Histology Exam 1 Flashcards
1
Q
what are the functions of cartilage?
A
provide flexible support
articular surfaces of joints
temporary template for skeleton
2
Q
spaces chondrocytes sit in
A
lacunae
3
Q
what are the ECM components of cartilage?
A
type 2 collagen
hyaluronic acid
GAGs
4
Q
dense outer layer of cartilage- what are its two layers
A
perichondrium- outer fibrous layer and inner cell layer with progenitor cells
5
Q
what is interstitial growth?
A
growth from within- chondrocytes make matrix around themselves and then get trapped
6
Q
group of chondrocytes in a lacunae
A
isogenous group
7
Q
what is appositional growth?
A
growth on a surface- progenitor cells in perichondrium differentiate into chondroblasts and make new matrix
8
Q
how does cartilage develop?
A
interstitial growth to begin, then appositional is used for repair
9
Q
where is hyaline cartilage?
A
upper airway (trachea, bronchii, larynx)
joints
ventral ribs
early skeleton
10
Q
what is hyaline cartilage made of?
A
type 2 collagen
11
Q
where is elastic cartilage?
A
epiglottis
larynx
ear
eustachian tube
12
Q
what is elastic cartilage made of
A
type 2 collagen
elastin fibers
13
Q
where is fibrocartilage
A
IVD
pubic symphysis
14
Q
what is fibrocartilage made of
A
type 1 and 2 collagen
15
Q
where does cartilage get nutrients from?
A
surrounding connective tissue
16
Q
bone matrix
A
collage type 1
GAGs
proteoglycans
non collagenous proteins
17
Q
where do osteoblasts come from?
A
osteoprogenitor cells
18
Q
where do osteoclasts come from?
A
blood cell precursor, monocyte lineage
19
Q
where do osteocytes come from?
A
osteoblasts that get stuck in the matrix
20
Q
what type of marrow is active?
A
red
21
Q
what type of marrow is inactive?
A
yellow
22
Q
what layer of bone has progenitor cells in it? where is it?
A
endosteum- between compact and spongy bone
23
Q
what is the layer on the outside of bone?
A
periosteum
24
Q
where are osteoblasts found? what do they look like?
A
cells in a line on the surface- do appositional growth
25
what are the phases of osteocytes?
quiescent- resting
formative- signal bone deposition
resorptive- signal bone resorption
26
which type of bone cells is multinucleated?
osteoclasts
27
what are hawship canals?
holes osteoclasts sit in
28
how are osteoclasts made?
osteoblasts produce MCSF which recruits monocyte stem cells to bone and RANKL
osteoclast precursor cells have RANK, RANKL binds to RANK and induces differntiation
29
what is osteoprotegrin?
blocks RANK and inhibits osteoclast maturation
30
steps of bone resorption
1. osteoclasts target bone via chemotaxis
2. attach via cell adhering molecules
3. seal to bone forming a resorptive cavity
4. release H to dissolve minerals (acidic environment)
5. lysosomes degrade collagen, MMPs degrade other things
31
what are lamellae?
concentric layers of bone surrounding Haversian cannals
32
steps of bone formation
osteiod is deposited (unmineralized bone)
osteoblasts release stuff that attracts Ca and PO4-
hydroxyapetite crystals form
continuous remodeling
33
what does osteoid look like
very irregularly arranged collagen
34
what happens to the osteoid?
reabsorbed by osteoclasts
35
what are the 2 types of bone formation?
intramembranous
| endochondral
36
describe intramembranous bone formation
osteoblasts secrete matrix which is then mineralized
| the bone is resorbed and reshaped
37
what is intramembranous bone formation used for?
flat bones
38
describe endochondral bone formation
cartilage forms first and then is replaced by bone
39
what is endochondral bone formation used for
long bones
40
steps in endochondral bone formation
1. temporary hyaline cartilage skeleton formed which is surrounded by perichondrium
2. bone formation starts in specific areas and moves outwards
41
where is the primary ossification center?
in the middle of the diaphysis
42
where is the secondary ossification center
epiphyses
43
what does parathyroid hormone related peptide do?
stimulates chondrocyte proliferation in the temporary cartilaginous skeleton
44
what causes dwarfism?
defects in Indian hedgehog protein- chondrocytes don't proliferate enough so bones aren't long eough
45
what does indian hedgehog protein do?
