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Flashcards in Skin Deck (148)
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1
Q

What are the three components of all connective tissues?

A

Cells, fibers, ground substance

2
Q

Connective tissue is derived from….

A

Mesoderm

3
Q

Fibroblast function

A

Create and repair ECM

4
Q

Fasciacytes function

A

Produce hyaluronan: space filling, lubrication, water homeostasis, creation of matrix that facilitates migration of cells through ECM

5
Q

Myofibroblast

A

Special CT cell that has contractile properties

6
Q

Fibroblast characteristics

A
  1. ) Long spindle shaped cells
  2. ) round or spindle shaped nuclei (round = active, spindle = inactive); 3.) pale cytoplasm
  3. ) contain rER and Golgi
7
Q

Adipocytes function

A

Store energy as TGs and produce leptin

8
Q

Cells that migrate into CT and stay

A

Macrophages, mast cells, and plasma cells

9
Q

Transient cells

A

Cells that wander in and out of CT; B and T lymphocytes, eosinophils, neutrophils, monocytes

10
Q

Macrophage characteristics

A
  1. ) Derived from monocytes found in circulating blood (leave circulation and develop into macrophages)
  2. ) phagocytic
  3. ) named differently based on location in which they’re found (Kupffer, osteoclasts, microglial cells, Langerhans)
11
Q

Mast cell characteristics

A
  1. ) derived from bone marrow
  2. ) inflammatory response
  3. ) oval/round cells with large basophilic granules in cytoplasm
  4. ) granules contain: heparin, histamines, chemotatic mediators
12
Q

Plasma cell characteristics

A
  1. ) Derived from B lymphocytes
  2. ) produce and release antigen specific antibodies
  3. ) eccentric nucleus, clock face chromatin, basophilic cytoplasm (rER), Golgi
13
Q

ECM contains…

A

Fibers, ground substance, and extracellular fluid

14
Q

Type I collagen fibers…

A

3 collagen polypeptide alpha chains»collagen molecules»fibrils»fibers (parallel fibrils)

15
Q

Collagen precursor proteins (called _______) are created in fibroblast _______ and assembled in _______

A

Tropocollagen; cytoplasm; EC space

16
Q

Collagen types

A
I: most common
II: cartilage
III: reticular 
IV: basal lamina of epithelial cells
VII: anchors basement membrane of epithelial cells
17
Q

Elastic fibers 1.) made by, 2.) composed of, 3.) function in

A
  1. ) fibroblasts, chondrocytes, and smooth muscle cells)
  2. ) elastin and fibrillin
  3. ) stretch and recoil
18
Q

Fibrillin serve as _____ for longer ______ molecules

A

Anchors; elastin

19
Q

How do elastic fibers provide so much elasticity?

A

Fibrillin and elastin molecules branch three-dimensionally and surround nearby collagen fibers to provide a greater degree of elasticity; ligaments have high density to allow them to snap back

20
Q

Reticular fibers 1.) made by and 2.) function to

A
  1. ) fibroblasts, Schwann cells, smooth muscle cells
  2. ) create frame meshwork of dense organs to support functional cells within (type I collagen takes up a lot of space; reticular fibers organize cells and take up less space)
21
Q

Matrix metalloproteinases

A

CT cells and some epithelial cells release these to break fibers into smaller chunks that can then be phagocytosed by macrophages, degraded by lysosomal enzymes, and removed

22
Q

Ground substance allows diffusion of _______ but not ________

A

water soluble molecules; large macromolecules and bacteria

23
Q

In ground substance, _______ release charged substances into the ______ to create a ________ environment. This promotes ______ to and from cells.

A

Fibroblasts; ECM; hydrophilic; diffusion

24
Q

Glycoproteins in ground substance help to…

A

Anchor cells to ECM

25
Q

Glycosaminoglycans (GAGs) in ground substance are…..

A

The most plentiful and are negatively charged, attracting water

26
Q

Proteoglycans are 1.) created by… 2.) and provide

A
  1. ) arranging GAGs like bristles stemming from a core protein
  2. ) Stability to the extracellular space while allowing diffusion to occur
27
Q

Stroma

A

Structural tissues of organs (scaffolding)

28
Q

Parenchyma

A

Functional parts of an organ

29
Q

Types of CT

A
  1. ) Embryonic (mesenchymal, mucous)
  2. ) CT Proper (dense reg and irreg, loose)
  3. ) specialized (adipose, supporting, blood, lymph)
30
Q

Composition of mesenchymal CT

A

Ground substance (semi-fluid, gelatinous)»cells (mesenchymal)>fibers (type III); allows for rapid growth without constricting the fetus

