Circulatory System: The Heart & Blood Vessels
Timing of Heart Cycle
*In a resting person a. Atrial systole last about 0.1 sec b. Ventricular systole about 0.3 sec c. Quiescent period, when all four chambers are in diastole, 0.4 sec -0.1 sec+0.3sec+0.4sec= 0.8 sec in 1 heart cycle beat
End Systolic Volume (ESV)
*The volume of blood contained within each of the ventricles AFTER their contraction (normal volume is 60 mL)
End Diastolic Volume (EDV)
*The volume of blood contained within each of the ventricles BEFORE their contraction (normal volume is 130mL)
To calculate Heart Rate (Timing of Heart Cycle)
*Use the formula X/60 Where X is the sum (total) of a,b,c above Ex: 0.8sec/60=75 bpm -Therefore, total duration of the cardiac cycle is 0.8 sec in a heart beating 75 bpm
Ventricular Filling
- During diastole, ventricles expand - Their pressure drops below that of the atria - AV valves open and blood flows into the ventricles
Isovolumetric Contraction
- atria repolarize, relax, and remain in diastole for the rest of the cardiac cycle. -create the QRS complex & begin to contract, AV valves close as ventricular blood surges back against the cusps heart sound S1 occurs at beginning of this phase 'Isovolumetric' because even tho the ventricules contract, they do not eject blood -Pressure in aorta 80mm Hg & in pulmonary trunk 10 mm Hg it is still greater than in ventricules.
Bundle of His
-20-40 bpm
AV Node
-40-50 bpm
Conditions that can lead to arrhythmia, including:
-A heart attack that's occurring right now -Scarring of heart tissue from a prior heart attack -Changes to your hearts structure, such as from cardiomyopathy -Blocked arteries in your heart (Coronary Heart Disease) -High blood pressure -Overactive Thyroid Gland (Hyperthyroidism) -Underactive Thyroid Gland (Hypothyroidism) -Diabetes -Sleep apnea -Infection with COVID-19
What is a heart murmur?
-Heart murmurs are abnormal heart sounds that can be caused by stenosis, prolapsed valves or an open foramen ovale.
Trabeculae Carnae
-Increases contraction force of the ventricles -Allows for EASY reopening of ventricles following contraction
Describe what happens during the:P wave QRS complex T wave P-R interval and Q-T interval
-P wave = Trigger atrial contraction. Atrial depolarization. -QRS complex- -Depolarization of the ventricles "sharp and fast"- Triggers ventricular contractions -T wave - Repolarize ventricles. Occur after ventricles contract. Ventricles relax. -P-R interval - Time it takes for the electrical signal to go from Atria to the verticals. -Q-T interval- Time for ventricle to depolarize (relax)
What is stenosis of a heart valve? What is a valve prolapse? What problems does each cause?
-Stenosis is narrowing of the valves and it makes it harder to eject blood. It can occur at any valve in the heart. Valve prolapse is when the vales go past the closed position which leads to backflow of blood.
What do the chordae tendineae and papillary muscles do? Why is this important?
-The chordae tendineae and papillary muscles anchor the heart valves in place.
Ventricular Ejection
-The ejection of blood begins when ventricular pressure exceeds arterial pressure and forces the semilunar valves open. a. Pressure peaks in left ventricle at about 120 mm Hg and 25 mm Hg in the right *Blood spurts out of each ventricle rapidly at first-rapid ejection; then more slowly under reduces pressure-reduced ejection -Lasts about 200-250 msec b. corresponds to the plateau phase of the cardiac action potential Twave occurs late in this phase. -Stroke volume of about 70 ml of blood is ejected of the 130 mL in each ventricle c. ejection fraction of about 54% d. as high as 90% in vigorous exercise end systolic volume-the 60ml of blood left behind.
List and describe the fetal circulatory shortcut. What would happen if these shortcuts did not close up about the time of birth? Why can fetal blood bypass the lungs?
