Cardiovascular System Flashcards
Cardiovascular system
Heart, arteries, veins, and
microvascular beds.
Pulmonary circulation
The right side of the heart pumps blood through pulmonary vessels, through the lungs for oxygenation, and back to the left side of the heart.
Systemic circulation
This is larger; it pumps blood from the left side of the heart through vessels supplying the head, limbs, and many organs, and back to the right side of
the heart.
Lymphatic vascular system
Returns interstitial fluid
from tissue spaces of the body to the blood.
General Blood Flow in the Heart
- Superior vena cava and inferior vena cava, returning systemic, deoxygenated blood, empty into the right atrium; no valves are present.
- Blood passes through the tricuspid (right atrioventricular) valve into
the right ventricle. - Blood then passes through the pulmonary (semilunar) valve, through
the pulmonary trunk and then two pulmonary arteries, to the lungs. - Blood returns from the lungs via the left and right pulmonary veins, and
enters the left atrium (no valve). - Blood then passes through the bicuspid (L atrioventricular) valve to the
left ventricle. - Blood next passes through the aortic valve (also semilunar) into the
ascending aorta, then to the aortic arch, which has branches to the head and upper limbs. - Blood then passes down the descending aorta to the rest of the body (lower limbs, abdominal organs, etc.).
Valves on Right Side of Heart
Tricuspid valve
(= R Atrioventricular)
Pulmonary valve
(= Semilunar)
Valves on Left Side of Heart
Mitral Valve
(= Biscuspid or L Atrioventricular)
Aortic Valve
(= Semilunar)
Diastole
Contraction of the atria.
Semilunar valves close and AV valves open
During diastole, the ventricular volume increases
Systole
Contraction of the ventricles
AV valves close and Semilunar valves open
Phonocardiogram
The sound labeled 1st
contributes to the S1 heart sound (the pulse) and is the reverberation of blood from the sudden closure of the mitral valve (left A-V
valve) and the tricuspid valve.
The sound labeled 2nd contributes to the S2 heart sound and is the reverberation of blood from the sudden closure of the aortic valve and the pulmonary valve (both semilunar).
Regurgitation
Abnormal valves may not close tightly, allowing slight regurgitation and backflow of blood.
May produce an abnormal heart sound referred to as a heart murmur.
Stenosis
The heart valves may not open properly (stenosis), and more force is needed to push blood through.
May produce an abnormal heart sound referred to as a heart murmur.
Endocardium
The innermost lining of the the heart. Contains areolar tissue and endothelium
Consists of a thin inner layer of endothelium and supporting connective tissue, a middle myoelastic layer of smooth muscle fibers and connective
tissue, and a deep layer of connective tissue called the subendocardial layer that
merges with the myocardium.
Myocardium
The middle and thickest layer. It is mainly cardiac muscle.
The myocardium is much thicker in the walls of the ventricles, particularly the left, than in the atrial walls.
Epicardium
Contains epithelium and areolar tissue
The outermost layer. It is a simple squamous
mesothelium supported by a layer of loose connective tissue containing blood vessels and nerves, and adipose tissue.
Pericardial sac
A double-layered sac that encases the heart. Between the two layers (parietal pericardium and visceral
pericardium), a fluid lubricates the surfaces and reduces friction between the layers when the heart beats.
Sinoatrial (SA) node
A node of specialized myocardial tissue in the right atrium known as the pacemaker
Impulses initiated by cells of the SA node move along the myocardial fibers of both atria, stimulating contraction.
Atrioventricular (AV) node
A node of specialized myocardial tissue in the right atrium followed by the AV bundle (of His) and the subendocardial conducting network.
Impulses reach the AV node from the SA node and stimulate depolarization of its
cells.
Conducting muscle fibers from the AV node form the AV bundle, pass into the interventricular septum, and bifurcate into
the wall of each ventricle as the left and right bundle
branches.
Purkinje fibers
Subdivisions of the left and right bundle branches that trigger waves of contraction through both ventricles simultaneously.
Innervation of the heart
Stimulation of the parasympathetic division (vagus nerve) slows the heartbeat, whereas stimulation of the sympathetic nerve accelerates activity of the pacemaker.
Atrial fibrillation
An abnormal heart rhythm (arrhythmia) characterized by rapid and irregular beating of the atrial chambers of the heart.
May cause ventricular tachycardia.
Ventricular Fibrillation
An abnormal heart rhythm in which the ventricles of the heart quiver, due to disorganized electrical activity.
Types of tissue in blood vessels
Walls of all blood vessels except capillaries contain three types of tissue:
smooth muscle, connective tissue, and endothelium.
