Muscular System
which solution from the protocol had NO muscle contraction?
KCl+MgCl2
formed by supporting proteins holding thick filaments together in the center of the H zone
M line
as a result of glycerination process_______is no longer needed for muscle contraction to occur, which is different from normal muscle contraction physiology within our bodies
Calcium
layers of connective tissues from the innermost to the outermost
Endomysium, perimysium, epimysium
Center of A band Only thick filaments
H zone
contains ONLY thin filaments
I band
entire length of the filament; contains area of overlap with thin filament
A band
within our bodies, muscular contraction can last for as long as there is enough:
ATP and calcium
a combination of _______ and _______ forms the cross bridge during a muscle contraction cycle
Actin and troponin
striated muscle
skeletal and cardiac
combined with connective tissue and neural tissue
skeletal muscle
multinucleated and superficial
skeletal muscle
skeletal muscle > muscle fascicle > muscle fiber > myofibril > sarcomere
skeletal muscle fiber in order from largest to smallest
type of muscle fiber needed to: run a marathon
slow oxidative fibers
muscle with involuntary contractions
smooth and cardiac muscles
Non-striated muscle
smooth muscle
found in the walls of blood vessels
smooth muscle
found in walls of digestive, respiratory, urinary, and reproductive organs
smooth muscle
connects a Z disc to the M line of a sarcomere. helping stabilize the position of the thick filament
titin
proteins that are considered structural proteins
titin, alpha-actinin, myomesin, nebulin, dystrophin
what is the function of post synaptic calcium in muscle contraction?
to bind troponin, change shape and move tropomyosin from the active site
formed by transverse tubules and two terminal cisternae
triad
this protein is a component of the thin filament that will cover the myosin-binding sites on the actin molecules
tropomyosin
proteins that are considered regulatory proteins
tropomyosin and troponin
this protein is a component of the thin filament and is where calcium ions will bind to during skeletal muscle contraction
troponin
(T/F) a fiber is categorized as slow or fast depending on how rapidly the ATPase in its myosin heads hydrolyze ATP
true
(T/F) depolarization of the motor end plate is what causes post-synaptic calcium ions to be released from the sarcoplasmic reticulum
true
(T/F) fast glycolytic fibers have low myoglobin content, few blood capillaries, few mitochondria, and appear white in color
true
(T/F) fast oxidative-glycolytic fibers have a high intracellular glycogen level, which allows them to generate ATP by aerobic respiration
true
(T/F) skeletal muscle fibers that have a high myoglobin content are termed RED muscle fibers
true
(T/F) slow oxidative fibers are smallest in diameter and are the least powerful type of muscle fibers
true
(T/F) slow oxidative fibers generate ATP mainly by aerobic respiration
true
cardiac, skeletal, muscle
types of muscles
narrow, plate shaped regions of dense protein
z disc
muscle with voluntary contractions
Skeletal muscle
structure present: muscle fascicle membrane surrounding: epimysium
Skeletal muscle
invaginations of the sarcolemma; filled with extracellular fluid
T-tubules
main component of the thin filament that has an active myosin-binding site
actin
present in the Z discs, it will attach to actin and titin molecules
alpha actinin
SO Fibers: high capacity by aerobic respiration FOG fibers: intermediate capacity by aerobic respiration and anaerobic glycolysis FG Fibers: low capacity by anaerobic respiration
capacity for generating ATP and method used
single nucleus and deep
cardiac and smooth muscle
located in the heart
cardiac muscle
muscle with intercalated discs
cardiac muscle
which process is used to create ATP to provide energy to muscles?
cellular respiration
SO Fibers: red FOG fibers: red FG Fibers: white
color
ability of muscle to contract forcefully when stimulated
contractibility
SO Fibers: slow FOG fibers: fast FG Fibers: fast
contraction velocity
this might help transmit the tension generated by sarcomeres to tendons
dystrophin
ability of muscle to return to original length and shape after contraction or extension
elasticity
ability to respond to certain stimuli by producing action potentials
electrical excitability
connective tissue surrounding each individual muscle fiber
endomysium
connective tissue wrapping around muscle
epimysium
What is the role of acetylcholine in skeletal contraction?