31
Q

Location of mesenchymal CT

A

Embryo and fetus

32
Q

Location of mucous CT

A

Umbilical cord (Wharton Jelly), subdermal CT of fetus, dental pulp of developing teeth

33
Q

Composition of mucous CT

A

Ground substance (semi-fluid, gelatinous)»cells (stellate fibroblasts)>fibers (few type I)

34
Q

Location of dense regular CT

A

Collagenous: tendons, ligaments, and aponeuroses
Elastic: some vertebral ligaments and suspensory ligaments of penis

35
Q

Composition of dense regular connective tissue

A

Fibers (mostly type I or elastic - fibers in one direction)»>cells (fibroblasts)>ground substance (very little)

36
Q

Locations of dense irregular CT

A

Dermis, submucosa of organs, scars, and organ capsules

37
Q

Composition of dense irregular CT

A

Fibers (mostly type I with some elastic and reticular)»cells (mostly fibroblasts with some macrophages and mast cells)>ground substance (very little)

38
Q

Location of reticular tissue

A

Dense organs (liver, kidney, spleen, bone marrow, lymph nodes)

39
Q

Composition of reticular tissue

A

Fibers (type III)>cells (reticulocytes, fibroblasts)>ground substance (very little)

40
Q

Location of oose (areolar) CT

A

Lamina propria: GI and Resp

Superficial fascia and invests in neurovascular bundles and around glands

41
Q

Composition of loose CT

A

Ground substance (watery tissue)»cells (fibroblasts with many transient immune cells)>fibers (very few)

42
Q

Composition of loose CT allows for _______ __________ of nutrients and other substances. Because these regions are in close contact with _________ environment, there are many ________ cells that move into the area to interact with _______ ________.

A

Rapid diffusion; external; transient; invading pathogens

43
Q

Unilocular (white) adipose

A

Distributed throughout body but mostly around neurovascular bundles, mesenteries, and hypodermis

44
Q

Adipose function

A

Storage of fat, thermal insulation, shock absoption

45
Q

Composition of adipose

A

cells>fibers>ground substance (very very little)

46
Q

Multilocular (brown) adipose

A

Found in neonate (and upper back of adults who endure low temps over prolonged periods); many droplets of TGs in cell cytoplasm vs single droplet in white fat; heat-generating (high content of mitochondria that release ATP)

47
Q

Function of epithelial tissue

A

Absorption
Secretion
Movement of material along surface
Protection from mechanical abrasion, chemicals, and pathogens
Reception of sensory signals
Reduction of friction
Secreting enzymes, hormones, lubricants, and other products
Synthesis of proteins, enzymes, mucins, hormones, and other substances

48
Q

What characteristics make epithelium different from other tissues?

A

Polarity, cell arrangement, avascular, and basement membrane

49
Q

Basement membrane is a thin ______ on the basal surface that binds ________ ______ to underlying tissues. It does not contain ______ or ______.

A

ECM; epithelial cells; cells; blood supply

50
Q

Layers of basement membrane from top to bottom…

A

Lamina lucida»lamina densa»lamina reticularis

51
Q

Basal lamina is made up of what 2 layers? What produces the basal lamina? What type of collagen is it?

A

Lamina lucida and lamina densa; epithelial cells; type IV

52
Q

Lamina reticularis is type ____ collagen and comes from ______ cells

A

III; CT

53
Q

Anchoring fibrils within the lamina reticularis are type ______ collagen

A

VII

54
Q

Metaplasia is a response to ________ ________ or _______.

A

chronic irritation; damage

55
Q

Microvilli function

A

Increase surface area for absorption and secretion

56
Q

Stereocilia function

A

Facilitate absorption in male genital ducts, sensory mechanoreceptors in ear

57
Q

Motile cilia function

A

Transport substances along epithelial surface

58
Q

Primary cilia function

A

Generate and transmit signals from outside to inside the cell

59
Q

Nodal cilia function

A

Development of left and right asymmetry or internal organs

60
Q

Pseudostratified columnar epithelium located in….

A

Respiratory tract

61
Q

Transitional epithelium located in….

A

Bladder and ureters

62
Q

Keratinization is a process by which ________ _____ produce the protein _______. It provides ________ and _______. It is found in _______, _______, and ______.

A

epithelial cells; keratin; waterproofing; protection; skin; hair; nails

63
Q

Goblet cells are ________ glands that produce ______.

A

Unicellular; mucin

64
Q

Endothelium are classified as _______ ________ epithelium. They are found lining the inside or _________ and _________.

