Ch 20 Heart
What is the ability to rhythmically depolarize without outside stimulation called?
Autorhythmic
The ions that affect cardiac muscle function are ----- ----- ----
Calcium Ca, Sodium Na, and Potassium K
The ------ refractory period is the time when the muscle cell cannot be further stimulated, no matter the strength of the stimulus..
absolute
atrial systole and ventricular diastole
atrial myocardium contract, pushing blood into the ventricles
The amount of blood reaching the right atrium from systemic circulation is referred to as ____
venous return *Reason: Cardiac output is the amount of blood pumped out of the ventricles per minute. Reason: Stroke volume is the volume of blood ejected by the left ventricle each contraction.
The chambers of the human heart include _
2 atria and 2 ventricles
The typical cardiac output in a resting healthy adult is ------ liters
5
Which is a typical cardiac output in a resting healthy adult?
5 liters
Under resting conditions, the normal stroke volume is approximately _____
70 ml
baroreceptor reflex in chronological order
A decrease in blood pressure within the aorta stimulates a decrease in frequency of action potential within the baroreceptors. Afferent signals sent to the medulla oblongata. Sympathetic response increases and parasympathetic response decreases. Herat rate and stroke volume increase. Response is an increase in blood pressure.
The group of autorhythmic cells in the interatrial septum of the heart that relays excitation from the atria to the ventricles is known as the
AV or Atrioventricular node
Period of isovolumetric contraction
As contraction proceeds, ventricular pressures continue to rise, but no blood flows from the ventricles because all the valves are closed. because the volume of the blood in the ventricles doesn't change, even though the ventricles are contracting.
Why does blood flow through the systemic circulation from the aorta ultimately to the right atrium?
Blood flows from high pressure to low pressure
Which autonomic system(s) innervate(s) the heart?
Both sympathetic and parasympathetic nerves
What is the difference (as in subtraction) between the maximum and resting cardiac output? Multiple choice question.
Cardiac Reserve
Identify the functional changes in the heart that occur with the normal aging process.
Cardiac arrhythmias Elevated pressures in chambers/arteries Decreased aerobic metabolism
Identify the cardiac measurements that will increase during exercise.
Cardiac output Stroke volume End-diastolic volume
Mean arterial pressure changes proportionally with changes in which variables?
Cardiac output Stroke volume Peripheral resistance
The blood vessels that supply nutrients and oxygen only to the heart muscle make up the specific type of circulation called the ______ circulation.
Coronary circulation
------- is a composite recording of all cardiac action potentials.
EKG or Electrocardiogram
True or false: The coronary circulation is made up of all of the systemic blood vessels.
F Reason: The coronary circulation pertains to the heart, so it consists of the blood vessels within the heart tissue.
True or false: The coronary circulation is made up of all of the systemic blood vessels.
FALSE: Reason: The coronary circulation pertains to the heart, so it consists of the blood vessels within the heart tissue.
True or false: A typical resting stroke volume is 5 liters per heartbeat.
False Reason: Five liters would be a typical cardiac output, whereas a typical stroke volume would be 70 milliliters.
True or false: The pumping activity of the heart rarely changes over the course of one's life.
False Reason: The heart is actually actively regulated to deal with changes in the metabolic activity of the tissues.
Place the events of the baroreceptor reflex their correct order. Start with an increase in blood pressure
Increase in blood pressure within aorta stimulates an increase in frequency of action potentials within the baroreceptors. Afferent signals are then sent to the medulla oblongata. Sympathetic responses decrease and parasympathetic increase. Heart rate and stroke volume decrease. Response is a decrease in blood pressure.
What is the double-layered sac that surrounds the heart called?
Pericardium
What must be overcome as blood travels through the vessels?
Peripheral resistance
Mean arterial pressure changes proportionally with changes in which variables?
Peripheral resistance Stroke volume Cardiac output
Define the Pulmonary Circulation vs Systemic circulation
Pulmonary Circulation: matches Choice, Transports blood from the right ventricle of the heart to the lungs for exchange of gases Transports blood from the right ventricle of the heart to the lungs for exchange of gases Systemic Circulation: Choice, Transports blood from the left ventricle to the body tissues to supply the tissues with oxygen and nutrients Transports blood from the left ventricle to the body tissues to supply the tissues with oxygen and nutrients
Diastole
Relaxation of the heart
Cardiac output is equal to which of the following?
SV x HR (stroke volume x heart rate)
ventricular repolarization
T wave represents, leads to ventricular diastole
In maintaining homeostasis, regulation of the pumping action of the heart ensures ______
The metabolic demands of tissues are maintained Reason: The pumping action of the heart is not altered to alter deliver of hormones.It is altered as metabolic demands of tissues is altered.
period of ejection
The semilunar valves are pushed open, and blood flows from the ventricles into the pulmonary trunk and aorta.
True or false: Normal aging does not substantially change the heart's ability to function at rest.
