Skeletal System Flashcards
Six functions of bone and skeletal system?
- Support.
- Protection.
- Assistance in movement.
- Mineral homeostasis.
- Blood cell production.
- Triglyceride storage.
Types of bones? Long.
Greater length than width.
Curved for strength.
Leg: Femur, tibia, fibula.
Arm: Humerus, ulna and radius.
Finger and toes: Phalanges.
Short bones?
Cuboid.
Most wrist and ankle bones.
Irregular bones?
Complex shapes.
Vertebrae and some facial bones.
Flat bones?
Thin.
Provide extensive surfaces for muscle attachment.
Sesamoid bone- Patella (knee cap).
Seven parts of a long bone?
Diaphysis
The main bone shaft the middle bit.
Epiphyses?
Top and bottom ends of the bone.
To connect adjacent bones to form joints.
Metaphyses?
Region where diaphyses joins epiphyses.
Epiphyseal growth plate?
A layer of hyaline cartilage.
Allows diaphyses of the bone to grow in length.
Epiphyseal line?
When growth in length stops, cartilage in plate replaced by bony structure.
Articular cartilage?
- Thin layer of hyaline cartilage covering the part of the epiphysis.
- Lacks perichondrium (which covers cartilages).
Periosteum?
Tough sheath of dense irregular connective tissue.
Surrounds bones surface when it’s not covered by articular cartilage.
Allows bone to grow in diameter.
Protects bone, fracture repair etc.
Medullary cavity?
Hollow cylindrical space within diaphysis that contains yellow bone marrow in adults.
Endosteum?
Thin membrane than lines medullary cavity.
Extracellular matrix contains?
25% water.
25% collagen fibres.
50% crystallised mineral salts.
Tissue hardening where mineral salts are deposited is called?
Calcification.
Calcification is initiated by?
Osteoblasts (bone building cells).
Osteoprogenitor cells?
Stem cells that develop into osteoblasts.
Osteoblasts?
Synthesise and initiates calcification.
Bone forming cells.
Osteocytes?
Most numerous cells and they maintain bone tissues.
Mature bone cells.
Osteoclasts?
Break down extracellular matrix to release nutrients, help bones grow and heal.
Activate to reduce blood calcium concentrations.
Compact bone?
Denser and arranged in osteons.
Each osteon has osteonic canal for blood supply and concentric lamellae.
Within lamellae is lacunae where osteocytes live.
Spongy bone?
No osteons.
Arranged irregularly in trabeculae.
Cavities filled with red bone marrow.
80% of the skeleton is?
Compact bone (strength and protection).
20% of skeleton is?
Spongy bone (for lightness).
Ossification is?
Bone formation.
How does ossification occur? 4 steps.
- Initial formation of bones in embryo.
- Growth of bones until adult sizes reached.
- Remodelling of bone (replacement of old bone with new).
- Repair of fractures.
Initial formation of the skeleton begins in embryo with 2 different patterns?
Either:
- Intramembranous ossification- Bone forms directly within mesenchyme. Look like membranes.
- Endochondral ossification-
Bone forms within hyaline cartilage that develops from mesenchyme.
Intramembrous ossification has 4 steps?
- Ossification centres where osteoblasts differentiate by secreting bone matrix.
- Calcification as osteocytes extend into osteons canliculi and deposit minerals that harden.
- Trabeculae formation creates spongy bone with red bone marrow.
- Periosteum development around spongy bone creates compact bone.
What is a canaliculi?
Small channel.
Endochondral ossification?
Long bones make up appendages of a human body initially formed by endochondral ossification.
- Cartilage development- form cartilage model.
- Cartilage model grows as matrix calcifies. Death of chondrocytes creates lacunae.
- Primary ossification centre develops as blood vessel stimulates cells to become osteoblasts.
As osteoclasts digest spongy bone?
Medullary cavity develops.
Blood vessels enter epiphyses?
Secondary ossification centre form.
Articular cartilage forms from?
Hyaline cartilage.
Bone resorption is?
Removal of minerals and collagen by osteoCLASTS.
Bone deposition is?
Addition of minerals and collagen by osteoBLASTS.
Calcium levels are controlled by?
Parathyroid hormone.
This stimulates resorption.
Calcitonin?
Stops bone resorption.
Secreted by thyroid glands.
Facial bone? Zygomatic?
Cheek bones.
Nasal?
Bridge of nose.
Inferior nasal conchae?
Located within the nasal cavity, increases surface area of the nasal cavity.
Palatine?
Forms part of the hard palate.
Maxilla?
Upper jaw and palate (around nose).
Vomer?
Middle part of nose.
Posterior.
Mandible?
Jaw.
Lacrimal?
Sunglasses resting area.
Ribs 1-7?
Attach independently to the sternum.
Ribs 8-10?
Attach to costal cartilages superior to them.
Ribs 11 and 12?
Do not have anterior attachment. Because of this they are sometimes called floating ribs.
Women have?
Smaller frontal bone.
Smaller temporal bones.
Smaller mandible.
Pelvis tipped forward larger llium.
Women lose bone mass rapidly than men.
