MSK summary basic principles

Question 1

SLE antibodies

Answer 1

ANA
antiDNA
Anti SM 
anti Ro 
anti rNP

Question 2

sjorgens antibodies

Answer 2

ANA
anti RO
anti la

Question 3

systemic sclerosis limited antibody

Answer 3

anticentromere

Question 4

systemic sclerosis diffuse anibody

Answer 4

anti scl 70

Question 5

small vessel vasculitis antibodies

Answer 5

ANCA

Question 6

what happens when Ca2+ binds to troponin on actin filaments?

Answer 6

tropomyosin is moved to uncover cross bridge binding sites on actin

Question 7

what happens cellularly in rigor mortis?

Answer 7

no ATP present so myosin head remains attached to actin fibre

Question 8

example of isotonic contractions?

Answer 8

body movements and moving objects

Question 9

example of isometric contractions

Answer 9

supporting objects in fixed positions and maintaing body posture

Question 10

do skeletal muscles have a neuromuscular junction?

Answer 10

yes

Question 11

do skeletal muscles have a gap junction

Answer 11

no

Question 12

where do skeletal muscles get CA from

Answer 12

entirely sacroplasmic retinculim

Question 13

where do cardiac muscels get CA from

Answer 13

ECF and sacroplasmiic reticulum

Question 14

what are the 3 metabolic pathways which supply ATP in muscle fibres?

Answer 14

creatine phosphate (transfer of high energy phosphate from creatine phosphate to ADP) 
oxidative phosphorylation (main source when O2 is present) 
glycolysis (main source when O2 is not present)

Question 15

describe type 1 muscle fibres

Answer 15

slow twitch
prolonged, low work eg walking
abundance of myoglobin + mitochondria

Question 16

decsirbe 2a type muscles fibres

Answer 16

fast oxidative
prolonged moderate work eg jogging
uncommon

Question 17

describe type 2b muscle fibres

Answer 17

fast glycocytic
short term, high intensity work eg jumping
fatigue early
few mitochondria + less myoglobin than T1

Question 18

what is the sensory receptor of the stretch reflex

Answer 18

muscle spindle

Question 19

what is the stretch reflex

Answer 19

a negative feedback that resists a passive change in muscle length to maintain optimal resting length of muscle

Question 20

which fibres are sound in muscle spindle and how do they run

Answer 20

intrafusal fibres

found in muscle belly and run parallel to extrafusal fibres (normal fibres)

Question 21

what are the sensory nerve endings of muscle spindles called

Answer 21

annulospiral fibres

Question 22

what is the efferent nerve supply of muscle spindles

Answer 22

gamma motor neurones

Question 23

which components of hyaline cartialge act as elassticy and reduce friction

Answer 23

water + proteoglycans

Question 24

what is the definitoin of OA

Answer 24

articular cartilage thinning or loss

Question 25

early vs late events of OA

Answer 25

early - injury to chondrocytes + matrix, fibrillation late - inflammaotry changes in synovium + subchondral bone --> bone on bone

Question 26

which scale is used for OA

Answer 26

kellgren - lawrence

Question 27

surgical treatment for OA

Answer 27

THA

Question 28

what causes reactive arthritis

Answer 28

chlamydia, shigella and salmonella

Question 29

what is the cause of enteric arthritis

Answer 29

organisms with high lipopolysaccharides in cell wall trigger immune reaction

Question 30

what bug causes infectious arthritis in kids

Answer 30

h influenza

Question 31

what bus causes infectious arthritis in adults

Answer 31

staph aureus

Question 32

explain the mechanisms behind increased uric acid synthesis?

Answer 32

diet -> purines -> xanthine -> uric acid

Question 33

what causes hyperuriacemia?

Answer 33

idiopathic 90% HGORT enzyme deficiency (lesche nyhans syndrome) increased cell turn over eg cancer and psoriasis

Question 34

causes of reduced excretion of uric acid?

Answer 34

thiazide diuretics

Question 35

definition of gout

Answer 35

inflammatory arthriis caused by deposition of uric acid in joints >0.42mmol/L

Question 36

how is uric acid excreted normlally

Answer 36

2/3rds from renal | 1/3rds from GI

Question 37

what causes gout?

Answer 37

joints of lower temperature (decreases solubility of urate) duration of hyperuricaemia loop diuretics eg furesomide

Question 38

what is gouty tophus

Answer 38

deposition in soft tissues

Question 39

histology findings of tophus

Answer 39

amorphous eosinophilic debris + inflammation (giant cells) | pyrophosphate arthropathy

