Chapter 19 Flashcards
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Do pulmonary arteries carry blood to the heart or away from the heart?
To the heart
What is the pulmonary circuit?
Carries blood to the lungs for gas exchange And returns blood to the heart
Do pulmonary veins carry blood away from the heart or to the heart?
Away from the heart
What side of the heart receives O2 poor blood from the body?
The right side
Where does the heart pump the blood into?
The pulmonary trunk
The pulmonary trunk divides into?
Left and right pulmonary arteries
What do the pulmonary arteries do?
They transport blood to the alveoli ( air sacs) of the lungs where gases are exchanged, CO2 is unloaded and O2 is loaded
02 Rich blood flows through pulmonary veins to which side of the heart?
The left side
Which circuit supplies blood to the organs of the body? (Systems made of organs)
The systemic circuit
Blood leaves the left side of the heart through what?
The aorta
What is the biggest artery in the body?
The aorta
What gives off smaller arteries to the organs?
The aorta
How does the O2 poor blood return to the right side of the heart?
By way of the superior vena cava and the inferior vena cava
Where is the heart located?
In the thoracic cavity
What is the shape of the heart?
It has a base which is the broad superior portion, point of attachment for the great Vessels
It has an apex which is the inferior blunt point
The heart looks like an upside down triangle
What are the five parts of the anatomy of the heart?
Pericardium The heart wall The chambers Valves Bloodflow through the chambers
Pericardium
What does peri mean?
What does cardi mean?
Peri- around
Cardi- heart
What is the pericardial sac (parietal pericardium)?
Parie -wall
Fibrous layer of dense irregular connective tissue and deep serous layer
(Fibrous layer- Anchors heart to diaphragm and lungs)
What is the Epicardium (visceral pericardium)?
Serious membrane on the external surface of the heart
Epi -on
Visc - organ
Visceral - like layer of Saran Wrap on organ
What is the pericardial cavity?
Space between parietal and visceral membranes
Parietal - lines the mediastinum
Visceral - lines the heart
What does Pericardial fluid do?
It lubricates the membranes and allows the heart to beat with minimal friction
What is pericarditis?
Inflammation of the pericardium. (Infection, radiation)
What do the heart and lungs look like in the thoracic cavity?
Two upright triangles which are the lungs and one upside down triangle for the heart in the middle
What are the four main parts of the heart wall?
Epicardium
Endocardium
Myocardium
fibrous skeleton
The heart wall
What is the Epicardium (This visceral pericardium) Of the heart wall?
Simple squamous
What is endocardium Of the heart wall?
Endo - Inside
The membrane that lines the interior surface of the heart chambers, the valves, and is continuous with the endothelium of the blood vessels.
What is infective endocarditis Of the heart wall?
Inflammation of the endocardium, due to bacterial infection. The bacteria attacks the heart valves.
What is the myocardium of the heart wall?
Myo means - muscle
Cardiocytes are short, thick and branched. Cardio (Heart muscle cell)
Cardiocytes have striations (sarcomeres) and a centrally located nucleus.
Myocardium of the heart wall continued……….
What are intercalated discs?
What are interdigitating folds? What are mechanical junctions? What are electrical (gap) junctions?
They join cardiocytes end to end.
They are the folds in the plasma membrane that interlock cells. They tightly join cells and prevent cells from pulling apart when they contract Channels that allow ions to flow from the cytoplasm of one cell into the next.
Cardiocytes of the myocardium are rich in ________________, ______________ and _________________. They depend on aerobic respiration to make _________.
Myoglobin (Carry 02 for ATP), Glycogen (Provide glucose) And mitochondria (Converts glucose to ATP using O2)
ATP
What is the fibrous skeleton of them heart wall?
Collagen and elastic fibers that provide structural (Holds open valves and great veins and prevents their stretching) support, anchor myocytes (Gives cells something to pull against) and electrically insulate the chambers (From each other).
The chambers of the heart are broken up into two groups what are they?
The atria
And the ventricles
What is the atria?
