Lecture 3: Integument And Barriers To Infection Flashcards Preview

HDM Midterm > Lecture 3: Integument And Barriers To Infection > Flashcards

Flashcards in Lecture 3: Integument And Barriers To Infection Deck (65):
1

Where is thick skin found?

Palms and soles

2

Thick skin is composed of ______ layers, lacks _______, and may be characterized by fingerprints

5
Hair

3

Where is thin skin found?

Everywhere on the body except the palms and soles

4

Thin skin is made up of _____ layers, contains _____ and _______ glands, and contains hair follicles

4
Sweat
Sebaceous

5

Thin skin is made up of 4 layers, while thick skin is made up of 5. Which layer is missing from thin skin?

Stratum lucidum

6

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

Each ridge follows the outline of an underlying ___________ _________

There is a tight interface at the _________ ___________ junction via hemidesmosomes

Epidermal ridges

Dermal ridge/papilla

Dermal-epidermal

7

What are the 5 layers of the epidermis that are found in thick skin?

Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale

8

The epidermis is composed of what 4 additional cell types?

Which one has immune function?

Keratinocytes
Melanocytes
Merkel cells
Langerhans cells (immune function)

9

The stratum basale layer of skin is mitotically __________.

Skin is replaced every ____-____ days.

It is a single layer of _____________ or low __________ cells bound to more apical ____________ via desmosomes

Active

15-30

Cuboidal; columnar; keratinocytes

10

Psoriasis is a skin condition resulting from the overproliferation in which skin layer?

Stratum basale

11

The stratum spinosum layer contains polyhedral ______________ that produce ___________, which aggregates to form ______________.

This layer thickens with pressure to produce corns and calluses.

The stratum spinosum + the stratum basale = __________ layer.

Keratinocytes; cytokeratin; tonofilaments

Malpighian

12

In the stratum granulosum, cells become progressively more flattened and contain ___________. It is 3-5 layers thick, cells have a distinct __________ and it is where terminal differentiation begins.

Granules
Nucleus

13

What type of granules, present in stratum granulosum, are basophilic and non-membrane bound?

Keratohyalin granules

14

What type of granules, found in stratum granulosum, are lipid-rich and function as a barrier to foreign material and water loss?

Lamellar granules

15

What layer of the epidermis consists of a translucent band of cells that do not contain organelles or nuclei?

Stratum lucidum

16

The stratum lucidum is a translucent band of cells without organelles or nuclei, but it does contain densely packed _______ filaments

Keratin

17

True or false: the stratum lucidum is mitotically active

False

18

Why does it make sense that the stratum lucidum does not contain nucleated cells?

The nucleus is lost after the granulosum layer because lucidum is no longer mitotically active. The nucleus would take up valuable space that is needed in order to pack more keratin into the cells

19

Stratum ________ consists of multiple layers of cells filled with mature keratin.

__________ are fully keratinized cells that are continuously shed.

In thick skin, this layer is made up of ____-____ layers.

In thin skin, this layer is made up of _____-_____ layers.

Corneum

Squames

15-40

10-20

20

The stratum corneum is typically the second thickest layer of the epidermis, while ___________ is the first

Stratum spinosum

21

Melanocytes originate in the _____ ______ and are visible from the 8th embryonic week.

They are the ____ cells to arrive in the epidermis.

The cell body is located in the stratum _______. Cytoplasmic extensions of one melanocyte establish contact with about 36 ____________, forming an epidermal-melanin unit.

Neural crest

First

Basale; keratinocytes

22

True or false: melanocytes and keratinocytes are associated to each other via desmosomes

False

23

___________ cells derive from a bone marrow cell precursor and are present in the embryonic skin 4-5 weeks after the arrival of the melanocytes

Langerhans

24

Langerhans cells are found in the stratum of _______ (spinosum and basale).

A langerhans cell is a peripheral __________ cell of the immune system that migrates to a local LN to present Ags to _____ cells to initiate responses to foreign antigens

Malpighi

Dendritic; T

25

Merkel cells derive from the ______ _______.

They appear in _________ and _________ epidermis at about 8-12 weeks gestation.

They are tactile mechanoreceptors but may also have a ___________ function.

Neural crest

Palmar; plantar

Neuroendocrine

26

Merkel cells are associated with the ______ _______.

Their cytoplasm contains ________.

A small _____ _____ is connected to a myelinated axon. Myelin is lacking on the short axon segment penetrating the basal lamina of the epidermis.

Basal lamina

Granules

Nerve plate

27

Keratinocytes are responsible for making keratin and __________ granules.

They form the ________ in stratum corneum.

They also house the pigment protein __________.

Lamellar

Squames

Melanin

28

What protects nuclei from UV radiation?

Melanin (pigment protein)

29

Once melanocytes produce melanin, where is it transfered?

Keratinocytes

30

What disease may result from overproliferation of melanocytes?

Melanoma

31

Melanin production increases in sun-exposed areas because the enzyme _____________is UV sensitive.

It is responsible for converting ___________ to ___________, which is then polymerized into melanin

Tyrosinase

Tyrosine --> DOPA (dihydroxyphenylalanine)

32

Langerhans cells are APCs that provide defense against pathogens. They develop in the bone marrow from a ________ precursor.

