Module 2 - Skeletal system Flashcards
what do the following prefixes mean:
intra-
meso-
peri-
intra= within
meso= middle
peri= around
what do the prefixes os/osteo mean
bone
what do the following suffixes mean:
-blast
-clast
-cyte
blast= create/ to form
clast= breakdown
cyte= cell
what are 4 connective tissues related to the skeletal system
- bone
- cartilage
- tendons
- ligaments
what are the 5 function of connective tissue that relate to the skeletal system
- connects
- supports moving parts
- protection (bone protects immune cells)
- store compounds (calcium and phosphate)
- enclose separate tissues (eg. periosteum)
what are the 2 function of connective tissue that dont relate the the skeletal system
- cushioning and insulation
- transportation
what are the 6 major functions of the skeletal system
- assists with movement
- support
- protection
- mineral homeostasis
- blood cell production
- triglyceride storage
what are chondroblasts
cells that make cartilage
what are chondrocytes
cells that maintain the extracellular matrix and produce the matrix
what are the mature and immature cartilage cells
chondroblasts are immature
condrocytes are mature
what is lacunae
spaces in the cartilage matrix that host chondrocytes
what is the structure of cartilage
matrix (dense network of collagen and elastic fibres)
and fluid
note- it is fairly metabolically inactive and there is no direct blood supply
what are the key features of cartilage
- avascular (nutrients comes from underlying bone)
- no nerves
- cartilage cells are formed from cells in the perichondrium (connective tissue covering cartilage) + these cells produce the matrix
describe the 2 types of cartilage growth
Appositional growth - cartilage added to the outside
Interstitial growth - chondrocytes within matrix divide and add more matrix between them
name the 3 types of cartilage and where are they needed
hyaline - areas where strong support and flexibility is needed
fibro - areas with lots of mechanical pressure (+mechanical stress)
elastic - where flexibility but rigidity is needed
what are the characteristics of hyaline cartilage
- gelatinous, glossy cartilage with evenly distributed collagen fibres
- found in ribcage and bronchi
what are the characteristics of fibrocartilage
- more collagen bundles than hyaline
- slightly compressible and very tough
- found in the knee, jaw, intervertebral disks
what are the characteristics of elastic cartilage
- matrix is similar to hyaline but has the addition of lots more elastic fibres
- somewhat flexible
- rigid
- found in external ear, epiglottis, auditory tubes
Describe the relationship between cartilage cells
- chondroblasts produce the matrix, once they are surrounded by it their name changes to chondrocytes and they stay in the lacunae
what are the 3 types of bone cells and what is their role
osteoblasts- bone forming cells, produce the matrix, found in the periosteum
osteocytes- maintain the matrix, located in lacunae
osteoclasts- bone destroying cells (specialised macrophages to break down matrix), large, multinucleated cells, originate in red bone marrow
how much of our bone matrix is organic and inorganic and what does this mean
35% organic and 65% inorganic
organic is made up of:
- collagen fibres and proteoglycans
- C,H,O,N
- made from carbs, proteins, lipid elements
inorganic is made up of:
- hydroxyapatite CaPO4 crystals
- Ca++ and PO4–
- made from absorbed inorganic ions
both are made by osteoblasts, the organic matter is also maintained by osteocytes
what is the process of making the bone matrix called
ossification/osteogenesis
why are mineral and collagen both needed in bone
- minerals stop it from being too bendable, collagen stops it from being too brittle
describe the 2 types of bone growth + when they are used
- woven - collagen arranged randomly - used in fetal development and initial repair
- lamellar - collagen fibres are parallel within sheets and different sheets run in different directions - replaces woven bone
what are the 2 types of bone DEVELOPMENT
- intramembranous ossification - takes place within connective tissue membrane
- endochondral ossification - takes place within cartilage template
what is the embryonic precursor cell for bone
mesoderm / mesenchymal tissue
describe the steps in forming woven bone via intramembranous development in fetal development
mesenchymal cells in connective tissue-> osteoprogenitor cells -> osteoblasts -> form woven bone
describe the process for endochondral ossification
Steps:
1.mesenchymal cells aggregate to become osteochondral progenitor cells
2. then differentiate to become chondroblasts (forming the cartilage framework)
3. blood vessels invade framework + osteochondral dells in perichondrium differentiate into osteoblasts
4. osteoblasts move into calcified cartilage framework and deposit new bone matrix
5. osteoblasts and osteocytes produce woven bone - this step continues until 18/20yrs old
what are the 2 directions of bone growth
interstitial (between) - to make them longer
appositional (on top) - to make them wider/thicker
what are the 2 types of bone
spongy and compact
describe spongy bone
- appears porous, contains columns of trabeculae
- weight bearing
- surrounded by a sleeve of compact bone
where is spongy bone found
- spine
- articulating joints
- ends of long bones
describe compact bone
- it is the strongest part of the bone
- basic unit is an osteon
- there are less osteocytes
- the osteocytes are located around the central canal not in lacunae (this is important for strength and support)
describe the composition of an osteon from innermost to outermost
- central canal
- concentric lamellae (around central canal)
- circumferential lamellae (around the surface of bone)
- lamellae interstitial (between osteons/remnants of previous osteons)
- perforating canal (connects periosteum BVs to central canal BVs
how do nutrients and waste travel within a bone
- interstitial fluid of lacunae and canaliculi (smaller canals radiating outward from central canal)
- from osteocyte to osteocyte by gap jumping
describe the path of blood flow to supply bones
- arteries pass through periosteum into medulla (the cavity with bone marrow)
- medullary arteries branch into ascending and descending
*blood moves into capillaries via perforating canals
*and move into the central canal.
what are the 4 bone classifications by shape
- long
- short
- flat
- irregular
what are the features of flat bones
- no diaphysis (shaft) or epiphyses (end knob)
- sandwich of spongy bone between compact bone
- some have sinuses
what are the features of short and irregular bones
- no diaphysis (shaft)
- whole structure is similar to the epiphysis
- compact bone surrounding spongy centre
what are the features of long bones
- have a diaphysis and epiphysis
- epiphyseal plate - hyaline cartilage between diaphysis and epiphysis ( present until growth stops and then the cartilage is replaced by bone and is call the epiphyseal line
- it has a medullary cavity that contains bone marrow
what is the difference between red and yellow bone marrow and when do we have them
children have red bone marrow everywhere
adults have red marrow everywhere except in the limb bones and skull where it turns yellow
- the difference comes from a change in adipose content
what are the 3 classes of fibrous joints and how do they join bones
suture - opposing bones interdigitate (like clasping hands) eg. coronal suture
syndesmosis - bones joined by ligaments eg. tibiofibular
gomphosis - pegs fitting into sockets eg. teeth