A

simple squamous; blood vessels; heart

65
Q

Mesothelium is classified as ______ _______ epithelium. It is found lining ______ ________.

A

simple squamous; body cavities

66
Q

Glandular epithelium characteristics

A

Secretory cells that arise as ingrowths of the epithelium; typically in single layers or clusters; cuboid or columnar

67
Q

Function and location of simple squamous epithelium

A

Diffusion, filtration; capillaries, alveoli, glomerulus

68
Q

Function and location of simple cuboidal

A

Secretion, absorption; ovaries, nephrons, renal tubules

69
Q

Function and location of simple columnar

A

Secretion, absorption; GI, repro, resp

70
Q

Function and location of stratified squamous

A

Protection; tongue, hard palate, esophagus, anus

71
Q

Function and location of stratified cuboidal

A

Secretion, absorption; glands

72
Q

Function and location of stratified columnar

A

Protection; conjuctiva, resp

73
Q

Function and location of pseudostratified columnar

A

Movement; trachea and upper resp

74
Q

Function and location of transitional epithelium

A

Stretch; bladder and ureters

75
Q

Microfilaments…

  1. ) Structural function?
  2. ) Motility?
  3. ) Energy for polymerization
  4. ) Polarity
  5. ) Components
A
  1. ) Yes
  2. ) Yes
  3. ) ATP
  4. ) Yes
  5. ) actin, myosin
76
Q

Microtubules…

  1. ) Structural function?
  2. ) Motility?
  3. ) Energy for polymerization
  4. ) Polarity
  5. ) Components
A
  1. ) Yes
  2. ) Yes
  3. ) GTP
  4. ) Yes
  5. ) tubulin
77
Q

Intermediate filaments…

  1. ) Structural function?
  2. ) Motility?
  3. ) Energy for polymerization
  4. ) Polarity
  5. ) Components
A
  1. ) Yes
  2. ) No
  3. ) None
  4. ) No
  5. ) Keratins, nuclear lamins, etc
78
Q

Cytoskeletal classes have both ________ and _______ function. __________ _________ do not have ________ function.

A

Structural; motile; intermediate filaments; motile

79
Q

Crosslinking proteins

A

Bind filaments together

80
Q

Networks

A

Filaments cross-linked into 3D, criss-crossed meshworks (resist stretching and compression)

81
Q

Bundles

A

Filaments cross-linked in parallel to form fibers that resist stretching

82
Q

Anchoring by junctions serve to anchor the __________, attach cells to the ________ ________ or to _____ _______, or allow cells to interact with _________.

A

cytoskeleton; basal lamina; each other; ECM

83
Q

Motility mechanisms include the use of _______ ______ an example of which is ________ _______ in muscle contraction and ____________________ an example of which is segregation of chromatids during anaphase.

A

motor proteins; sliding filaments (microfilaments); polymerization-depolymerization (microtubules)

84
Q

G actin subunits polymerizing into F actin filaments is driven by __________.

A

ATP hydrolysis

85
Q

Actin is ________ because the plus sides of G actin subunits point to one end and the minus to the other end of the F actin filaments

A

Polarized

86
Q

___________ and _______ bind F actin and interact with ______ heads to mediate _______ _________ _________.

A

Troponin; tropomyosin; myosin; sliding filament contraction

87
Q

Spectrin

A

Actin cross-linking protein that forms networks in erythrocytes

88
Q

Dystrophin

A

Cross-linking protein that forms striated muscle network

89
Q

Duchenne muscular dystrophy is a mutation of the X linked _________ gene

A

Dystrophin

90
Q

________ are finger-like projections of the plasma membrane that increase surface area for _________ and are supported by internal ______ bundles. They are present in ____ cells but most abundant on the brush border of ________ epithelium.

A

Microvilli; absorption; actin; all; intestinal

91
Q

These microfilaments serve as motor proteins for actin and some serve a structural role

A

Myosin

92
Q

Myosin heavy chains are composed of two _______ and two globular ________. The _____ coil around each other to form dimers which requires ___ __________.

A

tails; heads; tails; ATP hydrolysis

93
Q

Myosin light chains bind the _______ of each head. They serve as regulatory factors controlling __________ of the globular heads.

A

Neck; contraction

94
Q

The myosin tetramers associate with the ______ extending into the periphery, and the ______ pointing inward making the myosin microfilament _______. The heads provide the _______ force.

A

heads; tails; polar; motor

95
Q

Sliding filament model

A

ATP hydrolysis activates a conformational change of the myosin heads. These contractions cause myosin to crawl along actin. Hence, microfilaments slide past each other to induce contraction.

