Midterm Practice

Question 1 of 50

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The rate of Ca+ diffusion across a membrane is dependent on -

Select one of the following:

  • Permeability of the membrane on the solute

  • Concentration gradient

  • Existence of carriers and/or channels for the solute

  • All of these are true.

Question 2 of 50

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Na+ concentration on either side of a membrane plays a role in osmolarity, even if it is not permeable to the membrane.

Select one of the following:

  • True
  • False

Question 3 of 50

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The rate of diffusion for a solute across a membrane is dependent on -

Select one of the following:

  • Concentration gradient

  • Temperature

  • Viscosity of the fluid

  • All of these.

Question 4 of 50

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Homeostasis in physiological systems refers to the maintenance of a static or constant conditions in the internal environment.

Select one of the following:

  • True
  • False

Question 5 of 50

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Influences on receptor-mediated channels refers to a protein

Select one of the following:

  • Allowing other solutes to cross a membrane, after linking to a primary molecule.

  • Allowing other solutes to cross a membrane, after a voltage change to the inside of the cell.

  • Allowing other solutes to cross a membrane, after pressure changes to the inside of the cell.

  • All of these.

Question 6 of 50

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Osmotic pressure is the pressure necessary to allow the movement of water across a membrane.

Select one of the following:

  • True
  • False

Question 7 of 50

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Secondary active co-transporter proteins in a cell membrane have which of the properties listed below?

Select one of the following:

  • Selectiveity

  • Uses energy from solute concentration gradient (runs downhill)

  • Saturable

  • All of these.

Question 8 of 50

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Which statement below is NOT true?

Select one of the following:

  • Voltage is "pressure" that moves electrons or ions through a circuit.

  • Current is the number of electron or ions moving per unit of time.

  • Resistance is not associated with the lipid membrane.

  • Conductance is the reciprocal of resistance.

Question 9 of 50

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Active transport differs from facilitated diffusion in that it uses energy to move a substance uphill against its concentration gradient.

Select one of the following:

  • True
  • False

Question 10 of 50

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The equilibrium potential for a particular ion is the voltage in which that ions movement across a lipid membrane comes to a relative stop.

Select one of the following:

  • True
  • False

Question 11 of 50

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Depolarizing the membrane of excitable cells by ~10mV will initiate -

Select one of the following:

  • increases in Na+ conductance (ability to move across the membrane)

  • decreases Na+ in conductance (ability to move across the membrane)

  • closing of Na+ ions protein channels

  • cell death

Question 12 of 50

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The Nernst Equation is important for:

Select one of the following:

  • Determining the absolute membrane potential

  • Determining the electrical potential difference, for a single ion, needed to counter the concentration difference.

  • Determining the concentration difference, for multiple ion, needed to counter the concentration difference.

  • None of these

Question 13 of 50

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When determining the "equilibrium potential" for Na+, we have to assume the membrane is permeable to Na+.

Select one of the following:

  • True
  • False

Question 14 of 50

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Which channel is most responsible for the depolarization phase of an action potential across a cell membrane?

Select one of the following:

  • Open Na+ channels

  • Open K+ channels

  • Open Ca++ chanels

  • All of these

Question 15 of 50

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Which process listed below is most responsible for maintaining the electrochemical gradient?

Select one of the following:

  • Facilitated diffusion of Na+

  • Na+/K+ pump

  • Ca++ storage

  • Starbuck's Coffee and Krispy Cream.

Question 16 of 50

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What two factors make using the Goldman Equation more appropriate for determining the "Resting Membrane Potential", instead of using the Nertz Equation?

Select one of the following:

  • The number of voltage-gated channels located in the membrane and concentration of ions inside the cell.

  • The relative ion concentration on either side of the membrane and the relative permeability of the membrane to the ions.

  • The amount of Krispy Cream donuts and Starbuck's coffee outside the cell.

  • The inclusion of the relative permeability of the ions.

Question 17 of 50

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Which ion is most responsible for the initial change (depolarization) in membrane potential during the action potential?

Select one of the following:

  • Na+

  • K+

  • Ca++

  • Cl-

Question 18 of 50

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Ligand-gated channels are important for initiating an action potential at the neuromuscular junction.

