Lecture 1 & 2

Question 1

Skin (surface area)

Answer 1

Largest and most visible organ of the body, 16% of body weight, 1.5-2 m2 of surface area, bare makes us unique.

Question 2

Functions of skin + accessory structures.

Answer 2

• Detect touch, pain, pressure, temp stimuli and relay information to nervous system.
• Excrete salts, water, organic waste by integumentary glands
• Maintain normal core body temperature through insulation or evaporative cooling.
• Protect underlying tissue or organs from impact, abrasions, fluid loss, and chemical attack
• Produce melanin to protect underlying tissue from UV radiation
• Produce Keratin to protect against abrasions and serve as a water repellent.
• Synthesise Vitamin D3 (steroid converts to Calcitriol-hormone) important for normal calcium metabolism (homeostasis).
• Store Lipids in Adipocytes (in Dermis) and Adipose tissue (in Subcutaneous layer).

Question 3

3 Primary Layers in Skin are

Answer 3

Epidermis, Dermis, Hypodermis

Question 4

Epidermis (what layer inside, outside, middle)

3 things

Answer 4

outside layer, stratified barrier (made of different layers), mostly keratinocytes (cells with high amount of keratin-protein eg nails & hair, provides skin strength), Avascular (no blood vessels no circulation).

Question 5

Dermis (what layer inside, outside, middle)

4 things

Answer 5

Directly under epidermis and above hypodermis. Protein fibres for strength, provides structure, Vascular (blood supply) to nourish epidermis layers that are still alive.

Question 6

Hypodermis

1 thing

Answer 6

Adipose tissue for insulation

Question 7

Cutaneous layer

Answer 7

Epidermis and Dermis

Question 8

Subcutaneous layer

Answer 8

Hypodermis

Question 9

Epidermis layers are

Answer 9

Stratum Corneum, Stratum Lucidum (only in thick skin), Stratum granulosum, Stratum Spinosum, Stratum Basale.

Question 10

Stratum Corneum

Type of cells

Answer 10

outside, horny layer, made of dead dried flat cells (no nuclei), can be completely removed

Question 11

Stratum Lucidum

Type of cells

Answer 11

(only in thick skin) - clear layer, palms hands, soles feet

Question 12

Stratum granulosum

Type of cells

Answer 12

Granular layer, granules within that dries out cell, provides crosslinking of keratin fibres, secretion of waxy material into intercellular spaces to waterproof cells

Question 13

Stratum Spinosum

Type of cells

Answer 13

spiny layer, desmosomes (intercellular bridges) link cells together, begins process of cells flattening as they move upwards

Question 14

Stratum Basale

Type of cells

Answer 14

Base, basal layer, Columnar (tall) regenerative cells which migrates upwards to replenish layer above

Question 15

Epithelial cell types are

Answer 15

Squamous (scales), Cuboidal, Columnar

Question 16

Epidermis epithelial cell type is

Answer 16

stratified (layered) squamous epithelium.

Question 17

Dermis does Not

Answer 17

shed, Protein (collagen and elastic) fibres (cross links) provide strength, Vascular (nourishes epidermis), connective tissue.

Question 18

why do people have Saggy skin

Answer 18

As you age you lose strength as the protein fibres are not that rigid.

Question 19

Hypodermis contains

Answer 19

adipose tissue (made of adipocytes), Insulation, Subcutaneous.

Question 20

Hair (incl location, consists of,)

Answer 20

All over body

Hair shaft, hair follicle, arrector pili muscle, sebaceous gland

Question 21

Where is the sebaceous gland and what does it produce

Answer 21

on skin where there is hair
Produces sebum a Natural moisturiser/water repellent
Lanolin = sheep sebum (skincare)

Question 22

Acne cause

Answer 22

Blockage of hair follicles + infection

Question 23

Sweat glands

Answer 23

Eccrine (everywhere, thermoregulation)

Apocrine (specialised)

Question 24

Nails function

Answer 24

Protect fingertips, enhance sensation

Question 25

Accessory structures Receptors

Answer 25

Tactile lamellar Bulbous

Question 26

Skin accesories

Answer 26

Hair, Acne, sweat glands, nails, receptors

Question 27

Melanin pigment (What it does, Produced, Transported by)

Answer 27

absorb UV light and protects cells from UV damage Made in melanocytes Transferred by melanosomes

Question 28

Melanosomes (incl what it can do) *

Answer 28

Vesicles containing melanin able to proliferate (move along basement membrane) shed with keratinocytes

Question 29

Melanocytes location why it's found there

Answer 29

deep within epidermis to be protected from UV light as UV damages DNA and can cause cancer

Question 30

Highly pigmented areas

Answer 30

Mole and Freckle

Question 31

Mole

Answer 31

deep cluster of melanocytes within stratum basali. Overproliferation caused by sun exposure.

Question 32

Freckle

Answer 32

melanocytes overproducing melanosomes. | Overproduction Caused by sun exposure

Question 33

Melanocytes location

Answer 33

stratum basale only (mainly at the base). Not shed.

Question 34

Melanosomes location

Answer 34

throughout the epidermis

Question 35

Melanocytes density varies

Answer 35

through body not race

Question 36

why is human skin pigmentation so variable?

Answer 36

Different rates of production of melanosomes, keratins, sun exposure, vascularisation

Question 37

Skin pigmentation matches

Answer 37

UV exposure (in indigenous populations)

Question 38

Pigmentations correlate with UV exposure. describe pigmentation, skin colour, and UV exposure at each location At equador Northern latitudes Southern latitudes

Answer 38

- high p, darker skin, high UV - low p, fairer skin, low UV exposure - high p, darker skin, high UV

Question 39

Why is skin pigmentation important?

Answer 39

protection against UV by degrading chemicals (folate) which is important for evolution of pigmentation.

Question 40

Vitamin D essential for (incl effects when deficient)

Answer 40

normal calcium metabolism and strong bones | deficiency affects mood, cause rickets

Question 41

what is required for vitamin D synthesis?

Answer 41

UV exposure in skin

Question 42

2 types of skin cancer

Answer 42

Basal cell Carcinoma, Malignant melanoma

Question 43

Basal cell carcinoma

Answer 43

common benign Stratum basale Metastasis rare

Question 44

Malignant melanoma

Answer 44

``` Rare Deadly Melanocytes (pigmented) Highly metastatic Mortality rate depends on tumour size ```

Question 45

Metastasis

Answer 45

Tumour transplants into another site

Question 46

Tattoo

Answer 46

``` Artificial pigmentation deposited deep in skin Dermal layer (not shed) Captured (not broken down) inside immune cells (forms scar tissue to preserve tattoo) ```

Question 47

lena tattoo pigmentation of lymph nodes

Answer 47

broken down - faded | body has limited capacity to deal with pigmentation moves through lymphatic system to lymphnodes.

Question 48

Tattoo types

Answer 48

Trauma, decorative cosmetic (eg brows) Polynesian - Ta moko (maori), Pe'a (samoan)

Question 49

Skin age

Answer 49

thin epidermis and dermis (saggy-wrinkly - lose protein connective tissue lose rigidity) slower skin repair drier epidermis (sebaceous gland make less sebum) Impaired cooling (less sweat) Less pigmentation (pale skin, grey hair)