-The foramen ovale (Depression) is a hole in the Interatrial Septum, allowing the blood skips from right atrium to left atrium -The ductus arteriosis goes from the aorta to the pulmonary trunk -Fetal blood bypasses the lungs bcs the lungs are not yet expanded. The blood would continue to skip the lungs, and as a result would not be oxygenated.
How are the layers of tissues found in artery and vain walls similar and how are they different?
-Tunica Externa: FB connective tissue -Tunica Media: Artery Smooth Muscle and Elastic fibers. For veins smooth muscle only. -Tunica Intima (Interna): Simple squamous endothelium (Epithelial Tissue) & Connective Tissue layer & Internal Elastic Membrane
SA Node
-pacemaker of the heart -60-100 bpm
Blood flow through the heart
1-Blood enters right atrium from Superior & Inferior Vena Cava, 2-Blood in Right Atrium flows through right AV valve into right ventricle, 3-Contraction of Right ventricle forces pulmonary valve , 4- Blood flows through Pulmonary valve into pulmonary trunk, 5-Blood is distributed by right & left pulmonary arteries to the lungs, where it unloads CO2 & loads O2. 6- Blood returns from lungs via Pulmonary Veins to Left Atrium, 7- Blood in Left Atrium flows through left AV Valve into Left Ventricle, 8-Contraction of Left Ventricle (Simultaneous with step3)forces aortic valve open, 9- Blood flows through aortic valve into Ascending Aorta, 10- Blood in Aorta is distributed to every organ in the body, where it unloads O2 & loads CO2 11-Blood returns to heart via Venae Cavae
1. Sympathetic Nervous System 2. Parasympathetic Nervous System
1. Activated structures (organs) "Fight or Flight" response 2. Reduces activity "Rest & Digest" *BOTH influence heart rhythm by vagus nerve
Blood is received by the ____ & is pumped in circulation by the ___
1. Atria 2. Ventricles
What are the layers of the Heart Wall?
1. Epicardium 2. Myocardium 3. Endocardium
What are the layers of the Pericardium & of the Heart Wall
1. Fibrous Pericardium 2. Parietal Layer of Serous Pericardium 3.Pericardial Cavity 4. Epicardium (Visceral layer of Serous Pericardium) 5. Myocardium 6. Endocardium 7. Heart Chamber
Define the Cardiac Conduction System
1. SA Node fires 2. Excitation spreads through atrial myocardium 3.AV Node fires 4.Excitation spreads down AV bundle 5.Purkinje fibers distribute through ventricular myocardium.
Describe the three layers of tissue found in artery and vein walls.
1. Tunica Intima (Interna) 2.Tunica Media 3.Tunica Externa (Adventitia)
Major events of cardiac cycle "Heart Beat"
1. Ventricular Filling (Quiescent Period) 2. Isovolumetric Contraction 3. Ventricular Ejection 4. Isovolumetric Relaxation *Hint Valentines, February, Ice, Cold Vanilla, Eggnog, Iron, Rattler
Name the phases of the cycle and describe what is happening during each phase.
1.Atrial Systole- "atrial kick" In response to P wave events Atria contract Increase pressure Blood to ventricals 2.Atrial Diastole-Atria depolarize Muscle cell relax Decrease in pressure Begin to refill with blood 3.Ventricular systole Triggered by ventriclas Depolarization (QRS) a) Isovolumetric phase- Contraction has started to increase pressure, all 4 valves closed blood not leaving yet. b) Ejection phase- Continual contraction, increase pressure, now open semilunar valves, blood leaves ventricles "ejected" 3.Ventricular systole continued: Pressure in ventricles must exceed pressure in arteries, SL valves open (blood ejected) 4.Ventricular Diastole- early Allows repolarization "t-wave" Decrease pressure in ventricles All valves closed No blood moving No volumetric phase 5.Ventricular Diastole- Late Continue to decrease pressure Av valves open Blood flows passively to ventricles
What are the three major factors that influence stroke volume?
