Cardio section 1 PP Flashcards
When a pulse is irregular, what type of rhythm does someone most likely have?
Atrial Fibrillation
The Roots of Good Patient Care: Who invented the first sphygmograph? What did this lead to?
- Etienne Marey
- Sphygmomanometer
The Roots of Good Patient Care: Who is the father of the electrocardiography?
Willem Einthoven
The Cardiovascular System: What are the three primary components?
- The pump (heart)
- Circulating blood and all its components
- “Pipes” of the system—the vascular structures
The Cardiovascular System: What is the purpose of this system?
Purpose is to circulate blood containing oxygen and nutrients, while providing a means for waste removal at the same time
The Cardiovascular System: What system is the cardiovascular system closely tied to? What is their relationship?
Circulatory system is closely tied to the pulmonary system
-Changes in one will quickly result in changes to the other
Blood Vessels: Describe
Complex system of blood vessels including arteries, veins, and capillaries totals about 60,000 miles in length
Blood Vessels: Where does almost every cell in the body lie?
Almost every cell in the body lies adjacent to a capillary
Systemic Circulation: What is the route of oxygenated blood?
Oxygenated blood
- Leaves the left ventricle
- Travels through the aorta
- Travels to arteries, then to arterioles, then to capillary beds
How is oxygen and waste exchanged at the capillary level?
Much of this process occurs through diffusion and between pressure gradients found on each side of the membranes making up the blood cells and capillaries
The Venous System: Where does the venous system pick up in circulation?
Capillary beds come back together again to form the beginning of the venous system
The Venous System: Where does the venous system collect?
The venous system collects into the inferior or superior vena cava
The Venous System: Where does the inferior and superior vena cava end?
Inferior and superior vena cava end in the right atrium
The Heart: What is the function of the heart? Describe
Functions as a two-stage pump
- Right side is the low-pressure side
- Left side is the high-pressure side
The Heart: Where is the heart located?
Located in the middle of the chest between the lungs
-Backed by the vertebral column and anteriorly by the sternum
The Heart: Where is the heart in relation to the ribs?
The heart extends from just beneath the second rib downward and ends around the fifth rib.
The Heart: What is dextrocardia?
In a few individuals, the heart actually is tipped to the right, instead of to the left. This condition is referred to as dextrocardia.
Describe the blood flow through the heart. (14)
- Inferior vena cava
- Right atrium
- Tricuspid valve
- Right ventricle
- Pulmonary valve
- Pulmonary artery
- Pulmonary capillaries
- Pulmonary vein
- Left atrium
- Mitral valve
- Left ventricle
- Aortic valve
- Aorta
- Systemic arteries
The Heart: What is the apex of the heart? Where is it located?
The apex
- Bottom of the heart
- Located just left of the sternum at the fifth rib
The Heart: What is the PMI?
Point of maximal impulse
-The optimal place to auscultate the heart
The Heart: Where do the major blood vessels enter and exit the heart?
Superior aspect of the heart
The Heart: What is the pericardium?
Pericardium—covers the heart; is a fibrous tissue
The Heart: What are the two layers of the pericardium?
Has two layers:
- Parietal pericardium is the outer layer
- Visceral pericardium is the inner layer
The Heart: How are the two layers of the heart separated?
Layers are separated by a thin layer of fluid
The Heart: What is pericarditis?
Pericarditis—infection between the layers of the pericardium
The Heart: What are the three layers of the heart?
- The epicardium (outer)
- The myocardium (middle)
- The endocardium (Inner)
The Heart: What is the function of the epicardium?
serves as the “skin” of the heart and is a protective layer that contains most of the heart’s blood vessels, lymph vessels, and nerve fibers.
The Heart: What is the role of the myocardium?
The myocardium makes up the bulk of cardiac muscle tissue and also contains a rich blood supply from capillaries.
The Heart: What is the endocardium comprised of?
Comprised of mostly connective tissue, a few blood vessels, and the system of nerve fibers known as the Purkinje fibers
The Heart: What is the role of the endocardium?
The endocardium serves as the inner lining of the four chambers of the heart.
The Heart: What is the “potential space” of the heart?
The fluid-filled space between the layers is so thin that it is classified as a “potential space” and is called the pericardial space
The Heart: What is the role of the pericardial membrane?
The pericardial membrane secretes a small amount of serous fluid, which serves to lubricate the layers so there is no friction as the heart beats within the sac.
The Heart: Describe the elasticity of the two pericardium layers.
The parietal pericardium has little stretching ability, whereas the visceral pericardium can stretch a lot more.
Neither membrane will provide an excessive amount of stretch, and any collection of fluid between the membranes can cause problems for the patient.