96
Q

Examples of microfilament mediated motility

A

Intracellular membrane trafficking (directed along actomyosin or microtubule filaments), muscle (actomyosin organized into sarcomeres), contractile ring of cytokinesis (actomyosin ring that pinches the cell in two), amoeboid motion (pseudopodia), stress fibers (long bundles of microfilaments that lie along the basal surface of fibroblast that provide tension across a surface

97
Q

Chemicals that interfere with __________ assembly preferentially attack ________ cells because these rapidly dividing cells require microtubules for cell cycle progression. This occurs drugs during ___________ treatment.

A

microtubular; tumor; chemotherapy

98
Q

MAPs

A

microtubular associated protein (crosslinking protein that forms networks)

99
Q

__________ is a motor protein that moves ________, cilia, ________, and mitotic chromosomes associating with the mitotic ______. It also moves ______, ________, and ________ ______ up and down an axon.

A

Dynein; flagella; cytosolic vesicles; spindle; vesicles; organelles; cytoskeletal fragments

100
Q

______ is a motor protein that moves _______ _______ and ______ _______ associating with the mitotic spindle.

A

Kinesin; cytosolic vesicles; mitotic chromosomes

101
Q

Examples of microtubular mediated motility

A

Intracellular membrane trafficking, mitotic apparatus, and axonal transport (factors depleted by signal transduction have to be replenished)

102
Q

Intermediate filament _______ are used to identify the origin of tumor cells. Antibodies target the _______ and ______ of IFs due to their uniqueness. If the ______ were tagged, every IF would be bound to antibody.

A

Antibodies; heads; tails; core

103
Q

Ankyrin

A

Speicific IFAP that anchors desmin to the plasma membrane as well as spectrin to the band 3 anion transporter of erythrocytes

104
Q

Nuclear lamins

A

Meshwork of intermediate filaments on the nucleoplasmic face of the nuclear envelope

105
Q

Lamin B

A

Anchored to the inner membrane of the nucleus by an isoprenyl side group

106
Q

All 3 forms of lamins consist of _______ ________ and alpha helical ______ and _____.

A

globular heads; cores; tails

107
Q

During prophase, nuclear lamins are _________ by MPF. This causes them to _______, inducing nuclear membrane _______. During ________ the nucleus reforms because the lamins are _______, allowing their crisscrossed network to associate.

A

phosphorylated; depolymerize; breakdown; telophase; dephosphorylated

108
Q

Lamins A and C are released into the _______, while Lamin B remains bound to _____.

A

Cytosol; vesicles

109
Q

_________ force collagen alpha chains into left-handed helices due to ________ of the backbone, while _______ residues (every third amino acid) allows the helix to be left-handed due to its small _____ ______ (larger side chains would produce _____ _______).

A

Prolines; contortion; glycine; side chains; stearic hindrance

110
Q

_______ groups are bound to numerous prolines and lysines. They increase the ___-________ ________ of the collagen helices.

A

Hydroxyl; non-covalent stability

111
Q

Why does dietary deficiency of vitamin C result in scurvy?

A

The enzyme that produces hydroxyproline requires vitamin C as a cofactor

112
Q

Enzyme that drives cross-linking between lysines near tropocollagen termini

A

Lysyl oxidase

113
Q

Collagen synthesis

A

Procollagen spontaneously assembles into triple helices»post-translational modification in ER»exocytosis and cleaving of terminal regions (now tropocollagen)»crosslinkage of tropocollagen to form fibrils»aggregation into collagen fibers

114
Q

Excessive collagen production

A

Fibrosis

115
Q

Scurvy

A

Lack of hydroxyproline residues due to dietary deficiency of vitamin C. Symptoms include weak and malformed bones, teeth, skin, blood vessel walls, and dermal hemorrhaging.

116
Q

Ehlers-Danlos

A

Mutations resulting in underproduction or incomplete processing of different collagens. Symptoms range from loose skin and joints, to neonatal death. Contortionists often have this disorder.

117
Q

Osteogenesis imperfecta

A

Mutations of type I collagen, which interfere with triple helix assembly (e.g. substitution of glycines residues with bulkier amino acids). The most severe mutations result in lethality in utero or soon after birth. Less severe mutations produce brittle bones. Note, due to the numerous fractures observed in children with this disorder, it can easily be misdiagnosed as child abuse.

