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Cell and Tissue Biology > Test 2 > Flashcards

Test 2 Flashcards

1
Q

what kind of tissue is cartilage and what does it contain?

A

cartilage is a specialized connective tissue; it is avascular and lacks nerve fibers and contains cells, fibers, and ECM

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2
Q

what are the three types of cartilage?

A

hyaline cartilage, elastic cartilage, and fibrocartilage

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3
Q

describe hyaline cartilage

A

known for its “glassy” appearance and is the most common type; composed mostly of type II collagen

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4
Q

where can you find hyaline cartilage?

A

in places where it maintains a lumen/space open (nose, larynx, trachea, and bronchi), at articular surfaces of bones (ventral ends of the ribs that articulate with sternum, articulating surfaces of mobile joints such as femur), and at epiphyseal plates (“growth” plates of growing bones)

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5
Q

what are the functions of hyaline cartilage?

A

to maintain an open lumen/space, to act as a shock absorber, and to allow friction-free gliding between bones of moveable joints

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6
Q

what is the function of epiphyseal growth plates?

A

they allow long bones to grow in length; they start as hyaline and are eventually replaced completely by bone

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7
Q

describe the histogenesis of hyaline cartilage

A

mesenchymal cells retract their cell processes and become round-shaped cells. these cells form chondrification centers which are future cartilage sites. mesenchymal cells then differentiate into chondroblasts which synthesize more of this matrix in their surroundings, they become trapped in lacunae

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8
Q

what does “isogenous” mean?

A

isogenous cells are progeny of a single cell and are genetically uniform

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9
Q

describe the perichondrium

A

a connective tissue capsule that covers only hyaline and elastic cartilage; composed of 2 cell layers: the outer fibrous layer that contains fibroblasts and the inner cellular layer composed of chondrogenic cells

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10
Q

explain how cellular growth occurs in perichondrium

A

the perichondrium has vessels to provide oxygen and nutrients; the nutrients and oxygen can get into cartilage layer; when there isn’t enough diffusion, the cells in the hyaline cartilage layer break down and new cells form from the perichondrium and move inward

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11
Q

what are the 2 mechanisms of cartilage growth

A

interstitial growth (cartilage grows from within); appositional growth (cartilage grows on the surface)

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12
Q

where does interstitial growth occur?

A

during early stages of cartilage formation, in articular cartilage (does not have perichondrium), in growth plates, and deep within the cartilage

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13
Q

what makes up the hyaline cartilage matrix?

A

proteins (mainly type II collagen; cannot be seen with staining so that is why you see glassy), proteoglycans, glycoproteins, and extracellular fluid

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14
Q

what are the three different types of cartilage cells?

A

chondrogenic cells, chondroblast and chondrocytes

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15
Q

describe chondrogenic cells

A

arise from mesenchymal cells and differentiate into chondroblasts and osteoprogenitor cells

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16
Q

describe chondroblasts

A

differentiate from mysenchymal cells in the chondrification center and/or chondrogenic cells in the inner perichondrium; form matrix and fibers of cartilage

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17
Q

describe chondrocytes

A

“grown up” chondroblasts; have large nucleus and prominent nucleoulus; can go back to being chondroblasts; are trapped in lacuna, and monitor matrix composition; synthesize necessary molecules to maintain cartilage matrix

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18
Q

where would you find elastic cartilage?

A

pinna of the ear, internal and external auditory tubes, the epiglottis, and larynx

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19
Q

how is elastic cartilage different from hyaline cartilage?

A

it contains not only type II collagen, but also elastic fibers in the ECM and in the fibrous layer of the perichondrium; it also has larger chondrocytes than hyaline cartilage, is more flexible and elastic than hyaline cartilage, and is yellow in the fresh state

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20
Q

describe fibrocartilage

A

transitional form between dense connective tissue and hyaline cartilage; contains chondrocytes and type I collagen; lacks a perichondrium

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21
Q

where do you find fibrocartilage

A

in areas requiring tough, tensile strength; can be seen in intervertebral discs, pubic symphysis, articular dists, menisci of knee joints, and attached to bones (between tendons and bones)

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22
Q

how are fibroblasts and chondrocytes related

A

fibroblasts secrete proteoglycans that become surrounded by matrix and become chondrocytes

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23
Q

osteoarthritis

A

articular surface of bone where cartilage has degenerated, exposing the underlying bone; caused by the breakdown of hyaline cartilage which normally provides a slippery surface for articulating bones; most prevalent in older individuals

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24
Q

tell me some general things about bone

A

it is a specialized connective tissue; bone is mineralized, living tissue that is continuously being remodeled; bone serves as a storage depot for minerals; bone marrow is a blood-cell forming tissue; bone supports and protects

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25
Q

how does bone respond to pressure and tension?

