The Heart Flashcards
(116 cards)
1
Q
where does the heart lie?
A
within the thoracic cavity within the middle mediastinum
2
Q
what does the middle mediastinum include? So does that mean the heart lies within the pericardium?
A
the pericardium, the heart, and the roots of its great vessels; yes
3
Q
briefly describe the heart and its functions
A
Slightly larger than your clenched fist
Propels blood to all the parts of the body
Right side receives oxygen-poor blood and pumps it to the lungs
Left side receives oxygen-rich blood and pumps it to the body
4
Q
what is the heart supplied and drained by?
A
coronary vessels
5
Q
what is that the heart has that coordinates the movements of the walls of the chambers?
A
intrinsic conduction system
6
Q
the heart can be ascultated, T/F?
A
true
7
Q
what did we say occupies the thorax?
A
heart, lungs, and structures conveying blood and air between them (also contains esophagus)
8
Q
what is the shape of the thoracic cavity?
A
a truncated cone and thoracic skeleton resembles a birdcage
9
Q
what is the floor and what invaginates the thoracic cavity?
A
the floor is formed by the diaphragm, its deeply invaginated inferiorly by the abdominal viscera
10
Q
how is the thorax divided?
A
the central mediastinum and the right and left pulmonary cavities
11
Q
what is the mediastinum?
A
the region between the pulmonary cavities, considered the central compartment of the thoracic cavity
12
Q
what does the mediastinum contain?
A
all thoracic viscera and structures except the lungs – heart, great vessels, pericardium, esophagus, trachea, thymus
13
Q
is the mediastinum highly mobile?
A
Highly mobile region consisting mainly of hollow structures united by loose connective tissue
14
Q
how is the mediastinum divided?
A
superior and inferior with inferior being divided into anterior, middle, and posterior regions
15
Q
what is included in the middle mediastinum?
A
includes the pericardium, heart, and roots of its great vessels (ascending aorta, pulmonary trunk, SVC)
16
Q
what is the landmark dividing superior and inferior mediastinum?
A
the plane of the sternal angle
17
Q
describe the location of the plane of the sternal angle?
A
at the level of the superior border of the pericardium, the bifurcation of the trachea, the end of the ascending aorta, the beginning and end of the arch of the aorta, and the beginning of the thoracic aorta
18
Q
what is the pericardium?
A
a double fibroserous membrane that forms the pericardial sac surrounding the heart and origins of the great vessels
19
Q
*what are the attachments of the pericardium, the external layer?
A
Is continuous inferiorly with the central tendon of the diaphragm – pericardiacophrenic ligament (not separate structures and cannot be dissected apart)
Is continuous superiorly with the tunica adventitia (outer layer) of the great vessels and the pretracheal layer of deep cervical fascia
Is attached anteriorly to the posterior surface of the sternum by sternopericardial ligaments
Is bound posteriorly by loose connective tissue to structures in the posterior mediastinum
20
Q
what does the external layer of the pericardium protect for the heart?
A
it protects the heart against sudden overfilling
21
Q
describe the external layer of the pericardium?
A
fibrous
22
Q
what is the internal surface of the pericardium comprised of?
A
mainly of mesothelium
23
Q
describe the two layers of the internal surface of the fibrous pericardium (external layer)
A
serous pericardium, parietal layer
serous pericardium, visceral layer (this adheres firmly to the eternal surface of the heart known and is also known as the epicardium).
24
Q
what are the great vessels of the heart?
A
aorta, pulmonary trunk and veins, SVC, IVC
25
what supplies the pericardium?
pericardiacophrenic arteries
26
what are the pericardiacophrenic arteries?
branches of the internal thoracic artery
27
what are branches of the internal thoracic artery?
Smaller contributions come from the musculophrenic artery, some small branches of the thoracic aorta, and coronary arteries (visceral layer only)
28
whats the pericardium drained by?
pericardiacophrenic veins into the SVC through brachiocephalic or internal thoracic veins
May also be drained by variable tributaries of the azygos venous system
29
what innervates the pericardium?
Innervated by the phrenic nerve, vagus nerve, and branches from the sympathetic trunks which are vasomotor
30
what is significant to note about innervation of the pericardium by the phrenic nerve?
