Muscle Tissues 2 Flashcards
Clinical condition - what is myasthenia gravis?
- an autoimmune disease
- where antibodies are directed against ACH receptors.
- reduced synaptic transmission.
- leads to muscle weakness
- eg ptosis ( droopy eyelid)
What will be a difference in muscle fibre between someone who has got myasthenia gravis and not ?
- there would be more boutons ( pre synaptic axon terminals ) as nerves are not stimulated.
What are the two fibres actin is made up of ?
G actin fibres ) depolymerised )
And F actin fibres ( polymerised )
What is compartment syndrome ?
- trauma in one compartment in limb which causes internal bleeding - exerts pressure on blood vessels and limbs.
-
What are the symptoms of compartment syndrome ?
- parathesia ( pins and needles)
- tense / firm
- swollen , shiny skin
- prolonged capillary re fill time
-
How is compartment syndrome treated?
- -fasciotomy - limb is cut to relieve pressure / tension
- skin graft is then performed.
What is duchene muscular dystrophy
- inherited x linked recessive gene
- mutation of the dystrophin gene
- absence of this gene causes excess ca2+ to enter muscle cells , which is then taken up by mitchochondria, which then burst due to water uptake.
- this leads to rhabclomyolysis.
- creatine kinase and myoglobin levels in the blood then increase.
- muscle is then replaced with adipose tissue.
What aresymptoms of duhcene muscular dystrophy ?
- belly sticks outbdue to weak belly muscles
- shoulders and arms are held back.
- poor balance
- thick lower leg muscles ( muscles mostly fat)
What is creatine kinase and what can it be used to indicate ?
- creatine kinase levels in the urine could be a good indicator of rhabdomyolysis.
- muscular dystrophy
- overdoing in the gym
- myocardial infaraction.
- acute kidney injury
What is botulism toxin ?
- this toxin blocks the release of of ACH.
- this causes flaccid paralysis , characterised by reduced muscle tone.
- most common in children.
What are the symptoms of botulism ?
- diorreah
- NO fever
- swollen abdomen
- weakness of arms and legs
- vomiting
What is organophosphate poisoning ?
- inhibits the normal functioning of ACH esterase.
- often an insectice / pesticide
- excess ACH in body
-
What are symptoms of organophosphate poisoning ?
- tachycardia
- vomiting ( emesis)
What is the cause of malignant hyperthermia ?
- a severe reaction to medication during general anaesthesia
What does malignant hyperthermia result in ?
- excess ca2+ ions released in muscle cells which resulting a in continuous muscle contraction.
- this in turn , generates excess heat and leads to metabolic acidosis.
