Lecture 1

Question 1

The skin is the…?

Answer 1

Largest and most visible organ of the body covering around 1.5-2m^2 and weighing around 16% of our total body mass

Question 2

Evolution provided us with…?

Answer 2

Sweat glands as a cooling mechanism

Question 3

What are the accessory structures?

Answer 3

Hair follicles, sweat glands, nail beds, sebaceous glands and receptors

Question 4

What is the integumentary system?

Answer 4

The skin and accessory structues

Question 5

What are the functions of the integumentary system?

Answer 5

Protection, excretion, temperature regulation, melanin production, keratin production, synthesis of vitamin D3 to calcitriol, lipid storage, receptor detection

Question 6

What is a composite tissue?

Answer 6

A structure made up from more than one basic tissue type

Question 7

What basic tissue types is the skin made up of?

Answer 7

Epithelial, connective, muscle and nervous

Question 8

What are the three primary layers of the skin?

Answer 8

Epidermis, dermis and hypodermis

Question 9

What is the epidermis?

Answer 9

An avascular stratified barrier of mostly keratinocytes

Question 10

What is the dermis?

Answer 10

A vascular structure deep to the epidermis made from protein fibres (collagen and elastin) for strength

Question 11

What is the hypodermis?

Answer 11

A vascular structure deep to the dermis made from mostly adipose tissue which stores fat to be mobilised during a time of fasting or extended starvation for energy

Question 12

What is the cutaneous layer?

Answer 12

Epidermis and dermis

Question 13

What is the subcutaneous layer?

Answer 13

Hypodermis

Question 14

What is simple epithelia?

Answer 14

One layer of epithelial cells arranged as either squamous, cuboidal or columnar

Question 15

What is stratified epithelia?

Answer 15

Many layers of epithelial cells arranged as either squamous, cuboidal or columnar

Question 16

The epidermis is made primarily of…?

Answer 16

Stratified squamous epithelium

Question 17

What are the four layers of the epidermis?

Answer 17

Stratum corneum, stratum granulosum, stratum spinosum, stratum basale

Question 18

What is the stratum corneum?

Answer 18

Most superficial layer of the epidermis. Composed of dead, dried out hard cells without nuclei

Question 19

What is the stratum granulosum?

Answer 19

Second layer of the epidermis which contains granules that promote dehydration of the cell, crosslinking of keratin fibre. A waxy material is secreted into the intercellular spaces

Question 20

What is the stratum spinosum?

Answer 20

Third layer of the epidermis with intercellular bridges called desmosomes that link the cells together. The cells become increasingly flattened as they move upward. Contains immune cells

Question 21

What is the stratum basale?

Answer 21

Deepest layer of the epidermis with columnar regenerative cells. As the basal cell divides, a daughter cell migrates upwards to replenish the layer above

Question 22

What is a desmosome?

Answer 22

A structure which anchors adjacent cells together in the epidermis

Question 23

What is a hemidesmosome?

Answer 23

A structure which anchors the stratum basale of the epidermis to the dermis

Question 24

What is thick skin?

Answer 24

Skin with an extra layer of epidermis called the stratum lucidum found on the palms of our hands and soles of our feet. A seemingly translucent layer that functions to reduce friction between stratum corneum and stratum granulosum in these highly used areas.

Question 25

What is an epidermal ridge?

Answer 25

Projections downwards of the epidermis

Question 26

What is a dermal papilla?

Answer 26

Projection upwards of the dermis

Question 27

What do the epidermal ridges and dermal papilla do?

Answer 27

Increase surface area and bind the dermis to the epidermis

Question 28

What are the two layers of the dermis?

Answer 28

Papillary layer and reticular layer. Both contain blood vessels, lymphatics, sensory nerve fibres and accessory structures

Question 29

What is the papillary layer of the dermis?

Answer 29

Consists of highly vascularised tissues for nourishment, most superficial layer

Question 30

What is the reticular layer of the dermis?

Answer 30

A 'mesh-like' structure of collagen and elastin fibres for strength, deepest layer

Question 31

What is a plexus?

Answer 31

A network of either blood vessels or nerves

Question 32

What are the two plexuses of the dermis?

Answer 32

Cutaneous plexus and subpapillary plexus

Question 33

What is the cutaneous plexus?

Answer 33

A network of blood vessels superficial to the subcutaneous layer (hypodermis) , at junction of the dermis to the hypodermis. It supplies the hypoermis, deeper dermis, including the capillaries for hair follicles and sweat glands.

Question 34

What is the subpapillary plexus?

Answer 34

Network of branches of blood vessels from the cutaneous plexus. Lies deep to the papillary layer of the dermis and provides O2 and nutrients to the upper dermis and epidermis

Question 35

What is the hypodermis (subcutaneous layer)?

Answer 35

Deepest layer of the skin which is dominated by adipocytes that produce subcutaneous fat for energy and insulation. Is a common site of injections using hypodermic needles.

Question 36

What is a first degree burn?

Answer 36

Superficial (only outer layers of the epidermis), erythema, skin remains a water and bacterial barrier, usually heals within 3-10 days e.g. mild sun burn

Question 37

What is a normal second degree burn?

Answer 37

Epidermis + varying amounts of dermis, painful, red and blistered. Usually heals within 1-2 weeks with good dressings

Question 38

What is a deeper second degree burn?

Answer 38

Epidermis + varying amounts of dermis, can present whitish with waxy looking areas. Hair follicles and sweat glands may stay intact and some sensation may be lost. Usually heals within a month

Question 39

What is a third degree burn?

Answer 39

Full thickness burn extended into the subcutaneous tissue which may involve muscle and bone. Varied colour including waxy white, deep red or black. Skin appears hard, dry and leathery. No pain as sensory nerve endings have been destroyed. May require skin grafting and can take weeks to months to heal/regenerate. Scarring occurs