A

pressure applied to bone results in born resorption(breakdown); tension applied to bone results in bone deposition (addition)

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26
Q

what defines a long bone

A

long bones have long, cylindrical shaft and 2 epiphyses on either end (the heads of the bone)

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27
Q

define metaphysis

A

angulation between the epiphyseal plate and diaphysis

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28
Q

define diaphysis

A

diaphysis is the long cylindrical shaft between two epiphyses

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29
Q

what is the periosteum?

A

the external connective tissue capsule of bone; the periosteum of an actively growing bone has 2 layers - an outer fibrous layer and an inner cellular layer (not defined when inactive)

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30
Q

describe the outer fibrous layer of the periosteum

A

the outer layer consists of dense collagenous CT; it contains blood vessels, lymphatic vessels, and nerves that supply the bone; it is anchored into bone via Sharpey’s fibers (bundles of collagenous fibers) so it does not slide or peel off of the bone

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31
Q

describe the inner cellular layer of the periosteum

A

if the bone is actively growing, the inner layer contains osteoprogenitor cells; if the bone is mature and not growing, it contains periosteal cells that have the ability to differentiate into osteoblasts if necessary (for repair); it plays a role in the repair of bone fractures; covers the outer surface of bone, except the articular surface

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32
Q

describe endosteum

A

internal CT capsule of bone; consists of a thin CT layer with a single row of osteoprogenitor cells that have the ability to differentiate into osteoblasts or bone-lining cells; the endosteum lines the bone marrow cavity

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33
Q

what are the 2 component of bone matrix?

A

inorganic component and organic component

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34
Q

what makes up the inorganic layer of the bone matrix?

A

minerals; hydroxyapatite crystals (calcium phosphate), bicarb, citrate, magnesium, sodium, potassium

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35
Q

what makes up the organic layer of the bone matrix?

A

fibers (type 1 collagen mostly), ground substance (proteoglycans, glycoproteins, growth factors)

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36
Q

define osteonectin

A

serves as glue between collagen and hydroxyapatite crystals

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37
Q

define sailoproteins

A

help bind cells to bone matrix; examples are osteopontin and sialoproteins I and II; sailoproteins also begin calcium phosphate formation

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38
Q

define osteocalcin

A

traps calcium from the blood and stimulates osteoclasts to remodel bone

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39
Q

define trabeculae

A

islands of bone

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40
Q

what are the 2 ways to form bone?

A

via intramembranous ossification or endochondral ossification

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41
Q

what forms first - spongey bone or compact bone

A

spongey bone forms first, but it can become compact bone

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42
Q

how do blood vessels end up in bone?

A

during bone development, bone grows around blood vessels

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43
Q

intramembranous ossification

A

bone forms directly within a membrane of highly vascular mesenchyme; the mechanism by which flat bones form (face bone, skull, clavicle)

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44
Q

endochondral ossification

A

bone forms in hyaline cartilage; mechanism by which long bones form; forms a cartilage mold to be filled by bone

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45
Q

what are the layers of the eye

A

fibrous layer (corneoscleral coat), vascular layer (uvea), and retina (neural layer)

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46
Q

what are the chambers of the eye?

