Heart Flashcards
What consists of the Circulatory system?
Heart, blood vessels, and blood.
What consists of the Cardiovascular system?
Heart, arteries, veins, and capillaries
What are the two major divisions of the Cardiovascular system?
Pulmonary circuit and Systemic circuit.
Describe the Pulmonary circuit
The right side of the heart carries blood to the lungs for gas exchange.
Describe systemic circuit
Left side of the heart supplies blood to all the organs of the body
What cavity encases the heart and is located in between the lungs ?
Mediastinum
What part of the heart is the base ?
The broad superior portion of the heart
What part of the heart is the apex?
The inferior end, tilts to the left, tapers to a point .
True or false the heart rests on your diaphragm
True
The left side of the heart pumps _____ blood to the ____and the right side of the heart pumps_____blood to the _____.
Oxygenated blood to the body, pumps deoxygenated blood to the lungs.
What are the two Atrioventricular valves ?
Tricuspid valve, Bicuspid valve( Mitral)
Tricuspid valve is in the ___ side of the heart and Bicuspid valve is in the ___ side of the heart
Tricuspid is in the right side, and Bicuspid is on the Left side.
What is another name for the Bicuspid valve?
Mitral valve
True or false both the Atrioventricular valves only allow blood to flow down.
True
The superior and inferior vena cava pump their deoxygentated blood where?
Right Atrium
During systole where does the blood from the right ventricle go ?
Pulmonary trunk, which leads to the lungs
Where does the blood from your left ventricle go during systole ?
Aorta, pumps blood to your body and organs
What two valves allow blood out of the heart ?
Pulmonary semilunar valve and aortic semilunar valve
What are the three shunts in the fetal circulation ?
Ducuts Arteriosus, Ductus venosus, Foramen ovale
After birth the Ducutus Arteriosus seals and becomes what?
Ligamentum Arteriosum, Bypasses blood flow from right atrium to descending aorta
After birth the Ductus Venosus seals and becomes what?
Ligamentum Venosum, Connects the umbilical vein(oxygenated blood) to the inferior vena cava (deoxygenated blood)
After birth the Formamen ovale seals and becomes what ?
Fossa Ovalis, shunts highly oxygenated blood from right atrium to left atrium
What two layers make up the pericardium ?
Fibrous and serious layer
What layers make up the serous membrane ?
Parietal, directly beneath the fibrous pericardium and visceral, attached directly to the heart
What is another name for the visceral part of the serous membrane?
Epicardium
Where is pericardial fluid found?
In between the parietal and visceral layer of the pericardium (inside the pericardial cavity)
What is the function of pericardial fluid ?
Prevents friction between the membranes of heart
Define cardiac tamponade
Compression of the heart due to fluid accumulation within the pericardium
Pericardiocentesis is what?
Drainage of the pericardial fluid from the pericardium
Describe the myocardium
Thick muscle layer, network of collagenous and elastic fibers
Describe the endocadium
Smooth inner lining
What are the 4 chambers of the heart ?
Right and Left Atrium and right and left Ventricle
What does the atrioventricular sulcus seperate?
Seperates the atria and ventricles
What does the anterior and posterior sulci seperate?
the grooves seperated ventricles
Define interatrial septum
Wall the seperates atria (plural for atrium)
Where are pectinate muscles and what is said to be their function?
Muscles found in the right atrium and both auricles, said to help increase power of contraction
What does the interventricular septum separate?
Ventricles
Describre Trabaculae Carneae
Internal ridges in both ventricles, prevent suction that would occur with a flat surfaced membrane
What cords connect AV valves to papillary muscles(on floor of ventricles)
Chordae tendineae
What is the purpoes of semilunar valves?
control flow into great arteries
True or false both the Mitral and tricuspid valves are connected to chordae tendineae
true
True or False Semilunar Valves-prevent backflow into the ventricles
true
What are the two different types of mechanical valve? Which valves do they replace?
Older ball and cage replaces the Mitral (bicuspid valve)
modern tilting disk replaces the semilunar valves.
