L1 Anatomy Of The Skin - 1

Question 1

Skin is the _________ and ______ _________ organ of the body

Answer 1

-Largest
-Most visible

Question 2

How much of our total body weight is skin?

Answer 2

16%

Question 3

What is the surface area of skin?

Answer 3

1.5-2 m^2

Question 4

How did we come to have ‘bare’ and ‘sweaty’ skin?

Answer 4

Product of evolution- we went from a forested environment to open grasslands which required us to run long distances to hunt food. for that we need an efficient cooling system (sweat0 and less hair.

Question 5

What is the integumentary system comprised of?

Answer 5

Skin + accessory structures (integumentary is a collective term)

Question 6

What are the 8 functions of the integumentary system?

Answer 6

1. Protects underlying tissues and organs from abrasions, fluid loss, chemicals etc
2. Excretes salts, water, and organic wastes using glands
3. Temperature regulation by insulation or evaporative cooling as required - insulation… regain heat
4. Produces melanin: protects underlying tissues against UV radiation
5. Produces keratin: Protection against abrasions & water repelllent
   - hair + skin + nails
6. Synthesize Vitamin D3 (steroid) converted to calcitriol: a hormone important for normal calcium metabolism
7. Lipid storage in adipocytes, some in the dermis and mostly in adipose tissue in the hypodermis
   - fat storage
   - subcutaneous layer
   - For when there is starvation or insulation is needed
8. Detect touch, temperature, pain, and pressure stimuli and relay the information to the nervous system
   -make sense of environment and respond accordingly

Question 7

What tissue types is the skin made of?

Answer 7

ALL 4- epithelial + connective + muscle + nervous (skin is composite)

Question 8

What are the 3 primary layers of the skin?

Answer 8

1. Epidermis
2. Dermis
3. Hypodermis

Question 9

What is in the cutaneous layer?

Answer 9

1. Epidermis
   -sratified (stacked) barrier
   -mostly keratinocytes
   -avascular (no blood vessels or circulation)
   -capable of shedding
2. Dermis
   -protein fibres for strength
   -collagen +elastin for stretch ability
   -highly vascular (nourishes epidermis)

Question 10

What is in the Subcutaneous layer?

Answer 10

3. Hypodermis
   -adipose tissue (fat deposits that are mobilised for energy)

Question 11

What are the 2 layers of the Dermis?

Answer 11

1. Papillary Layer
2. Reticular Layer

Question 12

What tissue type is predominant in the the epidermis?

Answer 12

Epithelial

Question 13

What are the 6 types of Epithelia?

Answer 13

1. Simple
   -squamous
   -cuboidal
   -columnar
2. Stratified (stacked)
   -stratified squamous
   -stratified cuboidal
   -stratified columnar

Question 14

What are the 4 layers of the Epidermis? (From outmost layer)

Answer 14

1. Stratum corneum (spiky)
2. Stratum granulosum (granular)
3. Stratum spinosum (prickly)
4. Stratum basale (basal)

Question 15

Describe the cell type of stratum corneum

Answer 15

-dead dried-out hard cells without nuclei or organelles
-weakened desmosomes

Question 16

Describe the cell type of stratum granulosum

Answer 16

-contains granules that promote dehydration of the cell ‘killing’ the cell. Cross linking of keratin fibre
-waxy material is secreted into the intercellular spaces

Question 17

Describe the layers of stratum spinosum

Answer 17

-intercellular bridges (desmosomes) linking the cells together. Anchors cells to form a barrier preventing microorganisms
- cells become increasingly flattened as the move upwards