Skeletal System Flashcards
What are the 4 components of the skeletal system
bone, cartilage, ligaments & tendons
What are the 5 functions of the skeletal system & explain?
- Body support - BNS: bares body weight, CRTLG- allows flexibility, LGMNTS- holds bone and cartilage together .
- Organ protection- via bones.
- Body movement- SKLTL attaches to BNS, contractions provides movement with joints.
- Mineral storage: PO4, Calcium & adipose tissue.
- Red Blood cell production: via red bone marrow.
what are the 3 types of cartilage?
Hyaline, fibrous, elastic
what is the primary cell in hyaline cartilage & what are its 2 forms of maturity?
Chondral Cells.
Chondroblasts & chondrocytes
Explain what chondroblasts/ cytes are? where they are? and their function?
Blast:: immature cells in cartilage/ bone, in the matrix of hyaline cartilage& secrete a matrix creating cartilage & bones.
Cyte: rounded mature cells, in the lacunae & produces matrix to reinforce bone.
What is the perichondrium and explain its 2 layers?
protective CT sheath.
Outer: dense irregular dense fibres, with fibroblasts.
Inner: delicate, less fibres, contains chondroblasts.
How is nutrients received by the chondral cells?
blood vessels & nerves can penetrate the outer perichondrial layer, but not further. nutrients must diffuse through the cartilage matrix.
Whats the difference between appositional & interstitial chondroblasts?
appositional: contained within the perichondrium that add new matrix to the outside of bone.
interstitial: Within CT creating matrix between existing cells.
what is articular cartialge?
hyaline cartilage which covers the end of joint forming bones.
what is the percentage composition of organic & inorganic material in bone matrix? what are the organic & inorganic components.
35% - organic 65%- inorganic
organic: collagen & proteoglycans.
inoragnic: calcium phosphate & hydroxyapatite.
what are the 2 functional purposes of the organic & inorganic materials and what happens if one components is lacking?
Collagen (organic) - flexible strength.
low = bone becomes brittle.
minerals (inorganic) - weight bearing strength.
low = bones become overly flexible.
what are the 3 primary cells of bones? what do they do? and where is their location in the bone?
Osteblast (OB), osteocyte (OCY) & osteoclast (OC)
OB: bone building cells, large ER & lots of ribosomes.
Produce proteoglycans & matrix vesicles which have high concn of PO4 & Ca.
OCY: mature OB, account for 90-95% of bone cells. mostly inactive, produces components to maintain matrix. located in the lacunae and cell extensions in the canaliculi.
OC: Bone breaking cells, large multi nucleated cells differentiate from bone marrow. Causes the process of bone reabsorption.
Explain the process of bone reabsorption and its steps?
This process is to mobilise phosphate and calcium ions.
- OC access bone matrix, OB lining CT control the movement of OCs into the matrix.
- Integrins form (attachment structures that form when OCs make contact with bone).
- Podosomes (cellular protrusions): created a sealed chamber under OC .
- OC membrane differentiates into the ruffled border (highly folded membrane).
What is the ruffled border? what does it do? And describe the process of decalcification.
specialised reabsorption site.
acidic vesicles attach the the membrane of the border, ATP-powered H+ pumps and digestive enzymes are secreted into the membrane.
Creating an acidic environment causing decalcification of the bone.
Transcytosis of decalcification products through OC out into the ECF
What are osteochondral progenitor cells? And where are they found?
A specialised stem cell, can differentiate into either an osteoblast or an chondroblast.
located inner layers of the perichondrium & the inner CT layers - periosteum & endosteum.
