Quiz
Midterm Practice
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Perguntas do quiz (50)
1The rate of Ca+ diffusion across a membrane is dependent on -
- APermeability of the membrane on the solute
- BConcentration gradient
- CExistence of carriers and/or channels for the solute
- DAll of these are true.
2Na+ concentration on either side of a membrane plays a role in osmolarity, even if it is not permeable to the membrane.
- AVerdadeiro
- BFalso
3The rate of diffusion for a solute across a membrane is dependent on -
- AConcentration gradient
- BTemperature
- CViscosity of the fluid
- DAll of these.
4Homeostasis in physiological systems refers to the maintenance of a static or constant conditions in the internal environment.
- AVerdadeiro
- BFalso
5Influences on receptor-mediated channels refers to a protein
- AAllowing other solutes to cross a membrane, after linking to a primary molecule.
- BAllowing other solutes to cross a membrane, after a voltage change to the inside of the cell.
- CAllowing other solutes to cross a membrane, after pressure changes to the inside of the cell.
- DAll of these.
6Osmotic pressure is the pressure necessary to allow the movement of water across a membrane.
- AVerdadeiro
- BFalso
7Secondary active co-transporter proteins in a cell membrane have which of the properties listed below?
- ASelectiveity
- BUses energy from solute concentration gradient (runs downhill)
- CSaturable
- DAll of these.
8Which statement below is NOT true?
- AVoltage is "pressure" that moves electrons or ions through a circuit.
- BCurrent is the number of electron or ions moving per unit of time.
- CResistance is not associated with the lipid membrane.
- DConductance is the reciprocal of resistance.
9Active transport differs from facilitated diffusion in that it uses energy to move a substance uphill against its concentration gradient.
- AVerdadeiro
- BFalso
10The equilibrium potential for a particular ion is the voltage in which that ions movement across a lipid membrane comes to a relative stop.
- AVerdadeiro
- BFalso
11Depolarizing the membrane of excitable cells by ~10mV will initiate -
- Aincreases in Na+ conductance (ability to move across the membrane)
- Bdecreases Na+ in conductance (ability to move across the membrane)
- Cclosing of Na+ ions protein channels
- Dcell death
12The Nernst Equation is important for:
- ADetermining the absolute membrane potential
- BDetermining the electrical potential difference, for a single ion, needed to counter the concentration difference.
- CDetermining the concentration difference, for multiple ion, needed to counter the concentration difference.
- DNone of these
13When determining the "equilibrium potential" for Na+, we have to assume the membrane is permeable to Na+.
- AVerdadeiro
- BFalso
14Which channel is most responsible for the depolarization phase of an action potential across a cell membrane?
- AOpen Na+ channels
- BOpen K+ channels
- COpen Ca++ chanels
- DAll of these
15Which process listed below is most responsible for maintaining the electrochemical gradient?
- AFacilitated diffusion of Na+
- BNa+/K+ pump
- CCa++ storage
- DStarbuck's Coffee and Krispy Cream.
16What two factors make using the Goldman Equation more appropriate for determining the "Resting Membrane Potential", instead of using the Nertz Equation?
- AThe number of voltage-gated channels located in the membrane and concentration of ions inside the cell.
- BThe relative ion concentration on either side of the membrane and the relative permeability of the membrane to the ions.
- CThe amount of Krispy Cream donuts and Starbuck's coffee outside the cell.
- DThe inclusion of the relative permeability of the ions.
17Which ion is most responsible for the initial change (depolarization) in membrane potential during the action potential?
- ANa+
- BK+
- CCa++
- DCl-
18Ligand-gated channels are important for initiating an action potential at the neuromuscular junction.
- AVerdadeiro
- BFalso
19Slow, oxidative muscle fibers -
- AUse mainting oxidative phosphorylation to generate ATP.
- BHave large amounts of mitochondria.
- CHave large blood supply.
- DAll of these.
20The sarcoplasmic reticulum stores __________ when a muscle is relaxed and releases it for binding to _______ during contraction.
- Acalcium; troponin
- Bcalcium; tropomyosin
- Csodium; tropomyosin
- Dpotassium; tropinin
21Put 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.- A3,4,1,5,2
- B2,1,3,4,5
- C2,4,3,1,5
- D3,4,5,1,2
22Which molecule listed below is responsible for "physically" inhibiting the binding of the myosin head to the active binding site on actin?
- ATroponin
- BTropomyosin
- CG-actin
- Dall of these
23In order to allow discrete events to occur, calcium is rapidly removed from the cytoplasm by __________.
- Adihydropyridime channels
- Bcalcium-sequestering proteins in the cytoplasm
- Ccalcium pumps in the sarcoplasmic reticulum
- DDHP receptor
24When an action potential is generated within a motor unit -
- Athe muscle cells of the motor unit will occasionally contract.
- Bonly select muscle cells within the motor unit are stimulated to contract.
- Cevery muscle cell of the motor unit is stimulated to contract.
