Anatomy of the skin - Part 1

Question 1

How much does the skin make of the total human body weight?

Answer 1

16% with a 1.5-2mˆ2 SA

Question 2

What makes our skin unique?

Answer 2

We lost our hair through evolution as our skin was open to the savannahs we became bare and as we began to run, it became sweaty to cool our skin down

Question 3

How does sweating allow us to lose heat

Answer 3

Our muscles generate heat from movement and sweat evaporates the heat from our skin

Question 4

Why is the skin our first line of barrier?

Answer 4

It protects our internal organs and underlying tissues from the environment

Question 5

What does the keratin in our skin do?

Answer 5

Protects against abrasion and acts as a water repellent

Question 6

What pigments our skin and protects it prom UV radiation?

Answer 6

Melanin

Question 7

Where are lipids stored in the skin?

Answer 7

In the adipocytes in the dermis and adipose tissue in the subcutaneous layer

Question 8

How does the skin help us make sense of the world around us?

Answer 8

Through touch, pressure, pain and relaying info to the brain

Question 9

Why is skin a composite organ?

Answer 9

Made of all 4 tissue types

Question 10

3 layers of the skin

Answer 10

-Epidermis
- Dermis
- Hypodermis

Question 11

Epidermis features

Answer 11

• A stratified barrier
• Made of keratinocytes
• Avascular

Question 12

Dermis features

Answer 12

• Provides strength to skin through collagen and elastin
• Vascular
• Split into papillary and reticular layer

Question 13

Cutaneous layer

Answer 13

Epi + dermis

Question 14

Hypodermis features

Answer 14

• Fat reserve
• Made of adipocytes that make fat
• Subcutaneous layer

Question 15

What is epidermis predom made of?

Answer 15

Stratified Squamous Epithelial tissue

Question 16

What is squamous meaning

Answer 16

Scaly and flattened

Question 17

How many layers of epidermis?

Answer 17

4 - 5 layers
- Thin skin
- Thick skin

Question 18

What is the epidermis of the thin skin made of?

Answer 18

4 layers from outer to inner
- Stratum corneum - spikey layer
- Stratum granulosum
- Stratum spinosum
- Stratum Basale

Question 19

Stratum layer

Answer 19

• Exists purely to form a barrier
• Spiky layer
• Dead, dried out without a nucleus, flat

Question 20

Granulosum

Answer 20

• Granules dehydrates the cells and push them up
• Crosslinked by the keratin fibres, cells are held together
• Gaps filled by a waxy substance to prevent any leakage

Question 21

Spinosum

Answer 21

-Intracellular bridges i.e desmosomes, links cells within the dermis
- Where the flattening starts

Question 22

Basale

Answer 22

• STEM cells, columnar regenerative cells
• Cells divide and daughter cells migrate upwards and dehydrate and flatten along the way

Question 23

The only dead layer of the thin skin is…

Answer 23

The corneum

Question 24

Hemidesmosome

Answer 24

Attaches the stratum Basale to the Dermis layer, prevents layers from sliding off

Question 25

Thick skin

Answer 25

- Extra layer stratum lucidum so 5 layers - No hair -Below stratum corneum and above granulosum - Come Lets Get Some Burgers

Question 26

Dermis features

Answer 26

- Does not shed - Two layers: Papillary and reticular

Question 27

Dermis features

Answer 27

- Does not shed

Question 28

Papillary layer

Answer 28

Pokes the epidermal ridges, close to the dermal papilla - Highly vascularised layer that nourishes pap layer and basale layer

Question 29

Retucular

Answer 29

- Mesh like structure -Collagen, elastin + blood vessels, lymphatic and nerves - Gives strength to the skin

Question 30

Plexus

Answer 30

A network of nerves, bloodvessels or both

Question 31

Cutaneous plexus

Answer 31

- Present at hypo/dermis (reticular layer) junction - Bigger blood vessels that supply nutrients to hypo, deeper part of dermis, hair follicles and sweat glands

Question 32

Subpap

Answer 32

- Above cutaneous, branches from it - Below pap - Provides nutrients to upper dermis and epidermal layers

Question 33

Hypo

Answer 33

- Subcut layer - Dominated by adipocytes aka subcut fat that is used in fasting and insulation - Common site of injection i.e hypo/subcut injections

Question 34

1º burns

Answer 34

- Outer layers of epidermis - Redness aka erythema, dry and painful - No blisters eg most sunburns - Skin still has a barrier of repelling water

Question 35

2º burns

Answer 35

1st type: both epi and some layers of dermis - Blisters and moist - Pusy and red - Heals in 1-2 weeks 2nd type: Epi + deeper layers - Whitish, waxy areas - Hair follicles and sweat glands remain intact - Heals in a month - Some loss of sensation and scarring

Question 36

3º burn

Answer 36

aka a full thickness burn - extends into the subcutaneous and may affect bone and tissue - Varied color from waxy white through to deep red or black * Hard, dry and leathery skin * No pain in these areas as sensory nerve endings destroyed * May require skin grafting * Weeks to regenerate + scarring

Question 37

Where are the desmosomes most prominent

Answer 37

Spinosum

Question 38

Where are desmosomes found

Answer 38

All throughout the epidermis

Question 39

Where do desmosomes lose there holding strength?

Answer 39

In the granulosum layer so the cross linking of keratin holds it together