A

anterior segment (anterior chamber and posterior chamber), and posterior segment (vitreous chamber)

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47
Q

what are the 5 layers of the cornea (outside to in)

A

corneal epithelium, bowman’s membrane, corneal stroma, Descemet’s membrane, corneal endothelium

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48
Q

explain Bowman’s Membrane

A

acellular, does not regenerate, terminates at corneoscleral limbus, contributes to strength of cornea, is barrier to infections

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49
Q

corneal stroma

A

collagen fibrils arranged in lamellae; adjacent lamellae are arranged at right angles to each other, this maintains the transparency of the cornea; AKA substantia propia

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50
Q

Descemet’s membrane (posterior basement membrane)

A

regenerates after injury, thickens with age, helps maintain the normal curve of cornea

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51
Q

corneal endothelium

A

simple squamous epithelium, joined by zona adherens, zona occludens, and desmosomes; limited proliferative ability; responsible for virtually all of the metabolic exchange of the cornea

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52
Q

sclera

A

white of the eyeball that gives the eye shape; provides attachment for eye muscles; made up of 3 layers - episcleral/Tenon’s space, substantia propria (Tenon’s capsule), and suprachoroid lamina

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53
Q

iridocorneal angle

A

apparatus for outflow of aqueous humor

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54
Q

ciliary processes

A

secretion and anchoring of zonule fibers, form suspensory ligaments of the lens; form blood-aqueous layer, produce aqueous humor

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55
Q

what is the flow of aqueous humor?

A

posterior chamber –> pupil –> anterior chamber –> trabecular meshwork –> Canal of Schlemm –> venous system

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56
Q

open angle glaucoma

A

vision is damaged gradually; may take place over the course of some years; caused by blockage of meshwork leading to the canal of schlemm

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57
Q

fovea centralis

A

point of retina with the greatest visual acuity

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58
Q

Retinal Pigment Epithelium (RPE)

A

attached through Bruch’s membrane to the choriocapillary layer of the choroid; mechanical separation at this point is known as a “detached retina”

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59
Q

name 2 photoreceptors

A

rods and cones

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60
Q

name 2 conducting neurons

A

bipolar cells and ganglion cells

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61
Q

name 3 supporting/neuroglial cells

A

Muller’s cells, microglial cells, astrocytes

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62
Q

what are cones responsible for?

A

color

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63
Q

what are rods responsible for

A

low intensity light

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64
Q

are rods or cones more abundant?

A

rods

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65
Q

what vitamin is associated with rods?

A

vitamin A: retinal

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66
Q

what defines a bipolar cell?

A

1 cell body in the middle with the dendrites and axon coming off of a long neck

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67
Q

what is the most common cause of blindness?

A

diabetic retinopathy; neovascularization of the retina

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68
Q

what does macular degeneration affect?

A

the fovea centralis; causes blurriness in the center of your vision due to drusen (lipid deposit near the macula and fovea centralis)

69
Q

where does drusen occur?

A

inferior to RPE

70
Q

what are the three parts that make up the lens

A

the capsule (basal lamina), the subcapsular epithelium, and the lens fibers

71
Q

where does cataracts act?

A

the lens; loss of transparency

72
Q

what occurs to the lens as you age?

A

fibers stiffen and enlarge with age

73
Q

conjunctiva

A

stratified columnar epithelium with goblet cells and basal lamina overlying a loose connective tissue; secretions produce a tear film to protect cornea

74
Q

what are 2 sebaceous glands found in the eyelids?

A

Meibomian (tarsal) glands and Glands of Zeis (smaller glands opening into eyelash follicles)

75
Q

explain the layers of the tympanic membrane

A

external layer is thin epidermis, intermediate layer is collagen and elastic fibers (fibroblasts), and the internal surface is simple squamous to simple cuboidal

76
Q

what are the ossicles lined with?

A

simple squamous epithelium

77
Q

what histology defines the auditory tube?

A

pseudostratified columnar epithelium with goblet cells

78
Q

what are the 3 fluid-filled spaces in the internal ear?

A

endolymphatic space, perilymphatic space, and cortilymphatic space

79
Q

endolymph is found where

A

membranous labyrinth

80
Q

where can you find the perilymph?

A

bony labyrinth

81
Q

where can you find corilypmh

A

in the corticolymphatic space in the cochlear duct

82
Q

what fluid is perilymph similar to?

A

extracellular fluid (high in sodium, low in potassium)

83
Q

what fluid is endolymph similar to?

A

intracellular fluid (high in potassium, low in sodium)

84
Q

what are the sensory cells for the semicircular canals?

A

crista ampullaris; located in the amuplla of the semicircular duct and canal; senses angular, rotational movements of the head

85
Q

what is the sensory cell for the utricle and saccule?

