midterm review Flashcards
proteins found in a sarcomere
actin
myosin
ATPase
troponin
tropomyosin
proteins involved in muscle contraction
actin
myosin
ATPase
troponin
tropomyosin
proteins that can prevent muscle contraction
troponin
tropomyosin
fastest contracting fiber type
type Iix fiber
energy currency of a cell
ATP
enzyme involved in a muscle contraction
ATPase
which of the following is the smallest structure
a) muscle fiber
b) myosin
c) myofibril
d) sarcomere
myosin
an enzyme:
a) is a protein
b) is a molecule that increases the rate of chemical reactions
c) could change its level following
d) all of the above
d) all of the above
what suffix is commonly use to describe an enzyme
ase
using this suffix name the enzyme that is involved in the reaction where ATP is broken down for energy
ATPase
which protein interacts with myosin during muscle contraction
actin
which 2 proteins are involved in the blocking of myosin to prevent muscle contraction
troponin
tropomyosin
see diagrams
true or false
there are three main fiber types: fast (Iix), intermediate (IIa) and slow (I)
true
true or false
the fiber types an individual posses is determined by genetics and cannot be changed
false
true or false
Type I fibers are the fastest contracting fibers in humans
false
true or false
strength training leads to a conversion of slow fibers to fast fibers
false
types of myosin heavy chains
list from fastest to slowest contracting
type I
type Iix
type IIa
Type IIx
type IIa
type I
put in order from largest to smallest
-sarcomeres
-myofibrils
-whole muscle
-muscel fasicle
- actin and myosin
-muscle fibers
-myoisn heavy chains
Whole muscle
muscle fascicles
Muscle fibers
myofibirls
actin, myosin
myosin heavy chains
what are considered contractile proteins
actin and myosin
what are considered regulatory proteins
troponin and tropomyosin
which protien binds calcium
troponin
what is bordered by z discs
sarcomere
what protein blocks binding sites on actin
tropomyosin
what protein controls speed of contraction
ATPase
after muscle contracts, what ion must be removed from the cytoplasm of your muscle cells before muscle relaxation can occur
calcium
put in following steps in the process of contraction in proper order
-myosin binds to actin
-muscle relaxes
-calcium binds to troponin
-ATP broken down
-dissociation of actin and myosin
-calcium is removed from troponin
-troponin lifts off tropomyosin off actin
calcium binds to troponin
troponin lifts tropomyosin off actin
myosin binds to actin
ATP broken down
dissociation of actin and myosin
with which type of muscle contraction can you generate the most force
eccentric
which of the following shortens during a muscle contraction
sarcomere, myosin, actin
sarcomere
where is the enzyme ATPase found in skeletal muscle
myosin head
sarcoplasmic reticulum
mitochondria
how does ability to generate muscular force changes as velocity of concentration increases?
As velocity increases the ability to generate muscle force decreases, actin and myosin don’t from cross bridges as efficiently at faster speeds.
which fiber type has
high ATPase
fast-fatiguability
Type IIX
which fibre type has
low ATPase
slow twitch
Type I
which fiber type has
fast fatigue resistant
type IIA
see diagram
what is force summation and what causes it
Before a muscle relaxes from a contraction, if another electrical signal is applied once increased to a higher level
What causes it
* this is due to increased release of calcium from the SR
* the calcium will bind more troponin, lifting tropomyosin allowing more myosin actin cross bridges
what is tetanus and what causes it
Force will only summate up to a maximal level with receptive stimulation
This maximal level is reaches one all their for calcium on troponin have been occupied therefore no more cars bridges can occur
classification baed on myosin heavy chain chains (ATPase activity)
type I
type IIA
type IIX
classification based on metabolic properties
slow oxidative
fast glycolytic
describe how motor unit recruitment (recruitment of fast or slow twitch or intermediate motor units) would change as one goes from a duo walk to a jog to a sprint
Recruitment type 1 slow twitch during walk, as intensity increases recruit more and more fast twitch
which receptor, when activated causes reflex contraction of muscle ?
muscle spindle
which receptor when activated causes inhibition of contraction?
Golgi tendon organ
which receptor do you think causes inhibition if antagonistic musculastrucnture
muscle spindle
which receptor do you think causes activation of antagonistic musculastructure (if the receptor in the quadriceps is activated, it would cause activation of the hamstrings)
Golgi tendon organ
reflex contraction of a muscle after spindle activation
efferent
voluntary contraction of your biceps by recruitment of motor neurons in the spinal cord
efferent
your eyes transmit a signal to your brain about the position of a soccer ball
afferent
vestibular (inner ear) sensors send a message to your brain to correct your balance
afferent
a motor neuron recieven 10 excitatory impulses form one other neruon over the time period of 2 milliseconds
temporal summation
another motor neuron receives one excitatory impulse from each of 5 different neurons
spatial summation
true or false
a motor unit has only one motor neuron but many muscle fibers
true
true or false
a motor unit can have a mixture of slow twitch and fast twitch muscle fibers
false
true or false
when a motor neruon, is activated only a portion of the muscle fibers in that motor unit will contract if low intensity exercise is being performed
false
all or none
true or false
motor units in different muscles throughout the body are the same size
false
Some are big for grow movement others are small for fine movement
motor neuron, motor pool and motor unit
where calcium is stored
sarcoplasmic reticulum
influx/efflux of these cause change in membrane potential
sodium and potassium
transmit AP from neuron to muscle fiber
transerve tubule
nerve cells connected to muscles fibers
motor neurons
part of the brain where voluntary contraction originates
motor cortex
excites membrane and changes permeability
acetylcholine
covered by a myelin sheaf
axons
a motor neuron and all the muscle fibers that are connected to it
motor unit
fast twitch muscle fibers require a higher frequency electrical input to reach tetanus compared to slow bewitch fibers. why is this so?
Because they relax faster
membrane potential changes from -70 to -90 mV
hyper polarize
membrane potential changes from -70 to -50
-80 to -70
depolarize
membrane potential changes from +40 to -60mV
re-polarize
if someone trains just one limb for a period of time, but also sees an increase in strength in the opposite (untrained limb) this natural phenomena is called?
cross-education
mechanisms:
(recruiting ipsilateral pathways, ceiling effect,
the neural phenomenon of the sum strength of two unilateral limbs being greater than when both limbs are used simultaneously is called
bilateral deficit
mechanisms
(trunk stability, more stable with more joints
train bilaterally you can improve bilateral movement and decrease bilateral deficit
inter hemisphere inhibition )
largest to smallest
muscle
fascicle
muscle cell (muscle fiber)
myofibril
myofilaments
write out the steps of excitation contraction coupling, up to and including relaxation of the muscle
- Impulse is received, calcium causes sac like
Vesicles in the axon terminal release ACh. Ach diffuses across synaptic Cleft, attach to receptors in sarcolemma, changes membrane permeability - If at threshold, AP depolarizes T-tubule
- Depolarization of T-tubule
causes Ca2+ to be released from SR - Ca2+ binds to troponin and tropo-
myosin, allowing myosin & actin to combine - Actin combines with myosin, ATPase is Activated to split ATP = energy
- Sliding of actin and myosin, cross-bridge detaches from actin
- Continued new cross-bridge action occurs if Ca2+remains high (membrane depolarization inhibits action of troponin- tropomyosin complex)
- Muscle stimulation stops, Ca2+ moves back into SR
- Removal of Ca2+ reinstates troponin- tropomyosin inhibitory action, actin and myosin stay in relaxed state (disassociated)