Select one of the following:

  • True
  • False

Question 19 of 50

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Slow, oxidative muscle fibers -

Select one of the following:

  • Use mainting oxidative phosphorylation to generate ATP.

  • Have large amounts of mitochondria.

  • Have large blood supply.

  • All of these.

Question 20 of 50

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The sarcoplasmic reticulum stores __________ when a muscle is relaxed and releases it for binding to _______ during contraction.

Select one of the following:

  • calcium; troponin

  • calcium; tropomyosin

  • sodium; tropomyosin

  • potassium; tropinin

Question 21 of 50

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Put in to the correct sequence the following events involved in muscle cell contraction.

1. Voltage-gated sodium channels open, allowing sodium to flow in.
2. Spreading action potential reaches T-Tubles activating a DHP molecule.
3. Acetylcholine binds to receptors on muscle cell membrane.
4. Ligand-gated receptors allow small amounts of sodium into the cell changing membrane potential 10mV(+).
5. If enough sodium moves into the muscle cell, an impulse (action potential) develops.

Select one of the following:

  • 3,4,1,5,2

  • 2,1,3,4,5

  • 2,4,3,1,5

  • 3,4,5,1,2

Question 22 of 50

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Which molecule listed below is responsible for "physically" inhibiting the binding of the myosin head to the active binding site on actin?

Select one of the following:

  • Troponin

  • Tropomyosin

  • G-actin

  • all of these

Question 23 of 50

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In order to allow discrete events to occur, calcium is rapidly removed from the cytoplasm by __________.

Select one of the following:

  • dihydropyridime channels

  • calcium-sequestering proteins in the cytoplasm

  • calcium pumps in the sarcoplasmic reticulum

  • DHP receptor

Question 24 of 50

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When an action potential is generated within a motor unit -

Select one of the following:

  • the muscle cells of the motor unit will occasionally contract.

  • only select muscle cells within the motor unit are stimulated to contract.

  • every muscle cell of the motor unit is stimulated to contract.

  • the muscle cells from the neighboring motor unit will contract.

Question 25 of 50

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The releasing of Ca++ inside the skeletal muscle cell (intracellular) is initiated by which protein receptor listed below?

Select one of the following:

  • Actin

  • DHP

  • Myosin

  • Tropomyosin

Question 26 of 50

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The t-tubules are an extension of the cell membrane of the skeletal muscle cell.

Select one of the following:

  • True
  • False

Question 27 of 50

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The t-tubule of cardiac muscle

Select one of the following:

  • form the Z lines

  • stores K+

  • provides a means of rapidly transmitting action potential to the sarcoplasmic reticulum via the DHP molecule

  • are larger than those found in skeletal muscle.

Question 28 of 50

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The fusing of synaptic vesicles with the terminal button membrane is initiated by Ca++ influx into the cell.

Select one of the following:

  • True
  • False

Question 29 of 50

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The plateau of the cardiac action potential results from opening of voltage-gated, slow _______ channels in the membrane of the cardiac cell.

Select one of the following:

  • sodium

  • potasium

  • calcium

  • chloride

Question 30 of 50

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Heart muscle has long refractory period due to extended K+ channel opening.

Select one of the following:

  • True
  • False

Question 31 of 50

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Increased activity within the parasympathetic nervous system will result in changes primarily within the

Select one of the following:

  • sinoatrial node only

  • atrioventricular node only

  • ventricles only

  • sinoatrial node and atrioventricular node

  • sinoatrial node, atrioventricular node, and ventricles

Question 32 of 50

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Which of the following is NOT involved in triggering the normal coordinated contraction of cardiac muscle cells?

Select one of the following:

  • release of a neurotransmitter.

  • change in membrane potential within individual cardiac muscle cells

  • initiation of an action potential

  • a pacemaker potential

  • the conduction system of the heart.

Question 33 of 50

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The long refractory period of cardiac muscle prevents tetanic contraction of the heart.

Select one of the following:

  • True
  • False

Question 34 of 50

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The sinoatrial node requires external stimulation in order to generate an action potential.

