MSK Axilla and Pectoral region (Weeks 1-2) Flashcards
What is the axial skeleton comprised of?
Skull, vertebral column, sternum, ribs
what is the appendicular skeleton comprised of?
Limbs, pectoral and pelvic girdle
What is the role of bones in the body?
mechanical functions, support, anchoring points for muscles, acting as levers at joints
How are joints classified?
Due to the tissue which lies between the joint. You can get: fibrous, cartilaginous and synovial
what influences stability of joints?
shape, sixe, arrangement of articular surfaces
ligaments
tone of muscle around joint
Why are tuberosities, ridges and tubercles present on bones?
Ligament, muscle and tendon attachment
Why are grooves present on bones?
Pressure form nerves and blood vessels
Mechanical functions of bone (3)
Provide the rigid framework that supports the body.
Protect vulnerable internal organs (e.g. brain, heart, lungs, etc.).
Make body movements possible by providing anchoring points for muscles and by acting as levers at the joints.
What is the function of erythropoietin?
Erythropoietin is released from the kidney when blood oxygen levels are low (e.g., anaemia) to stimulate red blood cell production
Define: SAD
Synarthrosis
Ampiarthrosis
Diarthrosis
By classification, a joint may be immovable (synarthrosis), slightly movable (amphiarthrosis) or freely movable (diarthrosis).
Give examples of fibrous and cartilaginous joints
Fibrous joints – sutures (tight union between bones of the adult skull) syndesmoses (bones held together by fibrous tissues – interosseous membrane between long bones of the forearm & leg). Ghomphosi Cartilaginous joints – primary cartilaginous (epiphyseal growth plate in long bones) secondary cartilaginous (introvertebral discs)
What are the three main components of a synovial joint?
Articulating surface, capsule, membrane
What restricts movement at a synovial joint?
Ligament tension, muscle tension, interference of other structures (e.g. bony prominences)
What part of a joint is affected in OA?
Cartilage
What part of a joint is affected in RA?
Synovium
Describe the three different types of cells found in bone
Osteoblasts are bone-forming cells (secrete collagen to form a matrix which is calcified)
Osteocytes are former osteoblast cells that become encased in the bone matrix, forming tight junctions with each other across the matrix.
Osteoclasts are bone-breaking cells (resorb bone).
Explain the problems of hyper and hypocalaemia
Small decreases of calcium in plasma and extracellular fluid (hypocalcaemia) can cause the nervous system to become more excitable because of increased neuronal membrane permeability with resultant muscular spasm.
Too much calcium (hypercalcaemia) in body fluids depresses the nervous system and causes muscles to become sluggish and weak because the effects of calcium on muscles’ plasma membranes. Bones represent a calcium store for homeostasis.
Explain the role of PTH on bone (2 main points)
- PTH is released from the parathyroid gland in response to low calcium levels in the blood. The role of PTH is to take up calcium from bone, kidney and intestinal tract to return plasma calcium levels to normal.
- It also increases number and activity of osteoclasts in bone to increase calcium resorption from bone and stimulate release of minerals into blood.
Explain the role of calcitonin on bone
released from specific thyroid cells (parafollicular) in response to elevated calcium levels in the blood.
It acts by lowering calcium levels in the blood by inhibiting osteoclastic activity in bone and favouring calcium uptake by bone to promote bone formation and decrease blood calcium levels.
It effectively does the opposite of PTH
How does calcium and phosphate levels decreasing effect bone?
Calcium and phosphorous make up half of bone mass and are an essential nutrition for bone. Their deficiency causes bones to become brittle.
What is the effect of vitamin A deficiency on bone?
Imbalance of ratio of osteoblasts and clasts to slow growth rate.
What is the effect of vitamin C deficiency on bone?
Low levels of vitamin C inhibit growth to cause insufficient production of collagen (needed for hydroxylation of collagen in production) and bone matrix. This delays bone healing.
What therapy can be used for osteoporosis?
Bisphosphonates and calcitonin both inhibit osteoclast activity. Calcitonin also stimulates osteoblast activity and favours calcium uptake into bone.
Describe pagets disease
Progressive bone destruction disease followed by formation. this causes thickening of bones, usually of the skull, pelvis and lower extremities. Most common in over 60s.