- Dthe muscle cells from the neighboring motor unit will contract.
25The releasing of Ca++ inside the skeletal muscle cell (intracellular) is initiated by which protein receptor listed below?
- AActin
- BDHP
- CMyosin
- DTropomyosin
26The t-tubules are an extension of the cell membrane of the skeletal muscle cell.
- AVerdadeiro
- BFalso
27The t-tubule of cardiac muscle
- Aform the Z lines
- Bstores K+
- Cprovides a means of rapidly transmitting action potential to the sarcoplasmic reticulum via the DHP molecule
- Dare larger than those found in skeletal muscle.
28The fusing of synaptic vesicles with the terminal button membrane is initiated by Ca++ influx into the cell.
- AVerdadeiro
- BFalso
29The plateau of the cardiac action potential results from opening of voltage-gated, slow _______ channels in the membrane of the cardiac cell.
- Asodium
- Bpotasium
- Ccalcium
- Dchloride
30Heart muscle has long refractory period due to extended K+ channel opening.
- AVerdadeiro
- BFalso
31Increased activity within the parasympathetic nervous system will result in changes primarily within the
- Asinoatrial node only
- Batrioventricular node only
- Cventricles only
- Dsinoatrial node and atrioventricular node
- Esinoatrial node, atrioventricular node, and ventricles
32Which of the following is NOT involved in triggering the normal coordinated contraction of cardiac muscle cells?
- Arelease of a neurotransmitter.
- Bchange in membrane potential within individual cardiac muscle cells
- Cinitiation of an action potential
- Da pacemaker potential
- Ethe conduction system of the heart.
33The long refractory period of cardiac muscle prevents tetanic contraction of the heart.
- AVerdadeiro
- BFalso
34The sinoatrial node requires external stimulation in order to generate an action potential.
- AVerdadeiro
- BFalso
35Which of the following EKG events represents the depolarization of the ventricle?
- AP wave
- BQRS complex
- CPR interval
- DT wave
36The 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.
- AVerdadeiro
- BFalso
37The depolarization of the atria (by the Sino-Atrial Node) will be communicated (sent) to the ventricles (Purkinje fibers) by the _________.
- ASarcoplasmic reticulum
- BDHP molecule
- CA-V bundle (bundle of His)
- DActin and myosin filaments.
38Diastolic pressure generated by the right ventricle must overcome pressure in the aorta to get blood flow out to the rest of the body.
- AVerdadeiro
- BFalso
39The 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?
- AThe pacemaker mechanism of the heart is stimulated by increased input of blood to the left ventricle.
- BParasympathetic inhibition of contraction will allow more force to be generated.
- CStretched cardiac muscle has better actin/myosin filament alignment.
- DAll of these.
40Contraction of motor units is a(n) ____________ manner allows a muscle to maintain a level of force for a duration of time without fatiguing.
- ASynchronous
- BAsymmetrical
- CAsynchronous
- DRandom
41Skeletal muscle fibers operate at near-optimal sarcomere length in the normal individual.
- AVerdadeiro
- BFalso
42The speed at which the action potential travels through different parts of the heart conduction system is dependent on -
- Ablood flow through the heart
- Bfunctioning of the Atrio-ventricular valve.
- Cresistance to the spread of the action potential
- Dphases of the moon.
43The influx of calcium into the axon terminal of a chemical synapse is responsible for the ____________.
- Ainitiation of the action potential
- Btermination of an action potential
- Cfusion of the vesicles to the membrane and their exocytosis
- Dmovement of calcium through gap junctions
44Which substance below could be used to treat 'flaccid paralysis'?
- ACurare
- BBotulinum Toxin
- CTetanus Toxin
- DDiisoprophyl fluorophosphate
45Pressure in the right atria of the heart is ~0
- AVerdadeiro
- BFalso
46Ventricular cardiac muscle cells demonstrate a stable resting membrane potential with no evidence of the slow depolarization of the specialized cardiac pacemaker cells.
- AVerdadeiro
- BFalso
47Which specialized muscle tissues of the heart can generate the greatest number of action potentials in a minute?
- ASino-Atrial Node
- BAtrio-Ventricular Node
- CPurkinje fibers
- DAll of the these.
48An 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.
- AVerdadeiro
- BFalso
49The electrical potential of a membrane at rest is closest to potassium's equilibrium potential because ___________.
- Amore sodium channels are open, allowing more sodium to move into the cell.
- Bmore potassium channels are open, allowing more potassium to move in or out of the cell.
- Cmore sodium channels are closed, allowing less sodium to move in or out of the cell.
- Dall of the above.
50As a consequence of Frank-Starling's Law of the heart, _________________________.
- Aan increase in end-systolic volume will increase stroke volume.
- Ba decrease in end-diastolic volume will increase stroke volume.
- Can increase in end-diastolic volume will increase stroke volume.
- Dstroke volume is unaffected by end-diastolic volume.
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