BIOS 255: Week 2 - The Cardiovascular System (Heart) with expert curated questions and answers-Chamberlain

Which of the following membranes are found in the body cavities and have parietal layers that line the cavities and visceral layers that cover the organs?

serous membrane

Which is true of cardiac muscle tissue?

striated, uninucleated, intercalated discs

Epicardium characteristics & function

- outermost layer

- composed of elastic fibers & adipose tissue

- produces pericardial fluid

Myocardium characteristics & function

- middle layer

- composed primary of cardiac muscle

- generates force to pump blood

Endocardium characteristics & function

- innermost layer

- regulates contractility

Which chamber of the heart has the thickest myocardium?

left ventricle

Which valve separates the right atrium and the right ventricle?

tricuspid valve

Which valve separates the left atrium and the left ventricle?

bicuspid (mitral) valve

Which valve separates the heart from the vessel that delivers blood to the lungs to receive oxygen?

pulmonary valve

Which valve separates the heart from the vessel that delivers blood to the entire body?

aortic valve

Which valve is between the right ventricle and pulmonary trunk?

pulmonary semilunar valve

Which valve is between the left ventricle and ascending aorta?

aortic semilunar valve

What is the region of the thoracic cavity where the heart is located?

mediastinum

Which type of cell junction allows cardiac muscle tissue to transmit signals rapidly?​

gap junctions

Which of the following are functions of the pericardium?

- prevents the heart from bouncing in the thoracic cavity.​

- prevents the heart from overfilling with blood

- creates a near-frictionless environment through the production of serous fluid.​

Which elements are required to sustain a muscular contraction?

- calcium

- sodium

- potassium

- ATP

What term is given to the event whereby the voltage of an action potential begins to return to its resting potential from the height of its peak?

repolarization

What term is given to the event whereby another action potential cannot be propagated shortly after an action potential?

refractory period

​Cardiac _________ action potentials will have a rapid depolarization that is maintained via the presence of calcium.​

contractile

​Cardiac _________ action potentials will have both a rapid depolarization and repolarization with no refractory period.

autorhythmic

The ____________ phase of the action potential in cardiac muscle delays repolarization to the resting membrane potential in order to lengthen refractory period.​

plateau

Without a plateau, extending the refractory period, cardiac muscle cells might be stimulated so quickly that they would not relax, leading to a sustained contraction known as what?

tetany

A distinct, extended plateau occurs in the action potential in cardiac muscle cells, producing a refractory period of ______ milliseconds.​

250

Which of the following aspects of the conduction system would directly result in contraction of the myocardium in the ventricular walls?

purkinje fibers

During the depolarization phase of cardiac muscle ______________.​

voltage-gated sodium channels open​

What are the individual ion contributions to the resting membrane potential of the cardiac pacemaker cells?

- greater concentration of sodium outside the cell​

- greater concentration of potassium inside the cell​

- calcium gradient with more calcium outside the cell​

Assuming a patient is perfectly healthy, all blood in the right atrium will move into which area?

right ventricle

Which of the following phrases is true of arteries?

arteries always take blood away from the heart

Which structures are part of the pulmonary circuit?

- pulmonary veins

- pulmonary trunk

- lungs

- right ventricle

Which structures are part of the systemic circuit?

- left ventricle

- left atrium

- vena cava

- aorta

Oxygenated blood flows from the ___________ to the _____________ before being pumped into the system circulation.​

left atrium; left ventricle

Unidirectional flow in the heart is ensured because the heart contains _________ that prevent backflow.​

valves

Inferior and superior vena cava are associated with which chamber?

right atrium

Pulmonary trunk is associated with which chamber?

right ventricle

Pulmonary veins are associated with which chamber?

left atrium

The Aorta is associated with which chamber?

left ventricle

True or False: The right ventricle pumps deoxygenated blood to the lungs

true

True or false: Pulmonary veins pass blood into the left atrium whereas the pulmonary arteries carry blood away from the right ventricle

true

True or False: Oxygenated blood enters the left atrium

true

The right side of the heart pumps blood through the vessels to the lungs and back to the left side of the heart through the __________ circulatory pathway?​

pulmonary

Which of the following events of an action potential occurs with an influx of sodium ions?