The phrenic nerve is the primary source of sensory fibers (pain is commonly referred to C3-C5 dermatomes)
31
the sympathetic trunks that also innervate the pericardium are _____?
vasomotor
32
what is the pericardial cavity?
the space within the pericardial sac between the parietal and visceral layers of the serous pericardium
33
what is the pericardial cavity filled with?
a thin layer of serous fluid for frictionless movement of the heart
34
what are the two pericardial recesses?
transverse pericardial sinus and the oblique pericardial sinus
35
where do the two pericardial recesses form?
where the serous pericardium reflects around the roots of the great vessels (form as a result of the folding of the primordial heart tube)
36
what is the transverse pericardial sinus?
a passage between the inflow channels (SVC and pulmonary veins) and the outflow channels (aorta and pulmonary trunk) superior to the atria – surgically significant for cardiac procedures
37
what is the oblique pericardial sinus?
is a wide, pocket-like recess of the pericardial cavity posterior to the base of the heart
38
what is the heart?
a hollow muscular organ located in the middle mediastinum within the pericardial sac and rests on the central tendon of the diaphragm and flanked on either side by the pulmonary cavities
39
what shape is the heart?
conical shape
40
what is the base of the heart?
top portion of the heart, on its superior and posterior surfaces and is anchored by the great vessels. Formed mainly by the left atrium with a portion of the right atrium
41
what is the apex of the heart?
bottom portion of the heart, inferior and to the left, not anchored within the pericardial sac. Located approximately at the 5th intercostal space, projects anteriorly
42
what is the heart generally divided into?
four chambers – two atria and two ventricles
43
what are the extensions of the atria and visible externally?
two small appendages, the left and right auricles
44
what are the first branches of the aorta?
the coronary arteries
45
what do the coronary arteries supply?
supply the myocardium and epicardium (middle layer of cardiac muscle and external layer of visceral serous pericardium)
46
where do the right and left coronary arteries arise?
from the ascending aorta just superior to the right and left cusps of the aortic valve
47
what is the path of the right coronary artery?
it descends within the coronary sulcus around the right side of the heart with four major branches
48
what are the four major branches of the coronary artery?
SA nodal
right marginal
posterior inter ventricular branch
AV nodal
49
what does the SA nodal supply?
supplies right atrium and SA node
50
what does the right marginal supply?
supplies the apex and part of the right ventricle
51
what does the posterior interventricular branch supply?
(posterior descending artery, PDA)– supplies right and left ventricles and posterior third of the IV septum, anastomoses with the IV branch of the left coronary artery near the apex
52
what does the AV nodal supply?
supplies the AV node
53
what is the path of left coronary artery?
arises from the aorta posterior to the pulmonary trunk and divides into two large branches
54
what are the two large branches of the left coronary artery?
anterior inter ventricular artery
| circumflex artery
55
what is the path of the pathway of the anterior inter ventricular artery and its supply?
(left anterior descending, LAD) which descends in the anterior IV sulcus and supplies the anterior aspects of the right and left ventricles and anterior two-thirds of the IV septum including the AV bundle
56
what is the path of the circumflex artery?
runs around the left side of the heart in the coronary sulcus to supply the left atrium and branches into
Left marginal branch – supplies left ventricle
SA nodal in 40% of the population
57
Moving into the Coronary Heart, the large veins of the heart are tributaries for the _____?
coronary sinus
58
in terms of the coronary veins, what is the path of the coronary sinus?
it runs in the posterior coronary sulcus between the left atrium and ventricle
59
in terms of the coronary veins, what vessels does the coronary sinus receive? Also, this valve may prevent the regurgitation of blood into the sinus during the contraction of the atrium.
Receives the great cardiac vein at the coronary sulcus and the middle cardiac vein and small cardiac veins at its right end; thebesian valve
60
in terms of the coronary veins, what artery does the great cardiac vein travel with? what does it drain?
anterior inter ventricular artery ; drains the left atrium and both ventricles
61
in terms of the coronary veins, what does the left posterior ventricular vein drain?
the diaphragmatic surface of the left ventricle
62
in terms of the coronary veins, what is the path of the posterior inter ventricular vein or the middle cardiac vein?
runs in the posterior interventricular groove with the posterior interventricular artery to drain the posterior part of the interventricular septum
63
in terms of the coronary veins, what artery does the small cardiac vein accompany? what does it drain?
the right coronary artery in the atrioventricular groove (coronary sulcus)
drains the posterior right atrium and the right ventricle
64
in terms of the coronary veins, what does the anterior cardiac vein drain?
it drains the anterior surface of the right ventricle and drain directly into the right atrium
65
what are the important coronary veins we studied?
