Lecture Test 3 (8,9,10)

Question 1

The integument is made up of two layers

Answer 1

Cutaneous membrane (skin), and Accessory structures.

Question 2

General histology of epidermis

Answer 2

Cellularity- layers of cells that require cell-cell protein junctions.
Polarity- Apical and basal surfaces, related to function(sweat exits at the apical surface an ex.)
Attachment- basement membrane or basal laminate-dense layer of ECM proteins connecting the epithelium to underlying tissue.
Avascularity- no blood vessels.
Thick skin- covers most of the body, has four layers of keratinocytes.
Think skin- covers the plams of the hands and the soles of the feet, has five layers of keratinocytes.

Question 3

Describe the life cycle of a keratinocyte

Answer 3

Pysical and enviormental stress on skin means stratum corneum continuously sheds dead cells, dead kerantinocytes are replaced by mitosis in stratum basale and spinosum, keratinocytes in deeper strata divide and push cells above them into more superficial layers.

Question 4

Describe how desmosomes contribute to the mechanical strength of the epidermis

Answer 4

They are intercellular junctions that mediate cell-cell adhesion and anchor the intermediate filament network to the plasma membrane

Question 5

Describe how melanocytes produce melanin and protect us from damaging UV radiation

Answer 5

Melanocytes are cells in the deep layer of the epidermis between the layer of basal cells. Melanocytes make pigment called melanin this gives skin its natrul colour. The pigment helps to protect the body from UV rays by serving as a physical barrier that scatters UV and reduces the ammount of penetration through the epidermis.