depolarization

Which of the following ions is required to leave the cell in order to result in hyperpolarization?​

potassium

What tool can we use to determine the electrical events within the heart?

electrocardiogram

Place the events of the conduction system in the proper order:

1. SA node fires

2. AV node fires

3. signal travels to Bundle of His (AV bundle)

4. signal travels through bundle branches

5. Purkinje fibers fire

6. contraction of ventricles occur

The ___________ is the natural pacemaker of the heart.​ Select all that apply.

sinoatrial (SA) node

The rate of ventricular conduction is best determined by ______________ on an EKG.​

the number of QRS-complexes present within a specific unit of time

Which of the following aspects of the conduction system would directly result in the contraction of the myocardium in the ventricular walls?

purkinje fibers

The P wave is produced when a signal from the SA node spreads through the atria and _________ them.

depolarizes

The QRS complex is produced when the signal from the AV node spreads through the _________ myocardium and depolarizes the muscle.

ventricular

The T wave is generated by ventricular repolarization immediately before _________.

diastole

What happens during QRS complex?

ventricular depolarization

What happens during the P wave?

atrial depolarization

What happens during the T wave?

ventricular repolarization

____________ occurs when the heart is at its most relaxed.

diastole

Which valves are examples of semilunar valves?​

pulmonary & aortic

​Ventricular filling AV valves _________, and SL valves _________.

open; closed

Isovolumic ventricular contraction AV valves _________, and SL valves _________.​

closed; closed

Ventricular ejection AV valves _________, and SL valves _________.

closed; open

Isovolumic ventricular relaxation AV valves _________, and SL valves _________.

closed; closed

What occurs during ventricular systole?

- the semilunar valves open to allow blood to flow into the large arteries

- the AV valves close to prevent backflow of blood into the atria.​

During which event of the cardiac cycle does aortic pressure reach its maximum?

ventricular ejection

The ___________ is a low-pitched sound caused by vibration of the atrioventricular valves and surrounding fluid as the valves close at the beginning of ventricular systole.​

first heart sound

The AV valves close in response to the _______________.​

contraction of the ventricles and the resulting rise in ventricular pressure​

Regurgitation of blood through a prolapsed mitral valve (detected as a heart murmur) may cause _________ pressure in the __________ atrium.

increased; left

When blood is flowing out of the left ventricle, the bicuspid valve is ________ and the aortic semilunar valve is _________.​

closed; open

Which of the following would NOT increase heart rate?

stimulation by the vagal nerve

Which of the following regions of the brain contains the cardioregulatory center?

medulla oblongata

Detemine the cardiac output of a patient with a heart rate of 80 beats/min with a stroke volume of 75 mL/beat.

6 L/min

Detemine the cardiac output of a patient with a heart rate of 80 beats/min with an end diastolic volume of 80 mL and an end systolic volume of 120 mL.

3.2 L/min

Preload

the stretch of the atria during ventricular filling

Afterload

the pressure required to overcome the vascular resistance

Venous return

the amount of blood returned to the heart via the veins

Contractility

the intrinsic strength of the contractions of the cardiac muscle

Positive inotropic agents

increase contractility

- insulin

- catecholamine

- glucagon

- angiotensin II

Negative inotropic agents

decrease contractility

- antiarrhythmics

- beta blockers

Positive chronotropic agents

increase heart rate

- dopamine

- epinephrine

Negative chronotropic agents

decrease heart rate

- acetylcholine

- beta blockers

Sympathetic stimulation of the heart

- increases the contraction strength of the heart

- fibers pass through the cardiac plexus

- dilates the coronary arteries

Parasympathetic stimulation of the heart

- slows the heart rate

- little or no innervation to the myocardium

What variable(s) determine the effects of cardiac output?​

changes to both heart rate (HR) & stroke volume (SV)

The difference between the maximum and resting cardiac output is called ____________.​

cardiac reserve

As blood pressure increases, the volume of blood returned to the left ventricle will increase, stretching it more than typical, leading to an increase in stroke volume. This is an example of ______________.​

preload

Schwannomas are due to tumor formation within the Schwann cells of the peripheral nervous system. When they occur in the neck, removal is difficult due to the possibility of severing a cranial nerve responsible for parasympathetic activity in the heart. What is this cranial nerve?​

vagal