Select one of the following:

  • True
  • False

Question 35 of 50

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Which of the following EKG events represents the depolarization of the ventricle?

Select one of the following:

  • P wave

  • QRS complex

  • PR interval

  • T wave

Question 36 of 50

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The spontaneous action potential generated by the Sino-Atrial Node, Atrio-ventricular Node, and Purkinje Fibers is due to K+ leaking across the cardiac muscle cell membrane.

Select one of the following:

  • True
  • False

Question 37 of 50

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The depolarization of the atria (by the Sino-Atrial Node) will be communicated (sent) to the ventricles (Purkinje fibers) by the _________.

Select one of the following:

  • Sarcoplasmic reticulum

  • DHP molecule

  • A-V bundle (bundle of His)

  • Actin and myosin filaments.

Question 38 of 50

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Diastolic pressure generated by the right ventricle must overcome pressure in the aorta to get blood flow out to the rest of the body.

Select one of the following:

  • True
  • False

Question 39 of 50

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The Frank-Starling mechanism of heart contraction state that as more blood enters the heart, the heart will respond by contracting with greater force. Which is the statements below helps explain how this works?

Select one of the following:

  • The pacemaker mechanism of the heart is stimulated by increased input of blood to the left ventricle.

  • Parasympathetic inhibition of contraction will allow more force to be generated.

  • Stretched cardiac muscle has better actin/myosin filament alignment.

  • All of these.

Question 40 of 50

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Contraction of motor units is a(n) ____________ manner allows a muscle to maintain a level of force for a duration of time without fatiguing.

Select one of the following:

  • Synchronous

  • Asymmetrical

  • Asynchronous

  • Random

Question 41 of 50

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Skeletal muscle fibers operate at near-optimal sarcomere length in the normal individual.

Select one of the following:

  • True
  • False

Question 42 of 50

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The speed at which the action potential travels through different parts of the heart conduction system is dependent on -

Select one of the following:

  • blood flow through the heart

  • functioning of the Atrio-ventricular valve.

  • resistance to the spread of the action potential

  • phases of the moon.

Question 43 of 50

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The influx of calcium into the axon terminal of a chemical synapse is responsible for the ____________.

Select one of the following:

  • initiation of the action potential

  • termination of an action potential

  • fusion of the vesicles to the membrane and their exocytosis

  • movement of calcium through gap junctions

Question 44 of 50

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Which substance below could be used to treat 'flaccid paralysis'?

Select one of the following:

  • Curare

  • Botulinum Toxin

  • Tetanus Toxin

  • Diisoprophyl fluorophosphate

Question 45 of 50

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Pressure in the right atria of the heart is ~0

Select one of the following:

  • True
  • False

Question 46 of 50

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Ventricular cardiac muscle cells demonstrate a stable resting membrane potential with no evidence of the slow depolarization of the specialized cardiac pacemaker cells.

Select one of the following:

  • True
  • False

Question 47 of 50

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Which specialized muscle tissues of the heart can generate the greatest number of action potentials in a minute?

Select one of the following:

  • Sino-Atrial Node

  • Atrio-Ventricular Node

  • Purkinje fibers

  • All of the these.

Question 48 of 50

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An ion's overall electrochemical gradient will tend to force that ion across the membrane in a direction that will cause membrane potential to move toward that ion's equilibrium potential.

Select one of the following:

  • True
  • False

Question 49 of 50

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The electrical potential of a membrane at rest is closest to potassium's equilibrium potential because ___________.

Select one of the following:

  • more sodium channels are open, allowing more sodium to move into the cell.

  • more potassium channels are open, allowing more potassium to move in or out of the cell.

  • more sodium channels are closed, allowing less sodium to move in or out of the cell.

  • all of the above.

Question 50 of 50

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As a consequence of Frank-Starling's Law of the heart, _________________________.

Select one of the following:

  • an increase in end-systolic volume will increase stroke volume.

  • a decrease in end-diastolic volume will increase stroke volume.

  • an increase in end-diastolic volume will increase stroke volume.

  • stroke volume is unaffected by end-diastolic volume.

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Midterm Practice

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