Question 40

side effect of colcichine

Answer 40

diarrhoea

Question 41

how does allopurinol work

Answer 41

xanthine oxidase inhibitor | start it 2-4 weeks after acute attack

Question 42

which cartilage does calcium pyrophosphate / gout affect

Answer 42

fibrocartilge eg knees, wrists, ankles

Question 43

which type of pseudo gout causes milwaukee shoudler

Answer 43

calcium hydroxyapatite crystals | females 50-60

Question 44

grading score for joint hypermobility syndrome

Answer 44

modified beighton score

Question 45

definitoin of OP

Answer 45

quantitive defect | decreased BMD and increased porosity

Question 46

features of type 1 OP

Answer 46

post menopausal | colles fracture

Question 47

features of type 2 OP

Answer 47

secondary / old age / alcohol | femoral neck frcature + vertebral fractures

Question 48

casues of OP

Answer 48

decreased OB | decreased physcial acivity

Question 49

biochem of OP

Answer 49

decreased Ca increased PTH decreased vit D

Question 50

what is the causes of osteomalacia

Answer 50

softer bones -> fracture | decreased vit d (vit d sitmulates aborption of ca)

Question 51

roles of PTH

Answer 51

activates OC (releases calcium from bone) increases resorption of calcium by renal tubules increases urinary phosphate excretion

Question 52

which non-tumour is associated with hyperparathyroidism?

Answer 52

brown tumour

Question 53

what is the biochem of hypeparathyroidism

Answer 53

increased PTH and increased Ca

Question 54

what happens in secondary hyperparathyroidism?

Answer 54

overproduction of PTH secondary to hypercalcemia

Question 55

what happens in tertiary hyperparathyroidism?

Answer 55

chronic secondary >develops an adenoma which continues to produce PTH despite biochemical correction

Question 56

what happens in pagets disease of bone?

Answer 56

abnormality of bone turn over > thick excess bone > increased metabolism

Question 57

what are the genetic behind pagets?

Answer 57

SQSTM1 / p62

Question 58

what are the 3 stages of pagets

Answer 58

osteolytic mixed (OB and OC activity) osteosclerotic

Question 59

what are the extra manifestations of pagets?

Answer 59

warm skin AV shunt heart failure

Question 60

secondary malignnacies of pagets

Answer 60

osteosarcoma | fibrosarcoma

Question 61

pathophysiolgy of myasthenia gravis

Answer 61

auto-IgG binds with ACH receptors on muscle cells

Question 62

what can cause myasthenia gravis

Answer 62

thymic tumour 10%

Question 63

diangosis of myasthenia gravis

Answer 63

anti AChR IgG in serum + NMJ dysfunction

Question 64

treatment of myasthenia gravis

Answer 64

increase neurotranmission - pyridstigmine surgery - if thymic tumour immunosuppression - corticosteroids

Question 65

where are nuclei found in skeletal muscles

Answer 65

at peripheries of ibres, ust under sarcolemma (cell membrane of muscle fibres)

Question 66

what are fascices

Answer 66

bundles of muscle fibres

Question 67

what is epimysium

Answer 67

connective tissue which surrounds whole muscle

Question 68

what is perimysium

Answer 68

surrounds single fasicle

Question 69

what is endomysium

Answer 69

surrounds single fibre

Question 70

where are chondrocytes found

Answer 70

lacuna

Question 71

describe hyaline cartilage

Answer 71

blue-white translucent most common

Question 72

decsribe elastic cartilage

Answer 72

light yellow | flexible

Question 73

describe fibrocartialge

Answer 73

T1 collagen chondrocyytes cartliaginous Ecm white

Question 74

what is the composition of bone

Answer 74

65 % hydroxyapatite 23% collagen 10% water 2% non-collagen proteins

Question 75

what is the epiphysis

Answer 75

cancellous or trabecular bone

Question 76

what is diaphysis

Answer 76

cortical bone

Question 77

what are osteoproginator cells

Answer 77

located on bone surfaces eg under periosteum, pool of reserve OBs

Question 78

what secretes osteoid

Answer 78

OB

Question 79

types of pain

Answer 79

transduction transmission modualtion perception

Question 80

what is transduction pain

Answer 80

translation of noxious stimulus into electrical activity at the peripheral nociceptor

Question 81

what is transmission pain

Answer 81

propagation of pain signals as nerve impulses through the nervous system

Question 82

what is modulation pain

Answer 82

hidering of pain by opiates

Question 83

what is perception pain

Answer 83

concious experience of pain

Question 84

what are nociceptors

Answer 84

first order neurone / aferent sensory neurones

Question 85

where are nociceptors found

Answer 85

dorsal horn of spinal cord

Question 86

what is the neurotransmitter of nociceptors?

Answer 86

glutamate + peptides

Question 87

what are the 2nd order neurones in the nociceptive pathway?

Answer 87

the spinothalamic tract (pain perception) + the spinoreticular tract (autonomic respone to pain, arousal, emotional response + fear of pain)

Question 88

A$ subtype nociceptor

Answer 88

mechnical / thermal thinly myelinated conduction velocity 6-20ms-1 mediate first / fast pain

Question 89

C fibres nociceptor

Answer 89

unmyelinted conduction velocity 0.5-2ms-1 all noxious stimuli (polymodal ) mediate slow or secondary pain eg burning, throbbing, cramping, aching sensations