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mariamhammad333

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mariam hammad

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Biology11Chemistry2

QUESTION 8

Which of the following is NOT a feature of cardiac musclefibers?

(1)They are usually multi-nucleated.

(2)They are very rich in myoglobin.

(3)They are rich in glycogen.

(4)They depend almost exclusively on aerobic respiration.

(5)They have huge mitochondria.

QUESTION 9

At an intercalated disc

(1)two cardiac muscle fibers are connected by gap junctions anddesmosomes.

(2)the cell membranes of two cardiac muscle fibers are separatedby a synaptic cleft.

(3)cardiac muscle fibers are fused together by tightjunctions.

(4)adjacent sarcomeres within a myofibril are connectedtogether.

(5)t-tubules unite the membranes of the adjoining cells.

QUESTION 10

The plateau is a feature of

(1)action potentials of all electrically-excitable cells.

(2)pacemaker cell action potentials.

(3)action potentials of autorhythmic cells.

(4)cardiac muscle and pacemaker action potentials.

(5)cardiac muscle fiber action potentials.

QUESTION 11

The tricuspid valve regulates the opening between

(1)the right atrium and the left atrium.

(2)the right atrium and the left ventricle.

(3)the left atrium and the left ventricle.

(4)the left ventricle and the right ventricle.

(5)the right atrium and right ventricle.

QUESTION 12

End-systolic volume represents the amount of blood in the___________ at the end of _____________.

(1)

atrium; atrial contraction

(2)ventricle; ventricular ejection
(3)

atrium; isovolumetric relaxation

(4)ventricle, passive filling

(5)ventricle; ventricular filling

QUESTION 13

The pacemaker potential is a slow depolarization that beginswith _________ through If channels.

(1)Na+ inflow.
(2)

K+ inflow.

(3)Ca2+ inflow.

(4)Na+ outflow.

QUESTION 14

The Frank-Starling law of the heart states that stroke volume isproportional to

(1)the end-systolic volume.

(2)the end-diastolic volume.

(3)the afterload.
(4)

the heart rate.

(5)contractility.

QUESTION 15

Contractility of cardiac muscle increases when the__________________.

(1)intracellular potassium level rises
(2)

sarcomeres reach their optimum length

(3)calcium channels are blocked

(4)intracellular calcium level rises

(5)intracellular sodium level rises

QUESTION 16

(1)If the papillary muscles of the heart fail to contract

(2)

the AV valves will not open.

(3)the ventricles will not pump blood.

(4)the semilunar valves will not open.

(5)the AV valves will not close properly.

(6)the atria will not pump blood.

QUESTION 17

Which of these is not part of the cardiac conductionsystem?

(1)

the sinoatrial (SA) node
(2)

the tendinous cords (TC)
(3)

the atrioventricular (AV) node
(4)

the atrioventricular (AV) bundle (bundle of His)

(5)the Purkinje fibers

QUESTION 18

Which of the following describes the effect of end-diastolicvolume on stroke volume?

(1)A decrease in end-diastolic volume allows cardiac muscle torelax, conserving energy for the next contraction, therebyincreasing stroke volume of that next contraction.

(2)An increase in end-diastolic volume stretches ventricularmuscle cells to lengths greater than optimum, decreasing thestrength of contraction and thereby decreasing stroke volume.
(3)

A decrease in end-diastolic volume allows ventricular musclecells to relax more during diastole, allowing more blood to returnto the heart increasing stroke volume.
(4)

A decrease in end-diastolic volume creates a vacuum drawing moreblood into the ventricle increasing stroke volume.

(5)An increase in end-diastolic volume stretches ventricularmuscle cells to lengths closer to optimum, increasing the strengthof contraction and thereby increasing stroke volume.

QUESTION 19

The following is a list of vessels and structures that areassociated with the heart:

1. aorta

2. left atrium

3. left ventricle

4. pulmonary trunk

5. pulmonary veins

6. right atrium

7. right ventricle

8. vena cavae

What is the correct order for the flow of blood entering fromthe systemic circuit? Start with the vessels that carry the bloodback to the heart from the systemic circuit.