A

macula; have otolithic membrane, otoliths, and hair cells

86
Q

type 1 hair cells

A

surrounded entirely by efferent nerve

87
Q

type 2 hair cells

A

efferent nerve found on the base

88
Q

what are the three compartments of the cochlear duct?

A

scala media, scala vestibuli, and scala tympani

89
Q

scala media

A

the cochlear duct; filled with endolymph

90
Q

scala vestibuli

A

space above cochlear duct; located on the vestibule; filled with perilylmph

91
Q

vestibular (reissner’s) membrane

A

keeps the ionic gradient; has tight junctions to separate the endolymph and perilymph

92
Q

what is an active fibroblast?

A

posesses the cellular machinery for the synthesis and secretion of fibers and ground substance; typically do not divide, but may do so during wound healing (fibroplasia)

93
Q

what is a quiescent fibroblast?

A

commonly referred to as fibrocytes; smaller than the fibroblast, is spindle-shaped, possesses fewer processes. as an eosinophilic cytoplasm, nucleus is elongated and heterochromatic, and nucleoli are not visible; when stimulated, fibrocytes become fibroblasts

94
Q

how can you tell a quiescent fibroblast from an active fibroblast?

A

a quiescent fibroblast (fibrocyte) has an elongated, basophilic nucleus; an active fibroblast has a spherical nucleus and is lighter in color due to euchromatin

95
Q

what defines a unilocular adipocyte?

A

unilocular adipoctes or white adipose tissue is defined by the presence of a signet ring in light microscopy; this is due to the removal of lipid during tissue processing; the nucleus in unilocular adipocytes can be seen in the periphery of the cytoplasm

96
Q

how is collagen synthesized?

A
  1. 3 mRNA strands are made 2. triple helix is assembled in rER. each helix has extensions that make it soluble. these extensions are processed by fibroblasts 3. triple helix with propeptides are packaged in vesicles in the Golgi 4. when released into ECM, they are assembled into fibrils or larger collagen molecules; for this to happen they must become less soluble by eliminating extensions
97
Q

why is hydroxylation important in collagen formation?

A

proline and leucine must be hydroxylated for collagen to form properly; for this to happen vitamin C needs to be present; deficiency in vitamin C leads to scurvy

98
Q

what is a myofibroblast?

A

possesses characteristics of fibroblasts and smooth muscle cells; actin and myosin are present, thus it has contractile activity

99
Q

dupuytren’s contracture

A

repair of microvascular ischemia in the tissue leads to active myofibroblast and fibroblasts; increase of type III collagen forms cross links with myofibroblasts leading to the contraction of 4th and 5th digits

100
Q

what defins multilocular adipocytes?

A

aka brown adipose tissue; smaller than unilocular cells and well-endowed with mitochondria; nucleus is spherical and not displaced peripherally

101
Q

lipodystrophies

A

acquired or inherited loss of body fat to a general or confined area of the body

102
Q

what defines a mast cell

A

large, ovoid cell with membrane bound granules that contain diverse chemical compounds

103
Q

what are mast cells responsible for?

A

mediators of the inflammatory responses and hypersensitivity reactions; trigger causes mast cell to release the chemicals from secretory granules

104
Q

what is a macrophage derived from

A

a monocyte

105
Q

how is a macrophage formed?

A

a monocyte migrate into connective tissue from the bloodstream where it develops into a macrophage

106
Q

what defines a macrophage?

A

oval nucleus with clumps of heterochromatin; functions in phagocytosis; nucleus is indented

107
Q

what is a giant cell?

A

macrophages fuse together in states of chronic inflammation to form giant cells

108
Q

what are migratory cells?

A

cells that migrate into the connective tissue from the blood

109
Q

where are plasma cells derived?

A

B lymphocytes in the ECM

110
Q

what are 3 signature features of plasma cells?

A

basophilia due to large volume of rER; large negative Golgi with absence of secretory vesicles; clock face nucleus due to arrangement of euchromatin and heterochromatin

111
Q

what is the function of plasma cells?

A

synthesis and release of immunoglobins; can be seen where bacteria and antigens have entered connective tissue

112
Q

what is the function of leukocytes?

A

monocytes, lymphocytes, neutrophils, eosinophils, and basophils migrate from blood into the connective tissue during inflammatory response; neutrophils are the first response followed by monocytes as the second response

113
Q

what are the 2 classes of embryonic CT?