It is like the entrance foyer, it receives blood returning to the heart by way of the great veins
(Inferior and superior vena cava and pulmonary veins)
What are the two parts of the atria and what are their jobs?
The auricle or ear, an earlike extension that increases the atrial volume.
The interatrial septum which is a wall that separates the atria
(Inter - between), (septum - wall/ fence)
What do the ventricles of the chambers do?
They eject blood into the arteries (Aorta, pulmonary trunk)
What three parts make up the ventricles?
Coronary (AV) sulcus
Intraventricular Sulci
Interventricular (IV) septum
What is the coronary sulcus?
It is a groove that encircles the heart between the atria and ventricles, and contains blood vessels.
What is the interventricular Sulci?
It is the anterior and posterior grooves that overlie the IV septum, and contains blood vessels.
What is the interventricular septum?
The wall between the ventricles
What do the valves of the heart do?
They ensure one way flow of blood.
What are the three different types of valves of the heart?
Atrioventricular (AV) valves
Tendinous cords
Semilunar (SL) valves
What are atrioventricular valves?
They regulate the openings between atria and ventricles.
What do tendinous cords do?
They connect valve cusps to papillary muscles, preventing flipping or bulging of the cusps.
What do semilunar valves do?
There are two types, what are their names?
They regulate the flow of blood from the ventricles to the great veins.
- Pulmonary valve, it controls the opening from the right ventricle into the pulmonary trunk.
- Aortic valve, it controls the opening from the left ventricle into the aorta.
What is valve insufficiency?
It is the failure of the valve to prevent the backward flow of blood (regurgitation)
What are three types of valve insufficiency?
- Valvular stenosis, cusps are stiffened and the opening is constricted by scar tissue, it doesn’t open well
- Murmur, regurgitation of blood through an incompetent valve.
- Mitral valve prolapse, one or more left AV valve cusps bulge into the atrium during Ventricular contraction, often no symptoms, valve stretches > regurgitation
Bloodflow through the chambers
Figure 19.9, page 723
What is myogenic?
The signal originates with in the heart
What is autorhythmic?
Cardiocytes have the capacity to depolarize Spontaneously at regular time intervals.
What are the four categories under the cardiac conduction system?
Sinoatrial (SA) node - pacemaker
Atrioventricular (AV) node
Atrioventricular (AV) bundle
Purkinje fibers
What is the sinoatrial node?
Modified cardiocytes in the right atrium
Initiates each heartbeat and determines the heart rate
Signals (action potential) spread throughout the atria (via gap junctions) and down to the AV node stimulating the atria to contract almost simultaneously.
What is the atrioventricular node?
Modified cardiocytes near the right AV valve
Received signal from the SA node and directs it to the ventricles.
Signal slows (delays .1 sec) at AV node and allows ventricles to fill with blood (before they begin to contract)
What is the atrioventricular bundle?
Pathway the signal takes when it leaves the AV node
What is Purkinje fibers?
Nervelike processes that arise from the ends of the bundle branches and spread upward through the ventricles.
Information about cardiac rhythm
What is sinus rhythm?
It is normal heartbeat triggered by the SA node (70 to 80 BPM) at rest
What is nodal rhythm?
AV node takes over heart rhythm if SA node is damaged (40 to 50 BPM)
If neither SA nor AV node functions (heart block), what is needed?
An artificial pacemaker
What is an arrhythmia?
Abnormal cardiac rhythm
There are five different types of arrhythmias, what are they?
Heart block Atrial flutter Premature ventricular contraction Ventricular fibrillation Cardiac arrest
What is the failure of any part of the conduction system to transmit signals, damage to AV node Called?
Heart block
What is it called when the atria have extra contractions, rapid regular atrial contractions, (200 to 400 BPM)?
Atrial flutter
What is it called when ventricles fire early, before SA node does, setting off an extra heartbeat, from hypoxia, ion imbalance, caffeine, nicotine, stress, lack of sleep?
Premature ventricular contractions
What is it called when electrical signals arrive at different regions of the myocardium at different times causing the cardiocytes to contract independently and rapidly?
