Structure And Function Of Skin

Question 1

What is integument?

Answer 1

Skin, hair and nails collectively

Question 2

What are the functions of the skin?

Answer 2

Protection, thermoregulation, sensation, repair and vitamin D production

Question 3

What are the 3 names of the layers of skin?

Answer 3

Epidermis, dermis and hypodermis

Question 4

What are the functions of the epidermis?

Answer 4

Gives skin its colour, protects the body from pathogens and the environment and vitamin D production

Question 5

What are the functions of the dermis?

Answer 5

Tensile strength and elasticity - also contains blood vessels, skin glands and sensory receptors

Question 6

What are the functions of the hypodermis?

Answer 6

Insulate deeper tissue and anchors skin to the muscle

Question 7

What is the epidermis made up of?

Answer 7

Multiple layers of different keratinocytes

Question 8

What are the layers of the epidermis?

Answer 8

Basal layer, spiny layer, granular layer, cornified layer and stratum lucidum

Question 9

What is the basal layer of the epidermis made up of?

Answer 9

Stem cells

Question 10

What happens in the basal layer of the epidermis?

Answer 10

Daughter cells move up, differentiating as they go until they are shed from the outer surface

Question 11

What happens in the spiny layer of the epidermis?

Answer 11

Desmosomes between keratinocytes

Question 12

What does the granular layer of the epidermis contain?

Answer 12

Keratohyaline granules and lamellar bodies containing lipids

Question 13

What is the function of the cornified layer of the epidermis?

Answer 13

Outer protective layer

Question 14

What is special about the cornified layer of the epidermis?

Answer 14

Cells are keratinised, flattened, have lost the nucleus and non-polar lipids are between the cells

Question 15

What do melanocytes look like?

Answer 15

Neurons (ish)

Question 16

What is the function of melanocytes?

Answer 16

Synthesise melanosomes and transfers them to basal keratinocytes

Question 17

What is the function of langerhans cells?

Answer 17

Antigen presenting cell - seeks and deals with invading microbes

Question 18

What do langerhans cells look like?

Answer 18

Pale cells in non-basal epidermal layers

Question 19

What is the function of merkel cells?

Answer 19

Sensation

Question 20

How is melanin arranged in keratinocytes?

Answer 20

A cap distal to the nucleus

Question 21

What is the dermis made up of?

Answer 21

Layers of connective tissue characterised by interconnected mesh of elastin and collagen fibres, produced by dermal fibroblasts

Question 22

What are the principal cells of the dermis?

Answer 22

Fibroblasts

Question 23

What are the two layers of the dermis?

Answer 23

Thin papillary layer and deeper reticular layer

Question 24

What makes up the thin papillary layer of the dermis?

Answer 24

Finger-like protrusions into the epidermal layer

Question 25

What makes up the dermis?

Answer 25

Dense, irregular connective tissue

Question 26

What does collagen provide in the dermis?

Answer 26

Tensile strength - protection against abrasion and impact

Question 27

What is collagen made by?

Answer 27

Fibroblasts

Question 28

Why is the dermal-epidermal border often wavy?

Answer 28

To resist shear forces

Question 29

What are dermal papillae?

Answer 29

Finger-like protrusions of the dermal connective tissue into the epidermal layer

Question 30

What are rete ridges?

Answer 30

Extensions of the epidermis into the dermal layer

Question 31

What does the verhoeff- van gieson stain show?

Answer 31

Collagen fibres in red and elastin fibres in black

Question 32

What are some other names for the hypodermis?

Answer 32

Fascia or subcutis

Question 33

What is the hypodermis made up of?

Answer 33

Well vascularised loose areolar connective and adipose tissue

Question 34

What is the function of the hypodermis?

Answer 34

Fat storage, insulation and cushioning for the integument

Question 35

What parts of skin do not have hair?

Answer 35

Palms, soles of feet and lips

Question 36

What parts is a strand of hair made up of?

Answer 36

Shaft, root and bulb in a hair follicle

Question 37

What is a hair follicle?

Answer 37

Epidermal tissue that dips down into the dermis and interacts with other structures

Question 38

What other structures does the hair follicle interact with?

Answer 38

Apocrine glands, sebaceous glands, arrector pili muscle and nerve receptors

Question 39

What does the hair follicle contain?

Answer 39

The hair matrix active site of hair growth and pigmentation

Question 40

What are the two different cell types in a hair bulb?

Answer 40

Follicular keratinocytes and melanocytes

Question 41

What do follicular keratinocytes do?

Answer 41

Produce hard keratin (= hair)

Question 42

What causes baldness?

Answer 42

Follicular keratinocytes at the bulb replicate only a set number of times

Question 43

Why does hair turn white?

Answer 43

Over time, melanocytes stop producing melanin

Question 44

What are eccrine sweat glands?

Answer 44

Normal sweat glands

Question 45

What do eccrine sweat glands secrete?

Answer 45

Watery secretion onto skin surface, cools body by evaporation

Question 46

What are apocrine sweat glands and where are they found?

Answer 46

Secretes into hair follicles and found in the armpits and anogential region

Question 47

What do sebaceous glands secrete?

Answer 47

Oily sebum into the hair follicle

Question 48

What is the nail fold?

Answer 48

Where the skin seals the edge of the nail

Question 49

What is the eponychium?

Answer 49

Proximal skin fold that gives rise to the cuticle

Question 50

What is the cuticle?

Answer 50

Semi-circular layer of dead skin keratinocytes that covers the junctions where the nail enters the skin

Question 51

What is the function of the cuticle?

Answer 51

Preventing the entry of pathogens

Question 52

What is the nail matrix?

Answer 52

Creates the nail plate and contains special epidermal tissue and modified keratinocytes

Question 53

What do free nerve endings sense?

Answer 53

Nociception, thermal sensation and light touch

Question 54

What are examples of sensory receptors with encapsulated endings?

Answer 54

Pacinian corpuscles, merkels discs, meissner corpuscles, Ruffini endings, root hair plexuses and Krause end bulbs

Question 55

What do pacinian corpuscles sense?

Answer 55

Vibration or brief touch

Question 56

What do merkels discs sense?

Answer 56

Sustained touch/pressure

Question 57

What do meissner corpuscules sense?

Answer 57

Moving touch or vibration

Question 58

What do ruffini endings sense?

Answer 58

Steady pressure

Question 59

What do root hair plexus' detect?

Answer 59

Hair displacement

Question 60

What do Krause end bulbs sense?

Answer 60

Touch/pressure