BSC 2086 - Cardiovascular System - The heart

number of beats per minute (bpm)

HR (heart rate)

The cardiac center of the cardiovascular center is within the ______.

Medulla oblongata

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

Na+

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 Reason: They initiate and conduct electrical signals but they do not contract.

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

True Reason: People with impaired heart function can not do this but healthy people can.

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

apex

The two basic types of blood vessels are ______, which carry blood away from the heart, and ______, which carry blood toward the heart.

arteries; veins

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 heart is innervated by the ______ nervous system.

autonomic

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 three main components of the cardiovascular system are

blood, blood vessels, and the heart

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

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 ______ 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:

endocardium myocardium epicardium

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

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

increases

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

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, low, less, or lesser

The cardiac center is within the ______.

medulla oblongata

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

mesoderm

______ 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

Openings of ______ are visible in the left atrium.

pulmonary veins

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 single heart tube develops into what 4 structures?

sinus venosus primitive ventricle bulbus cordis primitive atrium

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

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

AV node

autonomic reflex that protects the heart from overfilling

Atrial Reflex also called bainbridge reflex

while the heartbeat is initiated by the SA node, both the heart rate and the strength of contraction are regulated by the

Autonomic Nervous System

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

Blank 1: AV or atrioventricular Blank 2: diastole or relaxation

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

Blank 1: pacemaker or auto Blank 2: potential or rhythmicity

______ 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

______ cells cannot exhibit tetany.

Cardiac muscle

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

EDV - ESV

Volume of blood that enters the heart at the end of heart relaxation

EDV - end-diastolic volume - 130mL

Volume of blood remaining in ventricle at the end of ventricle contraction

ESV - end-systolic volume - 60mL

True or false: Neurons have a pacemaker potential.

FALSE Reason: Nodal cells have pacemaker potential.

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

FALSE Reason: The walls do not absorb nutrients or oxygen by diffusion and are dependent on the coronary arteries to deliver them.

the volume of blood pumped from a ventricle during a ventricular contraction (i.e., the amount of blood ejected per heartbeat)

(SV) Stroke volume

true - false: The sarcoplasmic reticulum is more extensive in smooth muscle fibers than in skeletal muscle fibers.

False. Reason: Skeletal muscle and cardiac muscle fibers both have more extensive SR than smooth muscle fibers.

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

SA node fires action potential Action potential reaches AV node via gap junctions action potential is delayed at AV node Action potential travels down the bundle branches (bundle of his) Action potential travels up the Purkinje fibers

Volume of blood ejected during ONE beat (expressed in mL)

SV (Stroke Volume)

Which of the following are part of the cardiac muscle cells? T tubules sarcolemma myofibrils fasciculi

T tubules sarcolemma myofibrils

sustained muscle contraction without relaxation

Tetany