Histo - Cartilage/Bone Flashcards
What is the general composition of connective tissue?
cells + ecm (protein fibers and ground substance)
What are the 3 types of protein fibers?
collagen, reticular, elastic
What are the 3 examples of ground substance given?
- glycosaminglycans (GAGs ex: hyaluranic acid, chondroiton sulfate)
- proteoglycans
- multiadhesive glycoproteins (ex: laminin and fibronectin)
In epithelium, nervous tissue, muscle tissue, ___ is the major component of connective tissue.
In cartilage, ___ is the major component of connective tissue.
first: cells
second: ECM
ECM is usually secreted by ___
cells
Describe the ground substance characteristics
unstructured, amorphous materials between cells and fibers
provides a medium through which nutrients can diffuse
can be fluid, semi-fluid, gelatinious, or calcified.
hydrophilic.
All connective tissue is derived from ____
mesenchyme
What is mesenchyme?
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
What are chondroblasts derived from?
mesenchyme
What cells are found in cartilage?
chondroblasts (secrete ECM)
chondrocytes (secrete and maintain ECM)
What % volume is the ECM in cartilage?
95%
The ECM of cartilage is rich in ___ and ___. This allows it to withstand ____.
ECM of cartilage is rich in glycosaminoglycans and proteoglycans
allows it to withstand mechanical forces (it is resilient)
ECM allows it to withstand _____
mechanical forces (making it resilient)
What is the perichondrium?
the dense CT covering MOST of the cartilage
What does the perichondrium contain?
perichondrium contains blood vessels, nerves, chondrogenic cells, type I collagen
Perichondrium of cartilage is essential for ____
growth and maintenance of cartilage
Is cartilage avascular or vascular?
avascular
How do chondrocytes receive nutrients?
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)
What aspect of the cartilage allows for easy diffusion?
ECM is high in water content so allows for diffusion
What are the 2 mechanisms for cartilage growth?
- appositional growth
2. interstitial growth
What is appositional growth?
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)
What is interstitial growth?
growth by internal expansion
proliferation of chondrocytes to form isogenic groups
What are the 3 types of cartilage?
- hyaline cartilage
- elastic cartilage
- fibrocartilage
Describe the ECM of hyaline cartilage
high in % water
proteoglycans, hyaluronic, chondroiton sulfate, keratin sulfate, type II collagen
H2O bound to negative GAGs, makes it resilient and a shock absorber
Describe where hyaline cartilage is found
articular cartilage, nose, larynx, trachael rings, esophygeal plates, fetal bone models
Is perichondrium found in hyaline cartilage
Yes. in most hyaline cartilage..
there are a few exceptions
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
What are the 3 cell populations in hyaline cartilage?
chondrogenic cells
chondroblasts
chondrocytes
What are chondrogenic cells and where are they found?
inner portion of perichondrium, can develop into chondroblasts
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
Where are chondrocytes and where are they found?
They are in lacuna
they are more rounded than chondroblasts
found in isogenous groups (isogenic clusters)
What are isogenous groups? AKA ___
aka isogenic clusters
chondrocytes that recently went through mitosis
What are the 2 matrix types in hyaline cartilage?
territorial matrix and interterritorial matrix
what is territorial matrix?
rich in GAG poor in collagen
surrounds each chondrocyte and isogenic group
What is interterritorial matrix?
collagen more abundant, farther from chondrocytes/isogenous groups
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
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
Is there perichondrium in elastic cartilage?
present (perichondrium is acidophilic)
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
How do elastic cartilage and hyaline cartilage compare?
elastic cartilage has:
- elastic fibers
- higher ratio of chondrocytes to ECM
- fewer cells per isogenous group
As people age, the _____ cartilage in their epiglottis shrinks and is replaced by _____
elastic cartilage shrinks and is replaced with unilocular adipose tissue
What is the composition of the ECM if fibrocartilage?
type I and II collagen fibers, less proteoglycans than other cartilages
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
Is there a perichondrium present in fibrocartilage?
perichondrium is absent
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
Think of fibrocartilage as an intermediate between ___ and ____
fibrocartilage is the intermediate between hyaline cartilage and dense connective tissue
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
How is fibrocartilage similar to dense connective tissue?
fibrocartilage contains type I collagen which gives fibrocartilage high tensile strength
Fibrocartilage can withstand both ___ and ___ forces
compression and shearing forces
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
Often fibrocartilage is seen adjacent to ___, and the transition between the two is ____.
dense connective tissue
transition between the two is gradual
what is the general composition of connective tissue?
cells + ecm (protein fibers + ground substance)
What are examples protein fibers in bone?
collagen, reticular, elastic
What are examples of ground substance in bone?
- GAGs aka glycosaminoglycans (ex: hyaluronic acid, chondroiton sulfate)
- Proteoglycans
- Multiadhesive glycoproteins (ex: laminin and fibronectin)
What are the 5 functions of bones?
1 support 2 protection 3 movement 4 storage 5 blood cells formation
Describe how bones support the body
because bones are the framework of the body
Describe how bones protect the body
skull protects the brain, vertebrae protect spinal cord, ribcage protects the lungs
Describe how bones help with body movement
because skeletal muscles are attached to bones predominately via tendons and use bones as levers
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
Describe how bones assist in blood cell formation
occurs in red bone marrow found in bone marrow cavities and other locations
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
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
Describe short bones generally
cubed, equal length and diameter, includes the carpal and tarsal bones
Describe flat bones generally
thin, flattened, plate-like bones
ex: sternum, scapulae, ribs, most of skull
Describe irregular bones generally
complicated shape
vertebrae and hip bones
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
What are the 2 gross-observation classifications of bone?
compact (cortical) bone and spongy bone
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
Under histological observation, what is the difference between spongy and compact bone?
They are made up of similar composition
Describe the 4 parts of a long bone
1 diaphysis
2 epiphysis
3 metaphysis
4 epiphyseal plate/line
Diaphysis of long bone: what is the outside part and inside part?
outside part is compact bone
inside part is medullary (marrow) cavity