Term
| What are the five mechanical events of the cardiac cycle? |
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Definition
1) Late diastole
2) Artial systole
3) Isovolumic ventricular contraction
4) Ventricular ejection
5) Isovolumic ventricular relaxation |
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Term
| __________ __________ occurs when both sets of chambers are relaxed and ventricles fill passively. |
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Definition
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Term
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Definition
| 1) When both sets of chambers are relaxed and ventricles fill passively |
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Term
| __________ __________ is when atrial contraction forces a small amount of additional blood into ventricles. |
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Definition
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Term
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Definition
| 1) When a small amount of additional blood is forced into the ventricles by atrial contraction |
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Term
| __________ __________ __________ is the first phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves. |
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Definition
| 1) Isovolumic ventricular contraction |
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Term
| What is isolvolumic ventricular contraction? |
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Definition
| 1) First phase of ventricular contraction which pushes AV valves closed by does not create enough pressure to open semilunar valves |
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Term
| __________ __________ is when the semilunar valves open and blood is ejected due to ventricular pressure rises and exceeding the pressure in the arteries. |
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Definition
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Term
| What is ventricular ejection? |
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Definition
| 1) When the ventricular pressure rises and exceeds the pressure in the arteries, forcing the semilunar valves to open and blood to be ejected |
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Term
| __________ __________ __________ is when the pressure in ventricles falls and blood flows back into the cusps of the semilunar valves and snaps them closed due to ventricles relaxing. |
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Definition
| 1) Isovolumic ventricular relaxation |
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Term
| What is isolvolumic ventricular relax |
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Definition
| 1) As the ventricles relax, pressure in ventricles fall allowing blood to flow back into the cusps of semilunar valves and snaps them closed |
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Term
| __________ __________ is calculated from multiplying the heart rate by the stroke volume. |
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Definition
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Term
| __________ __________ is controlled by the ANS. |
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Definition
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Term
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Definition
| 1) The result of heart rate being multiplied by stroke volume |
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Term
| Without the ANS, the SA node fires at what rate? |
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Definition
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Term
| What does the cardiac output depends on? |
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Definition
1) Heart rate
2) Stroke volume |
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Term
| The __________ __________ consists of the beats of the heart per minute. |
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Definition
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Term
| The __________ __________ consists of the output of each ventricle per minute. |
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Definition
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Term
| The __________ __________ is the output of each ventricle per beat. |
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Definition
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Term
| What is the average cardiac output? |
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Definition
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Term
| What is the average heart rate? |
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Definition
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Term
| What is the average stroke volume? |
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Definition
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Term
| Changing __________ __________ is the most common way to change cardiac output; __________ __________ often remains relatively constant. |
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Definition
1) Heart rate
2) Stroke volume |
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Term
| What is the most common way to change cardiac output? |
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Definition
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Term
| __________ __________ is varied by altering the balance of parasympathetic and sympathetic influence on SA node? |
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Definition
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Term
| __________ stimulation slows heart rate; __________ stimulation speeds it up. |
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Definition
1) Parasympathetic
2) Sympathetic |
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Term
| What is the effect of the parasympathetic stimulation on the SA node? |
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Definition
| 1) Decreases the rate of depolarization to threshold; decreases the heart rate. |
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Term
| What is the effect of sympathetic stimulation on the SA node? |
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Definition
| 1) Increases the rate of depolarization to the threshold; increases the heart rate |
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Term
| What is the effect of the parasympathetic stimulation on the AV node? |
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Definition
| 1) Decreases excitability; increases the AV nodal delay |
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Term
| What is the effect of the sympathetic stimulation on the AV node? |
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Definition
| 1) Increases excitability; decreases the AV nodal delay |
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Term
| What is the effect of the parasympathetic stimulation on the ventricular conduction pathway? |
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Definition
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Term
| What is the effect of the sympathetic stimulation on the ventricular conduction pathway? |
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Definition
| 1) Increases excitability; hastens conduction through the bundle of His and Purkinje cells |
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Term
| What is the effect of the parasympathetic stimulation on the atrial muscle? |
