Bone and Cartilage Flashcards
What are the two different skeletons?
Axial skeleton: skull, rib cage, vertebrae of the spine
Appendicular skeleton: limbs and pelvis
What are the types of bones and what is their specific function?
Flat: protect organs and haemopoeisis
Long: framework for movement and haemopoeisis
What are the two types of bone marrow and what are their specific functions?
Red: haemopoeisis
Yellow: fat storage
What are the layers of the outer shell of bone?
Outer shell: (compact bone)
Periosteum (vascular connective tissue)
Circumferential lamellae
Osteons (made of concentric lamellae)
Interstitial lamellae (lamellae between osteons)
Volkmanns canal (connect Haversian canals in osteons)
Forms compact bone
What is the inner trabeculae made of?
Network of bone fibres (osteocytes between lamellae)
Marrow
Forms cancellous (spongy) bone
What are osteons made of?
Concentric lamellae:
Osteocytes occupy spaces called lacunae
Osteocytes extend processes through canaliculi (microcanals) to communicate with each other (connect via gap junctions)
Haversian canals:
Arteries, veins, lymph vessels and nerve fibres
What is bone matrix made of and what are their specific functions?
Osteoid - Organic for tensile strength: Proteins (osteocalcin and osteopontin) Type I collagen Hydroxyapatite - Inorganic for rigidity and density: Calcium phosphate crystals
What are the functions of the various bone cells?
Osteoprogenitor: become osteoblasts (osteoclasts come from monocytes)
Osteoblasts: secrete type I collagen, proteins, alkaline phosphatase (becomes hydroxyapatite)
Osteoclasts: secrete tartrate resistant acid phosphatase (resorbs bone)
What are the hormones that control bone development?
Resorption: (increases osteoclast activity)
Parathyroid hormone (PTH) and Calcitriol:
Increases the absorption of Ca2+ in intestines and kidneys
Build-up: (increases osteoblast activity)
Calcitonin:
Decreases the absorption of Ca2+ in intestines and kidneys
What is cartilage and what are some of it’s main features?
Connective tissue in which chondrocytes lie
Avascular
Aneural
High ratio of GAG’s : Type II collagen (readily diffuses)
What are chondrocytes and what are their specific function?
Fibroblast-like cells in the perichondrium become chondroblasts and eventually chondrocytes (lying in lacunae) Secretes and maintains Extracellular matrix Secretes collagen (strength) and elastin (flexibility)
What is the main components of cartilage?
What are the three types of cartilage and their specific function?
Extracellular Matrix and Type II collagen
Hyaline: reduce friction and absorb shock (articulated/non-articulated)
Elastic: provide shape and support (mix of hyaline and many elastic fibres)
Fibrocartilage: rigidity, absorb shock and resist shearing (mix of hyaline and dense regular CT - contains fibroblasts secreting type I collagen)
What are:
Ligaments
Tendons
Joints
Ligaments: connections between bones
Tendons: connections between bone and muscle
Joint: point where bones articulate
What is perichondrium?
Where is it absent?
Dense, irregular connective tissue that acts as a membrane around cartilage
Absent in fibrous and articulated hyaline
What directs the synthetic activity of chondrocytes?
Pressure loads applied to cartilage create: mechanical, electrical, chemical signals