Integument & Barriers To Infection

Question 1

List the three basic shapes of epithelial cells and describe their shape.

Answer 1

Squamous : squashed

Cuboidal : cube-shaped

Columnar : taller than it is wide

Question 2

In regard to layering of epithelium, one layer is referred to as _________ epithelium and multilayered is referred to as ____________ epithelium.

Answer 2

Simple

Stratified

Question 3

Two special categories of epithelium are…

Answer 3

Pseudostratified epithelium
&
Urothelium

Question 4

The integument is the __________ organ in the body (________ of body weight)

Answer 4

Largest

15-20%

Question 5

What functions does the integument provide?

Answer 5

Protection: physical, chemical & biological barrier
Sensation and excretion (sweat)
Thermoregulation 
Synthesis of Vitamin D3
(Sexual signaling)

Question 6

What are the differences in thick vs. thin skin?

Answer 6

Thick skin is only on palms and soles, has 5layers instead of 4, lacks hair and makes fingerprints (400-1400microM vs. 75-150microM)

Question 7

The surfaces of palms and soles have ________ with intervening furrows.

Each ridge follows the outline of an underlying ___________ (where we see creases and wrinkles)

Answer 7

Epidermal ridges

Dermal ridge/papilla

Question 8

The tight interface at the dermal-epidermal junction is due to __________

Answer 8

Hemidesmesomes

Question 9

List the 5 layers of the epidermis from outer layer to the innermost layer.

Answer 9

C- stratum corneum 
(L- stratum lucidum in thick only)
G - stratum granulosum
S - stratum spinosum
B - stratum basale

Question 10

What specific cells is the epidermis composed of? List 4.

Answer 10

Keratinocytes (most common)
Melanocytes
Merely cells
Langerhans cells - immune specific

Question 11

The mitotically active layer is the stratum _________.

Skin is replaced every _________ days.

Answer 11

Basale

15-30

Question 12

Stratum basale consists of what type of cells?

Answer 12

a single layer of cuboidal/low columnar

Question 13

Stratum basale sits on top of ___________ and these two are connected by a ________________

Answer 13

Connective tissue

Basement membrane

Question 14

Stratum ________ is typically the thickest layer, and can thicken enough with pressure to form corns and calluses. It produces polyhedral keratinocytes and cytokeratin, which aggregates to from tonofilaments.

Answer 14

Spinosum

Question 15

In the stratum ___________, cells become progressively more flattened and contain granules.

Answer 15

Granulosum

Question 16

The two types of granules in the stratum granulosum are __________ and ___________. Describe each type.

Answer 16

Keratohyalin granules: basophilic non-membrane bound granules
Cystine and histamine rich protein
Assembles keratin into bundles

Lamellar granules:
Lipid rich
Barrier to foreign material & water
loss

Provide a waterproof barrier

Question 17

Stratum ___________ is a translucent band of cells with no organelles or nuclei and has densely packed keratin filaments.

Why does it get rid of the nucleus?

Answer 17

Lucidum

The nucleus takes up space and energy and the cells are no longer dividing so it’s not needed (same as RBCs)

Question 18

Stratum __________ consists of multiple layers of cells filled with mature keratin that is continuously shed.

Answer 18

Corneum

Thick skin: 15-40 layers
Thin skin: 1-20 layers

Question 19

Melanocytes are located in the stratum ________

Answer 19

Basale

Question 20

Merkel cells are located in the stratum ________

Answer 20

Basale

Question 21

Langerhans cells are located in the _________ layer, which is made up of the stratum _________ and stratum _________

Answer 21

Malpghian layer

Stratum basale + stratum spinosum

Question 22

Keratinocytes make ________ & _________ granules, form ________ in stratum corners and house _______, the pigment protein.

Answer 22

Keratin & lamellelar

Squames

Melanin

Question 23

Fully keratinized cells are called ________ and are found in the stratum ________

Answer 23

Squames

Stratum corneum

Question 24

Melanocytes produce melanin and transfer it to keratinocytes. What is melanin and what does it do?

Answer 24

Melanin is a pigment protein that protects nuclei from UV radiation

Question 25

What is converted into what in order to be polymerized into melanin?

Answer 25

Tyrosine is converted into DOPA (3,4-dihyroxyphenylaline) by tyrosinase enzyme (a UV sensitive enzyme)

Question 26

Langerhans cells develop in the _______from a monocyte precursor and serve as ______________ that provide defense against ___________

Answer 26

Bone marrow APCs(antigen-presenting cells) Pathogens

Question 27

Merkel cells are nonencapsulated _________ for _______ touch and texture, reside in the stratum _________and are more numerous in _______skin. They are associated with _________

Answer 27

Mechanoreceptor "Light" Basale Thick Nerve endings

Question 28

The dermis is made up of ________ tissue, has two layers the ________ & __________ and contains skin appendages, vasculature and sensory nerve endings.

Answer 28

Connective Papillary & reticular

Question 29

Which of the dermal layers is more superficial, has loose connective tissue and contains Meissner corpuscles and dermal papilla used for sensation?

Answer 29

Papillary layer

Question 30

What corpuscle is in the papillary layer?

Answer 30

Meissner

Question 31

Which layer of the dermis is the deeper layer of dense, irregular connective tissue with elastic fibers (more fibers and less cells)?

Answer 31

Reticular

Question 32

Between the dermal layers lies the __________, capillary branches that provide a nutrient source In comparison the __________ is deeper with larger vasculature and lymphatics

Answer 32

Subpapillary plexus Cutaneous plexus

Question 33

The layer of the epithelium that consists of subcutaneous tissue (aka superficial fascia), loose CT that binds skins to underlying organs, adipocytes and an extensive vascular supply is the _________

Answer 33

Hypodermis

Question 34

Free nerve endings are the simplest ___________, involve numerous _______ fibers, are positioned along the _______________ and relay modalities such as temperature, touch, itching and pain.

Answer 34

Sensory receptor Afferent fibers Dermal-epidermal junction

Question 35

Meissner corpuscles have an _________ shape, encapsulate _________ to detect _______ touch or low frequency stimuli. They are frequently located in _________ partially surrounded by epidermis. They are numerous in ________, _________ & _________

Answer 35

Elliptical Touch receptors Light Dermal papillae Fingertips, palms and soles