Chapter 17: Muscle Skeletal system Flashcards
Characteristics of Muscle fibers
Irritability: ability to receive stimuli
Contractability: shortening in muscle length
Extensibility: ability to stretch or lengthen
Elasticity: ability to respond to resting length after being stretched
Muscle fiber structure
Epimysium -> Fasicle -> Muscle Fiber -> Myofibrils
What cover fasicle? muscle fibers? myofibrils?
perimysium
endomysium
sarcolemma
Contents of a muscle fiber?
Nuclei/ Mitochondrion
SR and T-tubules
Myofibrils
Sarcolemma
Contents of myofibril
sacromeres
What is sacromere composed of?
Actin/ Myosin Z disc, M line (central line of sarcomere) H zone: only myosin A band: overlapped myosin and actin I band: only actin
What are the components of actin?
troponin (C and I) and tropomyosin
What is responsible for conduction of action potential in muscle fibers?
T- tubules, run deep from epimysium to myofibrils
What trigger the release of Ca2+? Where does it release?
action potential conduction in T-tubules Sarcoplasmic reticulum (SR)
When does the power stroke of myosin occur?
the release of ADP and P(i)
How is the length of myosin and actin filament during muscle contraction?
they are not changing but sarcomeres do
Where is in the sarcomere there are more intermediate elastic filament? What does it do?
from Z-disc to central line
help sarcomere to contract
What are the muscle fibers type? and each motor neuron type
Slow oxidative (type 1 alpha motor neuron) Fast glycolytic (type 2 alpha motor neuron) Fast oxidative glycolytic (type 2 alpha motor neuron)
What type of muscle fiber that can swing between SO and FG?
FOG
How is the force generate by FG and FOG
they are the same
What are the chacteristics of slow oxidative fiber?
high mitochondrion, capilaries, myoglobin, oxidative enzyme
high triglyceride and low glycogen
What are the characteristics of FG?
high phosphate creatine store, high glycogen,
myosin-ATPase
How is the size of motor neuron of FG and FOG compared to SOG?
they are larger in size and well myelinated
What muscle fiber type can recruit more motor neurons than the other?
FOG and FG
How is the proportion of slow oxidative fiber in female compare to male?
female has higher slow oxidative fiber than male
How is the proportion of fast twitch fiber in both sex?
they are the same
What is the characteristic of myosin?
they contain 2 heads and a rod-like tail
The process whereby the electrical events in the sarcolemma are linked to
movement in the myofibril is called?
excitation-coupling reaction
The fast and slow property of muscle fibers depends on what subcategory
alpha motor neurons type and the enzyme activity of ATPase
What is required for both activation of myosin head and detachment of myosin and actin?
ATP
How is the fiber type relative to the motor unit?
Only one type of fiber in one motor unit
How many percent muscles account for male and female?
40-45%
23-25%
What is the different name for skeletal muscle fiber?
extrafusal muscle fibers
