Skin

Question 1

What is the largest organ in the body?

Answer 1

The skin

Question 2

What are the 4 tissue types that make up the skin?

Answer 2

Epithelium

Connective tissue

Muscle

Nervous

Question 3

Does the skin have its own blood and nerve supply?

Answer 3

Yes

Question 4

What does the skin provide evidence of diagnostically?

Answer 4

Underlying conditions

Question 5

What are some functons of the skin?

Answer 5

Prevents water loss (epidermis)

Permits body cooling (dermis)

Immune surveillance

UV protection

Energy storage

Sensory information

Question 6

What are the 2 layers of the skin?

Answer 6

Epidermis

Dermis

Question 7

What tissue type makes up the epidermis?

Answer 7

Epithelium

Question 8

What tissue type makes up the dermis?

Answer 8

Connective

Question 9

What is underneath the epidermis and the dermis?

Answer 9

Hypodermis

Question 10

What is the hypodermis?

Answer 10

A fatty layer that anchors the skin to underlying structures

Question 11

What does the hypodermis do?

Answer 11

Anchors the skin to underlying structures

Question 12

What is the class of the epithelium tissue of the epidermis?

Answer 12

Stratified, getting flatter as you go up

Question 13

What are the 4 basic cells in the epidermis?

Answer 13

Karatinocytes (contain keratine, waterproof)

Melanocytes (pigment formation, in basil layer)

Langerhans cells (immune surveillance)

Merkel cells (touch receptors)

Question 14

What are the layers of the epidermis like and what are they formed by?

Answer 14

Fine layers formed by maturing karatinocytes

Question 15

What are the 5 layers of the epidermis?

Answer 15

Stratum basule (basil layer)

Stratum spinosum

Stratum granulasum (keratine starts being synthesised)

Stratum lucidum

Stratum corneum

Question 16

What happens to keratine granules as you go up layers of the epidermis?

Answer 16

They breakdown and go up layers until they die and flatten out in the stratum corneum

Question 17

What is the class of cells in the stratum basal?

Answer 17

Tall columnar cells

Question 18

What cells are found in the stratum basal?

Answer 18

Melanocytes and merkel cells

Question 19

What are cells of the stratum basale bound to the BM by?

Answer 19

Hemidesmosomes

Question 20

What is the interface like between the stratum basale and the dermis?

Answer 20

Irregular

Question 21

What do the cells in the stratum basale do?

Answer 21

Stem cells that perform continuous proliferation

Question 22

What happens as cells go to the stratum spinosum?

Answer 22

They shrink and desmosome junctions create ‘spines’

Question 23

How does the stratum spinosum relate to keratinisation?

Answer 23

Preparative layer for keratinisation

Question 24

What defines the stratum glanulosum?

Answer 24

Pressure of granules

Question 25

What granules make up the stratum granulosum?

Answer 25

Granules of keratohyalin, precurser of keratine

Question 26

Are the properties of the stratum lucidum/corneum different?

Answer 26

Only that the stratum corneum has no cell organelles

Question 27

What happens in the stratum lucidum?

Answer 27

Converstion of keratohyalin to keratine

Question 28

What gives the strength of the stratum lucidum?

Answer 28

Disulphide bridges

Question 29

What is keratinisation?

Answer 29

Organic process where keratine is deposited in cells, becoming hard

Question 30

What does keratinisation allow dead cells to do?

Answer 30

Rub of (exfoliate)

Question 31

What properties does keratinisation give the skin?

Answer 31

Its resilience and strength

Question 32

How does the epidermis thickness vary around the body?

Answer 32

It varies around the body depending on function, hand and feet are thick, abdomen is thin

Question 33

What are the 2 layers of the dermis?

Answer 33

Papillary layer Reticular layer

Question 34

What is the papillary layer made of?

Answer 34

Loose connective tissue

Question 35

Where are macrophages found?

Answer 35

In the papillary layer of the dermis

Question 36

What is a function of the papillary layer of the dermis?

Answer 36

Protects against pathogens

Question 37

What is found in the papillary layer of the dermis and what does this allow?

Answer 37

Blood vessels (thermoregulation, nutrition) Nerve endings (sense organ)

Question 38

What kind of tissue if the reticular layer of the dermis?

Answer 38

Dense irregular connective tissue

Question 39

What is the reticular layer of the dermis composed of?

Answer 39

Collagen fibres in three planes Elastic fibres

Question 40

What happens to the elasticity of the dermis with age?

Answer 40

Loss of elasticity

Question 41

What is waterproofing a function of?

Answer 41

The dermis, because the keratine is waterproof

Question 42

What is skin colour due to?

Answer 42

The melanin that is produced by melanocytes (protects against UV light)

Question 43

What is the function of melanin?

Answer 43

Protects against UV light

Question 44

What layer is hair derived from?

Answer 44

The epithelial layer, has a continuity with layers of the epidermis

Question 45

What is a hair follicle composed of?

Answer 45

Arrector pili muscles Sebaceous glands

Question 46

What do arrector pili muscles do?

Answer 46

Straightens the hair when the muscle contracts

Question 47

Where are erector pili muscles found?

Answer 47

Attatched to follicle root and base of the epidermis

Question 48

Where are sebacceous glands found?

Answer 48

Between the hair follicle and arrector pili muscle

Question 49

What do sebaceous glands do?

Answer 49

Secretes sebum

Question 50

What are nails?

Answer 50

A specialised version of epithelium that becomes very hard due to keratine

Question 51

What is responsible for nails becoming very hard?

Answer 51

Keratine

Question 52

What are some skin glands?

Answer 52

Sebaceous glands Appocrine sweat glands Eccrine sweat glands

Question 53

Where does each gland secrete?

Answer 53

Sebaceous glands secrete directly into the hair follicle whereas the other glands do not

Question 54

What is the class of eccrine sweat glands?

Answer 54

Simple tubular gland

Question 55

Where are eccrine sweat glands located?

Answer 55

In the dermis

Question 56

What is the role of eccrine sweat glands?

Answer 56

Thermoregulatory role

Question 57

How is thermoregulation achieved?

Answer 57

Sweat glands Blood vessel dilation Hair (not in humans)

Question 58

What are some examples of nerve endings in the skin?

Answer 58

Meissner's corpuscles (light touch) Paccinian corpuscles (vibration and pressure) Pain receptors Thermoreceptors

Question 59

What is not formed in scar tissue?

Answer 59

Hair follicles or sweat glands

Question 60

What is skin very good at doing?

Answer 60

Repairing itself