A

mesenchymal and mucous

114
Q

what are the 2 classes of CT proper?

A

loose and dense; dense can be regular or irregular in arrangement

115
Q

what are the 5 types of specialized CT?

A

adipose, bone, blood, cartilage, reticular

116
Q

true or false: mesenchymal tissue is the most differentiated CT?

A

false; it is the least differentiated

117
Q

what defines loose CT

A

abundant, viscous, amorphous with hyaluronic acid, GAGs, proteoglycans, and glycoproteins

118
Q

mucoid degeneration of anterior cruciate ligament

A

presents in patients as knee pain or restricted movement; can be age related degeneration, congenital or acquired synovial tissue entrapment between ACL fibers

119
Q

what does dense regular CT look like

A

elastin forms thin sheets of fenestrated membranes; elastic fibers run parallel to one another with few collagen fibers

120
Q

where is dense regular CT found?

A

ligamentum flava, the suspensory ligament of penis, arteries, and vocal ligament

121
Q

are lamellae and laminae elastic fibers?

A

no, they lack microfibrils needed to form fibers; they do have elastin; can be found in aorta

122
Q

where can you find dense irregular CT?

A

organ capsules, dermis of skin, sleeve around nerves

123
Q

Ehlers-Dalos syndrome

A

presents as hyperelasticity of skin and hypermobility of joints; defect in type 1 collagen

124
Q

what is reticular CT made of

A

reticular (type III collagen)

125
Q

Achilles tendon xanthoma

A

results from macrophages invading area and phagocytosing cholesterol and accumulating cholesterol; also seen in arteries with atherosclerosis

126
Q

where is reticular tissue found?

A

red bone marrow, liver, and lymphatic tissues/organs

127
Q

what is fibronectin

A

an adhesive glycoprotein that assists chondroblasts and chondrocytes to adhere to the ECM

128
Q

describe the capsular/pericellular matrix of hyaline cartilage matrix

A

intensely-stained thin layer of matrix immediately around lacuna; contains highest concentration of proteoglycans, hyalouronan, and glycoproteins

129
Q

describe the territorial matrix of hyaline cartilage

A

the lighter-staining matrix that surrounds the isogenous group; contains collagen and a lower concentration of proteoglycans than the capsular matrix

130
Q

describe the interterritorial matrix of hyaline cartilage matrix

A

represents most of the matrix; fills the space around the territorial matrix

131
Q

osteoprogenitor cells

A

early stage, immature bone cells; arise from mesenchymal stem cells

132
Q

where can you find osteoprogenitor cells

A

the inner layer of periosteum (here they are called periosteal cells) and the endostem (here they are called endosteal cells)

133
Q

what do osteoprogenitor cells turn into

A

differentiate into osteoblasts and chondrogenic cells )in low oxygen tension)

134
Q

when are osteoprogenitor cells active?

A

during bone growth

135
Q

what is an osteoblast

A

cells that arise from osteoprogenitor cells; cuboidal-columnar shaped cells that synthesize and secret osteoid, the organic component of the bone matrix

136
Q

what is the function of osteoblasts

A

they are in charge of the mineralization of the bone matrix

137
Q

what do osteoblasts become when they are enclosed in the matrix they produce?

A

osteocytes

138
Q

explain the function of alkaline phosphatase

A

osteoblasts contain high levels of the enzyme alkaline phosphatase; when they synthesize bone, there is an increase in alkaline phosphatase levels in the blood; alkaline phosphatase splits pyrophosphate from groups from the macromolecules of the matrix

139
Q

what are bone-lining cells

A

arise from osteoblasts and cover one surface, protecting it from osteoclasts. expose bone is vulnerable to resorption by osteoclasts;

140
Q

what do bone-lining cells do?

A

function in nutritional support of osteocytes, function in the uptake and release of calcium

141
Q

what are osteocytes?

A

grown up osteoblasts, quiescent cells, that maintain bone matrix; enclosed in lacuna

142
Q

what is periosteocytic space

A

the space between the osteocyte cell membrane and the lacuna and canaliculi

143
Q

what are osteoclasts

A

multinucleated, motile, acidophilic, enormous cells; resorb, remodel, “chisel” bone;

144
Q

how does an osteoclasts break down bone?

