Connective Tissue
MSK Development
Bone + Calcium Endo/Biochem
Degenerative Disease
Anatomy (again)
100
Which type of collagen is most abundant in skin, and where is it found?
Collagen IV - Basal lamina of Basement Membrane
100
What is ossification?
The process of bone formation
100
Which cell initiates bone resorption?
Osteoclasts
100
What is degenerative disease?
Disintegrating tissue, or substituting a lower form of tissue for a higher form (i.e. tendons and ligaments replaced by bone)
100
What are the layers of the brain?
Dura, Arachnoid, Pia Mater
200
Name the components that make up ground substance
Glycosaminoglycans (GAGs), Proteoglycans (linking protein), Multi-adhesive glycoproteins
200
Name one way which enable MSK adaptation to physical activity
- Stresses by physical activity maintain bone strength and mass
- Mechanical and gravitational forces (Wolff's law: bone grows/remodels in response to forces to demands placed on it)
- Shape of bones reflect forces applied to them eg. bone in areas of muscle attachment.
200
What is the main inorganic compound making up bone (which makes bone hard)?
Hydroxyapatite
200
Name 2 causes of osteoperosis
- Ageing: Reduced osteoblast activity
- Hormonal changes: Decrease oestrogen ⟶ increase osteoclastogenesis ⟶ reduce osteoblast survival
- Glucocorticoid use
Decreased osteoBlast + osteocyte (formation)
Increase osteoclast (resorption)
Net bone loss
- Oxidative stress + Inflammation: Promote osteoclast + inhibit osteoblast
200
Name 2 areas of the body where avascular necrosis can occur
Hip, talus, scaphoid
300
Why and how do GAGs help absorb shock?
They are very negatively charged, creating a gel-like substance due to its attraction of water.
This creates osmotic swelling = hydrated gel to protect against abrasion.
300
What will a knee X-ray show in a developing child?
Epiphyseal growth plate
300
What are the possible fates of osteoblasts? Name at least 2.
- Apoptosis
- Transform into flat cells lining bones
- Turn into osteocytes
300
What is the difference in clinical presentation between osteomalacia and osteoperosis?
Osteomalacia: bone pain and muscle weakness
Osteoperosis: often asymptomatic until a fracture occurs
300
Difference between extradural and subdural haemorrhage in CT?
400
Which 3 alpha polypeptide chains make up collagen?
Glycine, Proline, Hydroxyproline
400
When do primary ossification centres develop? (hint: in utero)
By about 8 weeks in utero
400
What is the role of calcitonin in calcium homeostasis?
Reduces high levels of calcium in the blood by:
- Reducing renal absorption
- Reducing osteoclast activity
400
Name a microscopic appearance of osteoperosis
Thinning trabeculae + cortical bone
400
Which structures pass through the foramen magnum? (5)
- Spinal Cord
- Meninges of brain and spinal cord
- Spinal Accessory Nerve
- Spinal Arteries (anterior and posterior)
- Vertebral arteries
500
What are the 2 main roles of integrin?
- Transmembrane protein linking ECM to the cytoskeleton
- Activate intracellular signalling
500
2 main processes of bone ossification?
1. Endochondral ossification - bone replacing cartilage (most bones formed like this).
2. Intramembraneous ossification - bone developing directly from mesenchyme or fibrous CT (eg. cranial bones, clavicles). Mesenchymal cells differentiate into osteoblasts
500
What is the relationship between the Parathyroid hormone secretion and osteoclast activity?
PTH secretion stimulates osteoclasts to become more active, and break down bone to release mineralised calcium, which raises blood calcium levels.
500
Name one lab marker for osteomalacia
Low 25-Oh-D
Low/Normal Ca
Low Phosphate
Raised ALP & PTH
500
Which muscle depresses the mandible?
Lateral Pterygoid