Human Phys Hail Mary Method

A single muscle cell is also called a [A. muscle fiber/B. myofibril].

A — muscle fiber

The middle of a sarcomere is represented by the [A. M-line/B. Z-line].

A. M-line

For a muscle to change from unfused tetany to fused tetany, the stimulus frequency must [A. increase/B. decrease].

increase

iven dual innervation by autonomic neurons, if sympathetic activity inhibits pancreatic secretion, parasympathetic activity should [A. inhibit/B. stimulate] pancreatic secretion.

stimulate

The factor that determines the duration of a twitch in various types of fibers is the speed of [A. Ca2 + ion removal/B. ATP hydrolysis by myosin].

Ca2 + ion removal

In muscles used for fine actions, like moving a hand or finger, the size of a motor unit will be [A. bigger/B. smaller] than a motor unit in muscles used for power and strength.

smaller

Both temperature and pressure receptors are located in the skin. They send their information to the brain via [A. different/B. the same] neurons

different

How many motor neurons innervate a muscle fiber?

1

Alpha motor neurons

are innervated by several different descending tracts

When a muscle cell contracts,

some myosin heads form cross bridges as others release them

Which of the following is NOT a determinant of whole muscle tension?

the proportion of each motor unit that is contracting

The following is a graph of the tension that a skeletal muscle will generate as a function of its initial sarcomere length. At approximately which position, grey dots lettered a to e, are the myosin and actin barely overlapping to yield the least tension?

e

Considering alpha-gamma coactivation, which of the following is/are TRUE?

A. Alpha motor neurons control the contraction of extrafusal fibers.

B. Gamma motor neurons adjust the stretch sensitivity of the muscle spindle so that the spindle remains active during muscle contraction.

C. Coactivation allows the spindle to remain sensitive to stretch during a contraction.

A, B and C

How would you explain the difference between relaxation of a muscle and inhibition of a muscle?

Inhibition is a process affecting motor neuron activity, while relaxation is a muscle process without motor neuron input.

You and your lab partner use a living nerve and muscle preparation to study musclecontraction and were asked to investigate how drug ZZ might be working. Based on the following seven (7) experimental outcomes, what is the most likely effect of ZZ?

1. If you electrically stimulate the nerve the muscle contracts.

2. If you electrically stimulate the muscle directly it contracts.

3. Drug TTX, which inhibits voltage-dependent Na+ channels, blocks contraction with either nerve or muscle stimulation.

4. Inhibiting ACh-Rs with curare blocks muscle contraction with nerve but not muscle stimulation.

5. If you apply drug ZZ to the preparation (with no other reagent or stimulus) the muscle contracts.

6. If you add both curare and ZZ the muscle contracts.

7. If you add both TTX and ZZ, the muscle contracts.

A. stimulating Ca+ release from the SR.

When there is a resistance to the movement produced by a given limb muscle,

A. muscle tone is increased and more motor units may be recruited to the contraction.

Which of the following statements is/are correct regarding motor units and their activation?

A. In muscles of gross movement, a motor unit can have thousands of muscle cells.

The following is a representation of 9 different motor units (mu) from a single gross muscle (un- mixed) in the arm. Tension per mu is shown on y-axis, while x-axis is frequency of action potentials. Strictly there are 9 axis - one for each mu - but here they are collapsed onto one X-axis (as discussed in class). Based on this diagram which of the following statements is FALSE?

D. regulated firing of mu 3 and 4 together can yield a range of tension from 1 to 12 units worth.

Put these phases of the cardiac cycle in the correct order.

1. opening of the semilunar valves

2. isovolumetric contraction

3. beginning of atrial systole

4. closure of the AV valves

5. completion of ventricular filling

6. beginning of ventricular systole

7. ventricular relaxation

8. ventricular ejection

B. 3, 5, 6, 4, 2, 1, 8, 7

In the cardiac cycle, ________ leads to ________, which in turn leads to ________ and therefore ________.

depolarization ; muscle contraction ; change in pressure ; blood flow

Which of the following is INCORRECT?

The adrenal medulla is a modified parasympathetic ganglion with chromaffin cells secreting hormone into the blood

Which of the following is INCORRECT?

The adrenal medulla is a modified parasympathetic ganglion that secretes acetylcholine during fight or flight

Autonomic varicosities

allow wide-spread release of neurotransmitter at the target organ

The following is a diagram of the 1A afferent coming into the dorsal horn of a spinal cord from a muscle spindle (only half of the cord is shown). An interneuron (z) is shown as are two motor neurons (mnA & mnB). Based on the connectivity of this synaptic system

A. mnA will lead to the extrafusal fibers of the same muscle as the 1A afferent

B. mnB will lead to the extrafusal fibers of the same muscle as the 1A afferent

C. the interneuron Z must be an inhibitory interneuron

D. A and C

Which statement(s) apply to the parasympathetic division of the nervous system?