Endothelium
A specialized epithelium that is a semipermeable barrier between the blood and the interstitial tissue fluid. The endothelial cells of blood vessels are squamous, polygonal, and elongated
Smooth muscle fibers
In the walls of all vessels except capillaries and are
arranged in layers helically (like a spiral). In arterioles and small arteries, the smooth muscle cells permit vasoconstriction and vasodilation which are important for regulating
overall blood pressure.
Walls of Arteries and
Veins
Walls of arteries and
veins have three “tunics”:
tunica intima tunica media tunica adventitia (or externa)
Vasa vasorum
These bring O2 and nutrients to local cells: Arterioles, capillaries,
and venules
Antithrombogenic
Normal vascular endothelium is antithrombogenic, preventing adhesion of
blood cells and platelets, and preventing blood
clot formation under normal circumstances.
Elastic arteries
Tunica Intima: Endothelium;
smooth muscle
Tunica Media: Elastic fiber
layers alternating with
smooth muscle layers
Function: Conduct blood from heart; uses elastic recoil to maintain steady
pressure
The largest arteries contain considerable elastic material and expand with blood when the heart contracts. These include
aorta, the pulmonary artery, and their largest branches.
Muscular arteries
Tunica Intima: Endothelium;
less smooth muscle
Tunica Media: Much smooth muscle; fewer elastic fibers
Function: Move blood to organs; vasoconstriction and vasodilation
Small arteries
Tunica Intima: Endothelium; even less smooth muscle
Tunica Media: 3-10 layers smooth muscle
Function: Move blood to arterioles; vasoconstriction and vasodilation
Arterioles
Tunica Intima: Endothelium;
no smooth muscle
Tunica Media: 1-3 layers smooth muscle
Function: Control blood flow to capillaries using sphincters
Branch to form networks of
capillaries. These vessels are the major determinants of systemic blood pressure.
Windkessel Effect
The walls of large elastic arteries (e.g. aorta, common carotid, subclavian, and
pulmonary arteries and their larger branches) contain elastic fibers. These arteries distend when the blood pressure rises during systole and recoil when the blood pressure falls during diastole.
The Windkessel effect helps in damping the fluctuation in blood pressure over the cardiac cycle and assists in the maintenance of blood pressure during diastole when cardiac ejection ceases.
Arterial Sensory Structures
Arterial sensory mechanisms use chemoreceptors and baroreceptors.
Chemoreceptors
Monitor primarily partial pressure of O2, but
also CO2 and the pH levels.
They are located in the carotid bodies and aortic bodies in the walls of the carotid arteries and aortic arch, respectively.
Baroreceptors
Include the carotid sinus and aortic sinus. These are regions of the vessels where there are more
sensory nerve fibers that monitor the distension of the vessels and send signals to the brain to adjust vasoconstriction.
Atherosclerosis
A disease of elastic arteries and large muscular arteries that may play a role in nearly half of all deaths in developed
parts of the world.
It is initiated by damaged endothelial cells that oxidize low-density
lipoproteins (LDLs), which induces entry of macrophages to remove
the LDL.
Lipid filled macrophages accumulate and develop into fibro-fatty plaques, or atheroma.
Atheroma
In elastic arteries, atheroma produce localized destruction causing arterial bulges or aneurysms
In muscular arteries such as the coronary arteries, atheroma can occlude blood flow to downstream vessels, leading to ischemic heart disease.
Capillaries
Tunica Intima: Endothelium only
Tunica Media: –
Function: Exchange metabolites by diffusion across cells
Venules
Tunica Intima: Endothelium only
Tunica Media: Scattered smooth muscle cells
Function: Drain capillary beds.
Small veins
Tunica Intima: Endothelium and connective tissue
Tunica Media: 2-3 layers of smooth muscle
Function: Collect blood from venules
Medium veins
Tunica Intima: Endothelium and connective tissue, with valves
Tunica Media: 3-5 layers smooth muscle
Function: Carry blood to larger veins with no backflow
Large veins
Tunica Intima: Endothelium and connective tissue, with valves; smooth muscle
Tunica Media: >5 layers smooth muscle
Function: Return blood to heart
Valves
Large and medium veins have valves, which are thin folds of the tunica intima.
Arteriovenous
(AV) shunts or anastomoses
Commonly coiled, which directly connect the arterial and venous systems and temporarily bypass capillaries.
Venous portal systems
One capillary bed drains into a vein that then branches again into another
capillary bed. This allows molecules in the first set of
capillaries to be delivered quickly and at high concentrations to tissues at the second capillary bed,
which is important in the anterior pituitary gland
and liver.