1.Preload - 2.Contractility - 3.Afterload
The pericardium has how many layers?
2 layers
Arrange the structures in the following list in the order that blood will encounter as it flows from the output side to the input side of the cardiovascular flow circuit.1. venules2. arterioles3. capillaries4. elastic arteries5. medium veins6. large veins7. muscular arteries
4,7,2,3,1,5,6
Approximately how many times per minute do the ventricles contract?
70
Blue Veins
deoxygenated blood
Red Arteries
oxygenated blood
What are the 2 layers of the Pericardium?
parietal and visceral (Epicardium)
Right side of heart
receives oxygen-poor blood from tissues Pumps blood to lungs to get rid of CO2, pick up O2, via pulmonary circuit
Left side of heart
receives oxygenated blood from the lungs and pumps it to the body tissues via Systemic Circuit.
What are the 4 chambers of the heart?
right atrium, right ventricle, left atrium, left ventricle
TRUE/FALSE Arteries are thicker & more elastic than veins because they carry blood under high pressure.
~True~* veins are the opposite of arteries as far as structure goes.
Arteries carry blood ____ from the heart
AWAY from the heart
Tachycardia
Abnormally rapid heartbeat greater than 100 beats/minute.
Bradycardia
Abnormally slow heartbeat, less than 60 beats per minute
At the instant following the second heart sound, which heart valves are open?
All valves are closed
Rank the following blood vessels in order of their average pressure, from highest to lowest: artery, vein, arteriole, venule, aorta, capillary.
Aorta> artery> arteriole> capillary>venule>vein
What & where are the heart valves?
Aortic Semilunar Valve, Pulmonary Semilunar Valve, Atrioventricular Bicuspid (Mitral) Valve, & Tricuspid Valve.
Define and describe: Arrhythmia, atrial flutter, atrial fibrillation, ventricular fibrillation.
Arrhythmia- Irregular beating patterns. Atrial flutter-Atrial flutter (AFL) is an abnormal heart rhythm that occurs in the atria of the heart. Atrial Fibrillation- (A-Fib) Decrease stroke volume. Ventricular fibrillation- (V-Fib)- Stop circulation
What and where are the coronary arteries?
Arteries that branch off the aorta & surround the heart, ensuring that it gets all the oxygenated blood it needs.
Which kind of vessel is also called a resistance vessel? arteriole vein artery venule capillary
Arteriole
Where are each of the valves located?
Atrioventicular: Between the atria and ventricles. Tricuspid valve is in the right ventricle and Bicuspid valve in the left ventricle. Semilunar: valves are located between the ventricles and arteries. The aortic semilunar valves is between the left ventricle and aorta, the pulmonary semilunar valve is below the pulmonary trunk and aorta.
What are Mitral (Bicuspid) and Tricuspid valves?
Atrioventricular Valves
The valve on the LEFT SIDE of the heart is the ___ valve?
Bicuspid
In terms of being open or closed, what is the state of the mitral and tricuspid valves (left and right atrioventricular valves, respectively) at the end of the first heart sound?
Both are Closed
What prevents the valve in the right ventricle from opening backwards?
Chordae Tendinea
The atrioventricular (AV) valves do what two things?
Connect R. atrium to R. Vertical and L. Atrium to L. ventrical Permit blood to flow in one direction (from atria to ventricles)
Capillaries that have a complete lining are called fenestrated capillaries. sinusoidal capillaries. vasa vasorum. continuous capillaries. sinusoids.
Continuous Capillaries
Define Contractility
Contractility- Amount of force produced during a contraction, at a given preload. Based on how much (ca+2) is available. -Increase (ca+2) increase contractility, increase force,increase sv -Decrease (ca+2) decrease contractility, decrease force, decrease sv
Vasoconstriction is ______ of the smooth muscle in the artery wall.
Contraction
Vasoconstriction & Vasodilation result from?
Contraction & relaxation of smooth muscle in the arterial walls.
