C: Skin Flashcards Preview

Year 2 Term 2 C&M > C: Skin > Flashcards

Flashcards in C: Skin Deck (47):
1

What are the 4 main functions of the skin?

1) Protection
2) Thermoregulation
3) Providing sensory input from outside world
4) Metabolic function (synthesis vit D)

2

What 2 layers is the skin comprised of?

1) Epidermis - outer epithelial layer
2) Dermis - underlying area of connective tissue

3

What layer lies deep to the dermis, what does it contain?

Hypodermis or subcutis - layer of loose connective tissue containing variable amounts of fat

4

How is skin classified as thick or thin?

According to the thickness of the epidermis

5

How does the presence of hair follicles vary between thick and thin skin?

Thick skin is glabrous (non hairy)
Think skin has hair follicles

6

The epidermis is made up of what kind of epithelium?

Keratinised stratified squamous epithelium

7

What are the 5 layers recognised in thick skin?

1) Basal cell layer/ stratum basale/ stratum germinosum
2) Prickle cell layer/ stratum spinosum
3) Stratum granulosum/ granular cell layer
4) Stratum lucidum
5) Stratum corneum/ keratinised squamous layer

8

Describe the basal cell layer of the skin?

Single layer of basal cells (cuboidal/ low columnar) closet to the dermis

9

Describe the prickle cell layer/ stratum spinosum?

8-10 layers of keratinocytes, all with lots of desmosomes anchoring cells together and contain thick tufts of intermediate filaments

10

Describe the granular cell layer?

3-5 layers of cells, cells become gradually flatter as reach the surface, losing their nuclei and organelles and turn into keratinised squamous of next layer

11

Describe the stratum lucidum?

Thin. transparent layer, difficult to recognise in routine histological sections

12

Describe the stratum corneum/ keratinised squamous layer?

Layers of dead cells reduced to flattened scales or squames, filled with densely packed keratin, cells are flat and hard to see

13

What are the 3 types of non-epithelial cells present in the epidermis and what is their rough function?

1) Melanocytes - pigment cells of the skin
2) Langerhans cells - play an immunological role
3) Merkel cells - act as mechanoreceptors

14

Which of the 5 layers of the skin is absent or very thin in thin skin?

Stratum lucidum

15

What are the 3 main types of skin cancer and from which layer of the skin does each originate?

1) Basal cell carcinoma - stratum basale
2) Squamous cell carcinoma - stratum spinosum
3) Malignant melanoma - stratum basale

16

Which type of skin cancer is the least common and most dangerous?

Malignant melanoma

17

What are warts?

Benign skin growths caused by a viral infection in the skin - hyperkeratonic papules with a rough irregular surface

18

During development a number of downgrowths from the epidermis invade the underlying dermis to form which 3 structures?

1) Sweat glands
2) Sebaceous glands
3) Hair follicles

19

Which of the 3 structures found in the dermis are absent from thick skin?

All 3

20

Which structure in the dermis is involved in the development of acne, how?

Sebaceous glands
In puberty, size and activity of sebaceous glands increases, if the gland becomes blocked the sebum can be forced out into the dermis where it illicits and inflammatory response

21

Where are erector pili muscles located and what is their function?

Small bundles of smooth muscle associated with hair follicles, contraction of the muscles elevate the hair forming goose bumps to trap heat and help sebum be released from the gland into the duct

22

What is the nerve supply of the erector pili muscles?

Sympathetic

23

Other than the erector pili muscles, what other structures in the skin have a sympathetic nerve supply and what are the consequences of stimulating these fibres?

Sweat glands - cause glands to produce sweat

24

What fibres are contained in the connective tissue making up the dermis?

Irregular bundles of collagen fibres and networks of elastic fibres

25

What 2 layers is the dermis subdivided into?

1) Papillary layer - superficial and loosely woven
2) Reticular layer - deeper, thicker and denser

26

In areas of thick skin that are subjected to friction and shearing forces, how do the dermis and epidermis interdigitate?

Epidermal downgrowths - rete ridges
Upwardly projecting dermal papillae

27

Which layer of the skin contains the blood and nerve supply of the skin?

The dermis

28

What is a blister?

Split in the stratum spinosum, blister roof consists of normal and necrotic keratinocytes. Blister roof = normal and degenerating keratinocytes. Blister cavity's filled with clear transudate

29

What is damaged in first degree burns?

Superficial - just epidermis (eg. sunburn)

30

What is damaged in second degree burns?

partial thickness - epidermis and part of dermis

31

What is damaged in third degree burns?

Full thickness - destroy the epidermis and dermis and may go into the subcutaneous tissue

32

What is a dermatome?

The area of skin supplied by afferent nerve fibres of a single posterior spinal root

33

Branches of cutaneous nerves form a dermal nerve plexus where?

At the base of the dermis

34

Cutaneous nerve receptors are classified into what 2 groups?

1) Free nerve endings/unencapsulated nerve endings/ simple receptors
2) Encapsulated nerve endings/ compound receptors

35

What are free nerve endings?

Branching axons devoid of surrounding schwann cells

36

What 3 kinds of receptors can free nerve endings function as?

1) Nociceptors
2) Thermoreceptors
3) Mechanoreceptors (in the skin associated with the shaft of hair follicles and firing when the hairs are moved)

37

Some free nerve endings are associated with Merkel cells in the basal epithelium, what do the resulting Merkel-neurite complexes function as?

Mechanoreceptors which respond to pressure

38

Encapsulated nerve endings in the skin function as what kind of receptors?

Mechanoreceptors

39

Name 3 encapsulated nerve endings found in the skin?

1) Meissner's corpuscle
2) Pacinian corpuscle
3) Ruffini endings

40

Where are Merkel cell-neurite complexes found?

In the dermal-epidermal junction

41

What is the speed of adaptation of Merkel cell-neurite complexes and what do they detect?

Slowly adapting - detects pressure

42

Where are Pacinian corpuscle's located?

Deep in the subcutis

43

What is the speed of adaptation of Pacinian corpuscles and what do they detect?

Rapidly adapting - detects mechanical distortion. especially vibration

44

Where are Meissner's corpuscles located?

Dermal papillae

45

What is the speed of adaptation of Meissner's corpuscles and what do they detect?

Rapidly adapting - detects fine or discriminative touch

46

Where are Ruffini endings found?

In the dermis

47

What is the speed of adaptation of Ruffini endings and what do they detect?

Slow adapting - stretching and shearing forces