Cardiovascular System
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Questions and Answers

What is the primary function of circulation?

  • To regulate body temperature
  • To facilitate muscle movement
  • To remove waste from cells
  • To supply cells with the materials needed for survival (correct)
  • Hemodynamics is the study of the structure of the heart.

    False

    Why do more active cells need more blood per minute?

    Because they require more oxygen and nutrients to support their increased metabolic activity.

    Circulation is the only means by which cells can receive _______________ needed for survival and have their waste removed.

    <p>material</p> Signup and view all the answers

    Match the following statements with their correct descriptions:

    <p>Hemodynamics = Study of the heart's structure Circulation = Delivery of blood to cells Control mechanisms = Regulation of cardiovascular function</p> Signup and view all the answers

    What is the primary importance of circulation?

    <p>To supply cells with the materials needed for survival</p> Signup and view all the answers

    What happens to the membrane when it reaches the threshold potential?

    <p>It becomes more depolarized</p> Signup and view all the answers

    Conduction fibers are specifically adapted for slow conduction through the syncytium.

    <p>False</p> Signup and view all the answers

    What is the term for the continuous production of action potentials in the syncytium?

    <p>intrinsic rhythm</p> Signup and view all the answers

    The impulse conduction generates tiny electrical currents in the heart that spread through the surrounding tissues to the surface of the body, which can be recorded by an _______________________.

    <p>electrocardiogram</p> Signup and view all the answers

    Match the following components of the heart with their functions:

    <p>Pacemakers = Generate intrinsic rhythm of action potentials Conduction fibers = Rapid conduction of action potentials Syncytium = Muscle cells that contract together ECG = Records electrical activity of the heart</p> Signup and view all the answers

    What is the term for the specialized fibers that carry action potentials from pacemakers to more distant areas of the syncytium?

    <p>Conduction fibers</p> Signup and view all the answers

    What event marks the beginning of atrial systole?

    <p>The P wave of the ECG</p> Signup and view all the answers

    During atrial systole, the AV valves are closed.

    <p>False</p> Signup and view all the answers

    What is the result of the contracting force created during atrial systole?

    <p>A pressure gradient that pushes blood out of the atria into the ventricles</p> Signup and view all the answers

    Atrial systole is characterized by the electrical wave of _______________________ followed by contracting myocardium of the atria.

    <p>depolarization</p> Signup and view all the answers

    Match the following events with their descriptions:

    <p>P wave = Electrical wave of depolarization Atrial systole = Contraction of the atrial myocardium Ventricular diastole = Relaxation of the ventricular myocardium</p> Signup and view all the answers

    Atrial systole occurs simultaneously with ventricular systole.

    <p>False</p> Signup and view all the answers

    Which of the following nerves is involved in the parasympathetic impulses that regulate the heart rate?

    <p>Vagus nerve</p> Signup and view all the answers

    Increased peripheral resistance decreases blood flow.

    <p>True</p> Signup and view all the answers

    What type of reflex is influenced by emotions, exercise, hormones, blood temperature, pain, and stimulation of various exteroceptors?

    <p>Other reflexes</p> Signup and view all the answers

    The cardiac control center sends parasympathetic impulses through the _______________________ nerve to reach the SA node.

    <p>Vagus</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Peripheral resistance = The resistance to blood flow imposed by the force of friction between blood and the walls of its vessel Aortic reflex = A reflex that influences heart rate Vagus nerve = A nerve involved in parasympathetic impulses that regulate heart rate</p> Signup and view all the answers

    What type of impulses travel from the cardiac control center to the SA node?

    <p>Parasympathetic impulses</p> Signup and view all the answers

    Where are the receptors sensitive to changes in pressure located in the heart?

    <p>Two places in the heart</p> Signup and view all the answers

    The carotid sinus reflex is located at the end of the internal carotid artery.

    <p>False</p> Signup and view all the answers

    What nerve do the sensory fibers from carotid sinus baroreceptors run through?

    <p>carotid sinus nerve and the glossopharyngeal nerve</p> Signup and view all the answers

    The carotid sinus reflex is located at the _______________________ of the internal carotid artery.

    <p>beginning</p> Signup and view all the answers

    Match the following types of receptors with their locations:

    <p>Aortic baroreceptors = Carotid baroreceptors Heart = Beginning of the internal carotid artery</p> Signup and view all the answers

    What is the path of the sensory fibers from carotid sinus baroreceptors?

