Chapter 19. Cardiovascular System: Heart

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

Na+

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

Na+

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

Na+ ions causing depolarization depolarization causes the opening of voltage-gated K+ channels slow voltage-gated -Ca+ channels open causing a Ca2+ inducing Ca2+ release plateau occurs voltage-gated Ca2+ channels close repolarization occurs, returning the cell to the resting membrane potential

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

P

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 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

the _____ reflex protects the heart from overfilling.

atrial

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

auricle

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

auto potential

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

The volume of blood pumped by one ventricle in one minute is defined as _____ _____

cardiac output

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

circulatory

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

conduction system

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

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

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

increases

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

left

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.

less

Cardiac output is normally expressed as ______.

liters per minute

The pulmonary circulation includes the movement of blood to and from the _____ for gas exchange

lungs

The cardiac center is within the ______.

medulla oblongata

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

Like the right atrium, the left atrium also has ______ in its auricle.

pectinate muscles

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

pulmonary; systemic

The _____ atrium and ventricle are prominent when viewing the heart from the 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 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

Passive filling of the ventricles through the open _____ valves occurs at the beginning of the cardiac cycle while the ventricles are in _____

AV Relaxation

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

AV node

______ shorten as a result of sarcomeres shortening.

Both cardiac and skeletal muscle cells

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

Cardiac output

Stroke volume(SV) is equal to _____ minus _____

EDV ESV

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

False

True or false: Neurons have a 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

The average normal adult heart weighs about ______ grams.

300

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

70 mL

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

SA node fires an action potential Action potential reaches the AV node via gap junctions An action potential is delayed at the AV node An action potential travels down the bundle branches An action potential travels up the purkinje