The Blood Supply of the Heart: How is the heart supplied with oxygen?
The supply of oxygen to the heart is provided by a system of coronary arteries and veins
The Blood Supply of the Heart: What is oxygen supply to the heart dependent on? When does it occur/official name? Where does this pressure come from?
It is dependent on the back pressure in the arterial system from systole and occurs at the end of diastole
- This pressure is referred to as afterload
- Most of the pressure comes from the arteries
The Coronary Circulation: What are the two major vessels and where do they branch off from?
Consists of two major vessels branching off of the aorta:
- Left main coronary artery
- Right coronary artery
The Coronary Circulation: How does the left main coronary artery divide?
The left main divides into two other arteries:
- Circumflex
- Left anterior descending (LAD)
The Coronary Circulation: What structures does the left anterior descending (LAD) supply with blood? What happens if its blocked?
- Supplies the septum and ventricular walls
- If blocked, a majority of the left ventricle will become ischemic
The Coronary Circulation: What happens if the left main coronary artery is blocked?
If the left main coronary artery is blocked, a majority of the left ventricle will become ischemic, and if uncorrected this may result in sudden death
The Coronary Circulation: What structures does the right coronary artery supply with blood?
Supplies a majority of the right atrium and right ventricle
The Coronary Circulation: What does the right coronary artery lead to? What does that supply?
- Becomes the posterior descending artery
- Supplies blood to the sinus node and atrioventricular node
The Coronary Circulation: What is the role of coronary veins?
Collects blood from the capillaries into the coronary sinus
The Coronary Circulation: Where does the coronary veins terminate?
Terminates in the wall of the heart very near where the inferior vena cava begins
The Coronary Circulation: Where does the coronary veins deposit its blood?
Deposits its blood directly into the right atria
Cardiac Properties and Effects: What are the three unique properties of cardiac muscle tissue cells?
- Automaticity
- Excitability
- Contractility
Cardiac Properties and Effects: What is automaticity?
The ability to initiate an electrical impulse without outside nervous system stimulation
Cardiac Properties and Effects: What is excitability?
The ability to readily receive and respond to an electrical impulse
Cardiac Properties and Effects: What is contractility?
The ability to contract when stimulated
Cardiac Properties and Effects: What is inotropy?
The strength of the cardiac contraction
Cardiac Properties and Effects: What is chronotropy?
Influence on the heart rate
Cardiac Properties and Effects: What is dromotropy?
The excitability, or willingness, of the heart to conduct an impulse through the cardiac cells
Coronary and Systemic Blood Flow: What is the flow of blood into the atria dependent on? What is the name for this?
Dependent on pushing from behind caused by the continuous venous flow of blood
-Pressure from this process is called preload
What is the Frank-Starling mechanism?
States that the force of blood ejected by the heart is determined primarily by the length of the fibers of its muscular wall
Coronary and Systemic Blood Flow: What is atrial kick associated with?
Atrial kick of blood into the ventricles is associated with the atrial contraction
Coronary and Systemic Blood Flow: When does atrial kick occur?
Occurs just at the conclusion of the blood transfer between the atria and ventricles
Coronary and Systemic Blood Flow: What happens if there is no atrial kick?
Without it, the heart may lose as much as 25 percent of its output capability
Electrophysiology of the Myocardium: How are cardiac cells interconnected?
Cardiac cells are interconnected end to end
-Coupled to the next through an intercalated disk
Electrophysiology of the Myocardium: What does the system of conduction fibers allow?
A system of conduction fibers allows the impulse to travel all the way down to the apex of the heart
-Contraction begins at the apex and moves toward the base
Electrophysiology of the Myocardium: What are inside the intercalated disks?
Inside these intercalated disks are specialized plasma membrane channels called gap junctions.
Electrophysiology of the Myocardium: What are the roles of the gap junctions?
- These gap junctions allow ions and small molecules to pass between cells.
- They also facilitate conduction between cells and keep the heart beating in a synchronized manner.
Electrophysiology of the Myocardium: What is the first rule that governs cellular function throughout the body?
First, the body always wants all electrical forces neutral
Electrophysiology of the Myocardium: What is the second rule that governs cellular function throughout the body?
Second, the body will always attempt to maintain the numbers of particles in balance by diluting an area with higher concentrations of particles from an area with lower concentrations of particles
Electrophysiology of the Myocardium: In relation to the cell, where is the highest concentration of sodium? How does it remain there?
- Found in its highest concentration outside the cell
- Remains there as long as the protein gates, called the sodium channel gates, are closed
Electrophysiology of the Myocardium: In relation to the cell, where is potassium?
potassium is allowed into the cell, balancing the concentration gradient of potassium inside and outside the cell
Electrophysiology of the Myocardium: What is resting membrane potential?
