Podcast Beta
Questions and Answers
What are the names of the atrioventricular valves in the heart?
Which structure separates the atria from the ventricles in the heart?
How do the valves in the heart function during the cardiac cycle?
Which valves are categorized as semilunar valves?
Signup and view all the answers
Where is the musculature of the ventricles attached in the heart?
Signup and view all the answers
What is the primary function of arterioles?
Signup and view all the answers
Which structural characteristic is unique to capillaries?
Signup and view all the answers
How do veins regulate blood flow when there is a fall in arterial pressure?
Signup and view all the answers
What primary function do arterioles serve in the circulatory system?
Signup and view all the answers
What occurs during the systole phase of the cardiac cycle?
Signup and view all the answers
Which structure is responsible for initiating the heartbeat?
Signup and view all the answers
What structural feature of veins contributes to their ability to store blood?
Signup and view all the answers
What is the primary role of the ventricles during the cardiac cycle?
Signup and view all the answers
What characterizes diastole in the context of the cardiac cycle?
Signup and view all the answers
Which nerve stimulation decreases heart rate?
Signup and view all the answers
What is the typical stroke volume pumped by each ventricle per beat?
Signup and view all the answers
What is a consequence of partial blockage of coronary arteries?
Signup and view all the answers
What is the role of the aorta in coronary circulation?
Signup and view all the answers
What is the function of the elastic tissues in arteries?
Signup and view all the answers
What condition is suggested by a heart rate below 60 beats per minute?
Signup and view all the answers
What is the primary function of the cardiovascular system?
Signup and view all the answers
Which of the following correctly describes the structure of the heart?
Signup and view all the answers
In systemic circulation, the blood is primarily:
Signup and view all the answers
What is the role of the arteries in the cardiovascular system?
Signup and view all the answers
What type of circulation occurs in the pulmonary system?
Signup and view all the answers
Which of the following vessels carries deoxygenated blood?
Signup and view all the answers
What prevents backflow of blood within the heart?
Signup and view all the answers
Which chamber of the heart receives deoxygenated blood from the body?
Signup and view all the answers
Which of these blood vessels is responsible for nutrient absorption and exchange?
Signup and view all the answers
The left ventricle has a thick muscle wall because it:
Signup and view all the answers
What is the primary function of veins in the circulatory system?
Signup and view all the answers
The term 'lymphatics' is associated with:
Signup and view all the answers
Which structure is found between the atria and ventricles of the heart?
Signup and view all the answers
The heart acts as a:
Signup and view all the answers
What is the ending point of the systemic circulation pathway?
Signup and view all the answers
Study Notes
Circulation of the Blood
- The circulatory system acts as a transport system for the body
- Blood is the fluid medium that carries various substances
- Blood vessels are the tubes that carry blood
- The heart is a two-sided pump that drives the blood along the vessels
- The lymphatic system is part of the circulatory system
- The cardiovascular system includes the heart and blood vessels
Major Systemic Circulation
- The major systemic circulation starts in the left ventricle and ends in the right atrium
- The arterial system is oxygenated in the major systemic circulation
- The venous system is deoxygenated in the major systemic circulation
- The major systemic circulation is high pressure and high resistance
Lesser Pulmonary Circulation
- The lesser pulmonary circulation starts in the right ventricle and ends in the left atrium
- Oxygenated blood is carried from the pulmonary vein to the left atrium
- Deoxygenated blood is carried from the right ventricle to the pulmonary artery
- The lesser pulmonary circulation is low pressure and low resistance
Functional anatomy of the Heart
- The human heart is structurally and functionally divided into right and left halves (right and left heart)
- Each half of the heart consists of two chambers: an atrium and a ventricle
- One-way valves are present between atria and ventricles and at the origin of the aortic and pulmonary arteries
Valves of the Heart
- Right heart: The right heart has a tricuspid valve (atrioventricular valve) and a pulmonary valve (semilunar valve)