Which of these arteries does not originate on the aortic arch? left carotid left subclavian coronary brachiocephalic
Coronary
Heart Disease is also known as?
Coronary Artery Disease (CAD)
CAD happens when areas of partial or complete blockage of what happens?
Coronary Circulation
The blood supply to the heart tissue is via the __________ _____________.
Coronary Circulation
What is coronary circulation?
Coronary circulation is the circulation of blood in the arteries and veins that supply the heart muscle (myocardium). Coronary arteries supply oxygenated blood to the heart muscle.
The pulmonary trunk carries ___________ blood __________ the lung.
Deoxygenated to
The relaxation phase of the cardiac cycle is called
Diastole
The intrinsic beat intiated by the sinoatrial node along the conduction system through the mycardium -is a wave of electrical activity & is what is measured on a
ECG-Electrocardiogram
Formula for ESV
EDV-SV=ESV
Formula for EDV
EDV=SV+ESV
Calculation of Stroke Volume
End Diastolic Volume (EDV) - End Systolic Volume (ESV) *The volume of blood ejected per ventricle during ventricular systole (Contraction)-normal volume is 70 mL
The cardiac cycle is the period from the
End of one ventricular contraction to the end of the next ventricular contraction
What layer of the heart would be most immediately susceptible to infections caused by bacteria circulating in the blood?
Endocardium *Lines inside of heart & is in direct contact with circulating blood.
Capillaries is where?
Exchange takes place between blood & cells of the body
Even though an individual may feel comfortable at rest, what things can produce the sensation of pressure, chest constriction, and radiating pain?
Exertion or emotional stress
Which of these arteries does not originate on the abdominal aorta? femoral splenic renal
Femoral
Define Automatricity
Generates a signal for muscle contraction & sends the signal to the rest of the muscle
Formula for Cardiac Output (CO)
Heart Rate X Stroke Volume= CO
Ectopic Focus or pacemaker
IF problem w/ SA Node, THEN other nodes will fire in it's place. *Bachmann's bundle does not fire* Caused by : -Trauma (Physical) -Electrical Damage -Age (Proteins don't work properly) -Automaticity and triggered activity
Define Isovolumetric Contraction
Isovolumetric Contraction- Heart valves closed , volumes of ventricles change, increase in pressure
Which muscle wall in the heart is thicker and more powerful?
Left vertical wall
A sample of tissue displays many large flattened spaces lined by fenestrated endothelium. Blood moves slowly through these spaces. This tissue sample most likely came from the liver. heart. lungs. kidneys. skin.
Liver
How many phases occurs in Ventricular Filling?
Occurs in 3 Phases: 1. Rapid Ventricular Filling- first one-third *Blood enters quickly 2. Diastasis- second one-third *Marked by slower filling, Pwave occurs at the end of diastasis 3. Atrial systole- final one-third *Atria contract
Isovolumetric Relaxation
Period when all four valves are closed and ventricular blood volume does not change -Early ventricular diastole a. when T wave ends and the ventricles begin to expand elastic recoil and expansion would cause pressure to drop rapidly and suck blood into the ventricles b. blood from the aorta & pulmonary trunk briefly flows backwards c. filling the semilunar valves and closing the cusps d. heart sound S2 occurs as blood rebounds from the closed semilunar valves and the ventricle expands e. 'isovolumetric' because semilunar valves are closed and AV valves have not yet opened; ventricles are therefore taking in no blood f. when AV valves open, ventricular filling begins again
What vessels carry deoxygenated blood away from the heart?
Pulmonary Artery only
This circuit carries blood to and from gas exchange surfaces of the lungs.
Pulmonary Circuit
Define, Compare and contrast pulmonary and systemic circulation.
Pulmonary: Pumps blood through lungs, get O2 and removes CO2 Systemic: Delivers O2 through the rest fo the body, and picks up CO2
The difference between the systolic and diastolic pressures is called the ________ pressure. blood circulatory critical closing mean arterial pulse
Pulse Pressure
Vasodilation is ____ of smooth muscle in the artery wall.
