Structure and Function 1 & 2

Question 1

What kind of epithelium is the epithelium made out of?

Answer 1

Stratified cellular epithelium

Question 2

Which embryological layer gives rise to the epithelium?

Answer 2

Ectoderm

Question 3

What are the 4 layers of the epithelium?

Answer 3

Keratin
Granular
Prickle cell
Basal

Question 4

What is the dermis made of?

Answer 4

connective tissue

Question 5

Which embryological layer gives rise to the dermis?

Answer 5

endoderm

Question 6

What is below the dermis and what is this made of?

Answer 6

Subcuteanous tissue - predominantely fat

Question 7

What are melanocytes and where are they from?

Answer 7

Pigment producing cells

Neural crest

Question 8

What are Blaschko’s lines?

Answer 8

Developmental growth pattern of skin

Question 9

Apart from the 4 layers of cells, which other cells can be found in the epidermis?

Answer 9

Langerhans, Merkel cells and melanocytes

Question 10

Describe the basal layer of the epidermis?

Answer 10

Small cuboidal cells usually only one cell thick

Question 11

Describe the cells in the prickle cell layer,

Answer 11

large polyhedral cells with lots of desmosomes

Question 12

What are the important granules found in the granular layer?

Answer 12

Large keratohyalin granules

Question 13

What do the keratohyalin granules do/contain?

Answer 13

Contain structural filaggrin and involucrin proteins

Main function of waterproof barrier trough the production of keratin and lipids

Question 14

What are corneocytes in the keratin layer?

Answer 14

Overlapping non-nucleated cell remnants

these create an insoluble cornified envelope

Question 15

Does the keratin layer allow transpiration?

Answer 15

Yes

Question 16

Name the organelles in melanocytes that produce the pigment?

Answer 16

melanosomes

Question 17

What pigment(s) are produced by melaoncytes?

Answer 17

Eumelanin and phaeomelanin

Question 18

Why is the melanin pigment produced by the melanocytes?

Answer 18

Full melanosomes (melanin granules) are transferred to adjacent keratinocyes via dendrites and form a protective cap over the nucleus to protect the nuclear DNA

Question 19

What are freckles?

Answer 19

Bundles of melanocytes

Question 20

Why are Langerhans cells found in the skin?

Answer 20

Involved in skin immune system - antigen presenting cells

Question 21

Where do Langerhans cells originate?

Answer 21

Bone marrow (mesenchymal origin)

Question 22

What are the cells that are always asked in exams called?

Answer 22

Racket organelles/ Birbeck granules

Question 23

Where are Merkel cells found in skin?

Answer 23

basal - between keratinocytes and nerve fibres

Question 24

What is the use of Merkel cells?

Answer 24

Mechanreceptors, linked to free nerve endings, therefore very sensitive and allow “touch”

Question 25

What causes Merkel cell cancer?

Answer 25

Merkel cell virus

Question 26

What is the correct name for hair follicles?

Answer 26

Pilosebaceous unit

Question 27

What are the phases of growth of hair?

Answer 27

Anagen 	=  growing
Catagen 	=  involuting
Telogen   	=  resting

Question 28

Within the nail, the nail matrix is said to be what?

Answer 28

“stem cells reservoir” - cells move up the nail to become keratinized and replace lost cells

Question 29

Where is the nail matrix?

Answer 29

beneath the cuticle

Question 30

What do the lacrimal glands, eye lashes and sebaceous glands have in common?

Answer 30

Ocular mucosa