Trace blood flow in order through the major vessels and circuits.
Vena Cava, AV Valve, Right Ventricle, SL Valve, pulmonary artery, lungs, pulmonary vein, Left atrium, AV Valve, Left ventricle, SL Valve, Aorta
Which chambers of the heart are Oxygen poor?
Right atrium and ventricle.
What are the phases of the cardiac cycle?
Systole and diastole
Describe the muscular, valve, fluid, and electrical activity associated with systole
– ventricles contract; atria relax
– blood flows out of heart into pulmonary artery and aorta
– mitral and tricuspid valves closed
– aortic and pulmonic valves open
Describe the muscular, valve, fluid, and electrical activity associated with diastole
– ventricles relax; atria contract
– blood flows from atria into ventricles
– mitral and tricuspid valves open
– aortic and pulmonic valves closed
Given EDV , ESV , and HR, how do you calculate SV , CO, and EF?
CO = stroke volume (SV) x heart rate (HR)
SV = EDV-ESV
On average, how often does an RBC pass through the heart?
Starting with the outermost, name the three types of “—cardium”
– heart muscle responsible for pumping blood
– connective tissue for support and nerve conduction
smooth surface minimizes blood turbulence during pumping
What is the cause of the twisting or torque motion of the heart as it contracts?
Uneveness of the thickness in the cardiac wall.
During one minute, approximately how much time is spent in diastole and how much is spent in systole?
0.4 minutes in systole 0.6 minutes in diastole
Compare and contrast atrial and ventricular contraction in terms of strength, length, timing, valve activity, and maximum blood pressure.
atria only pump blood within the heart. Hence, they contract for a shorter amount of time and weaker. Atria contract before ventricles and atrioventricular valves prevent backflow when ventricles contract.
How would a massive drop in blood volume affect CO? Why would tachycardia be expected as a result?
A massive drop in blood volume would result in a drop in stoke volume. To maintain cardiac output despite lowered stroke volume, the heart rate would have to increase to abnormally fast rate. Remember that CO = SV*HR.
What factors affect SV?
– degree of stretch of heart muscle (preload)-increases EDV
– Strength of contraction (contractility)- decreases ESV
– Back pressure on ventricle (afterload)- minor except in people with BP↑↑
What factors can influence HR? What hormones, if any, regulate these factors?
– blood pressure
– blood composition (e.g. water, Na+ content)
– sympathetic/parasy mpathetic nervous
What is the sequence of events in the conducting system (nervous tissue) of the heart through one cardiac cycle? Correlate these events with the signals on an EKG.
• P wave: atrial depolarization
• QRS complex: ventricular depolarization
• T wave: ventricular repolarization
Why is rapid conduction of the electrical signal from the Bundle of His to the Purkinje fibers important for efficient pumping of blood?
Because they cause the ventricles to contract and pump blood throught the body
Resistance to blood flow is regulated primarily in which type of vessel? In these vessels, how is blood flow to an organ increased or decreased?
Blood Vessels. regulated by the vasoconstriction or vasodialation of the tunica media
Which type of vessel is most elastic and why is this important?
Arteries. They then have a higher resistance to high blood pressure.
Which type of vessel is least robust (against pressure increase, stresses, etc) and how is its inherent weakness associated with its function?
Venules and Veins. It makes it easier for them to intake blood and take the blood back to the heart.
the load, or resistance, against which the left ventricle must eject its volume of blood during contraction.
an adrenal hormone that causes elevation of blood pressure through the retention of sodium and the resultant increase in blood plasma volume.
Any of a group of peptides with vasoconstrictive activity that function physiologically in controlling arterial pressure.
A hormone, posterior lobe of the pituitary gland, constricts blood vessels, raises blood pressure,
The main blood vessel that leads away from the heart and the body's largest artery. The aorta carries blood from the heart through the chest and abdomen, providing major branches to all of the organs in the body
The valve between the left ventricle of the heart and the ascending aorta, consisting of three semilunar cusps.
a smaller arterial branch off an artery and connecting to a capillary.
one of the large blood vessels carrying blood in a direction away from the heart to the tissues
atrioventricular (AV) node
a collection of Purkinje fibers beneath the endocardium of the right atrium, continuous with the atrial muscle fibers and atrioventricular bundle; it receives the cardiac impulses from the sinoatrial node and passes them on to the ventricles.
atrioventricular (AV) valve
a valve in the heart through which blood flows from the atria to the ventricles. The valve between the left atrium and left ventricle is the mitral (bicuspid) valve; the right AV valve is the tricuspid valve
Either the right or the left upper chamber of the heart that receives blood from the veins and forces it into a ventricle.
a segment of the network of specialized conducting fibers that transmits electrical impulses within the ventricles of the heart. Bundle branches are a continuation of the atrioventricular (AV) bundle, which extends from the upper part of the intraventricular septum.
one of the minute vessels connecting the arterioles and venules, the walls of which act as a semipermeable membrane for interchange of various substances between the blood and tissue fluid.
a complete cardiac movement, or heart beat, including systole, diastole, and intervening pause
inability of the heart to pump blood at a rate adequate to fill tissue metabolic requirements or the ability to do so only at an elevated filling pressure
The volume of blood pumped from the right or left ventricle in one minute. It is equal to the stroke volume multiplied by the heart rate.
