chapter 22 heart
supply the thick & metabolically active cardiac muscle cells of the heart wall
Coronary arteries
These arteries are the only branches of the ascending aorta.
Left and right coronary arteries
packaged into spiral/circular bundles by crisscrossing CT fibers, assist to link areas of heart together
Myocardium
_____________ innervation decreases the heart rate, but generally tends to have no effect on the force of contractions.
Parasympathetic
______________ innervation comes from the medulla oblongata via the left and right vagus nerves (CN X). As the vagus nerves descend into the thoracic cavity, they give off branches that supply the heart.
Parasympathetic
_________________ axons project from the superior, middle, and inferior cervical ganglia and the T1-T5 ganglia, and travel directly to the heart through cardiac nerves.
Postganglionic
________________ axons enter the sympathetic trunk and ascend into the thoracic and cervical portions, where they synapse on ganglionic neurons.
Preganglionic
These bundles conduct the impulse to conduction fibers called ____________ ____________ that begin within the apex of the heart and extend through the walls of the ventricles. Purkinje fibers are larger than other cardiac muscle cells. Muscle impulse conduction along the Purkinje fibers is extremely rapid, consistent with the large size of the cells, and the impulse spreads immediately throughout the ventricular myocardium.
Purkinje fibers
_____________ valves are located within the walls of both ventricles immediately before the connections of the right and left ventricles to the pulmonary trunk and aorta,
Semilunar
______________ innervation increases the rate and the force of heart contractions.
Sympathetic
arises from the T1-T5 segments of the spinal cord
Sympathetic innervation
pericardium function
The pericardium restricts the heart's movements so that it doesn't bounce and move about in the thoracic cavity, and prevents the heart from overfilling with
Contraction of cardiac muscle composing the myocardium generates the force necessary to pump blood. The ventricular myocardium may change in thickness as we age. For example, it hypertrophies in response to narrowing of systemic arteries because the heart must work harder to pump the blood. True or False.
True
The heart wall consists of three distinctive layers:
an external epicardium, a middle myocardium, and an internal endocardium
The left coronary artery typically branches into the ____________ __________ artery (also called the left anterior descending artery), which supplies the anterior surface of both ventricles and most of the interventricular septum, and the ___________ artery, which supplies the left atrium and ventricle.
anterior interventricular circumflex
At the superior end of the ventricular cavity, the ________ _______ _________marks the end of the left ventricle and the entrance into the aorta
aortic semilunar valve
The two basic types of blood vessels are
arteries, which transport blood away from the heart, and veins, which transport blood back to the heart.
The first sound heard with a stethoscope is the result of the _______________ ____________ closing, producing a "lubb" sound. The second sound is produced when the ________________ _____________close, producing a "dupp" sound.
atrioventricular (AV) valves semilunar valves
This bundle, also known as the bundle of His, receives the muscle impulse from the AV node and extends into the interventricular septum before dividing into left and right bundles (also known as bundle branches).
atrioventricular bundle
Heart innervated by _____________ ____________ __________ via the ____________ ___________
autonomic NS coronary plexus
The heart exhibits___________, meaning that the heart itself (not external nerves) is responsible for initiating the heartbeat. Certain cardiac muscle cells are specialized to initiate and conduct muscle impulses to the contractile muscle cells of the myocardium. Collectively, these specialized cells are called the heart's __________ _____________
autorhythmicity conducting system
Separating the left atrium from the left ventricle is the left atrioventricular opening, covered by the left atrioventricular valve (also called the ___________ valve, because it has two triangular cusps). This valve is also sometimes called the _________valve, because the two triangular cusps resemble a miter (the headpiece worn by a bishop). Oxygenated blood flows from the left atrium, through the left atrioventricular opening when the valve is open, into the left ventricle. The left AV valve is forced closed when the left ventricle contracts, preventing blood backflow into the left atrium.
bicuspid mitral
myocardium is composed of _________ _________ ______ The myocardium is the thickest of the three heart wall layers. It lies deep to the epicardium and superficial to the endocardium.
cardiac muscle tissue
Efficient pumping of blood through the heart & blood vessels requires precisely coordinated contractions of the heart chambers. this is called
conducting system
At its superior end, the right ventricle narrows into a smooth-walled, conical region called the ________________ _____________. Beyond the conus arteriosus is the ____________ ________________ ____________, which separates the right ventricle and the pulmonary trunk. The pulmonary trunk divides shortly into right and left ________ _______________, which carry deoxygenated blood to the lungs.
conus arteriosus. pulmonary semilunar valve pulmonary arteries
Heart requires blood supply to function properly, supplied by
coronary circulation
sulci house vasculature that supply heart
coronary circulation
drains blood from the heart wall.