When nothing is flowing in or out of the cell
Electrophysiology of the Myocardium: How many phases are in the action potential that results in cardiac activity?
5
-4, 0, 1, 2, 3
Electrophysiology of the Myocardium: What phase is the resting membrane potential?
Resting membrane potential is phase 4
Action Potential: What happens during phase 4 (resting)? (4)
- Cardiac cell is at rest
- Na+ is under a great deal of pressure to enter
- Potassium concentration has balanced
- Calcium is waiting outside the cell also trying to balance its concentration with the inside of the cell
Action Potential: What happens during phase 0?
Sodium moves inside the cell
Action Potential: What are the steps to phase 0?
- Electric impulse passed on from specialized pacemaker cells or from the adjacent cell
- Sodium rushes in, the rapid change in electrostatic pressure begins to force K+ out of the cell
Action Potential: What happens to the interior of the cell during phase 0?
Causes the interior to become more positive than the exterior of the cells
Action Potential: During phase 0, what happens when a level of Na+ in the cell is achieved?
When a level of Na+ is achieved, the sodium channel gates are once again closed and the influx of Na+ is halted
Action Potential: What happens during phase 1?
Sodium pumps out
Action Potential: What helps move sodium out of the cell during phase 1?
The sodium/potassium exchange pumps are trying to move the Na+ back out of the cells again
Action Potential: What happens to the inside of the cell during phase 1?
The electrical charge inside the cell is now able to activate the calcium channel gates, allowing calcium to begin moving inside the cell
Action Potential: What happens during phase 2?
Calcium moves in
Action Potential: What is another name for phase 2?
Plateau phase
Action Potential: What is happening with Na+, K+ and Ca++ during phase 2?
Na+ is still being pushed out of the cell, K+ is pulled in, and now Ca++ is flowing into the cell
Action Potential: How is the electric charge during phase 2? What does this do for the cell?
- The electric charges remain relatively constant
- Protects the cell from being influenced by any other electrical impulses that may come along
Action Potential: What happens during phase 3?
Calcium moves out
Action Potential: When does phase 3 begin?
Begins when enough calcium has entered the cell to change the normal balance of electrical charges to a point that deactivates the Ca++ channel gates
Action Potential: How does phase 3 transition to phase 4?
The sodium/potassium exchange pump moves enough Na+ and Ca++ out of the cell to reset the cell to its original resting state, or phase 4
Cardiac Physiology: What three things are associated to cardiac depolarization?
- Resting Potential
- Action Potential
- Repolarization
The Refractory Period: What is the absolute refractory period?
After the cell is in the depolarized state, the electrical gradient is such that no matter how strong an impulse is, the cell is not capable of responding to it
The Refractory Period: What is the relative refractory period?
There is a small period of time during phase 3 when enough of an electrical gradient has been achieved to theoretically respond to a new electrical impulse if it is of sufficient size
Pacemaker Cells: What are the three primary states?
- The sinus (SA) node—primary
- Atrioventricular (AV) node—backup
- The Purkinje fibers—backup
Pacemaker Cells: How are pacemaker cells different from ordinary cardiac cells? What does that result in?
Differ from ordinary cardiac cells in that they have far fewer sodium channel gates
-Results in a shorter plateau phase as well as slower repolarization
Pacemaker Cells: What are the rates for the three types of pacemaker cells?
- The sinus (SA) node — primary is able to initiate depolarization at a rate of 60–100 bpm
- Atrioventricular (AV) node — backup will fire at a rate of 40-60 bpm
- The Purkinje fibers — backup over at an intrinsic rate of 20–40 bpm
Control of the Heart Rate: What influences the heart rate?
Actual heart rate is influenced by the sympathetic or parasympathetic branches of the autonomic nervous system
-Can also be influenced by drugs and hormones such as insulin or glucagon
Control of the Heart Rate: Why does the heart adjust its output?
Give the heart the ability to adjust its output based on the needs of the rest of the body
Control of the Heart Rate: What are baroreceptors?
Pressure receptors
-Can trigger the brain to tell the heart to slow down. The parasympathetic nervous system then exerts its influence via the tenth cranial nerve (the vagus nerve) to slow the heart rate down
Control of the Heart Rate: Where are baroreceptors found?
Found in the carotid arteries, aorta, and other sites
Components of the Conduction System: What are the specialized structures of the conduction system? (7)
- The sinus node
- Internodal pathways
- Atrioventricular node (AV node)
- Atrioventricular junction
- His bundle
- L and R bundle branches
- Purkinje network
The Sinus Node: Where is the Sinus node located?