Continuous capillaries
The most common type (skin), have tight and
occluding junctions sealing the endothelial cells to produce minimal fluid
leakage, as in the blood-brain barrier. Molecules cross the endothelium by
diffusion or transcytosis.
Fenestrated capillaries
Also have tight junctions, but perforations (fenestrations) through the endothelial cells allow greater exchange. Fenestrated capillaries are
found in organs where small molecular exchange with the blood is important,
such as endocrine organs, intestinal walls, and choroid plexus.
Sinusoids or discontinuous capillaries
Usually have a wider diameter than the other types and have large gaps between the endothelial cells. Sinusoids are found in organs where exchange or macromolecules and cells occurs readily between tissue and blood, such as in bone marrow, liver, and spleen.
The atrioventricular bundle is made of fibers made of impulse-conducting heart cells. It passes into the inter ventricular system and then branches into.
Left and Right bundles.
Endocardium (internal lining of the heart) includes two layers. They are
Endothelium and areolar connective tissue
Heart murmur is caused by some sort of defect in structure/function of a heart valve. Which of these is the most common cause of heart murmur?
Regurgitation of the mitral valve
Which very large vein(s) empties into the right atrium of the heart?
Superior and inferior vena cava.
Which of these heart chambers has the thickest muscular wall (myocardium)?
Left Ventricle
Which structure connects the chordae tendineae to the wall of the ventricle?
Papillary muscles
If the pericardial sac fills with fluid, this can cause severe problems. Why?
The fluid pressure prevents normal contraction of the heart
Which of these pairs of heart valves does not have chordae tendineae associated with them?
Pulmonary valves and aortic valves
As systole begins, which heart valves are closed?
The two atrioventricular valves
Trabeculae carneae of the heart are found in
Both ventricles
What is an aneurysm?
A bulging in an artery.
Which of these blood vessels is the major determinant of systemic blood pressure?
Arterioles
_____________________ are the “plaques” that adhere to arterial walls.
Atheromas
Which of these factors predisposes a person to developing atheroma?
A high LDL:HDL ratio.
Atherosclerosis typically occurs in which type of blood vessels?
Elastic and large muscular arteries
When we talked about the nervous system we discussed the blood-brain barrier. Capillaries of the blood-brain barrier are of which type?
Continuous
Moderate-sized arteries and veins have three tissue layers in common. They are
Endothelium, smooth muscle, and connective tissue.
The capillaries of endocrine organs are
Fenestrated to allow passage of hormones into the blood.
Fluid that seeps out of capillaries into the spaces between cells in the surrounding tissue is called
Interstitial Fluid
As one gets further away from the heart, the arteries
Have fewer elastic fibers.
In which vessels of the circulatory system is the loss of fluid from the blood into the surrounding tissue typically the greatest?
Postcapillary venules
A thrombosis may cause
Ischemia to the heart.
Valves in veins are formed from the
Tunica intima
In which type of vessels are passive valves most common?
Medium and large veins
Which type of vessel drains capillary beds?
Venules
Reversed prompt
Heart, arteries, veins, and
microvascular beds.
Cardiovascular system
Reversed prompt
The right side of the heart pumps blood through pulmonary vessels, through the lungs for oxygenation, and back to the left side of the heart.
Pulmonary circulation
Reversed prompt
This is larger; it pumps blood from the left side of the heart through vessels supplying the head, limbs, and many organs, and back to the right side of
the heart.
Systemic circulation
Reversed prompt
Returns interstitial fluid
from tissue spaces of the body to the blood.
Lymphatic vascular system
Reversed prompt
- Superior vena cava and inferior vena cava, returning systemic, deoxygenated blood, empty into the right atrium; no valves are present.
- Blood passes through the tricuspid (right atrioventricular) valve into
the right ventricle. - Blood then passes through the pulmonary (semilunar) valve, through
the pulmonary trunk and then two pulmonary arteries, to the lungs. - Blood returns from the lungs via the left and right pulmonary veins, and
enters the left atrium (no valve). - Blood then passes through the bicuspid (L atrioventricular) valve to the
left ventricle. - Blood next passes through the aortic valve (also semilunar) into the
ascending aorta, then to the aortic arch, which has branches to the head and upper limbs. - Blood then passes down the descending aorta to the rest of the body (lower limbs, abdominal organs, etc.).
General Blood Flow in the Heart
Reversed prompt
Tricuspid valve
(= R Atrioventricular)
Pulmonary valve
(= Semilunar)
Valves on Right Side of Heart
Reversed prompt
Mitral Valve
(= Biscuspid or L Atrioventricular)
Aortic Valve
(= Semilunar)
Valves on Left Side of Heart
Reversed prompt
Contraction of the atria.