They are typically identified in the stratum _________ by their _____ cytoplasm with ______ processes.

Monocyte

Spinosum; pale; long

33

True or false: Merkel cells are more numerous in thin skin

False; more numerous in thick skin

34

The dermis is composed of CT of ____________ origin.

It contains _________ and _________ layers, as well as skin appendages, vasculature, and sensory nerve endings.

Mesodermal

Papillary; reticular

35

Describe the papillary layer of the dermis

Superficial layer of loose CT

Contains Meissner corpuscles (sensation) and dermal papilla

36

Describe the reticular layer of the dermis

Deep layer of dense irregular CT (type I collagen) with elastic fibers

More fibers and fewer cells

37

Are hair follicles epidermally derived or dermally derived structures?

Epidermally derived, but the follicles do extend down into the dermis

38

Between the papillary and reticular layers of the dermis lies the __________ ___________, consisting of capillary branches that provide a source of nutrients.

Within the reticular layer is the ___________ _________ with larger vasculature and lymphatics.

Subpapillary plexus

Cutaneous plexus

39

The hypodermis is loose, subcutaneous tissue containing adipocytes. What is the primary function?

Binds skin to underlying organs

40

Why might a surgeon recommend that their patient lose weight prior to undergoing surgery?

Fatty tissue present in the hypodermis has an extensive vascular supply, and could increase the risk of bleeding during a procedure

41

What is the simplest sensory receptor?

Free nerve endings

42

Free nerve endings are made up of numerous _________ fibers positioned along the __________-________ junction.

They relay modalities such as temperature, touch, itching, and ______

Afferent

Dermal-epidermal

Pain

43

_________ ________ are elliptical-shaped, encapsulated touch receptors that detect light touch or low-frequency stimuli.

Meissner Corpuscles

44

Meissner Corpuscles are located in dermal ________, partially surrounded by _________.

They are numerous in ___________, palms, and soles.

Papillae; epidermis

Fingertips

45

________ _________ are large oval structures that detect coarse touch, vibration, or pressure.

They are found deep in the __________ dermis or hypodermis.

An outer CT capsule surrounds 15-50 thin concentric layers, and movement/pressure leads to a nerve impulse

Pacinian corpuscles

Reticular

46

What is the primary example of merocrine glands?

Sweat glands

[note that merocrine = eccrine; and apocrine glands can also be sweat glands]

47

How do merocrine glands release their contents?

Via exocytosis at apical ends

48

What is the primary example of holocrine glands?

Sebaceous glands

49

How do holocrine glands release their contents?

Disintegration of the cell with contents becoming the secreted product

50

What type of glands are mammary glands?

Apocrine

51

How do apocrine glands secrete their product?

Via membrane-enclosed vesicles at the apical end

52

The acinus of sweat (sudoriferous) glands is characterized by ____________ _______ epithelium.

____________ cells surround the acinus and expel the secretions

Simple cuboidal

Myoepithelial

53

The duct of sweat (sudoriferous) glands is characterized by _________ _________ epithelium (as opposed to acinus simple cuboidal).

The ducts are typically _______ staining.

Stratified cuboidal

Darker

54

Sebaceous glands are abundant on the face and scalp, and are often associated with the hair follicle.

They produce a lipid mixure called ________, via ___________ secretion.

They typically have a single duct made up of _________ ________ __________ epithelium.

Sebum; holocrine

Simple branched acinar

55

What is the purpose of the sebum produced by sebacous glands?

It is a waxy mix of triglycerides and cholesterol responsible for lubricating, softening, and waterproofing the skin

56

What is the difference between eccrine and apocrine sweat glands in terms of their distribution?

Eccrine sweat glands are found extensively throughout the skin

Apocrine glands are restricted to the dermis of the axilla, circumanal region, and areola

57

What type of sweat glands produces sweat for thermoregulation?

Eccrine

58

What type of sweat gland is under adrenergic regulation and responds to hormones?

Apocrine glands

59

Describe the sweat components of eccrine glands

Water, salt, ammonia, uric acid, and mucinogen granules

60

Describe apocrine secretions

Milky sweat secretion
Odorless until it mixes with bacteria

61

Hair follicles are epidermal derivatives. What two structures are they typically directly associated with?

Sebaceous glands
Arrector pili muscles

62

What are the 3 general components of hair

Hair bulb
Dermal/hair papilla
Hair matrix

63

What are the 3 components of the hair shaft itself?

Medulla = core of hair shaft
Cortex = middle layer
Cuticle = outer layer

64

What is the difference between vellus and terminal hair?

Vellus hair is thin and found diffusely around the body. Terminal hair is thicker and is typically generated in certain areas in response to androgenic hormones during puberty (males have more)

65

Nails are made up of highly keratinized cells on a bed of epidermis.

The nail _________ is the most proximal region of the nail plate, which forms from proliferating ______________.

The nail plate remains attached to the nail bed and is pushed forward by continuous growth.

The _________ is the crescent shaped white area near the nail matrix.

Root; keratinocytes

Lunula