excitatory neurotransmitter that helps in skeletal contraction
ability of muscle to stretch without damage
extensibility
(T/F) A triad consists of the motor end plate and its flanking terminal cisternae
false
(T/F) fast oxidative-glycolytic fibers are fast-twitch fibers adapted for intense movements of short duration like weight lifting or throwing a ball
false; best adapted for walking and sprinting
(T/F) fast glycolytic fibers are intermediate in diameter and have a high resistance to fatigue
false; moderate resistance to fatigue
type of muscle fiber needed to: weight lifting for body building
fast glycolytic fibers
type of muscle fiber needed to: walk to the bus stop
fast oxidative glycolytic fiber
SO Fibers: high FOG fibers: intermediate FG Fibers: low
fatigue resistance
SO Fibers: smallest FOG fibers: intermediate FG Fibers: largest
fiber diameter
smaller structure within myofibrils
filaments
serves as storage form of glucose; can be broken down and used to synthesize ATP
glycogen
SO Fibers: postural muscle such as the neck FOG fibers: lower limb muscles FG Fibers: upper limb muscles
location where fibers are abundant
SO Fibers: have many FOG fibers: have many FG Fibers: have few
mitochondria and capillaries
SO Fibers: first FOG fibers: second FG Fibers: third
order of recruitment
connective tissue surrounding a bundle of muscle fibers
perimysium
SO Fibers: maintaining posture and aerobic endurance activities FOG fibers: walking/sprinting FG Fibers: rapid intense movements of short duration
primary functions of fibers
SO Fibers: slow FOG fibers: fast FG Fibers: fast
rate of ATP hydrolysis by myosin ATPase
What is the role of acetylcholinesterase in skeletal contraction?
reuptake of NT into pre-synaptic terminal breaks down any ACh that is present in the synaptic cleft
plasma membrane of a muscle fiber
sarcolemma
repeating units of myofibril
sarcomere
thick and thin filaments
sarcomere
surrounded by the sarcolemma; the cytoplasm of the muscle fiber
sarcoplasm
storage center of calcium in relaxed muscle
sarcoplasmic reticulum
makes up the thick filaments. consists of 2 heads and a tail
myosin
proteins that are considered contractile proteins
myosin and actin
wraps around the entire length of each thin filament. it also helps to anchor thin filaments to Z discs in addition to regulating the length of thin filaments during development
nebulin
1- action potential occurs in the somatic motor neuron 2- ACh (excitatory neurotransmitter for skeletal muscle) that is stored in the synaptic vesicle of the synaptic end bull is released and diffused across the synaptic cleft 3- ACh binds to nicotinic ACh receptors on the motor end plate 4- Depolarizing graded potential called end plate potential (EPP) is generated 5- Adjacent regions of the sarcolemma are then depolarized, resulting in the generation of a muscle action potential. This action potential propagates through the muscle fiber membrane in both directions away from the NMJ towards the end of the fiber 6- At the onset of muscle fiber contraction, the sarcoplasmic reticulum releases calcium ions into the sarcoplasm 7- The calcium ions then bind to troponin, which moves tropomyosin away from myosin binding sites on actin 8- Now that the binding sites are free, ATP is hydrolyzed into ADP and a phosphate. This energizes the myosin head which then assumes the "cocked" position 9- The energized myosin head then attaches to the myosin binding site on actin and a phosphate is released. This is referred to as the "crossbridge" 10- The myosin head pivots changing its position from 90 degrees to 45, pulling the thin filament past the thick filament towards the center of the sarcomere. This is referred to as the power stroke 11- Another molecule of ATP binds to the ATP binding site on myosin allowing for myosin to detach from actin
muscle contraction steps
structure present: muscle fibers membrane surrounding: perimysium
muscle fascicle
structure present: myofibrils membrane surrounding: endomysium
muscle fiber
contractile element of the skeletal muscle fiber; containing thick and thin filament
myofibril
structure present: sarcomeres membrane surrounding: sarcoplasmic reticulum
myofibril
red, oxygen binding protein that is only found in the muscle; stores oxygen until it is needed by the mitochondria for ATP
myoglobin
SO Fibers: large amount FOG fibers: large amount FG Fibers: small amount
myoglobin content
forms the M line of the sarcomere. it also binds to titin molecules and connects adjacent thick filaments to one another
myomesin