamous cell carcinoma: stratume spinosum, squamous keratinocytes
Melanoma: malignant, stratum basale melanocytes

74

Where are most breast cancers from?

The ducts

75

Epithelial mesenchymal transition

When the breast cancer cells get the ability to invade out of the duct

76

Desmosomes vs Hemidesmosomes

D: linker protein is cadherin
H: linker proteins are integrins