    <p>Through the carotid sinus nerve and the glossopharyngeal nerve to the cardiac control center</p> Signup and view all the answers

    Match the following components of the heart with their descriptions:

    <p>Aortic baroreceptors = Located in the aorta Carotid sinus reflex = Located at the beginning of the internal carotid artery Carotid baroreceptors = Located at the end of the internal carotid artery Cardiac pressoreflexes = Receptors sensitive to changes in pressure</p> Signup and view all the answers

    Match the following nerves with their functions:

    <p>Glossopharyngeal nerve = Transmits parasympathetic impulses to the SA node Carotid sinus nerve = Transmits sensory information from carotid sinus baroreceptors Vagus nerve = Transmits sensory information from aortic baroreceptors Phrenic nerve = Transmits motor information to the diaphragm</p> Signup and view all the answers

    Match the following reflexes with their descriptions:

    <p>Carotid sinus reflex = Located at the beginning of the internal carotid artery Cardiac pressoreflexes = Receptors sensitive to changes in pressure Baroreceptor reflex = Regulates blood pressure Vasomotor reflex = Regulates peripheral resistance</p> Signup and view all the answers

    Match the following components with their locations:

    <p>Aortic baroreceptors = Aorta Carotid sinus reflex = Beginning of the internal carotid artery Carotid baroreceptors = End of the internal carotid artery Cardiac control center = Medulla oblongata</p> Signup and view all the answers

    Match the following fibers with their functions:

    <p>Sensory fibers = Transmit information from baroreceptors to the cardiac control center Motor fibers = Transmit information from the cardiac control center to the heart Parasympathetic fibers = Transmit parasympathetic impulses to the SA node Sympathetic fibers = Transmit sympathetic impulses to the SA node</p> Signup and view all the answers

    Match the following descriptions with their corresponding components:

    <p>Receptors sensitive to changes in pressure = Baroreceptors Located at the beginning of the internal carotid artery = Carotid sinus reflex Transmits sensory information from carotid sinus baroreceptors = Carotid sinus nerve Regulates blood pressure = Baroreceptor reflex</p> Signup and view all the answers

    Match the following components with their corresponding functions:

    <p>Cardiac control center = Regulates heart rate Carotid sinus reflex = Regulates blood pressure Aortic baroreceptors = Detect changes in blood pressure Glossopharyngeal nerve = Transmits parasympathetic impulses</p> Signup and view all the answers

    Match the following components with their corresponding locations:

    <p>Carotid sinus reflex = Beginning of the internal carotid artery Aortic baroreceptors = Aorta Cardiac control center = Medulla oblongata Carotid sinus nerve = Neck</p> Signup and view all the answers

    Match the following descriptions with their corresponding components:

    <p>Located in the aorta = Aortic baroreceptors Regulates peripheral resistance = Vasomotor reflex Transmits sensory information from aortic baroreceptors = Vagus nerve Detects changes in blood pressure = Baroreceptors</p> Signup and view all the answers

    Match the following components with their corresponding functions:

    <p>Carotid sinus nerve = Transmits sensory information Glossopharyngeal nerve = Transmits parasympathetic impulses Vagus nerve = Transmits sensory information from aortic baroreceptors Cardiac control center = Regulates heart rate</p> Signup and view all the answers

    What happens to the ventricular pressure when the SL valves close?

    <p>It drops</p> Signup and view all the answers

    What is the result of the closure of the SL valves?

    <p>The second heart sound is produced</p> Signup and view all the answers

    Why do the SL valves close?

    <p>To prevent blood from re-entering the ventricular chambers</p> Signup and view all the answers

    What is the significance of the SL valves snapping shut?

    <p>It produces the second heart sound</p> Signup and view all the answers

    What happens to the volume of the ventricular chambers when the SL valves close?

    <p>It remains constant</p> Signup and view all the answers

    What is the purpose of the closure of both sets of valves?

    <p>To prevent backflow of blood</p> Signup and view all the answers

    What occurs at the end of ventricular ejection?

    <p>The SL valves close</p> Signup and view all the answers

    What is the result of the closure of the SL valves on ventricular pressure?

    <p>It drops</p> Signup and view all the answers

    What is the significance of the second heart sound?

    <p>It is produced by the closure of the SL valves</p> Signup and view all the answers

    What is the purpose of the SL valves?

    <p>To prevent backflow of blood</p> Signup and view all the answers

    Study Notes

    Hemodynamics

    • Hemodynamics is a collection of mechanisms that influence the active and changing circulation of blood.
    • Circulation is a vital function and the only means by which cells can receive materials needed for survival and have their waste removed.
    • Different volumes of blood per minute are required for different organs at different times.
    • More active cells need more blood per minute than less active cells.

    Conduction Mechanisms

    • Conduction fibers are specifically adapted for rapid conduction through the syncytium.
    • They are high-speed carriers of action potential from pacemakers to more distant areas of the syncytium.

    Electrocardiogram

    • Impulse conduction generates tiny electrical currents in the heart that spread through surrounding tissues to the surface of the body.
    • The atrial systole begins with the P wave of the ECG, which is an electrical wave of depolarization followed by contracting (systole) myocardium of the atria.
    • The contracting force creates a pressure gradient that pushes blood out of the atria into the relaxed ventricles.
    • The AV (cuspid) valves remain open during this phase.