coronary sinus
•An enlarged vessels formed by joining of cardiac veins; empties into right atrium
coronary sinus
The atria are separated from the ventricles externally by a relatively deep __________ ______________ that extends around the circumference of the heart.
coronary sulcus (or atrioventricular sulcus)
atria interior smooth walled posterior portion & ridged anterior portion (pectinate muscle) separate by the
crista terminalis
The fibrous skeleton of the heart is formed from _________________ _______________ _____________ ____________ and is located between the atria and the ventricles
dense regular connective tissue
The right atrium receives _____________venous blood from the ____________ circulation and the heart muscle itself.
deoxygenated systemic
Intercalated discs have numerous ___________ and _____________ __________
desmosome gap junctions.
fibrous pericardium is attached inferiorly to the __________ and superiorly to the base of the ___________
diaphragm great vessels
fibrous structure after birth; prior forms the ___________ _____________, a vessel detour directing blood from pulmonary trunk to aorta
ductus arteriosus
layer of endothelium over thin layer of CT
endocardium
The internal surface of the heart chambers and the external surfaces of the heart valves are covered by ___________
endocardium.
is the outermost heart layer and is also known as the visceral layer of the serous pericardium.
epicardium
Conduction system ensures signal moves
fast enough through heart
outer layer that is loose fitting, tough dense CT layer and protects heart, anchors heart to surrounding structures & prevents overfilling
fibrous pericardium
It occupies the former location of the fetal foramen ovale, which shunted blood from the right atrium to the left atrium during fetal life, interatrial septum reveals an oval depression called the
fossa ovalis
hollow depression where foramen ovale existed in fetal heart
fossa ovalis
The coronary arteries are considered______________ ____________ __________ . In other words, whereas the left and right coronary arteries share some tiny connections, called ______________, functionally they act like end arteries, which have no anastomoses and are the "end of the line" when it comes to arterial blood flow. The anastomoses allow the coronary arteries to shunt a tiny amount of blood from one artery to another. However, if one of the arteries becomes blocked, as happens with coronary artery disease, these anastomoses are too tiny to shunt sufficient blood from one artery to the other.
functional end arteries anastomoses
The ______ _________ _________ runs alongside the anterior interventricular artery; the _________ _______ _________ runs alongside the posterior interventricular artery; and the _________ _________ __________ travels close to the right marginal artery. These cardiac veins all drain into the___________ ___________, a large vein that lies in the posterior aspect of the coronary sulcus. The coronary sinus drains directly into the right atrium of the heart
great cardiac vein middle cardiac vein small cardiac vein coronary sinus
The arteries and veins entering and leaving the heart are called the________ _________because of their relatively large diameter.
great vessels
drains blood from the lower limbs and trunk;
inferior vena cava
The __________ __________ forms a thin wall between the right and left atria.
interatrial septum
Neighboring cardiac muscle cells in the walls of heart chambers have formed specialized cell-cell contacts called _________ _______ which electrically and mechanically link the cells together and permit the immediate passage of muscle impulses
intercalated discs
The muscle impulse spreads via gap junctions between cardiac muscle cells throughout both atria, and to the atrioventricular (AV) node via ___________ _____________
internodal pathways.
forms a thick wall between the right and left ventricles.
interventricular septum
is a groove between the ventricles that extends inferiorly from the coronary sulcus toward the heart apex, and delineates the superficial boundary between the right and left ventricles.
interventricular sulcus
The____________ ventricular wall is typically three times thicker than the ____________ventricular wall
left right
the aorta conducts blood from the ________ __________ into the _____________ ____________
left ventricle systemic circulation.
The gap junctions provide a__________ ___________ __________ for ions to move between adjoining cardiac muscle cells. This path allows the muscle impulse to travel easily and instantaneously among cardiac muscle cells. Gap junctions are required for the synchronous beating of cardiac muscle cells. Therefore, cardiac muscle cells function as a single, coordinated unit; the precisely timed stimulation and response by cardiac muscle cells of both the atria and the ventricles are dependent upon these structural features.
low-resistance pathway
Permits compression necessary to pump large blood volumes out of ventricles
myocardium
is the middle layer of the heart wall
myocardium
specialized myocardial cells that are___________ & initiate/distribute impulses; so heart contracts in orderly, sequential manner
noncontractile
The right ventricle typically has three cone-shaped, muscular projections called _______ muscles, which anchor numerous thin strands of collagen fibers called____________ ______________ . The chordae tendineae attach to the lower surface of cusps of the right AV valve and prevent the valve from everting and flipping into the atrium when the right ventricle is contracting.
papillary chordae tendineae
the auricle and anterior wall exhibit obvious muscular ridges, called
pectinate muscles.