A. It is dominant during “resting and digesting.”

B. Its ganglia are nearby, on or within their target organs.

C. Epinephrine is the primary neurotransmitter of the parasympathetic division.

D. A and B

Compared to skeletal muscle, contraction of smooth muscle cells is

A. a slower response to a stimulus.

B. sustained without fatigue.

C. controlled by the somatic nervous system.

D. A and B

A [A. myofibril/B. myofiber] is a single muscle cell.

myofiber

The highly organized bundles of contractile proteins within a skeletal muscle cell are called the [A. myofibril/B. myofiber].

myofibril

The [A. z-line/B. M-line] is the structure that marks the boundary between sarcomeres.

z-line

Based on the following diagram of a sarcomere, which statement below is CORRECT?

Most of the molecules involved in regulating skeletal muscle contraction are located on the filament labeled A.

Which of the following statements is FALSE?

E. none of the above, they are all correct.

During a skeletal muscle contraction

A. the I band becomes shorter

Given how a muscle contracts to give us movement, which feature of the sarcomere is the most essential?

C. overlapping thick and thin filaments

Within a single fiber, the tension developed during a twitch depends upon the

E. length of the sarcomeres prior to contraction.

Which statement CORRECTLY describes a step in the cycle of interactions between myosin and actin during force generation?

E. The head of myosin moves forward (is cocked) when ATP is hydrolyzed to ADP & Pi.

The molecular event that occurs immediately after the power stroke is the

E. release of ADP from the myosin.

At the conclusion of the power stroke the myosin head is [A. bound /B. not bound] to actin.

bound

When a skeletal muscle cell contracts and the muscle shortens,

D. some myosin heads are forming crossbridges as others are releasing them.

ATP is required in skeletal muscle for each of the following EXCEPT

E. release of Ca2 + from the sarcoplasmic reticulum.

Excitation-Contraction Coupling occurs through a series of discrete steps. The six below are some of these steps so place them in the correct sequence from beginning to end.

1. activation of the DPH receptor

2. pumping of calcium back into the SR

3. entry of sodium from an ACh receptor

4. release of calcium from the SR

5. opening of the Ryanodine receptor

6. formation of a muscle action potential.

D. 3, 6, 1, 5, 4, 2

The role of calcium in muscle contraction is

C. to regulate when actin is free to bind to myosin.

The purpose of transverse tubules is to

A. rapidly conduct action potentials to the interior of the muscle fiber.

If the transverse-tubules of a skeletal muscle are disconnected from the plasma membrane, will you get a muscle contraction? Why or why not?

D. No, contraction will not occur, as muscle action potentials no longer communicate with the SR for calcium release

Which of the following is NOT correctly paired?

A. Ryanodine receptor ; voltage-dependent

In skeletal muscle, the speed with which force is developed is determined by this protein ________, while relaxation is the role of this protein ________.

B. Myosin ATPase ; Ca2+-ATPase

The following is a diagram of the NMJ and a muscle depicting aspects of excitationcontraction coupling. mn = motor neuron; T-t = T-tubule; SR =sarcoplasmic reticulum. Based on this diagram, which of the following statements is FALSE?

B. a mechanically gated calcium release channel is present at 5.

Phosphorylation of myosin light chains in smooth muscle is associated with a/an [A. increase/ B. decrease] in contraction.

increase

Smooth muscle contraction is mediated by the phosphorylation of ____________, which occurs as a result of a chain of biochemical events including the binding of calcium ions to ____________.

E. myosin light chain, calmodulin.

In smooth muscle, the protein directly activated by the Ca2+-calmodulin complex is

A. myosin light chain kinase

Which of the following statements about smooth muscle is FALSE?

E. In smooth muscle the primary mechanism regulating contraction is associated with tropomyosin.

In smooth muscle, the primary mechanism regulating contraction is associated with [A. actin /B. myosin] filaments.

myosin

Which characteristic differentiates skeletal muscle from both cardiac and smooth muscle?

C. stimulated by somatic motor neurons

Which of the following comparison of muscle types is INCORRECT?

C. Skeletal and cardiac muscle are characterized by thick filament regulation, while smooth muscle uniquely uses thin filament regulation.

Which of the following is NOT a correct comparison of cardiac myocytes to other muscle cell types?

C. Like skeletal muscle, contraction of cardiac muscle is under autonomic nervous control.

The bulk of our visceral smooth muscle is made up of [A. muti-unit/B. unitary] smooth muscle.

unitary

Which of the following is NOT a property of single-unit smooth muscles?

A. Each cell functions independent of its neighbor.

Which of the following statements concerning muscle types is FALSE?

B. Muscles with high glycolytic capacity are more resistant to fatigue.

[A. Oxidative/B. Glycolytic] muscle fibers contain less myoglobin

Glycolytic

A. Fast-twitch/B. Slow-twitch] fibers generate more force

Fast twitch

[A. Fast/B. Slow] twitch muscles fatigue easily.

Fast

Loads are moved by [A. isometric/B. isotonic] contractions.

isotonic

A contraction that generates force and moves a load is known as __________, whereas one that generates force without movement is known as __________.