Semilunar valves close and AV valves open
During diastole, the ventricular volume increases
Diastole
Reversed prompt
Contraction of the ventricles
AV valves close and Semilunar valves open
Systole
Reversed prompt
The sound labeled 1st
contributes to the S1 heart sound (the pulse) and is the reverberation of blood from the sudden closure of the mitral valve (left A-V
valve) and the tricuspid valve.
The sound labeled 2nd contributes to the S2 heart sound and is the reverberation of blood from the sudden closure of the aortic valve and the pulmonary valve (both semilunar).
Phonocardiogram
Reversed prompt
Abnormal valves may not close tightly, allowing slight regurgitation and backflow of blood.
May produce an abnormal heart sound referred to as a heart murmur.
Regurgitation
Reversed prompt
The heart valves may not open properly (stenosis), and more force is needed to push blood through.
May produce an abnormal heart sound referred to as a heart murmur.
Stenosis
Reversed prompt
The innermost lining of the the heart. Contains areolar tissue and endothelium
Consists of a thin inner layer of endothelium and supporting connective tissue, a middle myoelastic layer of smooth muscle fibers and connective
tissue, and a deep layer of connective tissue called the subendocardial layer that
merges with the myocardium.
Endocardium
Reversed prompt
The middle and thickest layer. It is mainly cardiac muscle.
The myocardium is much thicker in the walls of the ventricles, particularly the left, than in the atrial walls.
Myocardium
Reversed prompt
Contains epithelium and areolar tissue
The outermost layer. It is a simple squamous
mesothelium supported by a layer of loose connective tissue containing blood vessels and nerves, and adipose tissue.
Epicardium
Reversed prompt
A double-layered sac that encases the heart. Between the two layers (parietal pericardium and visceral
pericardium), a fluid lubricates the surfaces and reduces friction between the layers when the heart beats.
Pericardial sac
Reversed prompt
A node of specialized myocardial tissue in the right atrium known as the pacemaker
Impulses initiated by cells of the SA node move along the myocardial fibers of both atria, stimulating contraction.
Sinoatrial (SA) node
Reversed prompt
A node of specialized myocardial tissue in the right atrium followed by the AV bundle (of His) and the subendocardial conducting network.
Impulses reach the AV node from the SA node and stimulate depolarization of its
cells.
Conducting muscle fibers from the AV node form the AV bundle, pass into the interventricular septum, and bifurcate into
the wall of each ventricle as the left and right bundle
branches.
Atrioventricular (AV) node
Reversed prompt
Subdivisions of the left and right bundle branches that trigger waves of contraction through both ventricles simultaneously.
Purkinje fibers
Reversed prompt
Stimulation of the parasympathetic division (vagus nerve) slows the heartbeat, whereas stimulation of the sympathetic nerve accelerates activity of the pacemaker.
Innervation of the heart
Reversed prompt
An abnormal heart rhythm (arrhythmia) characterized by rapid and irregular beating of the atrial chambers of the heart.
May cause ventricular tachycardia.
Atrial fibrillation
Reversed prompt
An abnormal heart rhythm in which the ventricles of the heart quiver, due to disorganized electrical activity.
Ventricular Fibrillation
Reversed prompt
Walls of all blood vessels except capillaries contain three types of tissue:
smooth muscle, connective tissue, and endothelium.
Types of tissue in blood vessels
Reversed prompt
A specialized epithelium that is a semipermeable barrier between the blood and the interstitial tissue fluid. The endothelial cells of blood vessels are squamous, polygonal, and elongated
Endothelium
Reversed prompt
In the walls of all vessels except capillaries and are
arranged in layers helically (like a spiral). In arterioles and small arteries, the smooth muscle cells permit vasoconstriction and vasodilation which are important for regulating
overall blood pressure.
Smooth muscle fibers
Reversed prompt
Walls of arteries and
veins have three “tunics”:
tunica intima tunica media tunica adventitia (or externa)
Walls of Arteries and
Veins
Reversed prompt
These bring O2 and nutrients to local cells: Arterioles, capillaries,
and venules
Vasa vasorum
Reversed prompt
Normal vascular endothelium is antithrombogenic, preventing adhesion of
blood cells and platelets, and preventing blood
clot formation under normal circumstances.
Antithrombogenic
Reversed prompt
Tunica Intima: Endothelium;
smooth muscle
Tunica Media: Elastic fiber
layers alternating with
smooth muscle layers
Function: Conduct blood from heart; uses elastic recoil to maintain steady
pressure
The largest arteries contain considerable elastic material and expand with blood when the heart contracts. These include
aorta, the pulmonary artery, and their largest branches.