    Cardiac Reflexes

    • Cardiac pressoreflexes involve receptors sensitive to changes in pressure located in two places in the heart: aortic baroreceptors and carotid baroreceptors.
    • The carotid sinus reflex is located at the beginning of the internal carotid artery and involves sensory fibers running through the carotid sinus nerve and the glossopharyngeal nerve to the cardiac control center.
    • Parasympathetic impulses leave the cardiac control center, travel through the Vagus nerve, and reach the SA node.
    • The aortic reflex and other reflexes, including emotions, exercise, hormones, blood temperature, pain, and stimulation of various exteroceptors, also influence the heart.

    Peripheral Resistance

    • Peripheral resistance is the resistance to blood flow imposed by the force of friction between blood and the walls of its vessels.

    Heart Structure and Function

    • Valves ensure one-way flow, enabling the heart to act as a pump.
    • The heart is divided into four chambers: two upper chambers called the Atria (atrium singular) and two lower chambers called the Ventricles.
    • The Atria are separated into left and right chambers by a septum (interatrial septum).
    • The Atria are called "receiving chambers" as they receive blood from veins.
    • Veins pump blood toward the heart from various tissues.

    ECG Waves

    • The T wave reflects repolarization of the ventricles.
    • An inverted T wave is often seen after myocardial muscle damage.
    • A U wave can appear as a tiny hump at the end of the T wave, representing late repolarization of subendocardial branches (Purkinje fibers) in the papillary muscle of the ventricular myocardium.

    Blood Pressure Regulation

    • Arterial blood pressure is proportional to arterial blood volume.
    • An increase in arterial blood volume increases arterial pressure, and vice versa.
    • Factors that determine arterial pressure include cardiac output (CO) and peripheral resistance.

    Cardiac Output and Peripheral Resistance

    • Cardiac output affects the blood entering the arteries.
    • If cardiac input increases, the amount of blood entering the arteries increases, tending to increase the volume in the arteries.
    • Peripheral resistance affects the blood leaving the arteries.
    • If peripheral resistance increases, it decreases the amount of blood leaving the arteries, which increases the amount of blood left in them.

    Ejection Fraction and Afterload

    • Ejection fraction (EF) is the ratio of stroke volume (SV) to end-diastolic volume (EDV).
    • EF is usually expressed as a percentage (EF = (SV ÷ EDV) × 100).
    • Healthy adults have an EF of at least 55%.
    • EF goes down as the myocardium fails.
    • Afterload is also influenced by neutral factors.
    • Unusually high afterload from flow resistance in arteries can cause heart failure.

    Cardiac Pressoreflexes

    • Cardiac pressoreflexes have receptors sensitive to changes in pressure located in two places in the heart: aortic baroreceptors and carotid baroreceptors.
    • The carotid sinus reflex is located at the beginning of the internal carotid artery.
    • Sensory fibers from carotid sinus baroreceptors run through the carotid sinus nerve and the glossopharyngeal nerve to the cardiac control center.

    Hemodynamics and Cardiovascular System

    • Many controls mechanisms help regulate and integrate each function and component of the cardiovascular system.
    • Hemodynamics refers to the collection of mechanisms that influence the active and changing circulation of blood.

    Circulation

    • Circulation is a vital function and the only means by which cells can receive material needed for survival and have their waste removed.
    • Different organs require circulation of different volumes of blood per minute at different times.
    • More active cells need more blood per minute than less active cells.

    Electrocardiogram (ECG)

    • The T wave reflects repolarization of the ventricles.
    • An inverted T wave is often seen after myocardial muscle damage.
    • Sometimes a U wave can appear as a tiny hump at the end of the T wave, representing late repolarization of subendocardial branches (Purkinje fibers) in the papillary muscle of the ventricular myocardium.

    Cardiac Cycle

    • One cycle consists of contraction (systole) and relaxation (diastole) of both atria and both ventricles.
    • The two atria contract simultaneously, then as they relax, the two ventricles contract and relax, giving the heart a pumping action.
    • The cardiac cycle illustrates and integrates changes in pressure gradients in the left atrium, left ventricle, and aorta.

    Steps of the Cardiac Cycle

    • Step 1: SL valves remain closed as the arterial pressure is higher than the pressure in the relaxed ventricles.
    • Step 2: Isovolumic ventricular contraction, where intraventricular pressure begins to increase, closing the AV valves and producing the first heart sound.
    • Step 3: End of ventricular ejection, the SL valves close when the ventricular pressure drops, producing the second heart sound.
    • Step 4: (Not mentioned in the text)
    • Step 5: (Not mentioned in the text)

    Heart Failure

    • In heart failure, the residual volume remaining in the ventricles may greatly exceed that ejected during systole.
    • Diastasis-reduced ventricular filling of the heart occurs in heart failure.

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    Description

    Explore the controls and mechanisms that regulate and integrate the functions and components of the cardiovascular system, including hemodynamics.

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