The work that the heart is able to perform beyond that required of it under ordinary circumstances.
the inotropic state of the myocardium; a major determinant of cardiac output
the phase of the cardiac cycle in which the heart relaxes between contractions; specifically, the period when the two ventricles are dilated by the blood flowing into them.
the lowest pressure recorded in the arterial blood pressure cycle. Represents the minimal pressure in the left ventricle which can maintain its ejection phase
the proportion of the volume of blood in the ventricles at the end of diastole that is ejected during systole; it is the stroke volume divided by the end-diastolic volume
An elastic, fibrous mucoprotein, similar to collagen, and the major connective tissue protein of elastic fibers.
(EDV) the volume of blood in each ventricle at the end of diastole
(ESV) the volume of blood remaining in each ventricle at the end of systole
the layer of epithelial cells that lines the cavities of the heart
red blood cell
Rapid, uncoordinated contractions of the upper or the lower chambers of the heart.
The percentage by volume of packed red blood cells in a given sample of blood after centrifugation.
the pressure in the circulatory system exerted by the volume of blood when it is confined in a blood vessel.
persistently high arterial blood pressure
inferior vena cava
The biggest vein in the body, returning blood to the heart from the lower half of the body
white blood cells
The inner cavity or canal of a tube-shaped organ
mean arterial pressure
the average pressure within an artery over a complete cycle of one heartbeat.
that between the left atrium and left ventricle, usually having two cusps (Bicuspid)
Part of the cardiac cycle shown on an EKG as an inverted U-shaped curve that follows the T wave and precedes the QRS complex. It represents atrial depolarization.
the fluid portion of the blood in which the particulate components are suspended.
The smallest cells in the blood. They are formed in the red bone marrow
the volume of blood in the ventricle at the end of diastole.
the short, wide vessel that conveys venous blood from the right ventricle of the heart to the lungs.
A vein that carries oxygenated blood from the lungs to the left atrium of the heart.
the pocket like cardiac valve that protects the orifice between the right ventricle and the pulmonary artery.
the difference between systolic and diastolic pressures.
modified cardiac fibers in the subendocardial tissue that constitute the terminal ramifications of the conducting system of the heart. The term is sometimes used loosely to denote the entire system of conducting fibers.
the portion of the electrocardiogram comprising the Q, R, and S waves, together representing ventricular depolarization.
backflow of blood
One of three semilunar segments serving as the cusps of a valve preventing regurgitation, as in the aortic valve and the pulmonary valve.
sinoatrial (SA) node
cardiac muscle fibers located in the posterior wall of the right atrium of the heart that acts as a pacemaker of the cardiac conduction system by generating at regular intervals the electric impulses of the heartbeat.
skeletal muscle pump
a collection of skeletal muscles that aid the heart in the circulation of blood.
is the volume of blood pumped from one ventricle of the heartwith each beat.
superior vena cava
is a large diameter, yet short, vein that carries deoxygenatedblood from the upper half of the body to the heart's right atrium.
part of the cardiovascular system which carries oxygenated blood away from the heart to the body, and returns deoxygenated blood back to the heart.
is a phase of the cardiac cycle in which the myocardium contracts
the blood pressure measured during the period of ventricular contraction (systole). In blood pressure readings, it is the higher of the two measurements.
the deflection of the normal electrocardiogram following the QRS complex; it represents repolarization or recovery of the ventricles.
abnormally rapid heart rate
total peripheral resistance
the overall resistance to blood flow through the systemic blood vessels.
the valve located between the right atrium and right ventricle. Called also right atrioventricular valve.
the inhibitory control of the vagus nerve over heart rate and atrioventricular conduction.
Constriction of a blood vessel, as by a nerve or drug.
Dilation of a blood vessel, as by the action of a nerve or drug.
a vessel in which blood flows toward the heart
The blood returning to the heart via the inferior and superior venae cavae.
Lower cavities in the heart
any of the small vessels that collect blood from the capillary