Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

SGUL - Physiology 2 > Skin - Structure And Function > Flashcards

Skin - Structure And Function Flashcards

1
Q

What is the integumentary system of the body?

A

Skin, Hair and Nails

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

List some features of the integumentary system

A
  • Largest organ of the body
  • Heaviest organ of the body: 15% of adult body weight
  • Much GP time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 3 layers of the skin?

A
  • Epidermis
  • Dermis
  • Hypodermis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q
A

Hair, Skin glands, Nails and sensory receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the functions of the skin?

A
  • Barrier protection: Dehydration, Infection, Injury, Solar radiation
  • Thermoregulation
  • Sensation
  • Repair
  • Vitamin D production
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the Epidermis layer of the skin

A
  • Most superficial
  • Gives skin it’s colour
  • Protection from pathogens and environment
  • Vitamin D production
  • Made up of multiple layers of differentiating keratinocytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

List the 4 main layers of the Epidermis

A
  • Stratum Corneum
  • Stratum Granulosum
  • Stratum Spinosum
  • Stratum Basale
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the Stratum Basale: Basal Layer

A
  • First single layer contains stem cells arranged to the dermis
  • Stem cells constantly proliferate
  • Are dynamic: Daughter cells constantly move “up” (distally) through the epidermis, differentiating as they go
  • Until they are shed from the outer surface.
  • This takes 20-50 days
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the Stratum spinosum: Spiny layer

A
  • Cells (Keratinocytes) have many desmosomes (junctions) visible as spines between the cells
  • Strong bonds holding the epidermis together
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the Stratum Granulosum: Granular layer

A
  • 1-4 layers of cells containing granules of kreatohyalin: a precursor of the protein keratin
  • Also contain lamellar bodies containing lipids (seen by TEM)
  • Cells are differentiating to form the outermost layer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe the Stratum Corneum: Cornified layer

A
  • The outer protective layer of the epidermis
  • Cells are keratinised (cornified), Cytoplasm full of horny keratin (keratohyalin granules)
  • Thus tough and resistant to injury
  • Cells are flattened and lost their nuclei
  • Nonpolar lipids (waterproof) are between the cells from lamellar bodies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is Keratin also the main components of?

A

Horns, Hair, Nails, Claws and hoofs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

List some other epidermal cell types

A
  • Melanocytes (pigment)
  • Langerhans cells (defence)
  • Merkal cells (sensation)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How are melanocytes viewed under a microscope?

A

Via a special DOPA stain for melanin which shows their denitrification form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are Melanocytes?

A
  • They synthesise melanosomes
  • Transfers them to basal keratinocytes through long dendrites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is melanin arranged in the pigment?

A
  • Keratinocytes arrange melanin pigment in a cap distal to the nucleus (sunny side)
  • Especially in the Basal layer (Stem cells)
  • UV protection: black ppl only have about 10% as many skin cancers as white ppl with the same lifestyle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are Merkal cells?

A
  • Some pale cells in the basal layer are Merkal cells
  • These are touch sensors
  • Hard to tell the difference with H&E alone which is white skin, pale cells in or protruding from basal layer
18
Q

Describe the Langerhans cells

A
  • Function: Immune system, Seeks and deals with invading microbes
  • Antigen presenting cells (like macrophages)
  • They are dendritic cells, forming a network
19
Q

Describe the Vitamin D production in the skin

A
  • Vitamin D3 is made in the epidermis layer
  • Mostly in the basal cells but also in the Stratum spinosum
  • Requires UV light
  • Requires more UV light in dark skin (melanin barrier)
  • Converted to active form in liver in the liver and kidney
  • Commonly deficient in the UK
20
Q

Describe the dermis layer of the skin

A
  • Found below the epidermis
  • Has 2 layers
  • Tensile strength & elastic
  • Contains blood vessels, skins glands & sensory receptors
21
Q

Describe what the dermis layer is made from

A
  • Made up of layers of connective tissue
  • Characterised by interconnected mesh of elastin and collagen fibres
  • produced by dermal fibroblasts
  • Fibroblasts are the principal cell of the dermis
22
Q

What are the two layers of the dermis?

A
  • Thin papillary layer
  • Deeper reticular layer
23
Q

Briefly describe the dermis

A
  • Dense irregular connective tissues
  • Dense = full of collagen fibres
  • Irregular = Fibres run in all directions (not parallel)
24
Q

What are the functions of the dermis?