The ____________ is a narrow space between the parietal and visceral layers of the serous pericardium. Both layers of pericardium secrete lubricating serous fluid into the pericardial cavity to decrease friction when the heart beats and the layers rub against one another. The pericardial cavity is a potential space with just a thin lining of serous fluid. However, it may become a real space if the amount of fluid increases, as seen with inflammation
pericardial cavity
Heart enclosed by a double-walled sac called the
pericardium
The desmosomes prevent cardiac muscle cells from
pulling apart
which arteries do not carry oxygenated blood?
pulmonary arteries
the left atrium receives blood from the ____________ ____________
pulmonary circulation.
which veins do not carry deoxygenated blood?
pulmonary veins
Once gas exchange occurs in the lungs, the oxygenated blood travels through the ____________ ___________ to the _________ ___________
pulmonary veins left atrium
To maintain body homeostasis, blood circulates continuously throughout the body this is accomplished via the?
pumping action of the heart
Observe numerous mitochondria, in the cardiac muscle give cells high ______________ __________ ________________
resistance to fatigue
The pulmonary trunk transports blood from the________ ventricle into the _____________ circulation
right pulmonary
Although equal volumes in each circuit, __________ side requires less work because PC is short, low pressure system; SC, ______side, is longer and more resistant to blood flow, thus requires more work
right left
Separating the right atrium from the right ventricle is the___________ ____________opening. This opening is covered by a right atrioventricular valve (also called the tricuspid valve, because it has three triangular cusps). Blood flows from the right atrium, through the right atrioventricular opening when the valve is open, into the right ventricle. The right AV valve is forced closed when the right ventricle begins to contract, preventing blood from flowing back into the right atrium.
right atrioventricular
The right coronary artery typically branches into the_________ ________ artery, which supplies the right border of the heart, and the____________ ___________ artery, which supplies the posterior surface of both the left and right ventricles.
right marginal posterior interventricular
what valves are opened during ventricular systole
semilunar valves
A muscle bundle called the __________ _______________, or moderator band, connects the base of the anterior papillary muscle to the interventricular septum
septomarginal trabecula
The epicardium is composed of a ___________ ________ and___________________. As we age, more fat is deposited in the epicardium, and so this layer becomes thicker and more fatty.
serous membrane areolar connective tissue
The inner portion is a thin, double-layered serous membrane called the ___________?
serous pericardium
The endocardium, like the epicardium, is composed of a_______ _______ ______and an underlying layer of ____________. The epithelial layer of the endocardium is continuous with the epithelial layer called the endothelium, which lines the blood vessels
simple squamous epithelium areolar connective tissue
The heartbeat is initiated by the specialized cardiac muscle cells of the _________ ______________, which are located in the posterior wall of the __________atrium, adjacent to the entrance of the superior vena cava. The cells of the SA node act as the ___________, the rhythmic center that establishes the pace for cardiac activity. Under the influence of parasympathetic innervation, SA node cells initiate impulses 70 to 80 times per minute.
sinoatrial (SA) node right pacemaker
drains blood from the head, neck, upper limbs, and superior regions of the trunk;
superior vena cava
The right atrium receives blood from the _________ __________
systemic circulation
The cardiovascular system consists of two circulations: what are they?
the pulmonary circulation and the systemic circulation The pulmonary circulation conveys deoxygenated blood from the right side of the heart through blood vessels to the lungs for the pickup of oxygen and the release of carbon dioxide, and then back through blood vessels to the left side of the heart. The systemic circulation moves oxygenated blood from the left side of the heart through blood vessels to the systemic cells such as those of the liver, skin, muscle, and brain. Nutrients, respiratory gases, and wastes are exchanged with these systemic cells before blood is returned to the right side of the heart., .
the basic pattern of blood flow is
the right side of the heart → lungs → the left side of the heart → systemic tissues of the body → back to the right side of the heart
The left ventricle requires thicker walls because?
to generate enough pressure to force the oxygenated blood that has returned to the heart from the lungs into the aorta and then through the entire systemic circulation.