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Definition
| 1) Decreases contractility; weakens contraction |
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Term
| What is the effect of the sympathetic stimulation on the atrial muscle? |
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Definition
| 1) Increases contractility; strengthens contraction |
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Term
| What is the effect of the parasympathetic stimulation on ventricular muscle? |
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Definition
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Term
| What is the effect of the sympathetic stimulation on ventricular muscle? |
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Definition
| 1) Increases contractility; strengthens contraction |
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Term
| What is the effect of the parasympathetic stimulation on the adrenal medulla? |
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Definition
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Term
| What is the effect of the sympathetic stimulation on the adrenal medulla? |
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Definition
| 1) Promotes adernomedullary secretion of epinephrine, a hormone that augments the sympathetic nervous system's actions on the heart |
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Term
| What is the effect of the parasympathetic stimulation on the veins? |
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Definition
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Term
| What is the effect of the sympathetic stimulation on the veins? |
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Definition
| 1) Increases venous return, which increases the strength of cardiac contraction through the Frank-Starling mechanism |
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Term
| What are the effects on the heart rate by norepinephrine and epinephrine? |
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Definition
1) Increases inward movement of Na+ and Ca2+ through the If and T-type Ca2+ channels
2) Reduces AV delay by increasing conduction velocity enhancing the slow, inward Ca2+ current
3) Speeds the spread of action potentials throughout the specialized conduction system
4) Increases the contractile strength of contractile cells effect produced by increased inward of Ca2+ movement through prolonged opening of L-type Ca2+ channels, which ehance the slow Ca2+ influx and intensifies Ca2+ participation in Excitation-Contraction coupling
5) Not only increase the speeds of contraction by allowing great influx of Ca2+ into the cell but it also speeds up relaxation by enhancing the active Ca2+ pump in sacroplasmic reticulum, and removes Ca2+ from the cytosol. |
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Term
| What are the effects on the heart rate by acetylcholine? |
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Definition
1) Increased flow through K+ channels and decreased flow through Ca2+ channels
2) Enhances K+ permeability and hyperpolarizes the SA node membrane
3) By enhancing K+ permeability, vagal stimulation also opposes the automatic reduction on K+ permeability that contributes to the development of pacemaker potential
4) Acetylcholine by inhibiting cAMP pathway also depresses both inward movement of Na+ and Ca+ |
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Term
| __________ stimulation is a positive chronotrope on the regulation of heart rate. |
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Definition
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Term
| __________ stimulation is a negative chronotrope on the regulation of heart rate. |
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Definition
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Term
| Sympathetic stimulation of __________ __________ __________ __________ increases the rate of spontaneous depolarization; this increases __________ __________. |
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Definition
1) SA nodal beta receptors
2) Heart rate |
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Term
| Sympathetic stimulation increases conduction velocity through the __________ __________ and other parts of the conduction system, decreasing the duration of __________. |
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Definition
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Term
| Parasympathetic stimulation of __________ __________ __________ __________ decrease the rate of spontaneous depolarization, decreasing __________ __________. |
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Definition
1) SA nodal muscarinic receptors
2) Heart rate |
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Term
| Parasympathetic stimulation decreases conduction velocity through the __________ __________ and other parts of the conduction system, resulting in the increased duration of __________. |
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Definition
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Term
| Epinephrine is a __________ chronotrope secreted by the __________ __________ in response to sympathhetic activity. |
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Definition
1) Positive
2) Adrenal medulla |
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Term
| Epinephrine reinforces the effects of __________ stimulation on heart rate. |
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Definition
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Term
| Stimulation of SA nodal beta receptors by epinephrine increases the rate of spontaneous __________ and increases __________ __________. |
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Definition
1) Depolarization
2) Heart rate |
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Term
| Epinephrine increases the conduction velocity through the __________ __________ and other parts of the conduction system resulting in the decreased duration of __________. |
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Definition
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Term
| What are three examples of positive inotropics? |
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Definition
1) Adrenocortical steroids
2) Insulin
3) Pituitary hormones |
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Term
| __________ __________ increase rate and contractility of the heart, with effects that are both direct and indirect via sympathetics. |
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Definition
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Term
| Purpose of thyroid hormones? |
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Definition
| 1) Increase the rate and contractility of heart rate |
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Term
| Heart rate is regulated by the ANS through __________ __________ __________ in the medulla oblongata in the brain stem. |
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Definition
| 1) Cardiac control centers |
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Term
| Where are cardiac control centers which regulate heart rate located in the body? |
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Definition
| 1) Within the medulla oblongata in the brain stem |
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Term
| What are the two cardiac control centers? |
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Definition
1) Cardiacaccelerator center (V.M.C.)
