KIN 224 Chapter 19

The movement of ______ is responsible for the depolarization phase of the action potential in cardiac muscle cells.

Na+

Atrial contraction causes which to occur?

Openings of the great veins are compressed. Blood is pushed into the ventricles.

The wave of an ECG that reflects the electrical changes of atrial depolarization is the ___________ wave.

P

The common atrium is subdivided into a left and right atrium by an interatrial septum, which consists of two parts: the septum ______and the septum _________ that partially overlap.

Primum secundum

Action potentials received directly from ________________ stimulate the papillary muscles to contract, allowing for the proper _______________ of the AV valves.

Purkinje fibers; closing

The complex of an ECG that represents the electrical changes that are associated with ventricular depolarization is the __________complex.

QRS

True or False: The cells of the cardiac conduction system do not contract.

True

True or false: Healthy individuals can increase their cardiac output to meet the metabolic needs of their tissues when exercising.

True

The anterior interventricular artery (LAD) supplies the ______ wall of the left ventricle and ______ the interventricular septum.

anterior; most of

The left coronary artery typically branches into the ______ interventricular artery and the ______ artery.

anterior; circumflex

The inferior, conical end of the heart is called the ______.

apex

Toward the end of ventricular filling, the left and right ______ contract simultaneously.

atria

The fibrous skeleton of the heart is located between the ______.

atria and ventricles

When the ______ contract, blood is forced into the ______ through the open AV valves.

atria; ventricles

An ECG tracing from someone with a third-degree AV block is best described as a tracing with ______________________.

atrial depolarization occurring 70-100 times per minute and ventricular depolarization occurring 40-50 times per minute (2:1 ratio of P waves to QRS complexes)

The ________ reflex protects the heart from overfilling.

atrial or Bainbridge

The wrinkled flap-like extensions visible in the anterior view of the heart are the

auricle

The heart is innervated by the ______ nervous system.

autonomic

Arteries carry blood ______ the heart.

away from

The atrial reflex is initiated when __________ in the atrial walls are stimulated by an increase in venous return.

baroreceptors

The posterior-superior surface of the heart is called the ______.

base

The time from the start of one heartbeat to the initiation of the next is called a(n) ______________ cycle.

cardiac

______ cells cannot exhibit tetany

cardiac muscle

____________. _____________ is a measure of how effective the cardiovascular system is in fulfilling its function in transporting life supporting substances through the body.

cardiac output

The ______ system is responsible for the transport of blood in the body.

circulatory

The heart is a relatively small, conical organ approximately the size of a person's ______.

clenched fist

Electrical activity is started at the SA node, which causes an action potential to spread through the heart through the ______.

conduction system

The AV valves close in response to the

contraction of the ventricles and the resulting rise in ventricular pressure

The ______ delivers oxygen-rich blood to the thick heart wall while the ______ carries the deoxygenated blood away from the heart wall.

coronary arteries; coronary veins

A first degree block is caused by ________________.

delay of the action potential between the SA and AV nodes

Nodal cells in the SA initiate a heartbeat by spontaneously ___________ to generate an action potential.

depolarizing

The heart wall consists of three distinctive layers: ________ , __________ , and endocardium.

epicardium myocardium

The outermost heart layer of the heart wall is the ______ and is also known as the ______ layer of the serous pericardium.

epicardium; visceral

The _____ of the heart is formed from dense irregular connective tissue

fibrous skeleton

Cardiac muscle can use fatty acids, _________ lactic acid, amino acids, and _________ bodies as fuel sources.

glucose ketone

______ do(es) not contribute to the ability of a cardiac muscle to meet its energy demands.

glycolytic enzymes

The three main components of the cardiovascular system are __________, blood vessels, and the ______________

heart blood

Mitral valve prolapse severe enough to cause regurgitation may directly cause _________________ pressure in the ____________ atrium.

increased; left

When heart rate and stroke volume increase, cardiac output ______.

increases

The right and left ventricles are separated by the ______.

interventricular septum

The position of the interventricular septum is deep to the ______ located on the heart's superficial surface.

interventricular sulci

Oxygenated blood is transported from the lungs to the ______ side of the heart.

left

The circumflex artery supplies blood to the ______ ventricle.

left

The primitive ventricle forms most of the _______ ventricle.

left

Cardiac output is normally expressed as ______.

liters per minute

As the cardiac cycle begins, the semilunar valves are closed because the pressure exerted by the blood in the ventricles is _________than the pressure the blood exerts in the great arteries.

