80 Questions
Which type of cardiac muscle cells contract spontaneously?
Automatic cells
What is the role of non-automatic cells in the heart?
They require initiation by signal cells to contract.
Which cells make up the majority of cardiac myocytes in the heart?
Automatic cells
What happens when the automatic cells of the heart contract?
They initiate the contraction of non-automatic cells.
How do non-automatic cells in the heart start contracting?
By requiring initiation by automatic cells.
Automatic cells in the heart do not require external stimuli to initiate contractions.
True
Non-automatic cells in the heart are responsible for initiating the contractions of automatic cells.
False
Most of the cardiac myocytes in the heart are non-automatic cells.
False
Automatic cells contract first in the heart, followed by non-automatic cells.
True
Non-automatic cells rely on the automatic cells to be stimulated mechanically in order to start contracting.
False
What is the characteristic of automatic cells in the heart?
They spontaneously contract.
What is the primary role of automatic cells in the heart?
To initiate contractions and signal to non-automatic cells to contract.
Why do non-automatic cells in the heart require signaling from automatic cells?
Because they do not spontaneously contract.
What is the result of automatic cells contracting in the heart?
They signal to non-automatic cells to contract.
What percentage of cardiac myocytes in the heart are non-automatic cells?
Most of them.
Your heart beats regularly on it's own without you having to think about it ______
happening
There are two types of cardiac ______ cells (myocytes):
muscle
Non-automatic cells = do not spontaneously ______, they require their contractions to be initiated by the automatic cells
contract
When the automatic cells ______, they signal to the non-automatic cells contract
contract
Most cardiac ______ are non-automatic cells
myocytes
Match the characteristics of cardiac muscle cells with their definitions:
Automatic cells = They contract spontaneously without external stimuli. Non-automatic cells = They contract without being signaled by other cells.
Match the types of cardiac muscle cells with their roles in the heart's contraction:
Automatic cells = They respond to signaling from other cells. Non-automatic cells = They require signaling to contract.
Match the cardiac muscle cells with their contraction mechanisms:
Automatic cells = They contract spontaneously without external stimuli. Non-automatic cells = They contract after receiving signals from automatic cells.
Match the characteristics of the heart's contraction with the type of cardiac muscle cells involved:
Spontaneous contraction = Automatic cells Signaling-dependent contraction = Non-automatic cells
Match the descriptions with the types of cardiac muscle cells:
Cells that initiate the heart's contraction = Automatic cells Cells that respond to signaling from other cells = Non-automatic cells Cells that contract independently = Automatic cells Cells that require external stimuli to contract = Non-automatic cells
What is the typical location of the Sinoatrial node in the heart?
At the junction of the cranial vena cava and the right atrium
What is the function of the signal sent by the Sinoatrial node?
It causes both atria to contract and then spreads to the ventricles
What is the characteristic of the baseline rate of contraction of the Sinoatrial node?
It can be altered by input from the body
What is the next step in the cardiac cycle after the signal from the Sinoatrial node reaches the atrioventricular node?
The atria relax and the ventricles contract
What is the significance of the Sinoatrial node in the cardiac cycle?
It is responsible for regulating the heart rate
The Sinoatrial node is responsible for initiating ventricular contraction.
False
The atrioventricular node is located in the right atrium.
False
The Sinoatrial node has a fixed rate of contraction that cannot be altered.
False
The Sinoatrial node is a bundle of non-automatic cells.
False
The cardiac cycle starts with ventricular contraction.
False
The Sinoatrial node is a bundle of ______ cells that controls the heart rhythm and rate.
automatic
The Sinoatrial node is located at the junction of the ______ vena cava and the right atrium.
cranial
The Sinoatrial node sends out a signal that causes both ______ to contract.
atria
The signal from the Sinoatrial node then spreads to the ______ node in the atrioventricular septum.
atrioventricular
The ______ cycle starts with the contraction of the atria, followed by the contraction of the ventricles and then relaxation.
cardiac
What is the purpose of the closure of the AV valves during ventricular contraction?
