W2 - Layers of Skin

Question 1

List layers of skin from most external to most internal

Answer 1

Epidermis, dermis, hypodermis/subcutis

Question 2

The keratinocytes in the epidermis undergo upward migration during maturation, list the order of layers

Answer 2

Basal layer, stratum spinosum, granular layer, stratum corneum

Question 3

Why is there an upward migration of keratinocytes in the epidermis?

Answer 3

The cells at the surface are constantly shed so they need to constantly proliferate

Question 4

How many layers is the basal layer and what do the cells look like?

Answer 4

1 layer - cuboidal or low columnar

Question 5

How many layers is the stratum spinosum and what do the cells and nuclei look like?

Answer 5

Multiple layers - irregular cell shape, oval nuclei

Question 6

What happens in the granular layer of the epidermis and are the granules basophilic or acidophilic?

Answer 6

Keratinisation, basophilic

Question 7

What happens during keratinisation?

Answer 7

Cells undergo their final differentiation stage, keratin polypeptides are synthesised and are formed into keratin intermediate filaments

Question 8

What are the water repellent cells called in the stratum corneum and what is special about their contents?

Answer 8

Keratin squames - no nuclei or organelles

Question 9

What are the two layers of the dermis called? Most to least external

Answer 9

Papillary dermis and reticular dermis

Question 10

What are the peaks towards the surface and towards internal surfaces of papillary dermis called?

Answer 10

Surface - dermal papillae, Internal facing - rete ridges

Question 11

What is the difference between the collagen fibre bundles + elastic fibres in the papillary and reticular dermis?

Answer 11

They’re thicker in the reticular dermis

Question 12

The papillary dermis has looser connective tissue and is what?

Answer 12

Highly vascular

Question 13

Where can sensory receptors on nerve endings be present?

Answer 13

In the papillary dermis

Question 14

What is the intercellular substance of tissues called?

Answer 14

Ground substance

Question 15

What makes up the hypodermis/subcutis in terms of tissue?

Answer 15

Adipose tissue and fibrous bands (septa)

Question 16

Thickness and ………… (done by septa) varies from site to site in the subcutis

Answer 16

Partial compartmentalisation

Question 17

Where are there usually no hair follicles or apocrine glands?

Answer 17

Subcutis/hypodermis

Question 18

What is mesenchymal tissue?

Answer 18

Embryological tissue from which all connective + supportive tissues are derived

Question 19

What two shapes can mesenchymal tissue cells be?

Answer 19

Stellate and fusiform

Question 20

What two supportive tissues does mesenchymal tissue have?

Answer 20

Collagen and reticulin

Question 21

Definition of Epidermis

Answer 21

Stratified squamous keratinised epithelium divided into 5 strata

Question 22

Definition of dermis

Answer 22

Dense irregular connective tissue that supports epidermis

Question 23

Definition of hypodermis/subcutis

Answer 23

Loose connective tissue with adipose tissue

Question 24

Definition of the dermal papillary layer

Answer 24

Papillae that project into the dermis

Question 25

What does the dermal papillae do?

Answer 25

Increases adhesion between epidermis and dermis

Question 26

Definition of the dermal reticular layer

Answer 26

Dense, irregular connective tissue

Question 27

What do the keratinocytes in the granular layer contain?

Answer 27

Basophilic keratohyalin granules

Question 28

What do the keratinocytes in the stratum spinosum attach by?

Answer 28

Desmosomes on spiny processes

Question 29

What are the keratinocyte cells called in the basal layer of the epidermis?

Answer 29

Germinal cells

Question 30

Are keratin squames living or dead?

Answer 30

Dead