B. isotonic, isometric

Almost every contraction begins and ends as an [A. isotonic/B. isometric] contraction.

isometric

Before the entire muscle can change length, the force generated by the muscle must stretch the [A. contractile/B. elastic] elements within a fiber.

elastic

In order for the bicep muscle to shorten, the force applied by the muscle must be [A. less than/B. greater than] the load applied at the hand.

greater than

Which of the following represents the profile of a fully isometric contraction

A

In the body, the bones act as __________ whereas the joints form the __________, so that the muscles attached to the bones can create force when they contract.

E. levers, fulcrums

In the arm, the biceps brachii is a flexor whereas triceps brachii is an extensor. Which of the following statements is TRUE?

D. A and C

The following is a diagram showing development of tension in a muscle fiber subjected to neuronal stimulation. Based on this diagram, which of the following statements is CORRECT?

B. Trace B is demonstrating summation of two muscle twitches occurring in response to two closely timed neuronal stimulus.

The following is data from a muscle preparation in a physiology lab class. The top trace is muscle tension and the bottom is muscle action potentials. Based on this diagram, which statement below is TRUE?

B. Evidence of muscle fatigue is observed at position C (arrowhead & circle)

The brief period of time between the end of the action potential in the muscle and the beginning of contraction is referred to as

E. the latent period.

Muscle fatigue

D. may involve the degree of ACh release from the motor neuron

Motor neurons are often grouped together if they innervate the same gross muscle. These neurons have all of the following things in common EXCEPT:

B. being part of the same motor unit

Each of these statements is true, except one. Identify the exception.

D. The whole skeletal muscle contracts in an all-or-none manner.

The following is a representation of 9 different motor units (mu) from a single gross muscle (unmixed) of the arm. Tension per mu is shown on y-axis, while x-axis is frequency of action potentials. Strictly there should be 9 axis - one for each mu - but here they are collapsed onto a single axis (as per discussed). Based on this diagram which of the following is FALSE?

C. Synchronous maximum firing of mu 5 and 6 will yield a tension of 6 units.

Control of [A. frequency/B. recruitment] refers to the number of individual neurons involved in a gross muscle contraction.

recruitment

Which of the following does NOT complete this sentence correctly? “Alpha motor neurons …”

A. are inhibited by pre-synaptic mechanisms operating at the neuromuscular junction.

Which of the following statements regarding skeletal muscle is TRUE?

A given skeletal-muscle fiber will contract when excitatory nervous stimuli sufficiently exceed inhibitory nervous stimuli at the cell body of the alpha motor neuron that innervates that fiber

Motor neurons are sometimes inhibited by [A. muscle spindle/B. Golgi tendon organs] originating from the muscle it innervates

Golgi tendon organs

The reflex that prevents a muscle from exerting too much tension is mediated by the [A. muscle spindle/B. golgi tendon organ].

golgi tendon organ

Which of the following best describes features associated with the golgi tendon organ (GTO)?

A. contraction of extrafusal fibers increases action potential generation

A person is holding four bricks in his hand. If the Golgi tendon organ now fires a high volley of action potentials

C. the person will immediately drop the bricks

[A. Muscle spindles/B. Golgi tendon organs] maintain muscle tone at rest through tonic activity.

Muscle spindles

[A. True/B. False] Muscle spindles excite both alpha and gamma motor neurons

True

The “normal” contractile fibers of the muscle are also called the [A. extrafusal/B. intrafusal] fibers.

extrafusal

After stretching an intrafusal fiber, the next event is

E. an increase in action potentials along the associated sensory neuron.

The following is a diagram of the knee-jerk reflex with hammer (h) hitting patellar tendon. The ‘ms’ is pointing to a muscle spindle buried in muscle mA. A second muscle, mB, is on the opposite side of the bone. Based on this diagram which statement below is FALSE?

D. At position E, one additional excitatory interneuron should be shown.

Thinking about higher order motor control, which of the following is NOT matched correctly?

C. corticospinal tract ; postural reflex control.

With respect to motor control, which of the following is NOT matched correctly?

E. propriceptors ; coordinating antagonist muscle activity

Which of the following statements about control of body movement is true?

A. The corticospinal motor pathways control most fine, discrete muscle activity.

B. The brainstem pathways control postural.

C. The cerebellum fine-tunes ongoing movement and helps to coordinate movements.

E. A, B and C

Which of the following statement of motor control is FALSE?

The basal ganglia can directly control movement of the hands and fingers

Corticospinal motor pathways control most [A. fine/B. gross] muscle activity of the fingers.

fine

The highest level of the motor system hierarchical organization is the

B. premotor cortex

Movements are planned and programmed in the

D. supplemental motor cortex

Most reflex movements are integrated by [A. the somatosensory cortex/B. the spinal cord].

the spinal cord

The [A. parasympathetic /B. sympathetic] branch dominates during rest and digestion.

parasympathetic

The [A. parasympathetic/B. sympathetic] branch is characterized by a chain of ganglion running along side of the spinal cord.

sympathetic

The [A. preganglionic/B. postganglionic] neuron has its cell body in a ganglion.

postganglionic

Adrenal medulla cells function as [A. preganglionic/B. postganglionic] cells within one of the branches of the autonomic nervous system.

postganglionic

The adrenal medulla is closely associated with the [A. parasympathetic/B. sympathetic] branch of the autonomic nervous system.

sympathetic