Skeletal System Flashcards
What is the definition of cartilage?
Specialized connective tissues found in surfaces between bones and also some non-bony structures
What is a ligament?
Bands of fibrous dense regular connective tissue that anchor bones to other bones
What is a tendon?
Bands of fibrous dense regular connective tissue that anchor muscles to bones
What is bone matrix composed of?
Collagen mixed with calcium salts
What roles do the muscular system and the skeletal system play in the skeletomuscular system?
Muscles: movement, support, generates heat
Skeleton: support, protects tissues, stores minerals, forms blood clot
Why are cartilage and bone grouped together into one?
They both have a very dense/solid extracellular matrix
What is cartilage matrix made out of? What is bone matrix made out of?
Proteoglycans (protein +chondroitin sulfates); collagen + calcium salts
What are the two ways that chondrocytes can grow?
From within (interstitial), by adding new layers at the tissue surface (appositional)
How do chondrocytes maintain the ECM? At what stage of their life does this happen?
- live in lacunae and synthesize proteoglycans
- adult state
Does cartilage grow in adulthood?
Only under very unusual circumstances and then only appositional
What are the six types of bones in the skeleton?
Sutural, flat, irregular, short, long, sesamoid
What are the two kinds of bone?
Spongy and compact
What runs through the central canal?
Capillaries, venule, nerve
What are the four different kinds of cells that live within bone tissue?
Osteogenic, osteocytes, osteoblasts, osteoclasts,
What do osteogenic cells do?
They are stem cells that divide to maintain or increase the population of other cells
What are osteoblasts and what do they do?
Produce new areas of matrix by secreting proteins and minerals (ossification)
What are osteocytes?
Mature osteoblasts that occupy lacunae, maintain and turnover the mineral and protein in the bone matrix
What do osteoclasts do?
Live at the surface of the medullary cavity and can dissolve bone matrix
What are the two mechanisms for bone growth and when do they occur?
Appositional: osteoblasts adds layers of bone matrix to the outer surface
Endochronal: (in embryo) ossification of cartilage when blood vessels invade the cartilaginous skeletal structures
- the epiphyses ossifies, and the metaphysis remains cartilage and elongates the shaft through interstitial growth
How do dermal and sesamoid bones ossify?
From non-cartilaginous connective tissue
Dermal bones: develop from dermal tissue; ossification centres within the developing dermis
Sesamoid bones: form from ossification within the tendons
What is the feedback loop for regulating calcium levels?
Sensor: Parathyroid gland
Integrator: PTH (increases activity of osteoclasts)
Effector: osteoclasts
Feedback loop: negative, homeostasis
How does bone repair itself?
- Formation of blood clot (fracture hematoma)
- Cartilage forms
- Cartilage is replaced with spongy bone
- Spongy bone remodels into compact bone
What are the three types of joints/articulations?
- Synarthrosis (no mvmt)
- Ampiarthrosis (little mvmt)
- Diarthrosis (free mvmt)
What are the four types of synarthrosis?
- Fibrous (suture)
- Gomphosis (teeth)
- Cartilagenous (syndechondrosis: the cartilage between the manubrium and ribs)
- Bony (synostosis: line in frontal lobe)
What are the two types of amphiarthrosis?
Fibrous (syndesmosis: fibrous tissue between tibia and fibula)
Cartilagenous (symphysis: pubic symphysis)
What is an example of a diarthrosis?
Synovial joint
What is the synovial membrane made out of? What is its function?
Epithelium and areolar tissue
- lubrication, absorb impacts, nourishes cartilage
What kind of cartilage is in the synovial joint?
Articular (hyaline)
What happens when articular cartilage is damaged?
Increases friction at the synovial joint, inflammation, more pressure on remaining cartilage
What does osteoarthritis affect?
Synovial joints
What structural features make cartilage not repair very well? What is the advantage of it not repairing easily?
- no blood vessels,, no nutrients to repair with
- growth would require a perichondrial layer, and this compromises the smooth surface
- improper growth would compromise joint function
What are the two layers of periosteum and what are their three functions?
Cellular and fibrous
- Isolate bone from surrounding tissues
- Provides a route for the blood and nervous supply
- Actively participates in bone growth and repair
What is the purpose of perforating fibres in bone?
Cement tendons, ligaments, joint capsules to the circumferential lamellae with collagen fibres