increases PHrP receptors on chondrocytes to delay hypertrophy until the bone gets to be the correct length
46
what does fibroblast growth factor do?
inhibits cartilage growth
47
what causes achondroplastic dwarfism?
gain of function mutation in FGF- increased FGF binding inhibits cartilage growth, so bones aren't correct length
48
what regulates periosteal collar formation?
indian hedgehog protein
49
what is rickets?
vitamin D defiency in children resulting in soft bones due to defects in mineralization
50
what is osteomalacia?
vitamin D deficicy in adults resulting in demineralization of bone-->soft bones
51
what is osteoporosis?
increased bone fragility due to estrogen deficiency--> increased bone resorption without increased formation
52
what is Paget's disease
osteoblasts overcompensate for high osteoclast activity by laying down a lot of woven bone resulting in abnormally large bones that are prone to fracture because the osteoid isn't mineralized
53
synarthrosis?
immovable joint
54
amphiarthrosis
slightly movable joint
55
diarthrosis
movement
56
osteoarthritis
excessive wear of articular cartilage with secondary inflammation
57
rheumatoid arthritis
chronic systemic inflammation leading to thickening of synovial membrane
58
what is a pannus?
folds in synovial membrane from rheumatoid arthritis
59
what is bone fusion?
ankylosis
60
what is gout?
crystals deposits in joints
61
where is skeletal muscle?
typical muscles
| extraocular muscles of eye
62
where is visceral striated muscle?
in soft tissue- tongue, pharynx, lumbar diaphragm, upper esophagus
63
where is cardiac muscle?
heart
| large veins that drain into heart
64
why is connective tissue required for force transduction
ends attach muscles to other organ systems
forms tendon attachment
nerves and blood vessels are in it
65
type 1 fibers
```
slow oxidative
most metabolically active
high mitochondria
high myoglobin and cytochrome c
fatigue resistant
small red
```
66
type 2a fibers
```
fast oxidative glycolytic
middle size and color
high myoglobin and glycogen
anaerobic glycolysis
fatigue resistant
generate peak tension
```
67
type 2b fibers
```
fast glycolytic
large white fibers
fatiguable
high anaerobic activity
highest ATPase activity
generate high peak tension
used for precise movements
high nerve innervation
```
68
H band
myosin only- shrinks with contraction
69
A band
whole myosin filament- stays constant
70
I band
actin only- shrinks with contraction
71
what does alpha actinic do
bundles actin and anchors it to z line
72
what does nebulin do
helps alpha actinic anchor actin to z line
73
what does tropomodulin do
caps actin filaments for stabilization
74
what does tropomyosin do
regulates muscle contraction- 3 binding sites
75
what is titin
anchors myosin to z line
76
what is myomesin
holds thick filaments in order at m line
77
what is c protein
holds thick filaments in order at M line
78
what is the smallest contractile unit
sarcomere- z line to z line
79
what do muscle spindles do?
provide proprioception information
80
what innervates muscle spindle fibers?
gamma efferent neurons
81
where are the nuclei in skeletal muscle fibers?
pushed out of fiber
82
where are the nuclei in cardiac muscle fibers?
in center of fiber
83
what makes cardiac muscle look different from skeletal muscle?
nuclei are in center of fibers
intercalated discs
fibers branch
84
what type of muscle has terminal cisternae
skeletal muscle
85
what are purkinje fibers
specialized cardiac muscle cell that propagates signal through ventricles
86
what do purkinje fibers look like?
large nuclei that don't stain well
lots of glycogen
intercalated discs
87
what are the things in an intercalated disc?
desmosome
adherent junctions
gap junctions
88
what regulates smooth muscle contraction?
ca and calmodulin and MLCK
89
what are dense bodies?
attach thin and intermediate filaments to the membrane, connected by alpha actinin
90
3 layers of skin
epidermis
dermis
hypodermis
91
what is the tissue that makes up the epidermis?
keratinized stratified squamous epithelium
92
what cells are in the epidermis?