To prevent blood from flowing from the ventricles back into the atria
During which part of the cardiac cycle do the semilunar valves close?
End of systole/beginning of diastole
What is the resulting sound of the closure of the AV valves?
Lub
What is the function of the closure of the semilunar valves?
To prevent blood from flowing from the pulmonary artery/aorta back into the ventricles
What do the 'Lub' and 'Dub' sounds represent during auscultation of the heart?
Closure of the AV and semilunar valves
What is the purpose of the closure of the AV valves during ventricular contraction?
To prevent blood from flowing back into the atria
During which part of the cardiac cycle do the AV valves close?
During ventricular contraction
What is the resulting sound of the closure of the semilunar valves?
Dub sound
What is the function of the closure of the semilunar valves?
To prevent backflow of blood from the pulmonary artery/aorta to the ventricles
When do the semilunar valves close in the cardiac cycle?
During ventricular relaxation
What is the purpose of the heart's cardiac cycle?
To maintain blood pressure within a range
What happens during ventricular contraction in the cardiac cycle?
Ventricles empty into the aorta and pulmonary arteries
What is the significance of the 'Lub' sound during auscultation of the heart?
It represents the closure of the AV valves
What occurs during diastole in the cardiac cycle?
Ventricles relax and fill with blood from the atria
Why is it important to maintain blood pressure within a range?
To prevent a pressure that is too high or too low
What is the relationship between systole and diastole?
Systole is active, and diastole is passive
What is the main function of the AV valves in the cardiac cycle?
To prevent blood from flowing back into the atria during ventricular contraction
What occurs during the beginning of systole in the cardiac cycle?
The ventricles contract and the AV valves close
What is the relationship between the 'Lub' and 'Dub' sounds during auscultation of the heart?
The 'Lub' sound occurs during systole and the 'Dub' sound occurs during diastole
What is the characteristic of ventricular contraction in the cardiac cycle?
Active contraction of the ventricles
What is the purpose of the cardiac cycle?
To pump blood throughout the body
What is the difference between systole and diastole?
Systole is active contraction and diastole is passive relaxation
During ventricular contraction, the AV valves close to prevent blood flow back into the atria.
False
The 'Lub' sound is due to the closing of the semilunar valves during the cardiac cycle.
False
During diastole, the ventricles empty into the aorta and pulmonary arteries.
False
The 'Dub' sound occurs during ventricular relaxation at the end of systole.
True
The cardiac cycle consists of atrial contraction immediately followed by ventricular contraction.
False
Blood pressure is considered high during diastole and low during systole.
False
Match the heart sounds with their corresponding valve closure:
Lub = Semilunar valves Dub = AV valves
Match the phases of the cardiac cycle with their corresponding blood pressure:
Systole = Low pressure Diastole = High pressure
Match the characteristics of the cardiac cycle with their corresponding descriptions:
Systole = Ventricular relaxation Diastole = Ventricular contraction
Match the valves with their corresponding functions in the cardiac cycle:
AV valves = Prevent blood flow from pulmonary artery/aorta back into ventricles Semilunar valves = Prevent blood flow from ventricles back into atria
Match the cardiac cycle events with their corresponding phases:
Closure of AV valves = End of systole/beginning of diastole Closure of semilunar valves = Beginning of systole
Match the cardiac cycle phases with their corresponding pressures:
Systole = Small number (low pressure) Diastole = Big number (high pressure)
During ventricular contraction, the ______ valves snap shut
AV
The 'Lub-Dub' sounds heard when auscultating the heart are due to the ______ snapping shut
valves
The 'Dub' sound occurs during ventricular ______ at the end of systole
relaxation
It is important that blood pressure is maintained within a range to prevent having a pressure that is too high or too ______
low
During diastole, the ventricles fill up with blood from the ______
atria
Systole in the cardiac cycle is characterized by ventricular ______ into the aorta/pulmonary arteries
emptying
Learn about the two types of cardiac muscle cells responsible for the heart's regular beating: automatic cells that spontaneously contract, and non-automatic cells that require initiation from automatic cells. Discover how these cells work together to ensure proper heart function.
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