Hair, skin and nails

Question 1

Integumentary system and functions

Answer 1

• Skin, hair, sweat glands, sensory receptors
• Functions: homeostasis, stores blood, protection from external environment, cutaneous sensation, excretion and absorption of substances, vit D synthesis

Question 2

4 overarching layers of skin

Answer 2

Epidermis (outer layer)
Demris
Subcunaeous layer (blood vessels etc)
Hypodermis

Question 3

Epidermis

Answer 3

Protection

Keratinised, stratified squamous

Question 4

Stratum germinativum

Answer 4

Skin cells multiply and move away from blood supply

Question 5

Thick skin

Answer 5

Palms of hand, soles of feet, contains stratum lucid

Question 6

Thin skin

Answer 6

Rest of body - palms and soles

No stratum lucid

Question 7

Function of keratinocytes

Answer 7

Make keratin and lamellar granules (water repellant sealant)

Question 8

Where are melanocytes found

Answer 8

Stratum spinous

Question 9

Function of melanocytes

Answer 9

Produce melanin to give skin colour

Question 10

What are Langerhans cells

Answer 10

Macrophages in the skin, easily damaged by UV

Question 11

Function of Merkel cells

Answer 11

In contact with Merkel discs - detects fine touch

Question 12

How do we detect discriminatory touch

Answer 12

Merkel cells (epidermis) and Meissner’s corpuscles (dermis)

Question 13

Which cells detect deep sensation and pressure?

Answer 13

Pacinian corpuscles

Question 14

Layers of the epidermis

Answer 14

Corneum: continuously sheds dead keratinocytes
Lucidum: keratin
Granulosum
Spinosum: keratonicytes, Langerhans cells
Basale: metabolically active to make new keratinocytes, forms basement membrane

Question 15

Keratinisation

Answer 15

Newly formed epidermal cells from stratum basal to move outwards

Question 16

What molecules give dermis its tensile strength

Answer 16

Elastin and collagen

Question 17

2 regions of dermis

Answer 17

Papillary: dermal papillae project into epidermis, contains blood vessels and nerves
Reticular region: thicker, attached to subcutaneous layer, fibroblasts and connective tissue

Question 18

Function of melanin

Answer 18

Protects epidermal cells from UV and DNA changes

Question 19

What are commensal bacteria

Answer 19

Good bacteria to protect from bad

Question 20

What is sebum

Answer 20

Oily surface film with bactericidal chemicals

Question 21

Striae

Answer 21

Stretch marks
Damage to dermis
Disrupted lateral bonds between collagen fibres

Question 22

Keloid scars

Answer 22

Overhealing leads to lumpy scar

Question 23

Skin tension lines

Answer 23

Langer’s lines - where collagen fibres run in one direction

Important in plastic surgery

Question 24

Which three chemicals determine skin colour?

Answer 24

Melanin, haemoglobin and carotene (yellow-orange

Question 25

What are the two types of melanin and their colours?

Answer 25

Phenpmelanin (yellow-red) and eumelanin (brown-black) | Freckles are accumulations of melanin

Question 26

What is carotene a precursor of?

Answer 26

VitA

Question 27

Albinism

Answer 27

Inability to make melanin - red eyes, prone to skin cancer

Question 28

Vitiligo

Answer 28

Lose patches of melanocytes and melanin

Question 29

Function of arrector pili muscles

Answer 29

Stand hair on end

Question 30

What are the two types of sweat glands and their characteristics?

Answer 30

Apocrine sweat lands (causes BO, axillary and genitals) | Eccrine sweat glands (everywhere else on body, salty water)

Question 31

Different hair colours and their melanin proportions

Answer 31

- Dark hair = lots of eumelanin - Blonde and red hair = lots of pheomelanin - Grey hair = less melanin production - White hair = no melanin

Question 32

What is Laguno hair?

Answer 32

Fine hair in babies

Question 33

Stages of scalp hair growth

Answer 33

Scalp hair has 3 stages: growth (2-3y), regression (2-3w) and resting (2-3m) and then it is shed

Question 34

Hirsutism

Answer 34

Excessive body hair

Question 35

Different sections of a hair

Answer 35

``` Shaft Follicle Root Bulb Sebaceous ```

Question 36

What is the germinal matrix?

Answer 36

Where nail grows from

Question 37

What is a nail made from

Answer 37

Dead, keratinised epidermal cells

Question 38

What is the eponychium?

Answer 38

The cuticle - stratum corneum

Question 39

What is the lunula?

Answer 39

Thick white part of the nail