- coronary sinus
- great cardiac vein
- left posterior ventricular vein
- posterior inter ventricular vein or middle cardiac vein
- small cardiac vein
- anterior cardiac vein
66
what are the layers of the heart?
epicardium
myocardium
endocardium
67
what is the epicardium?
the thin outermost layer, is formed by the visceral layer of the serous pericardium (mesothelium)
68
what is the myocardium?
a thick helical layer composed of cardiac muscle, thickest in the ventricles
69
what is the endocardium?
thin inner layer that lines the chambers of the heart and covers the valves (endothelium and subendothelial connective tissue)
70
what is the cardiac skeleton?
made of dense fibrous connective tissue, forms four fibrous annuli (rings) and intervening trigones that separate the chambers of the heart
71
describe the cardiac skeleton?
Keeps the orifices of the AV and semilunar valves patent and prevent them from being overly distended
Provides attachments for the leaflets and cusps of the valves
Provides attachment for the myocardium
Forms an electrical insulator
72
describe the chambers of the heart?
The heart has four chambers and is divided into two sides
– one for pulmonary circulation and one for systemic circulation
The atria are receiving chambers that pump blood into the ventricles
The ventricles are the discharging chambers
The synchronous pumping action of the two sides of the heart constitute the cardiac cycle
73
what are the two types of cardiac valves?
atrioventricular and semilunar
74
what are cusps?
thin leaflets with free inner margins and outer margins attach to the annulus
75
what are the chord tendinae?
attach the free edges to papillary muscles in the ventricles to maintain closure of the valves during ventricular contraction
76
T/F, each cusp attaches to cords from more than one papillary muscle?
True
77
name the AV valves?
the tricuspid valve on the right and the bicuspid (mitral) on the left
78
what is the significance of the semilunar valves?
prevent outflow from ventricles as they fill and backflow into the ventricles after blood is expelled
79
what is the function of papillary muscle contraction?
they contract to put tension on the chordae tendineae just before contraction of the ventricle and during systole in order to resist the pressure generated during contraction of the ventricles (parachute strings)
80
what does the right atrium do?
forms the right border of the heart and receives deoxygenated blood from systemic circulation through the SVC and IVC
81
what is the right auricle of the right atrium?
a conical muscular pouch that projects from the atrium to increase the capacity of the chamber
82
what divides the right atrium?
a muscular ridge ,the crista terminalis (terminal crest) -important because this is where the conducito system lies
83
why is the crista terminales important?
this is where the conducito system lies, on the outside it is called the sulcus terminales
84
this structure is a smooth walled region on the posterior wall that contains the openings of the SVC, IVC, coronary sinus, and anterior cardiac veins?
sinus venarum
85
at what level does the superior part of the right atrium open?
the right 3rd costal cartilage
86
at what level does the inferior part of the right atrium open?
level of the 5th costal cartilage
87
what is the oval, thumbprint sized expression on the interatrial septum?
the oval fossa
88
what can we note of the oval fossa?
a remnant of the oval foramen and its valve through which blood was shunted from right to left atrium in fetal circulation
89
describe the left atrium?
forms the base of the heart, is smaller but thicker walled than the right atrium, and receives four pulmonary veins from the lungs
90
in relation to the left atrium, what makes up the floor of the oval fossa? what about the surrounding ridge?
A seminlunar depression in the interatrial septum; the valve of the oval fossa
91
what is in the interior of the left atrium?
A larger, smooth-walled part and a smaller muscular auricle with pectinate muscles
Four pulmonary veins (two superior, two inferior) entering its smooth posterior wall
A slightly thicker wall than the right atrium
An interatrial septum that slopes posteriorly and to the right
92
what is the largest part of the anterior surface of the heart?
the right ventricle
93
what does the right ventricle form?
forms the largest part of the anterior surface of the heart, a small part of the diaphragmatic surface, and almost the entire inferior border
94
T/F, The right ventricle is smaller and thinner than the left?