The internal wall surface of each ventricle displays characteristic large, smooth, irregular muscular ridges, called the
trabeculae carneae
Blood flows in a specific direction in the heart & this one-way flow is accomplished by heart valves which open & close in response to differences in BP true or false?
true
Blood flows through network of vessels that extend between heart and peripheral tissues; flows through circuits in sequence true or false
true
Both ventricles pump the same volume of blood per minute true or false?
true
Difference in the wall thickness between the left and right ventricles due to the demands placed on them. true or false
true
The innervation by autonomic centers in the brainstem doesn't initiate a heartbeat, but it can increase or decrease the rate of the heartbeat.. true or false
true
The smooth posterior wall of the left atrium contains openings for typically four pulmonary veins. Sometimes two of these vessels fuse prior to reaching the left atrium, thus decreasing the number of openings through the atrial wall. true or false
true
endothelium-lined dense connective tissue cusps that keep blood flowing in one direction by preventing its backflow
valve
inferior chamber, thicker walls, note vessels leave at basal surface
ventricle
Most coronary flow occurs during
ventricular diastole
why are the ventricle walls thicker than the atria walls?
¢Atria- primer pumps and ventricles- power pumps
List the characterisitics of muscle tissue that are different from skeletal muscle tissue
1. The sarcoplasmic reticulum in cardiac muscle is less extensive and not as organized as in skeletal muscle 2.Cardiac muscle has no terminal cisternae, whereas skeletal muscle does. 3. Cardiac muscle lacks the extensive association of sarcoplasmic reticulum and transverse tubules (T-tubules) present in skeletal muscle. 4. In cardiac muscle, T-tubules overlie Z discs instead of the junctions of A bands and I bands as seen in skeletal muscle. 5. The T-tubules in cardiac muscle have a less extensive distribution and a reduced association with SR compared to those in skeletal muscle, allowing for both the delayed onset and prolonged contraction of cardiac muscle tissue.
blood flow circulation through the heart (
1. blood flow into the superior and inferior vena cava 2. enters the right atrium 3. blood passes through the right av tricuspid valve 4. ventricular contraction pushes blood against the av valve causing them to close. the papillary muscles and chordae tendoneae prevent the valve from inverting 5. the blood in the right ventricle is pushed through the semilunar valve called the pulmonary valve through the pulmonary trunk out the pulmonary arteries 6. blood returns thought the pulmonary veins and enter the left atrium 7. blood is forced through the left AV valve called the mitral valve (bicupsid) into the left ventricle. 8. left ventricle contracts forcing the blood through the aortic valve to the ascending aorta
what are the 5 steps of the hearts conducting system
1. muscle impulse is generated at the sinoatrial node. it spread throughout the atria, and to the atrioventricular node via the inernodal pathways 2. AV node cells delay the muscle impluses as it passes to the av bundle 3. the AV bundle conducts the muscle impulse into the interventricular septum 4. within the interventricular septum the left and right bundles split from the atrioventricular bundle 5. the muscle impluse is delivered to purkinje fiber in each ventricle and distributed throughout the ventricular myocardium
the pericardium consist of 3 things
1.fibrous pericardium 2. serous pericardium 3. pericardial cavity
list the Anatomical characteristics that assist with function (3)
1.unidirectional flow of blood- valve prevent back flow 2. side-by-side pump- work at the same rate and pump the same volume of blood 3. develops blood pressure- through contraction and relaxation.
The__________ ___________ normally slows conduction of the impulse as it travels from the atria to the ventricles, providing a delay between activation of the atria and the ventricles.
AV node
The______________ ____________ is located in the floor of the right atrium between the right AV valve and the opening for the coronary sinus.
AV node
what valves are opened during ventricular diastole
AV valves
thin-walled, located superiorly, exterior extension-auricle
Atria
5 steps of cardiac cycle
1. Atrial contraction and ventricular filling 2. Isovolumetric contraction 3. Ventricular ejection 4. Isovolumetric relaxation 5. Atrial relaxation and ventricular filling
functions of the fibrous skeleton in the heart
1. Provides structural support at the boundary between the atria and the ventricles (separates them) 2. Forms supportive fibrous rings to anchor the heart valves 3.Provides a rigid framework for the attachment of cardiac muscle tissue -reinforce myocardium internally and anchors cardiac muscle 4. Acts as an electrical insulator to prevent action potentials in the atria from passing to the ventricles, so that the ventricles do not contract at the same time as the atria
Three major vessels empty into the right atrium:
(1) The superior vena cava drains blood from the head, neck, upper limbs, and superior regions of the trunk; (2) the inferior vena cava drains blood from the lower limbs and trunk; (3) the coronary sinus drains blood from the heart wall.
The serous pericardium may be subdivided into
(1) a parietal layer of serous pericardium that lines the inner surface of the fibrous pericardium, (2) a visceral layer of serous pericardium (also called the epicardium) that covers the outside of the heart. The parietal and visceral layers reflect (fold back) along the great vessels, where these layers become continuous with one another.