Anatomy: Anatomy of the Skin

Question 1

Which layer of the epidermis varies the most throughout the different skin surfaces of the body?

Answer 1

Keratin layer

Question 2

Which part of the hair bulb contains the keratin producing cells?

Answer 2

Hair matrix

Question 3

What is the function of the granular layer of the epidermis?

Answer 3

Cells secrete lipids, keratin, filaggrin and involucrin which go on to form the cornified envelope of the keratin layer

Question 4

What are the three distinguishing features of the keratinocytes of the prickle cell layer (epidermis)?

Answer 4

Lack of nuclei

High lipid content

Odland bodies

Question 5

Which division of the autonomic nervous system controls the eccrine glands?

Answer 5

Sympathetic

Question 6

In which layer of the epidermis does mitosis of keratinocytes occur?

Answer 6

Basal layer (stratum basale)

Question 7

Which germ layer gives rise to the dermis?

Answer 7

Mesoderm

Question 8

What is the function of the sebaceous glands?

Answer 8

Produce sebum

Question 9

What is the main distinguishing feature of Langerhans cells?

Answer 9

Birckbeck granules

Question 10

What stimulates the development of apocrine glands?

Answer 10

Androgens - develop at puberty

Question 11

What are corneocytes?

Answer 11

Overlapping non-nucleated cell remnants of keratinocytes found in the keratin layer of the epidermis

Question 12

Which germ layer gives rise to the epidermis?

Answer 12

Ectoderm

Question 13

Name the 4 layers of the epidermis from superficial to deep

Answer 13

Keratin layer (stratum corneum), granular layer (stratum granulosum), prickle cell layer (stratum spinosum), basal layer (stratum basale)

Question 14

Define melanocytes

Answer 14

Pigment-producing dendritic cells found in the basal layer and above which contain melanosomes

Question 15

What is the arrector pili muscle?

Answer 15

Smooth muscle attached to hair fibres which can pull the hair perpendicular to the skin during cold/fright (goosebumps)

Question 16

Define Meissners corpuscles

Answer 16

Groups of sensory nerves that are found high in the dermis which respond to light touch and vibration

Question 17

What is the dermo-epidermal junction?

Answer 17

Interface between epidermis and dermis

Question 18

Which part of the hair bulb contains the vasculature?

Answer 18

Dermal papilla

Question 19

What are the 3 phases of the hair cycle?

Answer 19

Anagen, catagen, telogen

Question 20

Define Blaschko’s lines

Answer 20

Lines of normal cell development in the skin; they are invisible under normal conditions but become apparent when some diseases of the skin or mucosa manifest themselves according to these patterns

Question 21

Which layer of the epidermis consists of 2-3 layers of flattened keratinocytes and Langerhans cells?

Answer 21

Granular layer

Question 22

What occurs during catagen in the hair cycle?

Answer 22

No active growth, involution of the hair

Question 23

What is vellus hair?

Answer 23

Fine hair found on the face of women and in prepubertal children

Question 24

What is the function of the keratin layer of the epidermis?

Answer 24

Acts as a waterproof barrier (most superficial layer)

Question 25

How is hair pigmentation produced during hair growth?

Answer 25

Via melanocytes above dermal papilla

Question 26

What are nails composed of?

Answer 26

Plates of cells filled with hard keratin

Question 27

What is the function of melanin granules?

Answer 27

Full melanosomes ('melanin granules') protect basal keratinocyte DNA from damage by UV radiation by absorbing the rays

Question 28

What is the primary function of the dermis?

Answer 28

To cushion and support the epidermis

Question 29

What is the majority of the dermis composed of?

Answer 29

Connective tissue - collagen, elastin and ground substance

Question 30

Name two functions of the eccrine glands other than thermoregulation

Answer 30

Control of salt loss, ultrafiltration

Question 31

What is lanugo hair?

Answer 31

Soft hair found in newborns

Question 32

Where is the nail plate found?