Elastic arteries
Reversed prompt
Tunica Intima: Endothelium;
less smooth muscle
Tunica Media: Much smooth muscle; fewer elastic fibers
Function: Move blood to organs; vasoconstriction and vasodilation
Muscular arteries
Reversed prompt
Tunica Intima: Endothelium; even less smooth muscle
Tunica Media: 3-10 layers smooth muscle
Function: Move blood to arterioles; vasoconstriction and vasodilation
Small arteries
Reversed prompt
Tunica Intima: Endothelium;
no smooth muscle
Tunica Media: 1-3 layers smooth muscle
Function: Control blood flow to capillaries using sphincters
Branch to form networks of
capillaries. These vessels are the major determinants of systemic blood pressure.
Arterioles
Reversed prompt
The walls of large elastic arteries (e.g. aorta, common carotid, subclavian, and
pulmonary arteries and their larger branches) contain elastic fibers. These arteries distend when the blood pressure rises during systole and recoil when the blood pressure falls during diastole.
The Windkessel effect helps in damping the fluctuation in blood pressure over the cardiac cycle and assists in the maintenance of blood pressure during diastole when cardiac ejection ceases.
Windkessel Effect
Reversed prompt
Arterial sensory mechanisms use chemoreceptors and baroreceptors.
Arterial Sensory Structures
Reversed prompt
Monitor primarily partial pressure of O2, but
also CO2 and the pH levels.
They are located in the carotid bodies and aortic bodies in the walls of the carotid arteries and aortic arch, respectively.
Chemoreceptors
Reversed prompt
Include the carotid sinus and aortic sinus. These are regions of the vessels where there are more
sensory nerve fibers that monitor the distension of the vessels and send signals to the brain to adjust vasoconstriction.
Baroreceptors
Reversed prompt
A disease of elastic arteries and large muscular arteries that may play a role in nearly half of all deaths in developed
parts of the world.
It is initiated by damaged endothelial cells that oxidize low-density
lipoproteins (LDLs), which induces entry of macrophages to remove
the LDL.
Lipid filled macrophages accumulate and develop into fibro-fatty plaques, or atheroma.
Atherosclerosis
Reversed prompt
In elastic arteries, atheroma produce localized destruction causing arterial bulges or aneurysms
In muscular arteries such as the coronary arteries, atheroma can occlude blood flow to downstream vessels, leading to ischemic heart disease.
Atheroma
Reversed prompt
Tunica Intima: Endothelium only
Tunica Media: –
Function: Exchange metabolites by diffusion across cells
Capillaries
Reversed prompt
Tunica Intima: Endothelium only
Tunica Media: Scattered smooth muscle cells
Function: Drain capillary beds.
Venules
Reversed prompt
Tunica Intima: Endothelium and connective tissue
Tunica Media: 2-3 layers of smooth muscle
Function: Collect blood from venules
Small veins
Reversed prompt
Tunica Intima: Endothelium and connective tissue, with valves
Tunica Media: 3-5 layers smooth muscle
Function: Carry blood to larger veins with no backflow
Medium veins
Reversed prompt
Tunica Intima: Endothelium and connective tissue, with valves; smooth muscle
Tunica Media: >5 layers smooth muscle
Function: Return blood to heart
Large veins
Reversed prompt
Large and medium veins have valves, which are thin folds of the tunica intima.
Valves
Reversed prompt
Commonly coiled, which directly connect the arterial and venous systems and temporarily bypass capillaries.
Arteriovenous
(AV) shunts or anastomoses
Reversed prompt
One capillary bed drains into a vein that then branches again into another
capillary bed. This allows molecules in the first set of
capillaries to be delivered quickly and at high concentrations to tissues at the second capillary bed,
which is important in the anterior pituitary gland
and liver.
Venous portal systems
Reversed prompt
The most common type (skin), have tight and
occluding junctions sealing the endothelial cells to produce minimal fluid
leakage, as in the blood-brain barrier. Molecules cross the endothelium by
diffusion or transcytosis.
Continuous capillaries
Reversed prompt
Also have tight junctions, but perforations (fenestrations) through the endothelial cells allow greater exchange. Fenestrated capillaries are
found in organs where small molecular exchange with the blood is important,
such as endocrine organs, intestinal walls, and choroid plexus.
Fenestrated capillaries
Reversed prompt
Usually have a wider diameter than the other types and have large gaps between the endothelial cells. Sinusoids are found in organs where exchange or macromolecules and cells occurs readily between tissue and blood, such as in bone marrow, liver, and spleen.
Sinusoids or discontinuous capillaries