When ventricles relax pressure____ ,semilunar valves____, AV valves____, and blood flow from the atria to ventricles.
pressure drops, semilunar vavles close, and AV valves open.
When ventricles contract pressure ____, AV valves____, papillary muscles ____, semilunar valves ____, and blood flows into the arteries.
Pressure rises, AV valves close, papillary muscles contract, semi-lunar valves open.
What are the blood vessels on the actual heart for?
nourish cardiac muscle
What two arteries branch off of the aorta to supply and nourish the heart muscles ?
Right and left coronary arteries
True or false both the left and the right coronary arteries are under the left and right auricles ?
True
The left coronary artery branches off into the Anterior (descending) interventricular artery and the circumflex artery. What do they supply?
Anterior interventricular supplies the interventricular septum and the anterior walls of the ventricles.
The circumflex supplies the left atrium and posterior wall of the left ventricle.
True or False the circumflex artery passes around left side of heart in coronary sulcus,
True
The right coronary artery branches off into the marginal and posterior interventricular artery, what do they supply?
Marginal artery supplies the lateral right atrium and ventricle. The posterior interventricular artery supplies posterior walls of ventricles.
Define myocardial infarction
sudden death of heart tissue caused by interruption of blood flow.
How does Anastomoses defend against interruption (clogs) in blood vessels?
provides alternate blood pathways
True or false 98% of the time myocardial infarction happens due to arteriosclerosis “hardening of the arteries”.
True
What are the 9 risk factors of heart disease?
Hypercholesterolemia•Hypertension•Cigarette smoking•Obesity•Lack of exercise•Diabetes mellitus•Genetic predisposition•Male gender•Alcohol
Define angioplasty
endovascular (within the blood vessel) procedure to widen the walls of veins or arteries due to plaque
What are the two different procedures for an angioplasty ?
Balloon Angioplasty and stent with balloon angioplasty (stent stays inside the artery)
Define an aneurysm
is a permanent, localized dilatation of an artery
True or False Ruptured Abdominal Aortic Aneurysm (AAA) has a very high mortality rate
True, 80% are fatal
What causes an aneurysm ? How can it be treated?
Weakening of the artery wall, has the potential to cause a blowout. Surgical grafting to reinforce the artery wall
Define collateral circulation
network of tiny blood vessels, and, under normal conditions, not open.
When the heart muscles have used the oxygenated blood ___% drains into the right ventricle and ___% returns to the right atrium via the coronary sinus
20% and 80%
The coronary sinus collects deoxygenated blood from what two veins and empties into the right atrium?
Great cardiac vein (ant. interventricular sulcus) and Middle cardiac vein (post. sulcus)
True or False The sarcoplasmic reticulum T tubules are much larger than in skeletal muscle, admit more Ca2+from ECF during excitation
True
What are the three distinct features of intercalated discs?
- Interdigitating folds 2. mechanical junctions 3.electrical junctions
What is the purpose of interdigitating folds?
Increase surface area
What is the purpose of mechanical junctions and what two structures aid in it?
tightly joined myocytes. Fascia adhearens (anchors actin to plasma membrane) Desmosomes (weblike junctions that prevent cells from pulling apart)
What is the purpose of electrical junctions?
Gap junctions form channels allowing ions to flow directly into next cell
True or False ? Cardiac muscle depends almost exclusively on aerobic respiration to make ATP
True
Why is cardiac muscle rich in myoglobin and glycogen ?
myoglobin(source of stored oxygen) and glycogen(source of stored glucose)
True or false the heart contains large mitochondria
True
The heart uses which organic fuels?
Fatty acids, glucose, ketones, lactic acid, and amino acids
True or False? The cardiac muscle is more vulnerable to oxygen deficiency than lack of fuel and is Fatigue resistant
True
What are the two types cells in cardiac muscle?
Contractile cells and Autorhythmic (automatic) cells.
True or false Autorhythmic cells do not have a stable resting membrane potential
True
Describe an action potential”pacemaker potential” for Auto-rhythmic cells.