lower

The right coronary artery typically branches into the right ______ artery, which supplies the lateral wall of the right ventricle, and the posterior ______ artery, which supplies the posterior surface of both the left and right ventricles.

marginal; interventricular

The cardiac center is within the ______.

medulla oblongata

By day 19 (middle of week 3), two endocardial tubes form from ______ in the embryo

mesoderm

Which of the following are part of the cardiac muscle cells?

myofibrils T tubules sarcolemma

______ in the SA node are the pacemaker cells that initiate a heartbeat.

nodal cells

The pericardium of the heart includes an ______ fibrous layer and an ______ serous membrane.

outer; inner

Cardiac muscle cells contain Ca2+ pumps that keep more Ca2+ ___________ the cell.

outside

Which type of blood flows through the left atrium?

oxygenated

A common error is to describe arteries as the vessels that always transport ______ blood instead of describing it as a vessel that takes blood ______ from the heart.

oxygenated; away

The ability to reach threshold without stimulation is called the __________ __________ of the SA node.

pacemaker (auto) potential (rhythmicity)

The single heart tube develops into what 4 structures?

primitive atrium bulbus cordis sinus venosus primitive ventricle

Openings of __ are visible in the left atrium.

pulmonary veins

The cardiovascular system consists of two circulations: the ______ circulation and the ______ circulation

pulmonary; systemic

During atrial contraction, the atria are contracting and the ventricles are

relaxed/filling

The __________ atrium and ventricle are prominent when viewing the heart from the anterior view.

right

Which side of the heart is more visible from an anterior view?

right

The right atrioventricular opening is covered by the ______ valve.

right atrioventricular tricuspid

In the heart, action potentials spread across the ______ of cardiac muscle cells, causing them to contract.

sarcolemma

The two categories of heart valves are ______.

semilunar and atrioventricular

The space between the parietal layer and visceral layer of the pericardium contains ______.

serous fluid

The heartbeat is initiated by the specialized cardiac muscle cells of the ______, which are located in the posterior wall of the right atrium, adjacent to the entrance of the ______.

sinoatrial node; superior vena cava

The sarcolemma of the cardiac muscle cells has fast voltage-gated ______________ channels that participate in the depolarization of the cell membrane.

sodium, Na+, or Na

The contraction of a heart chamber is called ______.

systole

The purpose for the delay in the conduction of the action potential from the AV node to the bundle branches of the ventricles is to allow ______, before the ventricles contract.

the atria to complete their contraction

The rate of ventricular conduction is best determined by _______________________ on an ECG.

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

Cardiac output is defined as the amount of blood pumped by one ______________ and is expressed as liters per minute.

ventricle or chamber

Heart rate is altered by stimulation of the SA node or the ______.

AV node

Passive filling of the ventricles through the open -__________ valves occurs at the beginning of the cardiac cycle while the ventricles are in ____________ .

AV or atrioventricular diastole or relaxation

______ shorten as a result of sarcomeres shortening.

Both cardiac and skeletal muscle cells

Stroke volume(SV) is equal to _____ minus _______ . Use abbreviations for your answers.

EDV ESV

The sarcoplasmic reticulum is more extensive in smooth muscle fibers than in skeletal muscle fibers.

False

True or False: Neurons have pacemaker potential

False

True or false: The heart myocardium is nourished primarily through the diffusion of nutrients from the blood in the heart chambers.

False

Place in the correct order the sequence of events resulting in the action potential for cardiac muscle cells.

1) Na+ ions enter causing depolarization. 2) Depolarization causes opening of voltage-gated K+ channels. 3) Slow voltage gated-Ca2+ channels open causing a Ca2-induced Ca2 release 4) Plateau occurs 5) Voltage-gated Ca2+ channels close6) Repolarization occurs returning to the resting membrane potential

Put the sequence of events in the correct order to describe the initiation and conduction of action potential through the heart.

1. SA note fires action potential 2. Action potential reaches AV node via gap junctions 3. Action potential is delayed at the AV node. 4. Action potential travels down the bundle branches 5. Action potential travels up the purkinje fibers.

During weeks ______, the single heart tube becomes partitioned into four chambers (two atria and two ventricles), and the main vessels entering and leaving the heart form.

5-8

Stroke volume (SV) in a healthy adult is approximately ______

70 mL

The ______ and primitive atrium form parts of the left and right atria.

Sinus venosus

Classify the following statements as belonging to either sympathetic or parasympathetic stimulation of the heart:

Sympathetic: Fibers pass through the cardiac plexus, increase the contraction strength of the heart, dilates the coronary arteries Parasympathetic: Little to no innervation to the myocardium, slows the heart rate