lecture 2 - anatomy of the skin 2

Question 1

What are the 4 key accessory structures of the skin?

Answer 1

hair, sweat glands, receptors, nails

Question 2

Where is hair not found on the exterior of the body?

Answer 2

Palms, soles of feet, lips

Question 3

What does hair consist of?

Answer 3

‘Dead’ keratinised cells forming a hair shaft that is produced inside a hair follicle.

Question 4

What is the function of the arrector pili muscle?

Answer 4

Attaches to hair follicle and contracts to produce goosebumps - hair shaft stands up straight.

Question 5

What muscle is responsible for making the hair shafts of the skin erect, thereby causing goosebumps?

Answer 5

Arrector pili muscle

Question 6

What is the structure and function of the root hair plexus?

Answer 6

Collection of sensory nerves at the base of each hair follicle that detects tiny interactions with the environment providing heightened sensation.

Question 7

What is the name for the network of sensory nerves found at the base of hair follicles?

Answer 7

Root hair plexus

Question 8

What are sebaceous glands?

Answer 8

Modified secretory epithelial cell glands found in the skin that produce sebum

Question 9

What is the function of sebum?

Answer 9

Oily secretion that nourishes hair shafts, moisturises skin and repels water.

Question 10

In terms of the sebaceous glands, what causes acne?

Answer 10

Blocked hair follicles and infection due to excess sebum production.

Question 11

What is the name for sebum secreted by sheep?

Answer 11

Lanolin

Question 12

What are the two types of sweat glands?

Answer 12

Eccrine, apocrine

Question 13

Where are eccrine sweat glands found?

Answer 13

In most parts of the skin

Question 14

What do eccrine sweat glands secrete?

Answer 14

Water secretions directly to the skin surface

Question 15

What is the function of eccrine sweat glands?

Answer 15

Thermoregulation, salt excretion, antibacterial action.

Question 16

Where are apocrine sweat glands found?

Answer 16

Armpit, groin, around the nipples

Question 17

What do apocrine sweat glands secrete?

Answer 17

Sticky/oily, sometimes odorous secretions into the base of hair follicles

Question 18

Where is apocrine sweat secreted?

Answer 18

Into the base of hair follicles

Question 19

What is apocrine sweat gland secretion controlled by?

Answer 19

Hormonal signalling

Question 20

What are the 3 types of sensory receptors in the skin?

Answer 20

Tactile, lamellar, bulbous

Question 21

What is the function of nails in terms of the skin?

Answer 21

Protect fingertips/toes, enhance sensation

Question 22

How are sensory receptors in finger/toe nails triggered?

Answer 22

Via deformation

Question 23

What are the characteristics of ageing skin?

Answer 23

Thin epidermis and dermis, sagging/wrinkling due to diminished collagen, slower skin repair, drier epidermis due to decreased sebum, impaired cooling due to less sweat, pale skin, grey hair

Question 24

Why does skin display sagging/wrinkling with age?

Answer 24

Collagen in the skin diminished reducing elasticity

Question 25

Why does the epidermis become dry with age?

Answer 25

Less sebum is produced

Question 26

Why is thermoregulation via the skin impaired with ageing?

Answer 26

Less sweat is produced by sweat glands, reducing cooling mechanisms.

Question 27

How does tobacco cause premature skin ageing?

Answer 27

Damages collagen and elastin, reduces healing, causes acne and cancers .

Question 28

How does vaping affect the skin?

Answer 28

Contains nicotine, which reduces blood circulation to the dermis causing contact dermatitis (rash)

Question 29

What pigment is used by the skin to protect cells from UV damage?

Answer 29

Melanin

Question 30

What cells produce melanin?

Answer 30

Melanocytes

Question 31

How is melanin transferred to epidermal cells from melanocytes?

Answer 31

Via melanosomes - vesicles carrying melanin.

Question 32

Where are melanocytes found?

Answer 32

In the stratum basale (innermost layer of the epidermis), because they are not shed

Question 33

Where are melanosomes found?

Answer 33

Throughout the epidermis of the skin, as they are shed with keratinocytes.

Question 34

What is a mole, on a cellular level?

Answer 34

A cluster of melanocytes that produce excess melanin

Question 35

What are moles often caused by?

Answer 35

Over proliferation of melanocytes due to sun exposure

Question 36

What is the cause of freckles?

Answer 36

Melanocytes over produce melanosomes (vesicles), in response to sun exposure.

Question 37

What is the function of Vitamin D?

Answer 37

Calcium homeostasis, bone strength.

Question 38

How is the skin involved in vitamin D synthesis?

Answer 38

UV exposure to the skin is required for synthesis.

Question 39

What is the result of Vitamin D deficiency?

Answer 39

Rickets and/or low mood

Question 40

Who is most susceptible to Vitamin D deficiency?

Answer 40

Highly pigmented people with dark skin

Question 41

What is a basal cell carcinoma?

Answer 41

A common, relatively benign form of skin cancer that originates in the stratum basale of the epidermis.

Question 42

Where do basal cell carcinomas originate?

Answer 42

In the stratum basale (bottom layer) of the epidermis.

Question 43

What is the term for the spread of a cancer from one site to another or several?

Answer 43

metastasis

Question 44

What is a malignant melanoma?

Answer 44

Rare form of skin cancer that is highly metastatic and can be deadly in left untreated.

Question 45

Where do melanomas originate?

Answer 45

In pigmented melanocytes (melanin producing cells) in the stratum basale of the epidermis

Question 46

Why do tattoos remain in the skin permanently?

Answer 46

They are deposited into the dermis layer of the skin, which is not shed. Cannot be completely broken down by immune cells.