Skeletal System Flashcards
Explain the functions of Bones.
Bone function
- Support
- Protection
- Assist in movements
- Mineral homeostasis
- Blood cell production
- Homepoiesis in red bone marrow
Explain the structure of long bones.
Long bones
- Parts of a long bone
- Diaphysis: Shaft of long bone; made up mostly of compact bone
- Epiphysis: Broad end of long bone; mostly spongy bone
- Metaphysis: Growth area between Diaphysis and Epiphysis
- Articular cartilage: Hyaline cartilage at joint.
- Periosteum: Fibrous covering over most of bone
- Medullary cavity: (Marrow) with fat and blood cells
- Endosteum: Membrane lining medullary cavity
Explain the microscopic structure of bone.
Microscopic Structure of Bone
- Matrix
- 25% water, 25% collagen fibers, 50% mineral salts
- Cells
- Osteogenic cells in periosteum ->
- Osteoblasts
- Secrete collagen fibers
- Build matrix and become trapped in lacunae
- Become ->
- Osteocytes that maintain bone
- Osteoclasts are formed from monocytes
- Digest bone matrix for normal bone turnover
Which cells are found in bone tissue?
Cells in bone tissue
- Osteogenic cell
- Osteoblast
- Osteocyte
- Osteoclast
Explain the Compact bone structure.
Compact Bone Structure
- Canaliculi (“little canals”)
- Contain extensions of osteocytes
- Permit flow of ECF between central canal and lacunae
- Compact bone is covered by Periosteum
- Perforating (Volkmann’s) canals
- Carry blood and lymphatic vessels and nerves from Periosteum
- They supply central (Haversian) canals and also bone marrow
Explain the structure of Spongy bone.
Spongy bone
- Not arranged in osteons
- Irregular latticework of trabeculae
- These contain lacunae with osteocytes and canaliculi
- Spaces between trabeculae may contain red bone marrow
- Spongy bone is lighter than compact bone, so reduces weight of skeleton
Explain Ossification
Bone formation
- Known as ossification
- Timeline
- Initial bone development in embryo and fetus
- Growth of bone into adulthood
- Remodeling: Replacement of bone
- Repair if fractures occur
- Mesenchyme (early connective tissue) model
- This initial “skeleton” model will be replaced by bone tissue beginning at 6 weeks of embyronic life
Explain Growth in Length.
Growth in Length.
- Chondrocytes divide and grow more cartilage on epiphysal side of the epiphyseal plate
- Chondrocytes on the diaphyseal side die and are replaced by bone
- Therefore bone grows from the diaphyseal side towards epiphyseal side
- Growth in length stops between 18-25 years; cartilage in epiphyseal plate is completely replaced by bone (epiphyseal line).
Bones of skull (anterior).
Bones of skull (anterior view).
Bones of Skull right lateral view.
Bones of Skull right lateral view.
Explain the functions of the Vertebrae.
Vertebrae - Functions
- Encloses spinal cord
- Supports head
- Point of attachement for muscles of back, ribs and pelvic girdle
List the regions of the Vertebrae
Vertebrae - Regions
- 7 cervical
- 12 thoracic
- 5 lumbar
- 1 sacrum and 1 coccyx
What is Disc herniation?
Disc herniation
Where are the Sacrum and Coccyx located?
Sacrum and Coccyx
Skeletal structure of Thorax.
Skeletal structure of Thorax.
Where are Right Ulna and Radius located?
Right Ulna and Radius
Where is Right Femur located?
Right Femur
Explain different types of fractures.
Types of Fractures
- Partial: Incomplete break (crack)
- Complete: bone broken in two or more pieces
- Closed (simple): not through skin
- Open (compound): broken ends break skin
Explain Remodeling and Repair.
Remodelin and Repair.
- Remodeling in response to use
- Resorption by osteoclasts and
- Deposition by osteoblasts
- Repair after fracture
- Dead tissue removed
- Chondroblasts -> fibrocartilage -> spongy bone deposited by osteoblasts -> remodeled to compact bone
Treatment of Fractures?
Treatment of Fractures
- Conservative
- Surgical - oestosynthesis
- Plates
- Screws
- Nails
- Ex-fix
Which is the standard treatment of Fractures?
Treatment Fractures
- Standard=conservative (children!)
- Reduction of bone ends
- Immobilisation in a plaster cast including joints above and below the fracture
- Time to heal!
- Traction
Explain the Negative Feedback Loop in bone remodeling.
Negative Feedback Loop
- Blood levels of Ca2+ controlled
- Negative feedback loops
- Parathyroid hormones (PTH) -> increases osteoclast activity + decreases loss of Ca2+ in urine
- Calcitonin -> decreases osteoclast activity
What are the effect of Exercise on Bone tissue?
Exercise and Bone tissue
- Bone strengthened in response to use
- Bone reabsorbed during disuse;
- During prolonged bed rest
- Fracture with cast/immobiliser
- Astronauts without gravity
How does aging effect the skeletal system?
Aging and skeletal system
- Birth through adolescence: more bone formed than lost
- Young adults: gain and loss about equal
- As levels of sex steroids decline with age:
bone resorption > bone formation - Bones become brittle and lose calcium
Osteoporosis = Disease where decreased bone strength increase the risk of fracture. More common amongst elderly.
