Connective Tissue II Flashcards
____ has a firm yet pliable matrix that resists mechanical stress.
cartilage
What are cartilage cells called?
chondrocytes
What cavity do chondrocytes occupy?
lacunae
Are chondrocytes free-moving or stagnate? Why
They are stagnate because of the stiffness of the matrix. They are trapped in the lacunae for life.
What are small clusters of chondrocytes called?
isogenous groups (cell nests)
How do chondrocytes’ appearance differ on a fixed slides versus how they appear in real life?
During the fixation process, chondrocytes shrink making the lacunae look empty. In the body, chondrocytes fill the void completely.
The cartilage matrix is ____— meaning it has no blood vessels, lymphatic vessels, or
nerves.
avascular
How are chondrocytes nourished?
They are nourished by the diffusion of substances through the matrix.
Cartilage has a ____ metabolic rate. How can this rate be altered.
low
It can be increased by excersise which compresses the cartilage allowing for nutrients and oxygen to be passed easier.
What are the C-shaped cartilages called?
menisci
Where are menisci found?
between the femur and tibia
What disease occurs when cartilage deteriorates (most common in the elderly)?
arthritis
What is the cartilage matrix stiffened by?
GAGs and proteoglycans
Most cartilage is also covered
with a sheath of fibrous tissue called the ____.
perichondrium
What is the significant about the perichondrium?
It is very vascular and allows for an immediate source of nutrients to such cartilages.
What is the most widespread type of cartilage in the body?
hyaline cartilage
What does “hyaline” mean? How does this relate to the appearance of hyaline cartilage?
clear, glassy
* It means that hyaline cartilage has a transluscent appearance. This is because the collagen fibers are barely visible.
Where are some locations where hyaline cartilage can be found?
- articular cartilage
- epiphyseal plates
- costal cartilages
- fetal skeleton
- respiratory system
These cover the ends of the long bones of the skeleton and ease the movement of bones at the joints, such as the knee, hip, shoulder, elbow, knuckles, and many others.
articular cartilages
These are bands of cartilage at one or both ends of the long bones in children and adolescents, and function as growth zones at an age when the limbs grow longer and a person grows taller.
epiphyseal plates
These are the cartilage strips that attach the ribs to the sternum.
costal cartilages
Most of the skeleton starts out as hyaline cartilage, which becomes replaced by bone during fetal development and childhood.
fetal skeleton
Hyaline cartilages form supportive plates and rings of the nose, larynx, trachea, and bronchi, holding these passages open to ensure a smooth airflow in this system.
respiratory system
What group attached te larynx to the hyoid bone in the neck?
infrahyoid group
Which kind of hyaline cartilage matrix is darker and has less collagen and more chondroitin sulfate?
territorial matrix
Which kind of hyaline cartilage matrix is lighter and has more collagen and less chondroitin sulfate?
interterritorial matrix
Where can elastic cartilage be found?
- external ear (pinna)
- auditory canal
- audiotory (eustachian) tube
- some small cartilages of the larynx
____ has conspicuous collagen bundles that often run in parallel
with each other, squeezing the chondrocytes into single-file rows between the collagen
bundles.
fibrocartilage
What is different about fibrocartilage as compared to hyaline and elastic cartilage?
it does NOT have a perichondrium
Where can fibrocartilage be found in the body?
- interpubic discs
- invertebral discs
- other joints
This is a cartilage pad that anteriorly joins the two halves of the pelvic girdle to each other. The interpubic disc plus the adjacent regions of bone are
collectively called the pubic symphysis.
interpubic disc
These are elliptical pads between the bodies of adjacent vertebrae in the cervical, thoracic, and lumbar regions of the spine. Each disc, like a jelly doughnut, has a soft gelatinous core called the nucleus pulposus, and a firmer fibrous ring around the core called the anulus fibrosus. The anulus fibrosus is composed of fibrocartilage.
invertebral discs
____ connect muscles to bone; ____ connect bone to bone
tendons; ligaments
Where does the development of cartilage begin?
In the mesoderm of the embryo
Mesenchymal cells congregate and differentiate into unipotent stem cells called ____.
chondroblasts
Chondroblasts secrete a matrix of GAGs, proteoglycans, collagen, etc. which eventually traps them forming ____ in lacunae.
chondrocytes
Other mesenchymal cells can differentiate into ____ to produce the perichondrium.
fibroblasts
What stage of growth occurs where the chondrocytes
continue to secrete matrix between them, and their lacunae gradually drift farther apart. This is important in the renewal of worn articular cartilages and in the growth of the long bones.
interstitial growth
STAGE ONE
What stage of growth occurs where chondroblasts in the inner layer of the perichondrium deposit matrix at the surface and the cartilage grows outward. This obviously cannot occur in the places that have no perichondrium.
appositional growth
STAGE TWO
What is the technical name for the connective tissue, bone.
osseus tissue
What is the matrix of bone hardened by?
the deposition of calcium phosphate and other salts
What important functions do bones provide?
