Tissues Flashcards
(23 cards)
what is cartilage?
cartilage is hard but flexible, compressible and elastic connective tissue consisting of cells imbedded in a matrix.
- there are no blood vessels within cartilage and so oxygen and nutrience must diffuse though the matrix to cells
what are the three types of cartilage?
Hyaline cartilage
Yellow elastic cartilage
White fibrous cartilage
where is yellow elastic cartilage found and what is its properties?
found in the ear and nose. is made of elastin fibres so is the most flexible.
where is hyaline cartilage found and what is its properties?
found on the end of bones and as rings in the trachea.
its a flexible support tissue made of collagen
- WEAKEST
- ossifies to form bone
where is white fibrous cartilage found and what is its properties?
found in the vertebrae discs, contains many bundles of collagen giving a much greater tensile strength than hyalin cartilage
what are the cells in cartilage called ?
chondrocytes
what produces the matrix
chondrocytes
what is compact bone?
the hard layer towards the outside of the bone
The compact bone matrix is composed of 2 components
organic 30% - resists fracture (squishy) MADE OF COLLEGEN
.
inorganic 70% - resists compression (hard) MADE OF CALCIUM PHOSPHATE
what are the two types of cells in compact bone?
Osteoclasts - digest and break down old bone
Osteoblasts - build up new bone (deposite new bone)
what happens when a bone breaks ?
osteoclasts break down bone fragments and the repair of new bones are made by the osteoblasts.
how does osteoporosis occur?
when the activity of osteoclasts exceed the rate of osteablasts
what is the structure of compact bone ?
its aranged in haverian systems (osteons) containing haversian canals in the centre which contain blood vessels and nerves. Volkmann canals carry blood vessels from the bone surface to the Haversian canals in the centre of each system.
what is lamella
layer, concentric ring of osteocytes and collegen fibres
what is the haversian canal?
channels through a bone, parallel to its long axis which contain blood vessles and nerves.
what is the canaliculi ?
fine threads of cytoplasm which connect the cells to the haversian canals for exchange of nutrience and oxygen to cells
what is the volkmanns canal ?
like haversian canals but at right angles, connecting to larger blood vessels via the periosteum. they conect the haversian cannals
does diffusion occur through matrix ?
no because its impearmeable.
what is rickets?
childhood bone disorder bones soften and become prone to fractures and deformity.
Caused by malnutrition : lack of vitimin D (vitamin D is needed to absorb calcium) , lack of sunlight (sunlight helps vitamin D function better)
Symptons :
- bowed legs
- low calcium levels
- bones break easily
list 2 sources of vitamin D
butter and eggs
what is osteoporosis
it is the abnormal loss of bone density in spongy and compact bone making it more fragile and likely to break.
CONTRIBUTING FACTORS :
- age
- alchohol / smoking / drugs
- familiy history
- artheritis
THE SYMPTOMS :
- decline in bone density
- increased risk of fractures
- pain
WHAT IS THE TREATMENT :
- regular weight/load bearing exercise
- calcium and vitamin D foods
- drugs for calcium
- hormone replenish treatment
is osteomalacia the same as rickets ?
yes but it effects adults instead of children
what is brittle bone disease / osteogenesis imperfecta?
imbalance between organic and inorganic components of bone
CAUSED by a mutation and glycine is replaced with a bulkier amino acid so the molecule cannot coil as tightly and so the hydrogen bonds holding the triple helix together are weaker.
SYMPTOMS :
- increased risk of fracture
- loose joints
- poor teeth development
- spine curvature
TREATMENT :
- drugs to increase bone mass
- surgery
- physiotherapy strengthening muscles and mobility