The cell is depolarized by a SLOW inward diffusion of calcium and potassium channels, thereby opening FAST calcium channels, repolarization with outward diffusion of potassium.
True or false the SA node does not have a stable membrane potential
true
Describe Pacemaker potential
gradual depolarization from -60 mV, slow influx of Na+
What is the threshold for a pacemaker potential?
-40 mV, after fast calcium channels open
After a pacemaker potential, the depolarizing phase goes up to what voltage before the potassium channels open?
0 mV
What is happening from 0 mV to -60 mV for an auto-rhythmic cell?
The cell is repolarizing due to potassium channels closing.
Each depolarization of the SA node creates one ____
Heartbeat
Unlike the pacemaker potential how do the contractile cells depolarize?
They depolarize by a rapid, FAST inward diffusion of sodium
How does a contractile cell repolarize?
A slow outward diffusion of potassium
In a contractile cell what creates the plateau phase at the beginning of repolarization ?
outward diffusion of potassium is offset by slow inward diffusion of calcium. (they are cross cancelling keeping the voltage at a steady charge)
What causes the plateau phase to end and for the cell to drop down to resting potential (repolarize)?
The calcium channels close and the membrane potential quickly reaches the ‘resting’ potential
What is the stable resting potential for myocytes in the myocardium?
-90mv, stable resting potential
True or false depolarization for myocytes is very brief?
True
For a myocyte, resting potential is ___mv and the peak of action potential is___
resting potential is -90 mV, Peak of action potential caused +30 mV.
For myocytes, how is the contraction sustained (plateau) ?
Slow Ca+2 channels open and the Ca+2 binds to fast Ca+2 channels on SR and increase Ca+2 into the cytosol resulting in contraction (contraction held because the Ca+2 is positive and is preventing the voltage from dropping down and re-polarizing the cell)
Explain Repolarization of a myocyte
Ca+2 channels close, K+channels open, K+ runs out of the cell quickly dropping the voltage and returning to resting potential (-90 mV)
Does the action potential on a myocyte use negative or positive feedback ?
positive because stimulus opens Na+gates, (Na+in) depolarizes to threshold, rapidly opens more Na+gates in a positive feedback cycle.
Define refractory period
membrane is refractory to further stimulation until the contraction is over.
True or false most of the muscle cells in the heart are contractile cells .
True
The atrioventricular (AV) bundle is also called?
Bundle of His
The bundle of his splits off into left and right branches that turn into what fibers ?
purkinje fibers
True or false the heart can survive with just the purkinje fibers working?
False , the only beat 20-40 beats per min , doesn’t allow enough blood flow to brain, you clot, and die.
What does myogenic mean?
heartbeat originates within heart muscle , not nerve impulse
Autorhythmic -depolarize_____regularly
spontaneously
What insulates the atria from the ventricles?
fibrous skeleton
What is the “normal “ ratio for a heartbeat? how is this monitored in the heart?
70-80 bpm they are monitored by a combination the SA and AV node.
Define Arrhythmia
abnormal cardiac rhythm
What two main things can cause Arrhythmia ?
bundle branch block and total heart block (damage to AV node )
Define 1st degree heart block
Electrical impulses are slowed , but they all successfully reach the ventricles. (rarely any symptoms )
Define 2nd degree type 1 heart block (Mobitz or Wenckebach AV block)
Electrical impulses are delayed longer with each heartbeat until a heartbeat is skipped entirely (may cause dizziness)
Define 2nd degree type 2 heart block
Some of the electrical impulses are unable to reach the ventricles (interference below the Av node, artificial pacemaker recommended)
Define bradycardia
Slow heartbeat
Define 3rd degree heart block
None of the electrical impulses can reach the ventricles leaving the ventricles to try and contract on their own via purkinje fibers , the heartbeat will be very slow and is a medical emergency because it can lead to cardiac arrest (heart stopping)
The AV node delays the SA node by 100 msec allowing the ventricles to do what?
To fill
True or false Papillary muscles get signal first and contract to stabilize AV valves
true they contract before the actual myocardium.