True
95
what is the muscular ridge of the right ventricle?
the supra ventricular crest
96
what does the supraventricular crest separate?
that separates the ridged muscular wall of the inflow part of the chamber from the smooth wall of the conus arteriosus
97
what is the conus arteriosus?
the superior region where the ventricle tapers and leads into the pulmonary trunk – also called infundibulum
98
what are the irregular muscular elevations of the interior of the ventricle called?
trabeculae carneae
99
what are the tricuspid valves attached too?
the annulus with tendinous cords that attach to anterior (from anterior wall) and posterior (from posterior wall) papillary muscles on the floor of the ventricle
100
in terms of the right ventricle, what arises from the interventricular septum?
a septal papillary muscle
Anterior – attached to anterior and posterior cusps
Posterior – attached to posterior and septal cusps
Septal – attached to anterior and septal cusps
101
what is the septomarginal trabecula?
it carries a branch of the AV bundle to facilitate coordinated contraction
102
what is the left ventricle?
the thickest-walled chamber of the heart and forms the apex, nearly all the left surface and border, and most of the diaphragmatic surface
103
what two flows the left ventricle divided into?
The inflow portion receives blood from the left atrium, is covered in trabeculae carneae that are finer and more numerous than on the right, and has anterior and posterior papillary muscles that arise from its floor and are larger than those on the right
The outflow portion – the aortic vestibule – is the smooth-walled, non-muscular outflow channel which directs blood to the aorta
104
what are the cusps of the bicuspid valve located in the left ventricle?
anterior and posterior cusps that attach via chordae tendineae to anterior and posterior papillary muscles
105
how does the bloodstream move through the left ventricle?
the bloodstream undergoes two right angle turns which result in a 180 degree change in direction – reversal of flow takes place around the anterior cusp of the mitral valve. Down and right back
106
describe the innervation of the heart?
Autonomic nerves of the cardiac plexus innervate the conduction system of the heart to regulate the rate, but they do not initiate the heartbeat
107
what does the sympathetic innervation of the heart do?
increases the rate and force of contractions by increasing the response of the SA and AV nodes and also allows dilation of the coronary arteries
108
what does the parasympathetic innervation of the heart do?
decreases the rate of contractions and causes vasoconstriction of the coronary arteries
109
what innervates the baroreceptors and the chemoreceptors of the heart
visceral sensory fibers, these also travel with parasympathetic fibers of the vagus nerve and with sympathetic fibers carrying pain sensation to T1-T5 of th spinal cord
110
what is the pacemaker of the heart?
The sinoatrial (SA) node is the pacemaker of the heart and initiates and coordinates the timing of the contraction of heart chambers
111
how fast are impulses transmitted to both atria and the AV node?
a rate of 60-70 bpm
112
where is the SA node?
Located on the external surface of the heart just within the myocardium of the right atrium at the junction with the SVC
113
what supplies the SA node?
Usually supplied by a branch of the RCA (SA nodal)
114
what is the AV node stimulated by?
SA node (myogenic conduction) and transmits impulses to the AV bundle (Bundle of His)
115
describe the pathway of the conduction of the heart?
The atrioventricular bundle (Bundle of His) arises from the cells of the AV node and transmits impulses to the walls of the ventricles
Runs first along the membranous part of the interventricular septum and then divides into right and left bundle branches
The bundle branches descend to the apex on either wide of the muscular part of the septum
Bundle branches end as Purkinje fibers (subendocardial fibers), modified cardiac fibers, which ascend within the muscular walls of the ventricles
116
how does the cardiac cycle work?
The intrinsic conduction system of the heart moderates the cardiac cycle – the coordinated systole (contraction) and diastole (relaxation) of the atria and ventricles
Initial diastole – atria and ventricles are relaxed and the AV and semilunar valves are closed
Late diastole – atria fill, AV valves open, and blood passively flows into ventricles
Stimulation from the SA node initiates contraction of the atria forcing remaining blood into ventricles
As pressure in the ventricles rises above pressure in the atria the AV valves close **LUB**
Stimulation from the AV node and the AV bundles initiates ventricular contraction (ventricular systole)
Rising interventricular pressure forces the semilunar valves to open and blood is ejected from the right ventricle into the pulmonary trunk and from the left ventricle into the aorta
Relaxation of the ventricles (ventricular diastole) causes backflow in the pulmonary trunk and aorta resulting in closure of the pulmonary and aortic valves **DUB**