2) Cardiacinhibitory center (C.I.C.) |
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Term
| What is the cardiacaccelerator center responsible for regulating? The cardiacinhibitory center? |
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Definition
1) Sympathetic fibers
2) Parasympathetic fibers |
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Term
| What factors affect the two control centers in the brain? |
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Definition
1) Higher brain areas
2) Sensory feedback from press receptors (baroreceptors) in the aorta and carotid arteries |
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Term
| What type of feedback do baroreceptor afferents provide to the medulla? What are the types of afferents? |
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Definition
1) Negative
2) Arterial (pressure)
3) Cardiopulmonary (volume) |
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Term
| What type of feedback do chemoreceptor afferents provide to the medulla? What are the types of afferents? |
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Definition
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Term
| What type of feedback do other afferents provide to the medulla? |
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Definition
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Term
| What is the pathway from sympathetic neurons (NE) to increasing heart rate? |
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Definition
1) Sympathetic neurons (NE)
2) B1 receptors of autorhythmic cells
3) Na+ and Ca2+ influx increase
4) Increases the rate of depolarization
5) Heart rate increases |
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Term
| What is the pathway from parasympathetic neurons (acetylcholine) to decreasing heart rate? |
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Definition
1) Parasympathetic neurons (acetylcholine)
2) Muscarinic receptors of autorhythmic cells
3) Increases K+ efflux and decreases Ca2+ influx
4) Hyperpolarizes cell and decreases the rate of depolarization
5) Decreases the heart rate |
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Term
| What are the three variables which regulate stroke volume? |
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Definition
1) EDV (preload)
2) Contractility (strength of contraction)
3) Total peripheral resistance (afterload) |
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Term
| __________ __________ is determined by the extent of venous return and by sympathetic activity. |
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Definition
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Term
| What is stroke volume determined by? |
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Definition
| 1) The extent of venous return and by sympathetic activity |
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Term
| What are the two types of controls that effect stroke volume? How do they effect stroke volume? |
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Definition
1) Intrinsic control (preload and afterload)
2) Extrinsic control
3) Increase stroke volume by increasing the strength of heart contractions |
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Term
| What are five factors that affect venous pressure? |
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Definition
1) Venoconstriction
2) Skeletal ms pump
3) Pressure differential
4) Arterial pulsation
5) Venous tone and capacity |
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Term
| What are two factors that affect blood volume? |
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Definition
1) Urine volume
2) Tissue-filed volume |
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Term
| What is responsible for regulating urine volume? |
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Definition
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Term
| __________ is tissue-fluid volume. |
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Definition
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Term
| What two factors affect contractility? |
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Definition
1) Starling's law of the heart (intrinsic control)
2) SNS (extrinsic control) |
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Term
| Normally, the strength of contraction is sufficient to eject __________-__________ mL/beat out of total EDV of __________-__________ mL. |
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Definition
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Term
| __________ are extrinsic chronotropic factors. |
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Definition
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Term
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Definition
| 1) Extrinsic chronotropic factors |
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Term
| __________ have an effect on heart rate such as pacemaker potential and conduction velocity. |
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Definition
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Term
| __________ are extrinsic and intrinsic inotropic factors that have an effect on stroke volume such as contractility and force of ventricular contraction. |
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Definition
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Term
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Definition
| 1) Extrinsic and intrinsic inotropic factors that have an effect on stroke volume stoke volume |
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Term
| What do chronotropes affect? Inotropes? |
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Definition
1) Heart rate
2) Inotropes |
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Term
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Definition
1) End-diastolic volume
2) End-systolic volume |
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Term
