Exam 2 Flashcards
What are the two main components of the cardiovascular system?
The heart (pump) and the 3 major types of blood vessels (delivery system)
The three major types of blood vessels are arteries, veins, and capillaries.
What is the primary function of capillaries?
Sites of exchange with alveoli in the lungs and systemic cells
What is the role of arteries in the cardiovascular system?
Transport blood away from the heart
What is the role of veins in the cardiovascular system?
Transport blood toward the heart
What does perfusion refer to?
The delivery of blood per unit time per gram of tissue expressed in millimeters per minute per gram (mL/min/g)
What is required for cells to remain healthy?
A continuous delivery of oxygen and nutrients and the removal of carbon dioxide and other waste products
What happens if the heart fails to pump sufficient volumes of blood?
Tissues will be deprived of needed oxygen and nutrients, waste products accumulate, and cell death may occur
What are blood vessels described as?
Conduits or soft pipes of the cardiovascular system that transport blood throughout the body
What are the major veins associated with the right side of the heart?
- Venae Cavae
- Superior Vena Cava (SVC)
- Inferior Vena Cava (IVC)
What is the associated arterial trunk of the right side of the heart?
Pulmonary trunk
What is the associated arterial trunk of the left side of the heart?
Aorta
What are the two types of valves in the heart?
- Atrioventricular (AV) Valves
- Semilunar Valves
What is the function of heart valves?
Ensure one-way, unidirectional flow of blood through the heart
What does pulmonary circulation involve?
Movement of blood to and from the lungs for gas exchange
What does systemic circulation involve?
Movement of blood to and from the systemic cells
What is congestive heart failure?
The impaired ability of the heart to pump blood
What is edema?
The accumulation of fluid in the interstitial space surrounding the cells
What is systemic edema a result of?
Impaired right ventricle (RV)
What is pulmonary edema a result of?
Impaired left ventricle (LV)
Where is the heart located?
Within the thoracic cavity
What is the mediastinum?
Median space of the thoracic cavity between the lungs
What is the apex of the heart?
Inferior, conical end of the heart
What is the pericardium?
Fibroserous membrane covering the heart
What is pericarditis?
Inflammation of the pericardium typically caused by infections
What is the coronary sulcus?
A relatively deep external groove that separates the atria and ventricles
What are the three layers that compose the wall of each heart chamber?
- Epicardium
- Myocardium
- Endocardium
What is the endocardium?
The internal surface of the heart and the external surfaces of the heart valves
What is the interatrial septum?
A thin wall that separates the right atrium (RA) and left atrium (LA)
What are pectinate muscles?
Muscular ridges on the internal wall of the right atrium
What is the fossa ovalis?
Oval depression on the interatrial septum that occupies the former location of the foramen ovale
What are chordae tendinae?
Thin strands of collagen fibers anchored by papillary muscles attached to the free edge of the right AV valve
What is the function of the mitral valve?
Controls blood flow between the left atrium and left ventricle
What is cardiomegaly?
A condition in which the heart is enlarged
What are the two normal heart sounds associated with each heartbeat?
- Lubb (S1 sound)
- Dupp (S2 sound)
What is a heart murmur?
An abnormal heart sound indicating potential heart valve problems
What is valvular insufficiency?
Occurs when one or more of the cardiac valves leak
What is valvular stenosis?
Scarring of valve cusps that prevents them from opening completely
What is coronary circulation?
A distribution system that supplies the walls of the heart with oxygen and nutrients
What are the major coronary arteries off the right side of the heart?
- Right coronary artery
- Marginal artery
- Posterior interventricular artery
What is a myocardial infarction (MI)?
Commonly known as a heart attack; results from sudden and complete occlusion of a coronary artery
What is the average weight of an adult heart?
Around 300 g (0.7 lb)
What are the two types of muscular projections in the ventricles?
- Trabeculae carnae
- Papillary muscles
What is Angina Pectoris?
A poorly localized pain sensation in the left side of the chest, left arm and shoulder, or sometimes the jaw and back
Generally results from strenuous activity when workload demands on the heart exceed the ability of the narrowed coronary arteries to supply blood.
Define Infarction.
The death of tissue due to lack of blood supply.
Describe Cardiac Muscle.
Composed of striated, relatively short, branched cells that usually house one or two central nuclei.
What surrounds each cardiac muscle cell?
Areolar connective tissue called an endomysium.
What are Intercalated discs?
Structures that link cardiac muscle cells together both mechanically and electrically.
What are Desmosomes?
Protein filaments that anchor into a protein plaque located on the internal surface of the sarcolemma; act as mechanical junctions to prevent cardiac muscle cells from pulling apart.
What are Gap Junctions?
Protein pores between the sarcolemma of adjacent cardiac muscle cells that provide a low resistance pathway for the flow of ions.
What is Function Syncytium?
A multinucleated mass that is formed by the union of originally separate cells.
What is Myoglobin?
A globular protein that binds oxygen when the muscle is at rest.
What does Creatine Kinase do?
Catalyzes the transfer of Pi from creatine phosphate to ADP, yielding ATP and creatine.
What type of respiration does cardiac muscle rely on?
Aerobic cellular respiration.
What is the role of Atrial Natriuretic Peptide (ANP)?