True,Reason: Age-related changes are easily compensated for under resting conditions
The strongest stimulus will not cause muscle contraction during the ______ refractory period.
absolute
A direct connection between multiple arteries that provides an alternate route of blood flow if blockage occurs is an arterial __
anastomosis
When blood pressure is measured in the brachial artery, it reflects blood pressure in the ___
aorta
When blood pressure is measured in the brachial artery, it reflects blood pressure in the ______.
aorta
What valves close at the time indicated by the circle?
atrioventricular (semilunar or tricuspid would be above
The structure that relays excitation from the atria to the ventricles is known as the ___
atrioventricular node
The chambers of the human heart are the right and left ------ ant the right and left ------
atrium ; ventricles
The cardiac muscle cells are described as ______ because individual cells can depolarize on their own without outside stimulation.
autorhythmic
beginning of cardiac cycle
av valves are open and semilunar valves are closed
Mean arterial pressure is defined as the _____.
average pressure in the aorta
The ------ valve and the ---- valve close at the same time of low pressure
bicuspid/mitral/AV/ Right atrioventricular and the tricuspid/Left atrioventricular
Period of isovolumetric relaxation
blood begins to flow back toward the ventricles, causing the semilunar valves to close. With closure of the semilunar valves, all the heart valves are closed, and no blood flows into the relaxing ventricle during this period.
At a given point in time, blood flows in the heart from ___
both atria to both ventricles (CO2 blood from R atrium to R ventricle then to lungs back into heart via left atrium then into the left ventricle then O2 blood to body ; the blood enters the heart from both atriums then the ventricle chambers take it in, close and push with their muscle to go out to the lungs or out the body
the difference between the maximum cardiac output and resting cardiac output is known as the ------- reserve
cardiac
The __ is a repeating series of contraction and relaxation events that move blood through the heart.
cardiac cycle
The sequence of events that begins with heart muscle contraction and ends with the beginning of the next contraction is called the ----- -------
cardiac cycle
What is the volume of blood ejected by the ventricles per minute called?
cardiac output
Mean arterial pressure is equal to _____
cardiac output times peripheral resistance
Mean arterial pressure is equal to ______.
cardiac output times peripheral resistance
t is important to know the location of the heart for ____
cardiopulmonary resuscitation applying leads for ECG listening to heart sounds
An organ or cell specialized to detect chemicals is classified as a
chemoreceptor
The input for the reflex response to blood pH comes from the ______ in the large arteries, which detect changes in blood chemicals.
chemoreceptors
Systole means
contraction
Colder body temperatures will result in a(n) ______ in heart rate.
decrease
During surgical procedures, the body temperature can be ______ to minimize blood flow.
decreased
Cardiac output is the volume of blood ______.
ejected by the ventricles per minute
What controls the opening of the ion channels in cardiac muscle cells during phases of the action potential?
electrical changes
Venous return increases the _____
end-diastolic volume
The three layers of the heart wall from deep to superficial are the
endocardium, myocardium, and epicardium
True or false: During one heartbeat, blood flows from the right atrium to the right ventricle, and during the next heartbeat, blood flows from left atrium to left ventricle.
false, Blood flows from both atria to both ventricles during each heartbeat.
at rest most pressure changes occur due to passive pressure changes resulting from opening and closing of
heart chambers
Regular aerobic exercise improves the heart's functional capacity ____
in all ages
An increase in venous return to the heart leads to a(n) ______ in preload and therefore a(n) ______ in stroke volume.
increase, increase
Increasing exercise will cause ____
increased heart rate increased stroke volume increased cardiac output
When mechanisms within the heart regulate cardiac output, it is referred to as _____ regulation.
intrinsic
The average pressure in the arteries is the _____.
mean arterial pressure
The electrical charge difference between the inside and outside of the plasma membrane in excitable cells is referred to as the resting membrane-----------potential.
membrane
The membrane potential when a cardiac muscle cell is relaxed is the resting __
membrane potential
An increase in stimulation by what branch of the nervous system lowers the heart rate?
parasympathetic
time period when blood is passively moving into ventricles is called
passive ventricular filling
The ------ is a doubled-walled sac enclosing the heart
pericardium
The mean arterial pressure is dependent on two factors: cardiac output and the force against which blood must be pumped or
peripheral resistance
Blood is transported from the right ventricle to the lungs for gas exchange and returned it to the left atrium of the heart by the--------- circuit, while blood is transported from the left ventricle to supply the tissues of the body with oxygen and nutrients by the--------circuit.
pulmonary ; systemic
atrial diastole
relaxation of the atrial myocardium
The amount of blood pumped during each heartbeat is called the------ -----
stroke volume
___ is the volume of blood ejected from the heart with each beat.
stroke volume
when systole and diastole are used alone
they refer to the ventricular myocardium
Cardiac output is equal to stroke volume ______ heart rate.
times
True or false: Systolic and diastolic blood pressures reflect pressure changes in the aorta.
true, Reason: Systolic and diastolic blood pressures measured in the brachial artery clinically reflect blood pressure in the aorta.
The heart sounds are made by the action of which of the following?
valves
Electrical changes across the membrane cause the opening and closing of -------gated ion channels..
voltage
Intrinsic regulation of cardiac output results from mechanisms ______ the heart
within
