Biology of the skin

Question 1

What does the skin protect against as a physical barrier?

Answer 1

mechanical damage, water entry, water loss, chemicals, particles, infectious agents

Question 2

Name some physiological functions of the skin

Answer 2

temperature regulation, sensation, nerve signalling, vitamin D synthesis.

Question 3

Name the 3 main layers of the skin

Answer 3

Epidermis
Dermis
Hypodermis/Subcutis

Question 4

Which type of skin is most abundant?

Answer 4

Thin skin

Question 5

Where can thick skin be found?

Answer 5

palms of hands and soles of feet

Question 6

In which type of skin is the stratum lucidum found?

Answer 6

Thick skin

Question 7

Where is the stratum lucidum found?

Answer 7

Between the stratum granulosum and stratum corneum

Question 8

What type of epithelium is the epidermis?

Answer 8

Stratified squamous

Question 9

What are the layers of the epidermis?

Answer 9

Basal layer
Spinous layer
Granular layer
Cornified layer

Question 10

Basal layer (of epidermis)

Answer 10

Single cell, contains basal cells which are stem cells of the epidermis.

Question 11

What cells are in the basal layer?

Answer 11

Basal cells

Melanocytes

Question 12

Spinous layer (of epidermis)

Answer 12

prominent intracellular keratin filaments form a scaffold. Desmosomes link them to adjacent cells

Question 13

Desmosomes are a type of…

Answer 13

cell-to-cell junctions

Question 14

Tonofibrils

Answer 14

Filaments which form a scaffold and converge at desmosomes.

Question 15

Granular layer (of epidermis)

Answer 15

Keratohyalin granules produces which contain proteins which bind to and aggregate keratin filaments.
Lamellar bodies contain lipid important for hydrophobic barrier to water.

Question 16

Where are lamellar bodies found?

Answer 16

Statum granulosum

Question 17

Cornified layer (of epidermis)

Answer 17

Cells have underwent apoptosis, loose nuclei and organelles.

Question 18

List the cells of the epidermis

Answer 18

Keratinocytes
Melanocytes
Langerhans cells
Merkel cells

Question 19

Melanocytes

Answer 19

Produce melanin, responsible for skin pigmentation and protection against UV damage. Produce melanin which is packaged into melanosomes which are transferred into neighbouring keratinocytes.

Question 20

What types of cell is a langerhan cell?

Answer 20

Antigen-presenting cell

Question 21

Merkel cells

Answer 21

Found in associated with nerve fibres responsible for fine touch sensations

Question 22

Name the 2 layers of the dermis

Answer 22

Papillary dermis

Reticular dermis

Question 23

Papillary dermis

Answer 23

thin layer underling the epidermis, relatively loose conceive tissue made up of collagen and elastin fibres.
contains capillary networks, lymphatics and nerve endings.

Question 24

How does the epidermis recieve blood supply?

Answer 24

Papillary loops in the papillary dermis

Question 25

Reticular dermis

Answer 25

Thick layer, dense irregular connective tissue containing thick bundles of collage fibres. Contains fibroblasts, immune cells, various vessels, nerves and nerve endings. Site of various skin appendages

Question 26

List the cells of the dermis

Answer 26

Collage + elastin fibres Fibroblasts Immune cells - mast, macrophages, lymphocytes Adipocytes

Question 27

Hypodermis

Answer 27

Loose connective tissue with adipose cells, larger blood vessels and nerves Adipose tissue connected by fibrous septa

Question 28

Functions of the hypodermis

Answer 28

insulation, protection, energy storage

Question 29

3 phases of hair

Answer 29

Growth (anagen) Transition (catagen) Resting (telogen)

Question 30

Name 2 types of glands

Answer 30

Sebaceous Eccrine Apocrine

Question 31

What do sebaceous glands secrete

Answer 31

sebum (a lipid containing substance that coats the hair to keep it soft, supple and waterproof).

Question 32

What structure does a sebaceous gland have?

Answer 32

Branched acinar

Question 33

What type of secretion does a sebaceous gland do?

Answer 33

Holocene

Question 34

Holocrine secretion

Answer 34

secretions produced in the cytoplasm of the cell and released by the rupture of the plasma membrane which destroys the cell

Question 35

What do eccrine glands secrete?

Answer 35

Sweat

Question 36

What type of secretion do eccrine glands undergo?

Answer 36

Merocrine

Question 37

Merocrine sections

Answer 37

excreted via exocytosis

Question 38

Structure of a merocrine gland

Answer 38

coiled tubular

Question 39

What stage of life do apocrine glands become functional?

Answer 39

puberty

Question 40

Healing superficial wounds

Answer 40

epidermis can regenerate from basal layer

Question 41

Healing of deep wounds

Answer 41

``` haemostats inflammation fibroplasia epithelialisation remodelling ```

Question 42

healing of deepest wounds

Answer 42

if dermis and deep parts of appendages destroyed over significant area, spontaneous healing not possible