Ventricular fibrillation
What is cessation of cardiac output called?
Cardiac arrest
What is rapid, violent, or throbbing pulsation, as an abnormally throbbing or fluttering of the heart called?
Palpitation
Pacemaker physiology
What is it called in SA node when a slow inflow of sodium causes gradual depolarization and cells slowly leak sodium?
Pacemaker potential
When the pacemaker potential reaches threshold, and calcium channels open and calcium flows in producing the rapid depolarization
At peak, potassium channels open and potassium leaves the cell causing the repolarization
Potassium channels clothes in the pacemaker potential starts over
Pacemaker physiology continued
Electrical behavior of myocardium
Cardiocytes only depolarize when?
When they are stimulated
A stimulus (action potential) opens the (voltage gated) sodium gates, the sodium inflow \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ The cell, Sodium gates then \_\_\_\_\_\_\_\_\_\_\_ quickly.
Depolarizes
Close
Slow (voltage gated) calcium channels _________, Calcium enters the cell triggering calcium channels in the _______________ _________________ To open releasing calcium inside the cell, the calcium then binds to __________ And triggers a __________.
Open
Sarcoplasmic Reticulum
Troponin
Contraction
________________Is prolonged creating a ______________ And sustained contraction.
Depolarization
Plateau
Calcium channels ________, Potassium channels open, Potassium _____________ Out of the cells, and the cell __________________, Meanwhile calcium is transported back allowing the muscle to ___________.
Close
Diffuses
Repolarizes
Relax
What is an electrocardiogram (ECG)?
A composite recording of all the action potential produced by the heart.
Figure 19.15, page 731 and figure 19.16, page 732
What is produced when a signal from the SA node spreads through the atria and depolarizes them in an ECG?
P wave
When atrial systole (Contraction) occurs In an ECG?
PQ segment
Produced when the signal from the AV node spreads through the ventricles and depolarizes the muscle in an ECG?
QRS complex
When Ventricular systole (contraction) occurs in ECG?
ST segment (plateau)
Ventricular repolarization immediately before diastole (relaxation) in ECG?
T wave
What is a cardiac cycle?
One complete contraction and relaxation of all four chambers
What are the four principles of pressure?
- Pressure of a liquid or gas depends on the volume of space it occupies.
- Greater the volume, lower the pressure
- Pressure difference between two points causes a fluid to flow from high-pressure to low-pressure which is called a pressure
gradient - Opening and closing of heart valves are the result of pressure gradients
- When ventricles are relaxed pressure is low, blood flows freely from atria into ventricles
- When ventricles are filled and begin to contract, pressure rises and blood pushes the AV valves closed which prevents
blood from entering the atria - When ventricle pressure rises above the atrial pressure, SL valves open and blood is ejected from the heart
What are the four phases of the cardiac cycle?
- Ventricular filling - during diastole (relaxation)
- Isovolumetric contraction - No change in ventricular volume
- Ventricular ejection - Blood spurts out
- Isovolumetric relaxation - Ventricular diastole
What happens during ventricular filling of the cardiac cycle?
First ventricles expand and the pressure drops below that of the atria
Next the AV valves open and blood flows in from the atria, which increases the ventricular pressure
Then the atria depolarize (P-wave)
Lastly, Atrial systole completes the filling
What happens during isovolumetric contraction of the cardiac cycle?
First, the atria repolarize, relax, and remain in diastole
Next, the ventricles depolarize (QRS complex) and begin to contract
Then the AV valves close as ventricular blood pushes against cusps
First heart sound occurs
Lastly, all four valves are closed and no blood is ejected
What happens during the isovolumetric relaxation Phase of the cardiac cycle?
First the T-wave ends and ventricles begin to expand
Next, the dicrotic notch which is when blood from the aorta and pulmonary trunk flows backward through the SL valves, the cusps fill with blood and close
Then the second heart sound occurs
Lastly, all four valves are closed and no blood enters
What is cardiac output?
The amount ejected by each ventricle in one minute
What does HR mean?
