Module 7-9 TBL Questions Flashcards
Which structure of sarcomere identifies each end of sarcomere?
Z disc
Which structure of sarcomere contains only myosin when at rest?
H band/zone
Which structure of sarcomere contains only actin attached to the Z line?
I band/zone
Which structure of sarcomere contains both actin and myosin?
A band/zone
Which structure of sarcomere is at the center of a sarcomere?
M line
What is titin in the sarcomere?
a coiled protein that holds actin and myosin in place
When an AP arrives at the axon terminal of a motor neuron it opens voltage gated _________ channels
calcium
What type of cholinergic receptor is located at the motor end plate?
nicotinic
In order for an AP to propagate across the sarcolemma it must open ______________________ channels and in order for the sarcolemma to repolarize it must open ________________________ channels for it to repolarize
voltage gated sodium, voltage gated potassium
What is the next event after an action potential moves down the T tubules?
ryanodine channels open calcium release channels in the SR
What is happening when more and more muscle fibers contract within the whole muscle to increase the strength of the contraction?
recruitment
What type of activity can increase the number of sarcomeres within a muscle cell?
stretching
Which antagonist blocks ACh release from a motor neuron?
botulinum toxin
How would you describe the resting membrane potential of a skeletal muscle cell?
negative on the inside and positive on the outside
What does calcium bind with after it enters the axon terminal in a resting motor neuron?
calmodulin
Which ion effectively stimulates vesicles to fuse with the active zone on the presynaptic membrane?
calcium
What does calcium bind to inside a skeletal muscle cell?
troponin
The influx of this chemical is responsible for depolarizing a skeletal muscle fiber
sodium
What must happen to end stimulation of the motor end plate?
ACh must be removed from the synapse
Which event stimulates the cross bridge formation in the sarcomere?
tropomyosin moves exposing myosin binding sites on the actin filament
What must happen to end a muscle cell contraction?
calcium must be removed from the sarcoplasm
Which event disengages the cross bridge formation between actin and myosin?
ATP binds to the free site on the myosin head
What type of whole muscle contraction appears smooth and continuous due to successive frequent contractions of muscle fibers within the whole muscle?
tetanization
Start position is full flexion of a biceps curl with an 15 lb weight. Now the dumbbell is lowered so that the forearm is parallel to the flow. What type of contraction is occurring in the bicep brachii muscle during the last phase of this activity?
eccentric
How does long term athletic events in extreme heat (>90 degrees) cause decreased potassium in blood?
stimulate continued aldosterone secretion
Athletic training will increase muscle size by increasing….
the amount of myofibrils within the muscle cell
How does nitric oxide effect exercising skeletal muscles?
causes vasodilation of immediate blood supply
Which muscle fiber is aerobic?
slow twitch
Which muscle fiber has more enzymes for phosphagen and glycogen systems?
fast twitch
Which muscle fiber has large amounts of myoglobin?
slow twitch
Which muscle fiber has few mitochondria?
fast twitch
Which muscle fiber is designed for strength?
fast twitch
Which muscle fiber fatigues easily?
fast twitch
Which muscle fiber is designed for endurance?
slow twitch
Which muscle fiber is dark in color?
slow twitch
Which muscle fiber is larger in size?
fast twitch
Which muscle fiber has fewer blood vessels?
fast twitch
Which muscle fiber has more active fibers?
slow twitch
How does an athlete significantly increase their cardiac output with only moderately increasing heart rate?
increase stroke volume
What is VO2 max?
rate of O2 usage under maximal aerobic metabolism
How does smoking cigs affect pulmonary ventilation?
contracts terminal bronchials and damages cilia
What is the main difference between male and female athletic performances if both athletes are the same age, height, and weight?
increased muscle mass due to higher levels of testosterone
What is oxygen diffusion capacity?
rate at which O2 can diffuse from alveoli into blood
Which body system is more performance limiting to a well trained athlete?
cardiovascular
Which situation is most likely the cause of a staircase effect?
increased calcium levels remaining in the cytosol
Which skeletal muscle energy system provides extra power during immediate athletic activity?
glycogen lactic acid
Which skeletal muscle energy system can cause oxygen and glycogen debt?
aerobic
During exercise, venous blood pO2 _____________ while pCO2 _____________
decreases, increases
Why is heatstroke a constant concern for athletes during performance event?
athletes increase O2 consumption during a performance to match energy demands
If a muscle is already contracted, then a force to stretch out the muscle will have to be _________ more force than can be achieved by shortening contraction
40%
How is muscle strength determined?
-force applied to muscle x distance the force is moved by the muscle
-total muscle mass
After strenuous athletic event is over, the athlete must repay the oxygen debt by deep ventilation until ______ liters is repaid
11.5
Is this an athletic heart, cardiomyopathy heart, or both?
-increase mass
both
Is this an athletic heart, cardiomyopathy heart, or both?
-decrease stroke volume
cardiomyopathy
Is this an athletic heart, cardiomyopathy heart, or both?
-decrease size of ventricle chamber
cardiomyopathy
Is this an athletic heart, cardiomyopathy heart, or both?
-increase strength of contraction
athletic heart
Is this an athletic heart, cardiomyopathy heart, or both?
-increased size is permanent
cardiomyopathy
Is this an athletic heart, cardiomyopathy heart, or both?
-works harder to meet CO demand
cardiomyopathy
Is this an athletic heart, cardiomyopathy heart, or both?
-not pathological
athletic heart
The glycogen lactic acid energy system is considered the….
in between system
Where is multi-unit smooth muscle found in the body?
ciliary muscle
Which type of smooth muscle contracts as a syncytium?
unitary
What anatomical structure allows smooth muscle cells to communicate simultaneously for a synchronized contraction?
gap junctions
How is actin and myosin arranged in smooth muscle?
actin and myosin are arranged diagonally to each other and the myosin heads pull the actin in opposite directions
Order the events of a smooth muscle contraction
1) AP opens voltage gated calcium channels
2) extracellular calcium influx
3) calcium binds to calmodulin
4) myosin light chain kinase is activated
5) side polar cross bridge forms
What happens during a smooth muscle contraction when the latch mechanism is activated?
a prolonged contraction
Smooth muscle can contract (shorten) up to ________ of its original length
80%
Which type of APs are seen in visceral unitary smooth muscle?
spike and plateau potentials
The conduction of which ion is primarily responsible for a plateau AP in smooth muscle?
calcium
Which condition can cause smooth muscle vasodilation?
A) hypokalemia
B) acidic
C) hypercalcemia
D) hyperventilation
B) acidic
Which smooth muscle structure might been a remnant of T tubules?
caveolae
Which protein holds actin secure during a smooth muscle contraction?
dense bodies
What does calcium bind with once it enters a smooth muscle cell?
calmodulin
What is the function of the myosin light chain kinase?
energize myosin to form a cross bridge with actin
What are cajal cells?
pacemaker cells
What is the major source of calcium ions required for a smooth muscle contraction?
ECF
Calcium binds to _______________ inside the SR
calsequestrin
The _____________ arrangement of myosin heads is responsible for smooth muscle’s ability to contract significantly shorter than its original length
side polar
