9 - Structure & Function of Skeletal Muscle Flashcards
what are the 3 types of muscle?
- skeletal
- cardiac
- smooth
where is skeletal muscle located?
connected to bones
where is smooth muscle located?
hollow organs
what is the morphology of each type of muscle?
skeletal - striated
cardiac - striated
smooth - smooth
what is the control of each muscle type?
skeletal - voluntary
cardiac - involuntary
smooth - involuntary
what is the power of each muscle type?
skeletal - high power
cardiac - high power
smooth - high power
what is the typical activity of each muscle type?
skeletal - usually relaxed
cardiac - pump / cyclic
smooth - usally contracted
draw a diagram with the qualities of each different muscle type?
* location
* morphology
* control
* type of work
* activity
where does skeletal muscle originate from?
paraxial mesoderm and somites
specifically what part of the somite does skeletal muscle originate?
myotome
label the somite
- neural tube
- notochord
- aorta
- dorsal somite
- ventral somite
- somitocele
how does skeletal muscle form?
in waves
label the skeletal muscle
what neurotransmitter is present at NMJ?
ACh
what is the importance of T tubules at NMJ?
they ensure synchronised depolarisation across all myofibrils
what are the elements of the troponin complex?
TnT
TnC
TnI
explain striated muscle contraction in 5 stages
- ATP binds to myosin head and causes dissociation of actin-myosin complex
- ATP hydrolysed - myosin heads return to resting conformation
- cross-bridge forms and myosin head binds in new position on actin
- P is released - myosin heads change formation, power stroke occurs, filaments slide past each other
- ADP released
what are the 2 different types of contraction?
isometric - muscle does not shorten, but tension increases
isotonic - most common, muscle shortens
what is a muscle unit?
muscle fibres innervated by a single MN
what is a motor unit?
muscle unit plus its motor neuron
what is a motor neuron pool?
collection of neurons innervating a single muscle
what is the difference between fine motor control and coarse control in terms of muscle fibres?
fine - few muscle fibres per motor unit
coarse - many muscle fibres per motor unit
typically a muscle is controlled by how many motor neurons?
100
typically each motor neuron controls how many muscle fibres over the muscle?
100-1000
what are type 1 muscle fibres?
oxidative
slow
red
what are type 2B muscle fibres?
glycolitic
fast
white
what are type 2A muscle fibres?
glycolitic
fast
red
what muscle fibres may a marathon runner typically have?
type 1
what muscle fibres may a sprinter typically have?
type 2A
what is a muscle strain?
- pulled muscle
- muscle is overstretched, overused, improperly used
*
what is a muscle tear?
- muscle and blood vessels that supply it are torn
- significant force is neede
what is rhabdomyolysis
- muscle fibres die and content released into blood stream
- results in kidney failure
what is muscle contusion?
- muscle bruise
- blunt object striked body and crushes underlying muscle tissue
muscle injury causes what two things?
- inflammation
- proliferation
what are 3 types of chronic muscle damage?
- genetic diseases
- chronic inflammatory diseases
- sarcopenia
what is sarcopenia?
reduction of muscle mass and strength associated to aging, cachexia, malnutrition
what is the gene responsible for muscular dystrophy?
- X-linked recessive disease
- mutuation of dystrophin gene
fill in this table of muscle fibres
