Anatomy : Skin

Question 1

What is skin know as ( - - - epithelium )
And what does that meannn?
(4)

Answer 1

1) stratified - layers
2) squamous - flat
3) keratinising- produces keratin and prevents infiltration by pathogens!
4) epithelium -thin layer of cells

Question 2

What is the structure of the  stratum ? 
Name all the stratums from deepest to the top ! 
( BTS 
SAID 
GRAMMIES 
LIKE 
COLLEcting )
(5)

Answer 2

Stratum Basale (deepest)
Stratum spinosum
Stratum granulosum
Stratum lucidum
Stratum Corneum (top)

Question 3

What’s the structure of skin ?

3

Answer 3

1) epidermis ( top layer split into stratums )
2) dermis (connective tissue contains epidermal appendages )
3) Hypodermis / subcontaneous tissue ( not strictly part of the skin)

Question 4

Outline the maturation of keratinocytes

8

Answer 4

1)Basale layer - cells divide to replace keratinocytes lost on top surface = MITOSIS & and makes PROTEINS called TONOFILAMENTS—>Tonofibrils( made of keratin)

2) the Basale cells migrate upwards and differentiation occurs as follows:
- spinosum cells produce lamellar body’s (they are filled with lipids)
- large amount of keratohyalin ( these contain a protein called profilagrin, which help to stick keratin together) are produced.
- desmosomes also anchor cells together

3) stratum granular cells- lipids are secreted from lamellar bodies = WATERPROOF
4) lucidum and corneum layers of the stratum ( top two) = no organelles left ! Deal cells ! Corneocytes/squams are continually shed.

Question 5

What’s an epidermal appendage ?

2

Answer 5

-hair follicle , nails, sebaceous glands , sweat glands present in DERMIS BUT derived from EPIDERMIS !

Question 6

What specialised cells are there in the epidermis?
(4)
What do they do?
(4)

Answer 6

1) keratinocytes -keratin production
2) melanocytes -in basale layer stored in melanosome = produce melanin which protects nucleus of keratinocytes from UV rays)
3) Langherhan cells =APCS found in all parts of the epidermis

4)Merkel cells = specialised sensory cells ( sparse in Basale )

Question 7

Structure of dermis ?

3

Answer 7

Immediately deep to the Epidermis and contains highly corrugated dermo-epidermal junction

1-Papillary layer ( interlocks with the epidermal ridges)

2-Reticular layer (attaches to underlying hypodermis)

Question 8

What structures does the Dermis contain?
(4)
And what do they do?
(4)

Answer 8

1-fibroblast : makes collagen and elastin
2-Mast cells: contain histamine and trigger the inflammatory response
3-blood vessels
4-skin appendages ( hair follicles , nails, sebaceous glands, sweat glands)

Question 9

What are the properties of skin and how is it specialised for this ?
(3)

Answer 9

Thermal regulation - Sweating / sebaceous and hair gland
Specialised arrector pilli muscle =contracts to raise hair and give us goosebumps
=pacifism corpuscle ( vibrations and pressure )

Question 10

What’s a sebaceous gland /hair follicle ?
1-structure ( where is the nucleus)/what’s the cytoplasm like
2-what does it do ? Two things
(4)

Answer 10

1-Round , large , centrally located nucleus
-cytoplasm =cloudy hence a LOT OF LIPIDS !
2-lubricates skin and stops bacterial growth

Question 11

Eccrine glands
-what are they and what do they do ?
-where are they found ?
(3)

Answer 11

• Major sweat gland which releases clear odourless substrate ( Nacl + water)
• it’s a thermoregulator
• found everywhere in body

Question 12

What’s a Appocrine gland ? 
Where ?
When ( in lifeline )?
Why does it smell ? 
(3)

Answer 12

• active from puberty onwards in auxiliary , genital , armpit region
• releases product high in fat and PROTEIN
• this protein is broken down by cutaneous microbes producing body odour

Question 13

What’s the pilosebaceous unit ?

3

Answer 13

Contains :

• sebaceous gland
• arrector pilli
• hair follicle