A
  • Collagen provides tensile strength hence protection against abrasion and impact
  • Also contains elastin providing elasticity
  • Carries blood and nerve supply for epidermis
  • Rich in blood vessels, sensory receptors and skin glands
25
Q

Describe the Dermal Epidermal border

A
  • Often wavy which helps resist shear forces
  • Has Dermal papillae: Finger like protrusions of dermal connective tissue into epidermal layer
  • rete ridges: Extension of epidermis into the dermal layer
  • Most apparent in thick skin of hands = fingerprints as well as feet
26
Q

Which dye is used on the Dermis?
What does it show?

A
  • Verhoeff Van gieson stain (VVG)
  • Shows the collagen fibres in red
27
Q

What is one effect of ultraviolet light on skin?

A
  • One effect is damage/loss of Elastic fibres
  • This results in the loss of elasticity causing wrinkles
28
Q

Describe the Hypodermis layer

A
  • Below the dermis
  • Helps insulate the deeper tissue
  • Anchors skin to the muscle with connective tissue
29
Q

What is the Hypodermis made up of?

A
  • Made up of well vascularised, loose, areoles connective tissue and adipose tissue
  • Functions as a mode of fat storage
  • Provides insulation and cushioning for the integument
30
Q

What is the Hypodermis composed of?

A
  • Composed of fat containing glands, hair follicles, nerves, blood vessels
  • Often the thickest layer of skin. Thickness varies with age
  • This is where you put a hypodermic needle for a subcutaneous injection
31
Q

Describe the hair

A
  • Found on nearly every part of the skin except the palms, soles and lips
  • Every strand of hair is composed of the shaft, root and bulb that sits in a pouch like structure called the hair follicle
32
Q

Describe the Hair follicles in detail

A
  • The hair follicle is epidermal tissue that dips down into the dermis
  • Interacts with other structures like apocrine glands, sebaceous glands, the affector pili muscle and nerve receptors
33
Q

Describe the bulb of the hair

A
  • Bulb contains the hair matrix: active site of hair growth and pigmentation
  • Contains different cell types: Follicular keratinocytes and Melanocytes
  • Follicular keratinocytes produce hard keratin = hair
34
Q

Describe the follicular keratinocytes

A
  • Keratinocytes filled with hard flatten out and are slowly pushed up the follicle resulting in root and shaft formation
  • Follicular keratinocytes at the bulb replicate only a set number of times
  • After the hair follicles stops growing and fall out leading to baldness
  • Overtime these melanocytes stop producing melanin which is why hair turns white as ppl age
35
Q

List the different types of skin glands

A
  • Eccrine Sweat glands
  • Apocrine Sweat glands
  • Sebaceous gland
36
Q

Briefly describe Eccrine sweat glands

A
  • Normal sweat glands
  • Watery secretion on to skin surface
  • Cools the body down by evaporation
37
Q

Describe the Apocrine sweat glands

A
  • Secrete into hair follicles
  • Found in the armpits and anogenital region
  • Oily fluid in humans
  • Function is unclear (contains pheromones)
  • Source of body odour after bacterial action
  • Only present after puberty
38
Q

Describe Sebaceous gland

A
  • Secrete oily sebum (lanolin) into hair follicle
  • Conditioner for hair and skin
  • Prevents dryness and flaking
  • Only present after puberty
39
Q

Describe the Nails: Nail folds and Eponyvhium

A
  • Nail folds: Where the skin seals of the edges of the nail
  • Eponychium: Proximal skin fold that gives rise to the cuticle
  • Which is a semi circular layer of dead skin keratinocytes that covers where the nail enters the skin
  • Preventing the entry of pathogens
40
Q

Describe the Nail matrix

A
  • Creates the nail plate, The hard part of the nail as well as the free edge that hangs over the skin
  • Special epidermal tissue that contains nerves, lymphatics and blood vessels that support the nail
  • Contain modified keratinocytes that replicate and undergo the process of keratinisation
41
Q

Where does the older and youngest keratinocytes go after keratinisation?

A
  • Youngest keratinocytes go to the nail matrix
  • Older cells go to the Keratinize which form the nail plate
42
Q

Describe the sensory receptors

A
  • Free nerve endings -> nociception, thermal sensation, light touch
  • Encapsulated endings
  • Pacinian corpuscles (rapidly adapting) → vibration or brief touch
    ➢Merkel’s discs (slowly adapting) → sustained touch/pressure e.g. skin indentation
    ➢Meissner’s corpuscles (rapidly adapting) → moving touch or vibration
    ➢Ruffini endings (slowly adapting) → steady pressure
    ➢Root hair plexus (rapidly adapting) → hair displacement.
    ➢Krause end bulbs → touch/pressure, possibly thermoreceptors.

SGUL - Physiology 2 (37 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions