Histo - Cartilage/Bone Flashcards
1
Q
What is the general composition of connective tissue?
A
cells + ecm (protein fibers and ground substance)
2
Q
What are the 3 types of protein fibers?
A
collagen, reticular, elastic
3
Q
What are the 3 examples of ground substance given?
A
- glycosaminglycans (GAGs ex: hyaluranic acid, chondroiton sulfate)
- proteoglycans
- multiadhesive glycoproteins (ex: laminin and fibronectin)
4
Q
In epithelium, nervous tissue, muscle tissue, ___ is the major component of connective tissue.
In cartilage, ___ is the major component of connective tissue.
A
first: cells
second: ECM
5
Q
ECM is usually secreted by ___
A
cells
6
Q
Describe the ground substance characteristics
A
unstructured, amorphous materials between cells and fibers
provides a medium through which nutrients can diffuse
can be fluid, semi-fluid, gelatinious, or calcified.
hydrophilic.
7
Q
All connective tissue is derived from ____
A
mesenchyme
8
Q
What is mesenchyme?
A
loosely organized embryonic connective tissue
contains elongated, spindle shaped undifferentiated stem cells
multipotent cells with oval and round nucleus, prominent nucleolus, fine chromatin, thin cytoplasmic processes
9
Q
What are chondroblasts derived from?
A
mesenchyme
10
Q
What cells are found in cartilage?
A
chondroblasts (secrete ECM)
chondrocytes (secrete and maintain ECM)
11
Q
What % volume is the ECM in cartilage?
A
95%
12
Q
The ECM of cartilage is rich in ___ and ___. This allows it to withstand ____.
A
ECM of cartilage is rich in glycosaminoglycans and proteoglycans
allows it to withstand mechanical forces (it is resilient)
13
Q
ECM allows it to withstand _____
A
mechanical forces (making it resilient)
14
Q
What is the perichondrium?
A
the dense CT covering MOST of the cartilage
15
Q
What does the perichondrium contain?
A
perichondrium contains blood vessels, nerves, chondrogenic cells, type I collagen
16
Q
Perichondrium of cartilage is essential for ____
A
growth and maintenance of cartilage
17
Q
Is cartilage avascular or vascular?
A
avascular
18
Q
How do chondrocytes receive nutrients?
A
chondrocytes in lacunae receive nutriets via diffusion from perichondrial blood cells
(remember: chondrocytes are in lacunae and the cartilage is avascular, so they need a new means to receive nutrients)
19
Q
What aspect of the cartilage allows for easy diffusion?
A
ECM is high in water content so allows for diffusion
20
Q
What are the 2 mechanisms for cartilage growth?
A
- appositional growth
2. interstitial growth
21
Q
What is appositional growth?
A
growth by additional to existing surface
generation of new chondroblast
when chondroblasts secrete new matrix so much that they are inside of it (now it’s called a chondrocyte)
22
Q
What is interstitial growth?
A
growth by internal expansion
proliferation of chondrocytes to form isogenic groups
23
Q
What are the 3 types of cartilage?
A
- hyaline cartilage
- elastic cartilage
- fibrocartilage
24
Q
Describe the ECM of hyaline cartilage
A
high in % water
proteoglycans, hyaluronic, chondroiton sulfate, keratin sulfate, type II collagen
H2O bound to negative GAGs, makes it resilient and a shock absorber
25
Describe where hyaline cartilage is found
articular cartilage, nose, larynx, trachael rings, esophygeal plates, fetal bone models
26
Is perichondrium found in hyaline cartilage
Yes. in most hyaline cartilage..
there are a few exceptions
27
What is the appearance of hyaline cartilage?
It is different in a fresh dissection and a histological dissection.
Fresh dissection - blu-ish white and translucent
Histologically - matrix generally is basophilic (because of negative GAGs.
- in HE stain: collagen fibers indiscernible because same refractie index as surrounding sunstance
28
What are the 3 cell populations in hyaline cartilage?
chondrogenic cells
chondroblasts
chondrocytes
29
What are chondrogenic cells and where are they found?
inner portion of perichondrium, can develop into chondroblasts
30
What are chondroblasts and where are they found?
elliptical shape, long axis parallel to cartilage surface
these begin to synthesize and secrete ECM
once completely surrounded by matrix (in lacuna) called chondrocytes
31
Where are chondrocytes and where are they found?
They are in lacuna
they are more rounded than chondroblasts
found in isogenous groups (isogenic clusters)
32
What are isogenous groups? AKA ___
aka isogenic clusters
chondrocytes that recently went through mitosis
33
What are the 2 matrix types in hyaline cartilage?
territorial matrix and interterritorial matrix
34
what is territorial matrix?
rich in GAG poor in collagen
| surrounds each chondrocyte and isogenic group
35
What is interterritorial matrix?
collagen more abundant, farther from chondrocytes/isogenous groups
36
What is the ECM composition of elastic cartilage?
it is essentially the same as hyaline cartilage with type II collagen fibers
and ADDITION OF ELASTIC FIBERS
37
Where is elastic cartilage found?
auricle (aka pinna), auditory canal, auditory (pharyngotympanic) tube, epiglottis
found in these locations because elastic cartilage is pliable and resilient
38
Is there perichondrium in elastic cartilage?
present (perichondrium is acidophilic)
39
What is the appearance of elastic cartilage?
different in a fresh dissection vs histologically
fresh dissection - yellowish (because elastic fibers)
histologically- with SPECIAL STAINING, elastic fibers are prominent. they are a dense network of branching/anastomosing fibers
40
How do elastic cartilage and hyaline cartilage compare?
elastic cartilage has:
- elastic fibers
- higher ratio of chondrocytes to ECM
- fewer cells per isogenous group
41
As people age, the _____ cartilage in their epiglottis shrinks and is replaced by _____
elastic cartilage shrinks and is replaced with unilocular adipose tissue
42
What is the composition of the ECM if fibrocartilage?
type I and II collagen fibers, less proteoglycans than other cartilages
43
Where is fibrocartilage found? Why?
found in intervertebral discs, pubic symphysis, major tendon-bond anchorages
because of components of the ECM, fibrocartilage is found in areas that undergo lots of pulling forces/compression forces
44
Is there a perichondrium present in fibrocartilage?
perichondrium is absent
45
What is fibrocartilage appearance histologically?
tissue is an intermediate between dense regular connective tissue and hyaline cartilage
chondrocytes are arranged in long rows, separated by coarse collagen fibers
matrix is more acidophilic
46
Think of fibrocartilage as an intermediate between ___ and ____
fibrocartilage is the intermediate between hyaline cartilage and dense connective tissue
47
How is fibrocartilage similar to hyaline cartilage?
fibrocartilage contains chondrocytes in lacunae and type II collagen which gives fibrocartilage the ability to withstand compression forces
48
How is fibrocartilage similar to dense connective tissue?
fibrocartilage contains type I collagen which gives fibrocartilage high tensile strength
49
Fibrocartilage can withstand both ___ and ___ forces
compression and shearing forces
50
Describe chondrocytes in fibrocartilage
there are fewer chondrocytes in fibrocartilage than there are in hyaline or elastic cartilage
chondrocytes are alligned along collagen bundles either singularly or in isogenous groups
51
Often fibrocartilage is seen adjacent to ___, and the transition between the two is ____.
dense connective tissue
transition between the two is gradual
52
what is the general composition of connective tissue?
cells + ecm (protein fibers + ground substance)
53
What are examples protein fibers in bone?
collagen, reticular, elastic
54
What are examples of ground substance in bone?
1. GAGs aka glycosaminoglycans (ex: hyaluronic acid, chondroiton sulfate)
2. Proteoglycans
3. Multiadhesive glycoproteins (ex: laminin and fibronectin)
55
What are the 5 functions of bones?
```
1 support
2 protection
3 movement
4 storage
5 blood cells formation
```
56
Describe how bones support the body
because bones are the framework of the body
57
Describe how bones protect the body
skull protects the brain, vertebrae protect spinal cord, ribcage protects the lungs
58
Describe how bones help with body movement
because skeletal muscles are attached to bones predominately via tendons and use bones as levers
59
Describe how bones assist in storage
bones are a reservoir for minerals (calcium and phosphate)
yellow bone marrow contains white/unilocular adipose cells which store triglycerides, potential chemical energy source
60
Describe how bones assist in blood cell formation
occurs in red bone marrow found in bone marrow cavities and other locations
61
What are the 5 classifications of bone according to shape?
```
1 long bone
2 short bone
3 flat bone
4 irregular bone
5 sesamoid bone
```
62
Describe long bones generally
longer than wide
have shaft and 2 end parts
all bones of extremeties except patella, carpal bones, tarsal bones
some long bones (phallanges) not that long but are still longer than they are wide
63
Describe short bones generally
cubed, equal length and diameter, includes the carpal and tarsal bones
64
Describe flat bones generally
thin, flattened, plate-like bones
| ex: sternum, scapulae, ribs, most of skull
65
Describe irregular bones generally
complicated shape
| vertebrae and hip bones
66
Describe sesamoid bones generaly
- special type of short bone that forms a tendon
- there is only one named sesamoid bone - = petallar bone
- number of sesamoid bones varies in individuals
- act to alter direction of pull of tendon
67
What are the 2 gross-observation classifications of bone?
compact (cortical) bone and spongy bone
68
What is the difference between compact and spongy bone in gross observation?
in GROSS observation, compact (cortical bone) looks solid to naked eye (is not actually solid)
in GROSS observation, spongy bone contains thin bone spicules called trabeculae
69
Under histological observation, what is the difference between spongy and compact bone?
They are made up of similar composition
70
Describe the 4 parts of a long bone
1 diaphysis
2 epiphysis
3 metaphysis
4 epiphyseal plate/line
71
Diaphysis of long bone: what is the outside part and inside part?
outside part is compact bone
| inside part is medullary (marrow) cavity
72
What can the medullary (marrow) cavity of the diaphysis of a long bone be filled with?
1. RED bone marrow (hematopoesis)
| 2. YELLOW bone marrow (triglyceride storage)
73
In adults, what occurs with hematopoeisis?
over time, hematopoesis is limited to certain areas of the body because most red bone marrow has begun to convert to yellow
74
Epiphysis: what is the outside part and inside part?
compact bone on outside
| spongy bone on inside
75
Where is the diaphysis on the long bone?
the shaft
76
Where is the epiphysis of the long bone?
on the bone ends
77
What is located between the bone spicules of spongy bone in long bones?
red or yellow bone marrow
78
Where is the metaphysis on the long bone?
flared portion of bone between epiphysis and diaphysis
each metaphysis extends from the diaphysis to the epiphyseal line
79
Where is the epiphyseal plate/line found on a long bone?
between the metaphysis and epiphysis
80
What is the epiphyseal plate? What is it made up of?
epiphyseal plate is in still growing areas aka the growth plate
composed of hyalie cartilage
81
What takes place in the epiphyseal plate?
activities that take place in plate allow for long bone to grow lengthwise
82
What is the hyaline cartilage of the epiphyseal plate replaced with? Once replaced, what is the new term?
replaced with bone
then called epiphyseal line
83
What are the two membranes of long bone?
periosteum and endosteum
84
Where is the periosteum on a long bone?
covers the outer surface of bone with exceptions of articular surfaces and tendon and ligament insertion
85
Is the periosteum vascular or avascular?
vascularized
86
Periosteum is double layered. What are the 2 layers?
outer portion = fibrous dense irregular CT
inner portion = osteogenic layer (osteogenic cells, osteoblasts, osteoclasts)
87
What is the periosteum connected to? How?
Periosteum is connected to underlying bone via perforating/sharpey's fibers (which are collagen fibers)
88
What are perforating/sharpey's fibers? Where are they? What do they do?
Collagen fibers
attach periosteum to underlying bone
89
Describe the endosteum
Consists of cells that belong to the stroma of the marrow or are derived from resting osteoblasts
main source of lining cells of cortical haversion canals
90
What is articular cartilage?
articular joint surfaces covered with cartilage
composed of hyaline cartilage
cushions opposing ends of bones during movement and absorbs different stresses
91
Do the short/flat/irregular/sesamoid bones have the same parts as the long bones?
no.
| short/flat/irregular/sesamoid bones do not have a diaphysis, epiphysis, metaphysis or marrow cavity
92
What are the components of short / flat / irregular / sesamoid bones?
look like chocolate dipped oreo cookies
chocolate covering - periosteum of compact bone
cookie - compact bone
cream filling - spongy bone in middle (called diploe)
93
What is a diploe?
The spongy bone in the middle of the compact bone
94
What is the covering for the trabeculae of diploe (spongy bone) and the covering for the passageways of the compact bone?
endosteum
95
What is between the endosteum lined trabeculae?
either red or yellow bone marrow
96
How are the trabeculae of diploe lined up?
lined up along stress lines
although they look like they are lined up randomly
97
What is the composition of bone tissue?
cells + ECM
98
What are the 4 cells types of bone tissue?
osteogenic cells, osteoblasts, osteocytes, osteoclasts
99
What are the 2 components of ECM in bone tissue?
1. organic part (osteoid part)
| 2. inorganic part
100
What is the organic (osteoid) part of the ECM of bone tissue secreted by?
osteoblasts
101
What does the organic (osteoid) part of the ECM of bone tissue contain?
type I collagen, bone matrix proteins (GAGs, hyaluronic acid, chondroitin sulfate, glycoproteins, osteocalcin, osteonectin)
102
What is osteocalcin and where is it found?
found in the organic (osteoid) part of the ECM of bone tissue
osteocalcin is a bone-specific multiadhesive glycoprotein
103
What is osteonectin and where is it found?
found in the organic (osteoid) part of the ECM of bone tissue
osteonectin is a vitamin-k-dependent polypeptide, important for the calcification of bone
104
What is the in-organic part of ECM of bone tsisue composed primarily of?
hydroxyapitite crystals (most abundant component of inorganic part of ECM in bone tissue)
105
What makes up 50% of the dry weight of bone matrix in bone tissue?
inorganic part of ECM
106
In the inorganic part of ECM of bone tissue, the association between collagen fibers and inorganic portion (HA crystals) is responsible for _____
hardness/resistance of bone
107
What are the 4 types of bone cells?
1 osteoprogenitor cells/osteogenic cells
2 osteoblasts
3 osteocyte
4 osteoclasts
108
What do osteoprogenitor cells develop into?
osteoblasts
109
What are osteoprogenitor cells?
basically mesenchymal stem cells
110
Osteoprogenitor cells have the potential to divide via ____ to differentiate into ___
potential to divide via mitosis to differentiate into osteoblasts
111
Where are osteoprogenitor cells found?
inner layer of periosteum and endosteum
112
What develops into the osteoblasts?
osteoprogenitor cells
113
Osteoblasts are responsible for synthesis/secretion of _____
organic component of ECM (osteoid)
114
What bone cell is responsible for the synthesis/secretion of organic component (osteoid) of ECM?
osteoblast
115
Osteoblast activity signals for ____ of bone.
calcification of bone.
| This is the depositing of the inorganic part of ECM
116
Which bone cell type activity is responsible for calcification of bone (aka deposits the inorganic part of the ECM)?
Osteoblasts
117
Where are osteoblasts located?
osteoblasts are located on the surface of bone matrix, side by side like simple epithelium
118
Which type of bone cell looks like simple epithelium, aligned along the surface of bone matrix?
osteoblasts
119
What happens to osteoblasts histologically when they are actively producing matrix?
they are cuboidal/columnar in shape with a basophilic cytoplasm
120
Which type of cell becomes cuboidal/columnar in shape with a basophilic cytoplasm when they are actively producing matrix?
osteoblasts
121
What happens with the osteoblast secretes so much matrix that they encapsulate themselves?
they are now called osteocytes
122
Where do osteocytes sit?
in lacunae in the matrix
| which they themselves maintain
123
As osteocytes transition from osteoblasts, they extend ____ that are found in ____.
long cytoplasmic extensions of osteocytes are found in tunnels called canaliculi
124
Which bone cell type has cytoplasmic extensions? when they do they develop?
osteocytes have long cytoplasmic extensions
they develop when the osteocytes are formed from osteoblasts
125
Where are the long cytoplasmic extensions of osteocytes found?
the tunnels called canaliculi
126
What are caniliculi? What is found within them?
Caniliculi are tunnels
found within them are the long cytoplasmic extensions of osteocytes (which develop when osteocytes are being formed from osteoblasts)
127
Which bone cell type is associated with caniliculi?
osteocyte
128
Describe the organelles of osteocytes
more reduced rER, reduced golgi complex, more condensed chromatin than osteoblasts
129
What do osteoclasts do?
remove/resorb bone
130
Are osteoclasts large or small?
large
131
How long can osteoclasts live?
many years
132
What are osteoclasts derived from?
derived from same stem cells that produce macropahges (aka are derived from monocytes)
formed by the fusion of many monocytes that is why osteoclasts are multinucleated
133
How do osteoclasts dissolve bone matrix?
by secreting enzymes and hydrogen ions, creating an acidic environment
134
Osteoclasts sit in ____
pits called resorption bays or howship's lacunae
135
What are resorption bays? AKA ____
What sits in resorption bays?
resorption bays aka howship's lacunae
osteoclasts sit there
136
Osteoclasts have a ___ border. What does that do?
osteoclasts have a ruffled border
That is where the cell is actively working to break down the bone matrix
137
What are the two classifications of bone tissue histologically?
1 primary bone (aka woven bone/immature bone)
| 2 secondary bone (lamellar bone/mature bone)
138
What is the first type of bone to develop? When does this begin?
primary bone
develops in embryonic development and fracture repair
139
How are collagen fibers arranged in primary bone?
laid down in a random order
140
Describe primary bone's mineral content and osteocyte amount?
low mineral content
more osteocytes
141
Is primary bone permanent or temporary?
temporary.
eventually replaced with secondary bone in most locations
142
How are collagen fibers arranged in secondary bone?
very organized, collagen fibers arranged in layers with ALL fibers in parallel direction of concentrically vascular canal
143
What is the structural unit of a compact bone called?
osteon
144
Osteon aka ____
haversian system
145
Around vascular canals are ____
lamellae
146
Lamellae (around vascular canals of haversian systems) are composed of _____
bone ECM
these central canals and repeating concentric layer of lamellae are what compose an osteon
147
What composes the osteon?
the central canal and the repeating concentric layer of lamellae
148
What about the collagen fibers in lamellae increase the strength of the osteon?
they are parallel to each other and follow a helical course
then they are at a right angle (90deg) in the next lamellae, this increases the strength of the osteon
149
Between each lamellae are ____
osteocytes in their respective lacunae
150
Where are osteocytes located within the osteon?
osteocytes are located in their respective lacunae between each lamellae in the osteon
151
What is the cement line of the osteon? What is it composed of?
the outermost boundary of the osteon
VERY rich in collagen fibers
152
What is the outermost boundary of the osteon? What is it composed of?
cement line of osteon
VERY rich in collagen fibers
153
In long bone of compact bone, how are osteons arranged?
osteons in long compact bone are arranged parallel to the long axis of the diaphysis
154
Each osteon is composed of ____
4-10 concentric lamellae around a central/haversian canal
155
What are central canals of osteons lined with?
endosteum
156
What is within the central canal of osteons?
blood vessels, nerves, loose CT
157
How do central canals communicate with marrow cavity and periosteum?
via transverse/oblique perforating canals
AKA Volkmann's
158
Transverse/Oblique perforating canals aka ____
Volkmann's canals
159
Do transverse/oblique perforating canals have concentric lamellae around?
No.
160
What do the transverse/oblique perforating canals do?
transverse/oblique perforating canals AKA Volkmann's canals
communicate with periosteum and marrow cavity
161
Why do the osteons need to communicate with the periosteum?
Because periosteum has the blood vessels in it.
Osteons need the nutrients.
162
In compact bone, are lamellae associated with central/haversian canals?
no
example: we see external and internal circumferential lamellae just beneath periosteum
163
Which type of bone has external and internal circumferential lamellae?
compact bone
these are located just beneath periosteum
164
Between osteons in compact bone are ____
interstitial lamellae
165
What are interstitial lamellae created by? Where are they located?
interstitial lamellae are created by numerous parallel lamellae between osteons
166
What are interstitial lamellae?
interstitial lamellae are actually remnants of former osteons
because bone is constantly being remodeled
167
Do spongy bone contain osteons?
NO
168
In Spongy bone, what surround red marrow space?
trabeculae
169
Bone is considered a ____ and is derived from ___
bone is considered a connective tissue
bone is derived from mesenchyme
170
Bone is composed of ____
cells and an ECM
171
What are the parts of the long bone?
diaphysis, epiphysis, metaphysis, epiphyseal plate/line, medullary (marrow) cavity, periosteum, endosteum
172
Osteoprogenitor cells produce ____
osteoblasts
173
Osteoblasts produce ____
| - Signals for it's _____
Osteoblasts produce osteoid
Ostoblasts signal for osteoid mineralization
174
Osteocytes reside in ____ and maintain the surrounding ____
reside in lacunae and maintain the surrounding bone matrix
175
Osteoclasts ___ bone matrix
resorb
176
Histologically, bone tissue is categorized as either ___ or ___
primary or secondary bone
177
Compact bone and Spongy bone are both ___
secondary bone
178
Which bone type has osteons/haversian system, composed of a concentric lamellae and a central/haversian canal?
compact bone
179
Which bone type does NOT have osteons/haversian systems, but still consists of lamellae?
spongy bone