A

the acidic environment created by osteoclasts breaks down the inorganic component of bone. the minerals released pass into the cytoplasm of the osteoclasts and are then transported into capillaries

145
Q

what happens to osteoclasts after they complete their bone resorption assignment?

A

apoptosis!

146
Q

what enzymes are released from osteoclasts to break down organic components of the decalcified matrix?

A

lysosomal hydrolases and metalloproteinases

147
Q

describe compact bone

A

dense, solid bone that forms a shell around the exterior of long bones; an example is the calvaria; contains Haversian systems (osteons)

148
Q

describe cancellous bone

A

spongey, porous bone that lines the marrow cavity of long bones; fills epiphyses of long bones; contains mainly irregular arrangement of bone lamellae

149
Q

describe primary (immature, woven, bundle) bone

A

forms during fetal development and bone repair; contains irregular bundles of collagen; less mineral content than mature bone; this is a temporary tissue that is resorbed by osteoclasts and replace them with secondary bone

150
Q

describe secondary (mature, lamellar) bone

A

consists of parallel or concentric bone lamellae; has more mineral content than primary bone, so it is stronger; may exist as spongy or compact bone

151
Q

what is a Haversian canal?

A

aka osteonal canal; a vascular space that encloses a neurovascular bundle; has a vein, artery, and nerve, but no lymphatic vessels; consists of concentric bone lamellae

152
Q

what are Volkmann’s canals

A

obliquely oriented canals that connect osteons that are next to each other; they do not have concentric lamellae of bone that is characteristic of Haversian systems

153
Q

how do osteons form

A

during bone formation, osteons form from outside to inside; the bone grows around an existing blood vessel which then becomes trapped in bone

154
Q

what is ankylosis?

A

trauma introduced that damages hyaline cartilage; this results in fusion of two articulating bones, obliterating the joint and creating a joint without movement; can occur in the foot and knee joints of athletes and the hand and finger joints of musicians

155
Q

rheumatoid arthritis

A

autoimmune disease that attacks synovial joints, damaging articular cartilages and producing severe pain and disfigurement

156
Q

Gout

A

accumulation of uric acid crystals in the joints, especially the joints of the fingers and toes

157
Q

Rickets

A

a disorder resulting from calcium deficiency during development, or from inadequate dietary supply of vitamin D; causes osteoid to form incorrectly

158
Q

Osteoporosis

A

condition characterized by a reduction in bone mass both in organic and inorganic components of the matrix; bone breakdown by osteoclasts exceeds bone formation by osteoblasts resulting in porous bones that break easily; in women, a drop in estrogen levels causes a increased release of substances that boost osteoclast activity

159
Q

how do bones grow in length?

A

long bones grow from the epiphyseal plates; there is cartilage growth in the direction of the epiphysis and bone grown towards the diaphysis

160
Q

how does the thickness of the growth plate change as you grow? distance between growth plates?

A

the thickness stays the same and the growth plates grow apart

161
Q

what is the order of zones in the epiphyseal plate from epiphyseal side towards diaphysis?

A

zone or reserve cartilage, zone of proliferation, zone of hypertrophy, zone of calcified cartilage, zone of resorption

162
Q

zone of reserve cartilage

A

resting zone with typical hyaline cartilage

163
Q

zone of proliferation

A

chondrocytes proliferate and form isogenous groups; produce organic matrix

164
Q

zone of hypertrophy

A

glycogen in chondroytes and enlarged lacunae

165
Q

zone of calcified cartilage

A

lacunae coalesce, chondrocytes die, calcification of cartilage matrix

166
Q

zone of resorption

A

calcified cartilage remnants form long spicules in the direction of diaphysis, blood vessels bring osteoprogenitor cells to invade this zone; osteoprogenitor cells emigrate to calcified cartilage matrix area and differentiate into osteoblasts

167
Q

how do you distinguish between calcified cartilage and mineralized bone?

A

with H&E staining: calcified cartilage is basophilic without cells; mineralized bone is acidophilic and has living cells

168
Q

achondroplasia

A

characterized by decrease in production of cartilage cells in epiphyseal growth plates of long bones; cartilage is replaced by bone in a slow rate, resulting in short upper and lower limbs

Cell and Tissue Biology (3 decks)

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