- Left heart: The left heart has a mitral valve (atrioventricular valve) and an aortic valve (semilunar valve)
- Atria and ventricles are separated by a single fibrous skeleton
- The fibrous skeleton consists of four interconnected rings of dense connective tissue
- The valves on both sides of the heart open and close simultaneously
Blood flow from the heart
- Atrial Syncytium: Both atria contract simultaneously to push blood into the respective ventricle
- Ventricular Syncytium: Both ventricles contract simultaneously to push blood into the respective artery
- Primer Pump: Atria; Primary Pump: Ventricles
Systole Phase
- Systole phase is the contraction stage
- Contraction increases pressure, opening the valve in front and closing the valve behind
- The chamber empties, decreasing volume after ejection
- Atrial contraction is followed by ventricular contraction
Diastole Phase
- Diastole phase is the relaxation stage
- Relaxation decreases pressure, opening the atrioventricular valve and closing the semilunar valve
- The chamber fills with blood, increasing volume (ventricular filling)
- Filling and emptying occur simultaneously under normal conditions
- If filling does not equal emptying, heart failure occurs
- Heart sounds are produced by closing valves
Phases of Cardiac Cycle
- Stroke volume: The volume of blood pumped by each ventricle per beat (approximately 70 ml)
- Cardiac output: The volume of blood pumped by each ventricle per minute (5–6 L)
- Diastole (Relaxation stage): Includes isovolumetric ventricular relaxation and ventricular filling
- Systole (Contracting stage): Includes isovolumetric ventricular contraction and ventricular ejection
Origin and Spread of Cardiac Excitation/Impulses
- SA Node: The pacemaker
- SA Node signals to the left and right atrium muscle cells
- Left and Right Atrium Muscle cells signal to
- AV Node
- AV Node signals to the
- Bundle of His
- Bundle of His signals to the
- Right and Left Bundle Branches
- Right and Left Bundle Branches signal to the
- Purkinje fibers
- Purkinje fibers signal the
- Ventricular muscle cells
Coronary Circulation
- The aorta gives rise to two coronary arteries:
- Right coronary artery: Supplies the right side of the heart
- Left coronary artery: Branches into left circumflex artery and left anterior descending artery, supplying the left side of the heart
- Blockage in the coronary arteries by atherosclerosis can decrease blood flow to the heart
- Partial blockage can cause chest pain (angina)
- Total blockage can cause a heart attack (infarction), a medical emergency.
Nerve Supply of the Heart
- Normal heart rate: 60-100 beats/min
- Sympathetic nerve stimulation causes release of norepinephrine, increasing the rate and force of contractions
- Parasympathetic nerve stimulation causes release of acetylcholine, decreasing the rate and force of contractions
- Increase in HR: Tachycardia
- Decrease in HR: Bradycardia
Blood Vessels
- Blood vessels are the tubes that carry blood in the body
Arteries (Damping Vessels)
- Arteries have large amounts of elastic tissue (elastic arteries)
- The "Windkessel" effect describes the elastic reservoir of arteries
-
Function of the arteries:
- Dampen huge pressure fluctuations with each cardiac contraction
- Give a fairly steady driving pressure for tissue perfusion by means of elastic recoil
- Act as a secondary pump during the diastole phase to maintain forward blood flow
Arterioles (Resistance Vessels)
- Structure of arterioles: Less elastic tissues, more smooth muscles with cholinergic and adrenergic receptors (muscular arteries)
-
Function of arterioles:
- Major site of resistance to blood flow
- Regulate systemic arterial blood pressure by regulating arteriolar contraction
- Regulate blood flow to different organs
Capillaries (Exchange Vessels)
- Structure of capillaries: Single layer of endothelial cells
-
Function of capillaries:
- Exchange of materials by diffusion between blood plasma and interstitial fluid (ISF)
- Exchange of respiratory gases and metabolites
Veins and Venules (Capacitance Vessels)
- Structure of veins and venules: Thinner walls (less elastic tissues and muscles), with larger lumen
-
Function of veins and venules:
- Greater capacity to store blood
- Shunt blood into systemic arterial circulation by venoconstriction when arterial pressure falls
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz explores the intricacies of the circulatory system, covering its components such as the heart, blood vessels, and blood. It also delves into the major systemic and lesser pulmonary circulations, detailing the processes of oxygenation and deoxygenation. Test your knowledge on how blood circulates throughout the body!