Located where the superior vena cava meets the right atrium
The Sinus Node: What is the Sinus node?
The primary pacemaker controlling the heart rate under normal conditions
The Sinus Node: How is the sinus node innervated?
Innervated by both the sympathetic and parasympathetic nervous system
The Sinus Node: Where does the sinus node receive its blood supply?
Node receives its blood supply from a branch of the RCA
The Atrioventricular Node: What is the role of the atrioventricular node?
- Acts as a gateway, electrically connecting the atria to the ventricles
- Slows down the conduction to allow for the atrial kick
The Atrioventricular Node: What happens if the SA node fails?
The AV node acts as the secondary pacemaker for the heart
The Atrioventricular Node: What does the AV node communicate and with what?
AV node communicates with the bundle of His and allows it to pass into the ventricles
The Bundle Branches: What is the role of the bundle branches?
Quickly transmit the electrical impulse into the apex of the ventricles
The Bundle Branches: Where does the bundle branches end?
Both bundle branches terminate in a network of small conduction fibers known as the Purkinje network
The Purkinje Network: What is the Purkinje Network?
Network of conduction fibers
The Purkinje Network: What happens if both the SA node and AV node fail?
The Purkinje Network is capable of acting as the third and final primary pacemaker site
Cardiac Physiology: Name the components of the cardiac conductive system. (7)
- Sinoatrial Node
- Internodal Atrial Pathways
- Atrioventricular Node
- Atrioventricular Junction
- Bundle of His
- Left and Right Bundle Branches
- Purkinje Fibers
The Electrocardiogram: How does the electrocardiogram measure?
Measures the flow of electricity occurring between a negative and positive electrode over time
What are the charges for the limbs of Einthoven’s Triangle?
RA: -.-
LA: +.-
LL: +.+
What are the three leads dealing with Einthoven’s Triangle?
Lead I: RA(-) to LA(+)
Lead II: RA(-) to LL(+)
Lead III: LA(-) to LL(+)
The Electrocardiogram: What are the three rules that dictate an ECG’s appearance?
Electrical impulses
- Traveling toward a positive lead will result in an upright deflection
- Traveling away from the positive lead will result in a negative deflection
- Traveling perpendicular to the lead will result in a biphasic pattern, equal deflection both positive and negative
The Electrocardiogram: What type of lead are leads I, II, III?
Bipolar
Augmented Leads: What causes downward waveforms?
Impulses moving away from the positive lead
Augmented Leads: What causes an upward waveform?
Impulses moving toward the positive lead
The Electrocardiogram: What type of leads are the precordial leads?
Unipolar
The Electrocardiogram: What are the precordial leads?
V1-V6 around the chest
The ECG monitor: What is the ECG monitor capable of doing with the placed leads?
Capable of monitoring several leads simultaneously and displaying the pattern on a screen
The ECG Wave Pattern: What does the P wave identify? What does it look like?
Identifies atrial depolarization
-Usually upright and rounded in lead II
The ECG Wave Pattern: What is the duration of the P wave? How high does the P wave show on the monitor?
- Duration is 0.10 seconds or less
- Rarely over 2 mm high
The ECG Wave Pattern: What does the PR segment identify?
The delay caused by the AV node
The ECG Wave Pattern: What is the duration of the PR segment?
An isoelectric line approximately 0.08 seconds long
The ECG Wave Pattern: How can the PR segment become shorter?
The P–R segment may be shorter if the P wave comes from an ectopic site
The ECG Wave Pattern: How is the PR interval calculated? What is its average time?
- Calculated by adding the time from the beginning of the P wave to the end of the P–R segment
- Normally measures between 0.12 and 0.2 seconds in duration
The ECG Wave Pattern: What does the QRS complex represent?
Represents depolarization of the right and left ventricles
The ECG Wave Pattern: What are the components of the QRS complex?
Components of the QRS complex are the Q wave, R wave, and S wave
The ECG Wave Pattern: What does the T wave represent?
Normal T wave represents the repolarization of the ventricles
The ECG Wave Pattern: What is the direction and duration of the T wave?
Normal direction of the T wave is upright and 0.10 to 0.25 seconds in duration
The ECG Wave Pattern: What does the QT interval represent?
The time represented from the start of the QRS complex to the end of the T wave
The ECG Wave Pattern: What is the QT interval dependent on? Explain.
The QT interval is rate-dependent; it gets longer as a rate gets slower
The ECG Wave Pattern: What does the U wave represent?
The U wave represents the final stage of ventricular repolarization, although it is not commonly seen
The ECG Wave Pattern: When will abnormally tall U waves be seen?
Abnormally tall U waves may be present in hypokalemia, cardiomyopathy, and diabetes