Relaxation
Receiving Chambers of the heart
Right atrium-Receives blood returning from systemic circuit Left atrium-Receives blood returning from pulmonary circuit
Pumping Chambers of the heart
Right ventricle-Pumps blood through pulmonary circuit Left ventricle-Pumps blood through systemic circuit
Formula for Stroke Volume
SV = EDV - ESV
What valves are found @ the entrances of the pulmonary trunk & aorta?
Semilunar Valves (Pulmonary and Aortic Valves) that look like moons
This circuit carries blood to and from the body and the blood alternates between this system and the pulmonary system.
Systemic Circuit
The contraction phase of the cardiac cycle is called
Systole
Define Systole and Diastole
Systole- Fibers shorten Chamber pressure rising Moves blood forward Atrial and ventricular Systole-separate Diastole-Relaxation phase Fibers lengthen Chamber pressure falling/ low Chambers re-fill Atrial & Ventricular Diastole separate
Veins carry blood
TOWARD the heart
TRUE/FALSE The walls of the arteries are thick & elastic, because they carry blood under high pressure.
TRUE
The contraction & relaxation influence blood pressure & blood distribution to the tissues.
TRUE
True/FalseValves between the atria & ventricles include the tricuspid on the RIGHT SIDE of the heart & the bicuspid on the LEFT SIDE of the heart.
TRUE
Which ventricle is thicker and why?
The left ventricle is thicker because it needs to pump blood to the entire body, meanwhile the right ventricle receives blood.
What is Cardiac Output?
The volume of blood that can be ejected by each ventricle per minute.
The valve on the RIGHT SIDE of the heart is the ___ valve?
Tricuspid
What is another name for the right atrioventricular (AV) valve?
Tricuspid Valve
Starting from the right atrium, which of the following is the correct pathway for blood flow through the human circulatory system?
Tricuspid valve, right ventricle, pulmonary artery, left atrium
Which of the following is the innermost layer of a blood vessel? internal elastic membrane tunica media external elastic membrane tunica externa tunica intima
Tunica Intima
The layer of the arteriole wall that can produce vasoconstriction is the tunica media. tunica adventitia. tunica externa. tunica intima. tunica mater.
Tunica Media
How can the circulatory system promote heat retention/conservation, such as on a cold day?
Vasoconstriction
Which part of the vascular system functions as a blood reservoir and contains over 60% of the body's blood? veins systemic arterioles arteries capillaries pulmonary arteries
Veins
What is the most important chamber in the heart?
Ventricles
Define Ventricular ejection
Ventricular ejection- Pressure in ventricle exceeds that - muscle cells of atrial trunk, sl valves open, tension production remain constant.
How many layers do vessel walls have?
Walls have 3 layers
Does blood transport oxygen & nutrients to body cells?
YES
What are cardiac arrhythmias and how do they occur?
a. Heart Rhythm problems (Heart arrhythmias) occur when the electrical impulses that coordinate your heartbeats don't work properly, causing your heart to beat too fast, too slow, or irregularly b. Heart arrhythmias may feel like a fluttering or racing heart and may be harmless. However, some heart arrhythmias may cause bothersome-sometimes even life threatening
Vein walls are ___a___ & less ___b___ than those of the arteries, because they carry blood under lower pressure.
a. Thinner b. Elastic
Blood drains from the ____a_____ directly into the ___b__ __b__ through the ___c__ __c__.
a. myocardium b. right atrium c. coronary sinus
The hearts intrinsic beat is initiated by the __a__ _a__ and transmitted along the conduction system through the __b____.
a. sinoatrial node b. Myocardium
The contraction phase of the cycles is __a__; the relaxation phase is __b__.
a. systole b. diastole
The vascular system contains?
arteries, capillaries, veins
The smallest arteries are called?
arterioles; The suffix -ole means little, small; Arterioles carry blood to the tiniest of the blood vessels, the capillaries.