Answer 32

Sits on the nail bed

Question 33

Describe the structure of eccrine glands

Answer 33

Coiled, tubular structures which open directly onto the skin

Question 34

Bullae are associated with alterations of which structure?

Answer 34

Dermo-epidermal junction

Question 35

What is the structure of the apocrine glands?

Answer 35

Found deep within the dermis, project up towards and open out into the hair follicle

Question 36

What is terminal hair?

Answer 36

Course hair found on the scalp, beard and pubic region

Question 37

Describe the structure of the sebaceous glands

Answer 37

Lobulated masses which wrap around hair follicles

Question 38

Why is the blood supply to the dermis larger than the metabolic demand?

Answer 38

Allows the skin to undertake its role in thermoregulation

Question 39

What stimulates the production of sebum by the sebaceous glands?

Answer 39

Hormones - sebaceous glands are quiescent pre-puberty

Question 40

Which layer of the epidermis is composed of corneocytes and the cornified envelope?

Answer 40

Keratin layer

Question 41

What is the cornified envelope?

Answer 41

Protective waterproof barrier found in the keratin layer

Question 42

What occurs during telogen in the hair cycle?

Answer 42

Resting phase of the cycle when the hair falls out

Question 43

What is the function of apocrine glands?

Answer 43

Produce an oily, scented fluid

Question 44

What are Langerhans cells?

Answer 44

Dendritic cells found within the prickle cell level in epidermis, the dermis and lymph nodes

Question 45

Where are apocrine glands found?

Answer 45

Primarily found in the axillae and perineum

Question 46

Which germ layer gives rise to the melanocytes?

Answer 46

Ectoderm - migrate from the neural crest to the epidermis in the first 3 months of foetal development

Question 47

What occurs at the nail matrix?

Answer 47

Cells divide and then produce hard keratin

Question 48

Where are sebaceous glands found?

Answer 48

Primarily found in face, chest and upper back, not present in palm and sole skin

Question 49

Define Pacinian corpuscles

Answer 49

Groups of sensory nerves found deeper in the dermis which respond to heavy, deep pressure

Question 50

What is the epidermis?

Answer 50

The most superficial, protective layer of skin, which consists of stratified squamous epithelium that is mainly made up of keratinocytes

Question 51

What is the primary function of Langerhans cells?

Answer 51

Antigen presentation to T cells

Question 52

What do the free nerve endings in the basal layer of the epidermis and in the dermis respond to?

Answer 52

Pain

Question 53

What occurs during anagen in the hair cycle?

Answer 53

Active growth

Question 54

What are the functions of the dermo-epidermal junction?

Answer 54

Support, anchorage, adhesion, growth and differentiation of basal cells Semi-permeable membrane acting as barrier and filter

Question 55

What is sebum composed of?

Answer 55

Squalene, wax esters, TG and FFA

Question 56

What is the hyponychium?

Answer 56

Area of epithelium underlying the free edge of the nail plate on the nail

Question 57

Name the 4 layers of the dermo-epidermal junction, from superficial to deep

Answer 57

Basal cell plasma membrane, lamina lucinda, lamina densa, sub-lamina densa zone

Question 58

What is the cuticle?

Answer 58

Extension of the skin fold covering the nail root

Question 59

What is the function of melanosomes?

Answer 59

Convert tyrosine to melanin pigment When full the melanin granules will protect basal keratinocyte DNA from damage by UV radiation

Question 60

What are Merkel cells?

Answer 60

Cells found within the basal layer of the epidermis involved in mechanoreception

Question 61

Which layer of the epidermis contains larger polyhedral keratinocytes joined by desmosomes?

Answer 61

Prickle cell layer

Question 62

Which layer of the epidermis contains stem cells, Merkel cells, melanocytes, an abundance of intermediate filaments (keratin) and a single layer of small cuboidal keratinocytes?

Answer 62

Basal cell layer

Question 63

What is the function of sebum?

Answer 63

Controls moisture loss and protects against fungal infection