A and P II Test #2 (17-19)
Calculate the cardiac output if the heart rate is 85 beats/minute, end-diastolic volume (EDV) is 130 ml, and the end-systolic volume (ESV) is 60 ml?
5950 ml/min
Which hormone decreases cardiac output by decreasing blood volume and preload?
Atrial natriuretic peptide
How do cardiac cells sustain a membrane potential of around 0 mv during the long plateau phase?
Calcium channels remain open
High pressured blood in the ventricles forces?
Forces the semilunar valves open
What ion movement changes the membrane potential in a contractile cell from negative to positive?
Influx of calcium ions
What phase is the S1 heart sound heard?
Isovolumetric contraction phase
The apex of the heart is situated towards the?
Left hip
Which chamber experiences a maximum pressure of around 118 mm Hg during contraction?
Left ventricle
The pulmonary circuit involves blood flow from the heart to and from the?
Lungs
The heart is situated in the middle of the thoracic cavity in a region known as the?
Mediastinum
A contractile cell with a membrane potential of 0 mv is experiencing what phase?
Plateau phase
The degree of stretch experienced by the sacromeres in the ventricle cells before they contract is called?
Preload
What does NOT return blood to the right atrium of the heart?
Pulmonary vein
Which vessels carries oxygenated blood?
Pulmonary vein
What vessels(s) deliver oxygenated blood to the left atrium?
Pulmonary veins
A damaged right bundle branch will prevent the passage of the action potential to the?
Purkinje fibers in the right ventricle
What can be used to measure heart rate?
R-R interval
The rapid influx of sodium ions into contractile cells creates a positive membrane potential inside the cell and initiates the?
Rapid depolarization phase
What valve prevents the backflow of blood from the right ventricle into the right atrium?
Right atrioventricular valve (tricuspid valve)
The P wave on an electrocardiogram (ECG) represents the depolarization of cells in the?
Sinoatrial (SA) node
What normally serves as the pacemaker of the entire heart?
Sinoatrial (SA) node
What would be the impact if the connection between the sinoatrial (SA) node and the atrioventricular (AV) node becomes blocked?
The ventricles will beat more slowly
Blood in the right atrium should travel next to the?
Tricuspid valve and into the right ventricle
Which cranial nerves have a negative chronotropic effect on heart rate?
Vagus nerves (CN X)