(1)8,6,7,4,5,2,3,1

(2)1,8,6,7,4,5,2,3

(3)8,6,7,5,4,2,3,1

(4)5,2,3,1,8,6,7,4
(5)

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

QUESTION 20

Rapid repolarization occurs in cardiac muscle cells andpacemaker cells when

(1)potassium channels open and potassium ions leave thecell.

(2)sodium ions are pumped out of the cell.
(3)

potassium channels open and potassium ions enter the cell.

(4)calcium ions are pumped into the sarcoplasmic reticulum.

(5)calcium channels open and calcium ions leave the cell.

QUESTION 21

Which of these is the correct sequence of events of the cardiaccycle?

(1)ventricular filling → isovolumetric relaxation →isovolumetric contraction → ventricular ejection

(2)ventricular filling → isovolumetric relaxation → ventricularejection → isovolumetric contraction

(3)ventricular filling → isovolumetric contraction →isovolumetric relaxation → ventricular ejection

(4)ventricular filling → isovolumetric contraction → ventricularejection → isovolumetric relaxation

(5)ventricular filling → ventricular ejection → isovolumetriccontraction → isovolumetric relaxation

QUESTION 22

_____________ increase(s) stroke volume.

(1)High arterial blood pressure

(2)Negative inotropic agents
(3)

Increased venous return
(4)

Increased afterload

(5)Dehydration

QUESTION 23

________________ cause an increase in the contractility ofcardiac muscle.

(1)Negative chronotropic agents

(2)Negative inotropic agents

(3)Positive inotropic and positive chronotropic agents

(4)Positive inotropic agents

(5)Positive chronotropic agents

QUESTION 24

What happens when pressure in the aorta exceeds pressure in theleft ventricle?

(1)There is no relationship between pressures in these chambersbecause they are not directly connected to each other.

(2)AV valve opens

(4)AV valve closes

(5)semilunar valve opens

(6)semilunar valve closes

QUESTION 25

Friction between membranes of the heart is reduced by

(1)the epicardium.

(2)a cushion of air that surrounds the heart.

(3)serous fluid in the pericardial cavity.

(4)fluid between the epicardium and the myocardium.

(5)a blood-filled sinus called the pericardium.

QUESTION 26

The sac around the heart is the

(1)myocardium.

(2)pericardium.

(3)pleural sac.

(4)peritoneum.

(5)epicardium.

QUESTION 27

The first heart sound is heard when the

(1)AV valves close.
(2)

atria contract.

(3)semilunar valves close.

(4)AV valves open.

(5)blood enters the aorta.

QUESTION 28

Which of the following would shorten the pacemaker potential andaccelerate heart rate?

(1)inhibiting the opening of If channels

(2)opening more K+ channels

(3)inhibiting the opening of Na+ channels

(4)opening more Ca2+ channels

(5)hyperpolarizing the cell

QUESTION 29

About 2/3 of the volume of blood that enters the ventriclesduring ventricular filling occurs

(1)during atrial diastole.

(2)during atrial systole.

(3)during isovolumetric relaxation.

(4)during ventricular systole.

(5)when the AV valve is closed.

QUESTION 30

As blood leaves the left ventricle, it passes

(1)into the pulmonary trunk.

(2)into the right atrium.

(3)through the aortic semilunar valve.

(4)through the bicuspid valve.

(5)into the right ventricle.

QUESTION 31

The fibrous skeleton serves as electrical insulation between the______________.

(1)atria and ventricles

(2)sinoatrial node and atrioventricular node

(3)left and right ventricles

(4)left and right atria

QUESTION 32

The left ventricular wall of the heart is thicker than the rightwall in order to:

(1)pump blood through a smaller valve.

(2)accommodate a greater volume of blood.
(3)

pump blood with greater pressure.

(4)expand the thoracic cage during diastole.

(5)receive blood that is under higher pressure.

QUESTION 33

Isovolumetric contraction:

(1)occurs only in people with heart valve defects.

(2)occurs while the AV valves are open.

(3)refers to the short period during ventricular systole whenthe ventricles are completely closed chambers.

(4)produces the stroke volume as blood is ejected from theventricles into the great vessels.

(5)occurs immediately after the semilunar valves close.

QUESTION 34

The opening and closing of the atrioventricular and semilunarvalves is driven by _________.