| What does the Frank-Starling Law of the Heart state? |
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Definition
| 1) That the heart normally pumps out during systole the volume of blood returned to it during diastole |
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Term
| What describes the relationship between the EDV and stroke volume? |
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Definition
| 1) Frank-Starling Law of the Heart |
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Term
| What are two factors that affect stroke volume? |
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Definition
1) Ventricular contractility
2) End diastolic volume (EDV) |
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Term
| What are two factors that affect ventricular contractility? |
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Definition
1) Sympathetic activity
2) Epinephrine |
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Term
| As EDV increases, the __________ __________ force also increases. |
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Definition
| 1) Ventricular contraction |
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Term
| As afterload increases, the __________ __________ __________ also increases. |
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Definition
| 1) End systolic volume (EVS) |
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Term
| What occurs as contractility increases? |
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Definition
| 1) Ejection fraction increases |
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Term
| What occurs as EDV increases? |
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Definition
| 1) Ventricular contraction force increases |
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Term
| What occurs as afterload increases? |
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Definition
| 1) End systolic volume (ESV) increases |
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Term
| __________ refers to end diastolic volume. |
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Definition
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Term
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Definition
| 1) Refers to end diastolic volume |
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Term
| What occurs due to an increase in filling pressure of the heart? |
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Definition
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Term
| __________ can be described as the pressure that the chamber of the heart has to generate in order to eject blood out of the chamber, and thus is a consequence of the aortic pressure, since the pressure in order to open the aortic valve. |
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Definition
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Term
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Definition
| 1) The pressure that the chamber of the heart has to generate in order to eject blood out of the chamber, and thus is a consequence of the aortic pressure, since the pressure in order to open the aortic valve. |
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Term
| What factors can cause end diastolic volume (EDV) increase? |
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Definition
1) Heart rate decreases -> filling time increases -> venous return increases -> atrial pressure increases
2) Central venous pressure increases -> venous return increases -> atrial pressure increases
3) Atrial contraction causes atrial pressure to increase |
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Term
| What is the EDV, stroke volume, and ESV for a normal stroke volume? |
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Definition
1) EDV: 135 mL
2) Stroke volume: 70 mL
3) ESV: 65 mL |
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Term
| What is the EDV, stroke volume, and ESV for a stroke volume during sympathetic stimulation? |
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Definition
1) EDV: 135 mL
2) Stroke volume: 100 mL
3) ESV: 35 mL |
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Term
| What is the EDV, stroke volume, and ESV for a stroke volume with combination of sympathetic stimulation and increased end-diastolic volume |
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Definition
1) EDV: 175 mL
2) Stroke volume 140 mL
3) ESV 35 mL |
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Term
| The more the __________ muscle is stretched, the stronger the __________. |
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Definition
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Term
| __________ __________ is a vasodynamic parameter that relates the cardiac output to the body surface area, thus relating heart performance to the size of the individual. |
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Definition
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Term
| The normal range of the cardiac index is __________-__________ L/min per square meter. |
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Definition
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Term
Cardiac output is a function of what two factors?
Heart rate is determined by what factor? Stroke volume?
The rate of depolarization in autorhythmic cells decreases because of what? What increases it?
The force of contraction in ventricular myocardium is influenced by what factors?
EDV varies with what? What is this aided by? |
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Definition
1) Heart rate and stroke volume
2) Heart rate: Rate of depolarization in autorhythmic cells
Stroke volume: Force of contraction in ventricular myocardium
3) Decrease: Parasympathetic intervention
Increase: Sympathetic innervation and epinephrine
4) Contractility and EDV
5) Venous return
6) Skeletal muscle pump and a respiratory pump |
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