L11) Muscles 1 (structure) Flashcards
what are the two muscle types?
striated: skeletal and cardiac muscles
non-striated: smooth muscles
what are the features of a skeletal muscle
myoglobin present
voluntary control
direct nerve-muscle communication
what are the features of a cardiac muscle?
myoglobin present
involuntary control
indirect nerve-muscle communication
what are the features of a smooth muscle?
myoglobin absent
involuntary control
indirect nerve-muscle communication
what is a myoglobin?
oxygen-storing protein
found only in striated muscle
how do myoglobin and haemoglobin relate?
myoglobin structurally similar to a single subunit of haemoglobin
haemoglobin gives up O2 to myoglobin, esp at low pH
what is the clinal relevancy of myoglobin?
when striated muscles die (muscle necrosis)
or when damaged (rhabdomyolysis)
myoglobin is released into the bloodstream (myoglobinaemia)
what are the manifestations of myoglobinaemia?
Can cause renal damage
kidneys remove myoglobin from the blood into the urine (myoglobinuria)
tea-coloured urine
what is the outer membrane of a muscle cell called?
sarcolemma
what is the cytoplasm of a muscle cell called?
sarcoplasm
what is the mitochondrion of a muscle cell called?
sarcosome
what is the contraction unit of a striated muscle called?
sarcomere
what is the smooth endoplasmic reticulum of a muscle cell called?
sarcoplasmic reticulum
broadly describe the structure of a skeletal muscle
striated muscle cell = muscle fibre
plasmalemma of muscle cell = sarcolemma
each cell (fibre) contains numerous myofibrils
describe the structure of a myofibril
the sarcomere