(1)contraction of the ventricles and atria that pull the valvecusps into place.

(2)differences in pressure in the compartments on each side ofthe valve.

(3)constriction and dilation of the opening by the fibrousskeleton.

(4)contraction and relaxation of the valve.

(5)contraction of muscles attached to the valves.

QUESTION 35

If the vagal nerves (carrying parasympathetic signals) to theheart were cut, the result would be that:

(1)the heart would stop, since the vagal nerves trigger theheart to contract.

(2)the heart rate would increase to its intrinsic rate.

(3)heart rate would decrease.

(4)the AV node would become the pacemaker of the heart.

QUESTION 36

Conduction of the electrical signal slows down as it passesthrough the _______________.

(1)AV bundle

(2)Purkinje fibers

(3)bundle branches

(4)fibers of the AV node

(5)internodal pathways

QUESTION 37

In the contractile fibers of the myocardium, the depolarizationphase of the action potential is the result of

(1)decreased membrane permeability to sodium ions.

(2)increased membrane permeability to chloride ions.

(3)increased membrane permeability to sodium ions.

(4)increased membrane permeability to sodium and calciumions.

(5)increased membrane permeability to potassium ions.

QUESTION 38

The coronary circulation receives its blood supply from vesselsthat arise from the

(1)

base of the aorta
(2)

left atrium
(3)

pulmonary trunk
(4)

right ventricle
(5)

left ventricle
Answer: 8.(1) 9.(1)
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1. During intense exercise, the metabolic activity of muscle ______________ the partial pressure gradient for carbon dioxide, ____________ its movement out of the tissue. A. decreases : facilitating B. increases : reducing C. increases : facilitating D. decreases : reducing

2. Which of the following statements about the central chemoreceptors is correct-? A. They are only sensitive to changes in O2 levels B. They are only sensitive to changes in CO2 levels C. They are sensitive to changes of hydrogen ion levels D. They are located in the carotid and aortic bodies

3. The Frank-Starling mechanism of heart contraction hypothesizes that as more blood enters the heart, the heart will respond by contracting with greater force. Which other organ/tissues of the body demonstrate this same “general” principle of filament contraction? A. Skeletal muscle. B. Esophagus. C. Blood vessels. D. All of the above

4. The plateau of the cardiac action potential results from opening of voltage-gated, slow ______ channels in the membrane of the cardiac cell. A. Sodium B. Potassium C. Calcium D. Chloride

5. Which of the following conditions would not result in a decreased compliance of the lungs? A. an increase in Type II alveolar cells activity B. a thickening of the lung tissue C. decreased surfactant production D. decreased elasticity of the lung

Answer: 1. c 2. b 3. a 4. c 5. c
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Answer: 1.b 2.a 3.2
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1. Babies born prematurely may be at risk for respiratory distress syndrome if their lungs do not yet produce which detergent-like substance that lowers surface tension within the alveoli?

a. mucus

b. pneumothorax

c. surfactant

d. oxygen

2. What determines lung compliance?

a. Lung compliance depends on the muscular forces of the respiratory muscles and on the reduced surface tension of mucus lining the alveoli.

b. Lung compliance depends on the elasticity of the lungs and on the surface tension of surfactant lining the alveoli.

c. Lung compliance depends on the high elasticity of the lungs and on the reduced surface tension of surfactant lining the alveoli.

d. Lung compliance depends on the elastic recoil of the chest wall and on the flexibility of the alveoli

3. Which of the factors increases airway resistance and causes bronchoconstriction?

a. sympathetic stimulation

b. epinephrine

c. carbon dioxide

d. histamine

e. a, b and c

4. The diaphragm is the most important muscle of respiration. It is innervated by the __________ nerve.

a. phrenic

b. accessory nerve

c. abducens

d. hypoglossal nerve

5. What effect does an increase in temperature have on hemoglobin’s ability to bind oxygen?

a. Increases in temperature have no effect on the affinity of hemoglobin for oxygen.

b. Increases in temperature decrease the affinity of hemoglobin for oxygen.

c. Increases in temperature increase the affinity of hemoglobin for oxygen.
Answer: 1. c 2. b 3.d 4. a 5. b
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