Integumentary system Flashcards

1
Q

Name the 3 layers of the skin

A

epidermis, dermis and hypodermis

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2
Q

Explain the role of the epidermis

A

It is a stratified epithelium that contains keratinocytes which produce keratin fibres, they are tied together by desmosomes which create a long sheet that provides the epidermis with strength. The epidermis also acts as a physical barrier preventing entry of pathogens (primary defense)
The epidermis contains: keratinocytes, Merkel cells, melanocytes and dendritic cells

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3
Q

What is a desmosome

A

They are cell junctions which fuse cells together in tissues exposed to mechanical forces

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4
Q

Function of melanocytes

A

Are specialised cells involved in the production of melanin, (skin pigmentation) it acts as a sunscreen for keratinocytes and protects us from UV rays

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5
Q

Function of merkel cells

A

These cells are associated with nerve endings as they are involved in touch, texture and light response

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6
Q

Function of dendritic cells

A

These are antigen presenting cells (APC), they digest pathogens, rips them apart. They are a primary defense and activate the immune system, found deep within the skin

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7
Q

Name the layers of the epidermis from top to bottom

A

Stratum corneum
Stratum granulosum
Stratum spinosum
Stratum basale

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8
Q

Function of the basal membrane in the epidermis

A

It pushes the older dead cells to the top to be sloughed

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9
Q

Function of the stratum spinosum

A

They produce keratin from keratinocytes found in this layer, they also contain Langerhans cells which engulf and digest bacteria

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10
Q

Function of stratum granulosum

A

Consists of 4-6 layers of cells, they start to spread/flatten out, keratin is accumulated. Acute lamellae help keratin become waterproof

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11
Q

Function of stratum corneum

A

Consists of 20-30 layers of cells, thickest layer, these cells are programmed to die, as they become keratinised. This causes them to become very resistant to chemicals, water and mechanical pressures. Forms a solid physiological and biological barrier

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12
Q

Define & explain the process of sloughing

A

Sloughing is the shedding of cells, a normal part of the skin cycle, 50000 skin cells are lost per minute
This is a protective feature as we lose bacteria, flora from the skins surface. This is how the body physically cleans itself
occurs every 21-45 days

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13
Q

Describe the structure of the dermis layer

A

It contains: BV’s, elastic fibres, collagen, nerve endings, sweat glands and hair follicles
Has a papillary layer which provides a large SA of diffusion of nutrients, enhances the sense of touch
the reticular layer of the dermis provides elasticity and flexibility to the dermis (elastic & collagen fibres)

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14
Q

What are the main functions of the skin?

A

-primary defense
-physical barrier for bacteria, chemicals, water and mechanical pressures
-thermoregulation
-prevents UV damage
-secretion of sebum to waterproof skin

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15
Q

Purpose of sweating

A

Sweating allows the body to cool itself, to lower body temp, hair erector muscles relax and so hair lies flat. sweat is secreted from eccrine gland, water in the sweat then evaporates off skin surface, providing a cooling effect. Sweat also produces antibodies on skins surface in attempt to control microbiome

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16
Q

Purpose of vasodilation

A

Dilation of the blood vessels occurs when we need to lower our body temperature, therefore blood flows closer to the surface, giving a flushed appearance, and allows heat to diffuse. The hypothalamus sends a signal to the subpapillary plexus to relax allowing blood to flow closer to surface

17
Q

Purpose of vasoconstriction

A

This occurs to conserve heat, blood flows further from skin surface, hair erector muscles contract and hair follicles are pulled up, trapping a layer of warm air close to the skin

18
Q

Purpose of secretion

A

sebaceous glands produce sebum, an oily fatty substance (pH of 4-6), slightly acidic to control bacteria on skin surface, antibacterial membranes are also released to disrupt bacteria & growth

19
Q

What is the apocrine gland and it’s function

A

A form of sebaceous gland that secretes a milky yellow substance, activates during puberty in armpits and genital regions, they produce pheromones, give maturity

20
Q

Explain the cutaneous sensation

A

These are free nerve endings that respond to damage to the skin.
Hair plexus can tell us what is proximal to the skin, they can sense movement & vibration
The Pacinian corpuscle found deep within responds to vibrations/pressures

21
Q

Explain the sensory homunculus

A

It is a model used to refer to the distribution of nerve endings found on the body, with most being found in the hands and lips

22
Q

Gives examples of non-verbal communication that the skin causes

A
  • blushing
    -sweating
    -pheromones
    -odor/stress odor
23
Q

Describe and explain the Stratum lucidium

A

A thick non-hairy layer of the skin that has 2-3 translucent layers, found in the bottom of the hands and feet. It contains flat & dead keratinocytes as well as Pacinian corpuscles. Lying above the stratum granulosum, thickens the skin in specific areas

24
Q

Factors affecting skin colour

A
  • melanin
    -carotene
    -haemoglobin
25
Q

Define cyanosis

A

This is poor circulation which leads to a bluish colour of the skin

26
Q

Define jaundice

A

Jaundice is a yellowish pigment to the skin, caused by bilirubin in breakdown of RBC, build up causes a yellow colour that indicates liver/kidney failure

27
Q

Define albinism

A

a lack of melanocytes, less production of melanin, giving pale complexion

28
Q

Define a Haematoma

A

Occurs when tissue suffers damage, blood vessels break and blood flows into the tissues, Hb is broken down