keratinocytes
93
layers of the epidermis superficial to deep
```
stratum corneum
stratum lucidum
stratum granulosum
stratum spinosum
stratum basale
```
94
describe stratum basale
attached to basal lamina via hemidesmosomes
cells attached to each other via desmosomes
highest proliferation rate
95
describe stratum spinosum
spiny cells with processes filled with keratin
moderate cell proliferation
processes connected by desmosomes
96
describe stratum granulosum
thin layer with keratinosomes (lamellar bodies) that release phospholipids to coat keratinocytes to make them waterproof
97
stratum lucidum
cells lose organelles as they move up and die
plasma membrane is packed with keratin
**only in thick skin
98
stratum corneum
keratinocytes filled with keratin filaments cross link with other proteins
layer in which shedding occurs- rates vary by location
99
what is unique about thick skin?
thick stratum corneosum
| hairless
100
where is thick skin?
palms and soles
101
what is unique about thin skin?
has hair
| thin stratum corneosum
102
what are finger and toe prints?
epidermal ridges
103
where is hard keratin?
hair
104
where is soft keratin?
skin
105
what are other cells in the epidermis?
melanocytes
langerhan cells
merkel cells
106
what are melanocytes derived from?
neural crest
107
what do melanocytes do?
make melanin
108
what determines pigmentation?
rate of melanin synthesis, transfer, and degradation
109
what are the 3 types of melanin?
eumelanin- black or brown
pheomelanin- red
neuromelanin- brain
110
what causes gray hair?
decreased melanin synthesis and increased H2O2 due to decreased catalase
111
what is the science word for moles?
navi
112
what is tyrosine kinase used for in skin?
melanin synthesis
113
albanism
defect in melanin synthesis
114
vitiligo
decreased number of melanocytes per area
115
melanoma
neoplastic transformation of melanocytes
116
purpose of langerhan cells
immune- antigen presenting
117
purpose of merkel cells
specialized cell receptor that synapses with sensory neurons for touch
118
what are the layers of the dermis?
```
papillary layer (top)
reticular layer (bottom)
```
119
what is in the papillary layer?
loose CT
blood vessels
receptor endings
type 7 collagen and fibrillian
120
what is in the reticular layer?
dense irregular CT
elastic fibers
reticular fibers, type 1 collagen
121
what is in the hypodermic?
loose connective tissue
| adipose
122
what is the nail equivalent to?
stratum corneum
123
what is the nail bed equivalent to?
stratum basale and spinosum
124
what layer are hair follicles from?
epidermis
125
parts of a hair follicle
```
hair bulb
dermal papilla
hair shaft
inner root
external root
hair cuticle
```
126
what is the hair bulb?
produces the hair shaft and internal root sheath
127
what is the dermal papilla
bulb base from CT
128
how do sebaceous glands secrete
holocrine secretion onto hair follicles or epidermis surface
129
what are the types of sweat glands
merocrine
apocrine
modified apocrine
130
describe merocrine sweat glands
secrete a watery/salty solution liver most of body, used for thermoregulation
131
describe apocrine sweat glands
viscous secretion triggered by external stimulus
| located in perineum, anus, and axilla
132
where are modified apocrine sweat glands?
external ear
| eyelids
133
where are arrestor pilli muscles?
smooth muscle bundles between the epidermis and the hair bulb
134
what are free nerve endings for
thermal
pain
light tough
135
what are merle discs for
touch
136
what are meissner's corpuscles for, where are they, what do they look like
touch
in the papillary dermis
round
137
what are pacinian corpuscles for, where are they, what do they look like?
pressure
hypodermis
encapsulated- onion like
138
what are rufini organs for and where are they
stretch
| dermis
139
what is hyperkeratosis
thickening of corneum and granulosum
140
what is parakeratosis
corneum cells keep their nuclei--normal in oral cavity but also associated with pathological conditions
141
what is acanthosis
abnormal epidermal thickening (spinosum)
long epidermal extensions into papillary layer of dermis
associated with chronic inflammatory conditions
"sugar line"
142
what is intraepidural edema
fluid accumulation in epidermis
| associated with trauma
143
eczema
inflammatory, allergic component
144
psoriasis
chronic inflammatory disease characterized by rapid keratinocyte proliferation with fast upward movement resulting in surface cells not having enough keratin
scaly white regions an dmicroabcesses in dermis
145
basal cell carcinoma
invades dermis, but rarely metastasizes
| neoplastic transformation of stratum basale
146
squamous cell carcinoma
well demarcated highly keratinized tumors that invade the dermis and regional lump nodes