- protective enclosure
- leverage
- support
- electrolyte balance
- acid-base balance
In long bones such as the humerus and femur, what is the long shaft in the middle part called?
diaphysis
What is the wider, expanded ends or “heads” of bones called?
epiphysis
What is the marrow space within a bone called?
medullary cavity
The medullary cavity within bones are covered with a tight fibrous sheath called a(n) ____.
periosteum
The medullary cavity is also lined with a more delicate fibrous membrane called the ____.
endosteum
What are the four overarching types of cells in bone tissue?
- osteogenic cells
- osteoblasts
- osteocytes
- osteoclasts
These are unipotent stem cells that lie beneath the surfaces of the
periosteum and endosteum and line certain central (osteonic) canals. These cells arise from the embryonic mesenchyme. They are mitotically active and able to multiply and differentiate into osteoblasts.
osteogenic cells
These are cells at the bone surface that synthesize the collagen and other organic components of the bone matrix. They form a sheet of cells along the bone surface that resembles an epithelium. Immediately beneath them is a histologically clear zone of soft, uncalcified matrix called osteoid tissue. They secrete a matric all around themselves, eventually becoming trapped, and forming osteocytes.
osteoblasts
These are mature bone cells housed in lacunae. They have a very unusual shape, with a somewhat lemon-shaped cell body and long, slender cytoplasmic
processes that reach out from it into minute channels in the matrix called canaliculi. These maintain the matrix and function as strain detectors. They monitor fluid flow.
osteocytes
These are large bone-dissolving cells found on the surface, under the periosteum and endosteum. Unlike the other three cells, these come from a separate lineage, arising from the same stem cells that produce blood monocytes and macrophages. Those stem cells coalesce with each other, each contributing one nucleus to the developing cell. It is quite large and has usually a few nuclei and sometimes up to 50.
osteoclasts
What is the primary function of osteoclasts?
To dissolve bone tissue for such purposes as remodeling a bone to meet the stress or lack of stress placed on it. They act as a “calcium bank”.
Because osteoclasts dissolve bone, they typically etch a depression into the bone surface called ____.
Howship’s lacuna
What is the precursor for macrophages?
osteoclasts
**The organic part of the bone matrix is mainly composed of what?
type I collagen
The inorganic part of the bone matrix is mainly composed of what?
calcium and phosphorus… hydroxyapatite crystals
____ ____ are deposited on the collagen fibers like sugar crystals forming on a string if you make rock candy by suspending a string in hot saturated sugar water and let it cool.
hyrdroxyapatite crystals
What are the two kinds of osseous tissue?
- compact (dense) bone
- spongy (cancellous) bone
Which kind of bone exhibits an opaque, smooth white surface?
compact (dense) bone
How did spongey bone get its name?
The porous tissue which makes up the bone resmebles a sponge. Cancellous means “full of holes” which is sometimes more accurate.
Compact bone has structures called ____ which resemble that of an onion. Within this structure, a matrix of ____ surrounds the inner cavity called the ____.
osteon; lamellae; central Haversian canal
Haversian canals are connected within the bone through ____ canals.
Haversian canals are connected to the inner and outer bone surfaces through ____ canals.
Volkmann
Between lamellae are dark-staining fusiform spaces called the ____.
lacunae
Stretching across a lamella from one lacuna toward another are delicate radial channels, the ____.
canaliculi
Which kind of lamellae are located at the outer edges of the osteon and which are located towards the center of the osteon?
- circumferential lamellae - outer
- interstitial lamellae - inner
In which form of bone can collagen fibers be viewed the easiest?
decalcified bone
What are the collagen fibers called that pass between the bone matrix and the fibrous periosteum around the bone?
These also bind the periosteum to the bone matrix and anchor tendons and ligaments to the bone.
Sharpey’s fibers
What is the process by which bone is formed from other connective tissue?
ossification
What are the two types of ossification called?
- intramembranous ossification
- endochondral ossification
What disease occurs when bone resorption outpaces bone deposition, and the bones become progessively eroded and porous?
osteoporosis
occurs in premenopausal women
Collapse of the vertebrae often causes exaggerated curvature of the upper spine, a condition called ____.
kyphosis
“Widow’s hump” or “hunchback”
What is the difference between yellow bone marrow and red bone marrow?
- yellow bone marrow - composed of adipose tissue
- red bone marrow - composed of hemopoietic tissue
What are giant marrow cells called?
megakaryocytes
Red bone marrow is often sucked out of the bones, or ____, for purposes of biopsy (e.g., for myeloid leukemia) or transfusion.
aspirated