Decreases blood pressure by stimulating the kidneys to increase urine output and dilating blood vessels.
What initiates the heartbeat?
The SA node.
What does the cardiac center do?
Modifies the activity (rate and force of contraction) of the heart.
How does Parasympathetic Innervation affect heart rate?
Decreases heart rate but generally has no direct effect on the force of contraction.
What is the role of Sympathetic Innervation?
Increases both heart rate and the force of heart contraction.
What is the Cardiac Cycle?
The inclusive changes within the heart from the initiation of one heartbeat to the start of the next.
What does Cardiac Output (CO) measure?
The amount of blood that is pumped by a single ventricle in 1 minute.
What is the formula for Cardiac Output?
HR x SV = CO.
What is Stroke Volume (SV)?
The volume of blood pumped from a ventricle during a ventricular contraction.
What is Preload?
The heart muscle wall stretch just prior to contraction.
Define Frank-Starling Law.
As the volume of blood entering the heart increases, there is greater stretch of the heart wall (preload) resulting in greater contraction.
What are Chronotropic Agents?
Factors that increase or decrease heart rate.
What is Afterload?
The resistance in arteries to the ejection of blood by the ventricles.
What is the role of the cardiac conduction system?
Initiates and conducts electrical signals in the heart.
What is the resting membrane potential (RMP) of SA nodal cells?
-60 millivolts (mV).
What is a pacemaker potential?
The ability to reach threshold without external stimulation.
What is the sequence of events in cardiac action potential conduction?
- SA node fires an action potential
- Action potential reaches the AV node via gap junctions
- Action potential is delayed at the AV node
- Action potential travels down the bundle branches
- Action potential travels up the Purkinje fibers.
What is Ectopic Pacemaker?
A pacemaker other than the SA node.
What is the normal resting heart rate?
75 beats per minute (bpm).
What is the significance of the plateau phase in cardiac muscle cells?
It prevents tetany, allowing for proper heart function.
What is the role of the fibrous skeleton of the heart?
Provides structural support and electrical insulation between atria and ventricles.
What is the role of the autonomic nervous system in heart function?
It influences heart rate through sympathetic and parasympathetic divisions.
What are the openings of pulmonary veins visible in?
The left atrium (LA).
What does the P wave of the ECG reflect?
Atrial depolarization.
What does the heart depend on for nutrients and oxygen?
Coronary arteries.
What is the typical end-systolic volume (ESV) in an adult?
60 mL.
What does the term ‘Tetany’ refer to?
A sustained muscle contraction without relaxation.
What is an action potential?
A rapid change in membrane potential that propagates along the membrane of cardiac muscle cells
It initiates contraction in the heart muscle.
How does an action potential reach the AV node?
Via gap junctions
Gap junctions allow for electrical communication between cardiac cells.
What happens to an action potential at the AV node?
It is delayed
This delay allows for proper filling of the ventricles before contraction.
Where does an action potential travel after the AV node?
Down the bundle branches
This is part of the conduction pathway in the heart.
What is the role of Purkinje fibers in action potential conduction?
They conduct the action potential up
Purkinje fibers ensure coordinated contraction of the ventricles.
What type of channels are involved in depolarization of cardiac muscle cells?
Fast voltage-gated Na+ channels
These channels open rapidly in response to membrane depolarization.
Define the cardiac cycle.
The time from the start of one heartbeat to the initiation of the next
It includes all mechanical and electrical events of the heart.
List the sequence of events resulting in the action potential for cardiac muscle cells.
1) Na+ ions enter causing depolarization
2) Depolarization opens voltage-gated K+ channels
3) Slow voltage-gated Ca2+ channels open, causing Ca2+-induced Ca2+ release
4) Plateau occurs
5) Voltage-gated Ca2+ channels close
6) Repolarization occurs
This sequence is crucial for cardiac muscle contraction.
How do cardiac and skeletal muscle cells compare in terms of contraction?
Both shorten as a result of sarcomeres shortening
This is a fundamental mechanism of muscle contraction.
What is cardiac output?
A measure of the effectiveness of the cardiovascular system in transporting life-supporting substances
It reflects the heart’s ability to pump blood.
What is the Bainbridge Reflex?
Atrial reflex that protects the heart from overfilling
It adjusts heart rate in response to increased venous return.
What occurs toward the end of ventricular filling?
The left and right atria contract simultaneously
This helps to push blood into the ventricles.
What is the state of the semilunar valves at the beginning of the cardiac cycle?
They are closed
This is due to lower pressure in the ventricles compared to great arteries.
How is heart rate altered?
By stimulation of the SA node or the AV node
These nodes are the primary pacemakers of the heart.
What structures develop from the single heart tube?
Sinus venosus, primitive atrium, bulbus cordis, and primitive ventricle
These structures form the basis of the mature heart.
What initiates the atrial reflex?
Stimulation of baroreceptors in the atrial wall by an increase in venous return
This reflex helps regulate heart function.
What is a healthy stroke volume (SV) in an adult?
70 mL
This value can vary based on individual fitness and health.
What happens to cardiac output when heart rate and stroke volume increase?
Cardiac output increases
This is a fundamental principle of cardiovascular physiology.
What occurs by day 19 of embryonic development concerning the heart?
Two endocardial tubes form from mesoderm
This is an early stage in the development of the heart.