Ventricular systole begins at ____ and progresses up
Apex
What is a Electrocardiogram (ECG) and what does it do?
recording of all action potentials detected in the heart in the order that it contracts through electrodes on the arms, legs, and chest.
What does the P wave mean in a ECG?
SA node fires causes atrial depolarization—> atrial systole
What is the QRS complex in a ECG?
Atrial re-polarization and diastole , AV node fires causing ventricular depolarization , and ventricular systole occurs
What does the T wave mean in a ECG ?
ventricular re-polarization
What is Auscultation ?
listening to sound made by the body
Describe the first sound (S1) of the heart?
The AV valves are closing “lubb” creating a louder and longer sound
Describe the seconds sound(S2) of the heart ?
The semilunar valves are closing “dupp” creating a softer and sharper sound
In people less than 30 S3 is ____ heard
rarely , occurs when the rush of blood into the filling ventricle is suddenly halted, resulting in a vibration of the ventricle and surrounding structures.
In the Quiescent period of the cardiac cycle what 3 things are occurring?
all chambers are relaxed, AV valves are open, and blood is flowing into the ventricles.
Define EDV
end diastolic volume , blood in ventricles at the end of diastole (130 ml)
What does Isovolumetric mean ?
no change in volume
Define SV
stroke volume, amount ejected into arteries from ventricles
Define ESV
End-systolic volume, amount left in the heart after systole
How do you find the the ejection fraction ?
SV/EDV = %
True or false both ventricles must eject the same amount of blood
True
What happens when the right ventricular output exceeds the left ventricular output?
pressure backs up , fluid accumulates in pulmonary tissue , and leads to left ventricular output.
What happens when the left ventricular output exceeds right ventricular output?
pressure backs up, fluid accumulates in systemic tissue, and leads to congestive heart failure of right ventricle
Define Cardiac output ?
CO is amount ejected by each ventricle in one min. CO=HRxSV
Define cardiac reserve?
difference between maximum and resting CO
True or false as the HR increases the time spent in diastole is reduced but the time in systole remains fairly constant.
True this results in less time for ventricular filling
Define Tachycardia
abnormally rapid heart rate
True or false Infants and elderly have higher beats per minute than average.
True
True or false Positive chronotropic agents raise HR and negative chronotropic agents lower HR
True
The cardioacceleratory center stimulates what 3 things in the heart during sympathetics?
SA node, AV node, and myocardium. (HR can also go up with nor-epinephrine)
The Cardioinhibitory center stimulates the vagus nerve that in turn stimulates what?
right vagus nerve stimulates SA node and left vagus nerve stimulates AV node. ACH binds and opens K+ channels , hyper polarizing and inhibiting potentials.
Define vagal tone
background firing rate holds HR to sinus rhythm of 70 to 80 bpm
True or flase Hypercapnia(high levels of CO2) and acidosis(high levels of acid in blood) stimulates cardiac center to ↑HR.
true
True or false caffeine , hormones, and nicotine raise BP?
true
Rapid rise of K+ makes myocardium unusually _____, and Slow rise of k+ makes myocardium ____ excitable than normal.
Excitable, leads to systolic arrest.
Less Excitable leads to arrest in diastole.
Define hypercalcemia
reduces the heart-rate and strengthens contraction strength
Define hypocalcemia
increases the heartrate and weakens contraction
Define preload
Amount of tension in ventricular myocardium before it contracts
Define Frank-Starling law of heart
ventricles eject as much blood as they receive, more they are stretched (↑preload)the harder they contract
Frank-Starling law of heart is based on what knowledge ?
The arrangement of the myofilaments generate maximal contraction , the more they stretch the stronger the contraction
Define contractility
Contraction force for a given preload
what influence is one that modifies the contractile state of the myocardium independent of Frank-Starling mechanism?
Inotropic influences states that the heart can contracts harder without expanding (franks law needs to expand) by increasing the amount of calcium available.
Define afterload
pressure that the heart must generate to move blood into the aorta