118
Q

Marfan syndrome

A

Mutation of fibrillin gene

119
Q

Functions of skin

A

Protection (barrier and immunologic)
Homeostasis (waterproof and temp regulation)
Sensory
Metabolic (endocrine and excretion)

120
Q

Keratinocytes

A

Most abundant cell in epidermis; functions: produce keratins (structural protein), form epidermal water barrier; stem cells on basement membrane; differentiate as they migrate to surface

121
Q

Langerhans

A

Dendritic cells of the epidermis (originate in bone marrow and travel to CT in dermis and migrate up); Birbeck granules; phagocytize foreign structures in epidermis and present T lymphocytes in regional lymph nodes; not readily visible with H&E (clear cells)

122
Q

Melanocytes

A

Derived from neural crest; location: basale; produce melanosomes (transferred into keratinocytes)

123
Q

What mechanisms are involved with natural skin color variation?

A

Rate at which melanin granules are produced and degraded (impacted by both intrinsic and extrinsic factors)

124
Q

One melanocyte and its associated keratinocytes

A

Epidermal-melanin unit

125
Q

Processes involved with tanning of the skin?

A

UV light darkens existing melanin AND increases the rate of melanin synthesis

126
Q

Merkel cells

A

Location: basale

Function as mechanoreceptors; most abundant in areas of high tactile sensitivity

127
Q

Thick vs thin skin

A

Thick: palms, soles; 5 layers; lacks hair follicles
Thin: everywhere else; 3 well-defined layers

128
Q

Epidermal layers

A
Stratum corneum
Stratum lucidum*
Stratum granulosum*
Stratum spinosum
Stratum basale
129
Q

Basale

A

Single layer of cuboidal/columnar cells; new cells (keratinocytes) undergoing mitosis

130
Q

Spinosum

A

Keratinocytes appear prickly (desmosomes); keratins being synthesized by free ribosomes (more superficial gets stained darker due to increased assembly of intermediate filaments)

131
Q

Tonofilaments

A

Intermediate filaments composed of keratin and most visible in spinosum; converge at desmosomes; provide support for areas under constant friction and pressure (thicker spinosum)

132
Q

Granulosum

A

1-3 layers of keratinocytes with granular appearance; cytoplasm being filled with dark keratohyalin granules; initiates promotion of keratin filaments into tonofibrils, converting granular cells into cornified cells (keratinization); cells in superficial layers undergoing apoptosis

133
Q

Lucidum

A

only present in thick; translucent layer of keratinocytes; nuclei and organelles lost and replaced by densely packed keratin filaments

134
Q

Corneum

A

dead, keratinized cells; protection against abrasion

135
Q

Lamellar granules

A

Keratinocytes produce these lipid-rich membrane coated granules; secreted by exocytosis into spece between granulosum and corneum for water barrier

136
Q

Cells in dermis

A

Fibroblasts, macrophages, mast cells, B lymphocytes (skin homeostasis and immunosurveillance)

137
Q

Layers of dermis

A

Papillary (loose CT)

Reticular (into hypodermis - dense irregular CT)

138
Q

Structures in dermis

A

Meissner (papillae - light touch), Pacinian (reticular and hypodermis; onion; transmit vibration and pressure

139
Q

Merocrine

A

Secrete product via exocytosis (form and packaged into Golgi»plasma membrane fusion)

140
Q

Apocrine

A

Products are pinched off, along with apical portion

141
Q

Holocrine

A

Products accumulate in cell, which undergoes programmed cell death and discharges material

142
Q

Eccrine sweat gland

A

Merocrine secretion; throughout body; watery; clear cells - produce sweat, dark cells - filled with granules with antibacterial properties, myoepithelial cells - contractile located near basal lamina of secretory portion of gland; duct extends to skin surface; thermoregulation

143
Q

Apocrine sweat gland

A

Merocrine secretion; axillary, areola, anal; development dependent on sex hormones; ducts open to follicles; lumens much larger than eccrine glands

144
Q

Sebaceous gland

A

Produce and excrete sebum (released via holocrine secretion)

145
Q

Pilosebaceous unit

A

Arrector pili muscle, hair follicle, sebaceous gland

146
Q

Vasculature

A

Capillary loops in dermal papillae; superficial plexus right underneath (allows blood to come up if you’re hot); communicating vessels connecting the plexi; deep plexus (allows blood to move down if you need to warm up)

147
Q

Innervation

A

Merkel - mechanoreceptors in basale
Free nerve endings - terminate in granulosum; most abundant; sense touch and temp
Pacinian - pressure and vibration in dermis and hypodermis
Meissner’s - light touch in dermis

148
Q

Hypodermis

A

Subcutaneous; not part of skin; DICT and adipose; sometimes Pacinian; highly vascularized