What does SV mean?
Heart rate - Beats per minute (how fast)
Stroke volume - Milliliters per beat (how much)
What Is the CO?
What is the resting CO?
How does exercise increase the CO?
Cardiac output - CO = heart rate (HR) X stroke volume (SV)
5.25 L/min
By Increasing the HR and SV
What is the average heart rate (pulse) in young adults?
64 to 80 bpm
What is tachycardia?
What is bradycardia?
Persistent resting heart rate above hundred BPM (stress,anxiety,drugs, fever)
Persistent resting heart rate below 60 BPM
What are some of the different cardiac centers in the medulla oblongata? There are five
Cardiostimulatory effect
Cardioinhibitory effect
Vagal tone
Baroreceptors (Which are pressure sensors in the aorta and internal carotid artery)
Chemoreceptors (in aorta And carotids)
What is the transmission of signals by way of the SNS to the SA node, AV node and myocardium to speed up the heart rate?
Cardiostimulatory effect
What is the transmission of signals by way of the Vagas nerve to the SA and AV nodes to slow the heart rate?
Cardioinhibitory effect
What is it when the vagus nerve holds the heart rate at 70 to 80 bpm when the natural heart rate would be 100 bpm?
Vagal tone
This sends signals to the medulla in response to changes in blood pressure
(Decreased blood pressure equals increased heart rate)
(Increased blood pressure equals decreased heart rate)
Baroreceptors
These sends signals to the medulla in response to increase in CO2, H+ or decrease in O2 to increase heart rate
Chemoreceptors
Epinephrine, Norepinephrine, caffeine, nicotine, and thyroid hormone increase or decrease our heart rate?
Increase our heart rate
What is it called when cardiocyte repolarization is inhibited and our heart rate slows?
Hyperkalemia
Potassium diffuses in from the blood
What is it called when cardiocytes hyperpolarize and are harder to stimulate and our heart rate slows?
Hypokalemia
(Potassium diffuses out to bloodstream, too little potassium inside the cell thus more sodium must enter to reach threshold)
When our heart rate is slow and there is a strong prolonged contraction, this is called?
Hypercalcemia
Calcium binds to cell surface and sodium channels are reluctant to open
Heart rate is fast and there is a weak contraction, what is this called?
Hypocalcemia
The increased sodium permeability equals increased sodium excitability
Another factor in cardiac output is stroke volume
What are the three variables that stroke volume is governed by?
SV=stroke volume
Preload= Increase in SV Contractility= Increase in SV Afterload= Decrease in SV
The amount of tension in the ventricle before it begins to contract is called?
Preload
The principle that states ventricles tend to reject as much blood as they receive; the more they are stretched, the harder they contract, is called?
The Frank starling law
How hard the ventricles contract, is called?
Contractility
In this stage of stroke volume Ca2+ increases the strength of each contraction which prolongs the plateau, this is called?
Contractility
In this stage the blood pressure in the aorta and pulmonary trunk opposes the opening of the SL valves, and is called?
Afterload
Hypertension (increases or decreases) afterload and opposes Ventricular ejection.
Increases
Chest pain from temporary and reversible deficiency of blood flow to the cardiac muscle, is called?
Angina pectoris
Sudden death of a patch of myocardium resulting from long-term obstruction of coronary circulation, is called?
Myocardial infarction (heart attack)
Inadequate blood flow to the myocardium, is called?
Myocardial ischemia
Fluid accumulation due to insufficiency of ventricular pumping, is called?
Congestive heart failure
An accumulation of lipid deposits that degrade the arterial wall and obstruct the lumen is called?
Artherosclerosis
Constriction of the coronary arteries resulting from atherosclerosis, is called?
Coronary artery disease
Seepage of fluid from the pericardium into the Pericardial cavity, Is called?
Pericardial effusion
Compression of the heart by an abnormal accumulation of fluid or clotted blood in the pericardial cavity, is called?
Cardiac tamponade
Abnormal openings in the interarterial or interventricular septum resulting in blood passing through septum, is called?
Septal defects
