T19 Heart Flashcards
1
Q
What type of pump is the heart?
A
A muscular double pump
2
Q
What transports blood to and from the lungs?
A
Pulmonary circuit
3
Q
What transports blood to and from body tissues?
A
Systemic circuit
4
Q
What receives blood from the pulmonary and systemic circuits?
A
Atria
5
Q
What are the pumping chambers of the heart that propels blood toward the pulmonary and systemic circuits?
A
Ventricles
6
Q
How much does the heart weigh?
A
250-350 grams (healthy heart)
7
Q
The heart is the largest organ of the what?
A
Mediastinum (a membranous partition between two body cavities or two parts of an organ, especially that between the lungs)
8
Q
What is the heart located between?
A
The lungs
9
Q
The apex of the heart lies to the ____ of the midline
A
Left
10
Q
The base of the heart is the…
A
Broad posterior surface
11
Q
What are the four “corners” of the heart?
A
Superior right, Inferior right, Superior left, Inferior left
12
Q
What are the 3 heart sulci?
A
Coronary sulcus, Anterior interventricular sulcus, Posterior interventricular sulcus
13
Q
What’s the function of the coronary sulcus?
A
Forms a “crown” by circling boundary between atria and ventricles and contains left and right coronary arteries and coronary sinus (vein)
14
Q
What’s the function of the anterior interventricular sulcus?
A
Marks anterior position over the interventricular septum and contains anterior interventricular artery and great cardiac vein
15
Q
What’s the function of the posterior interventricular
A
Marks posterior position over interventricular septum. Contains posterior interventricular artery and middle cardiac vein.
16
Q
What are the coronary artery branches?
A
Left coronary artery, and right coronary artery branches
17
Q
What makes up the LEFT coronary artery?
A
Circumflex artery, Anterior interventricular artery
18
Q
What makes up the RIGHT coronary artery branches?
A
Marginal artery, Posterior interventricular artery
19
Q
What are 3 examples of serous cavities in the body?
A
Pericardium (heart), pleura (lung) and peritoneum (abdominal)
20
Q
What are serous cavities in the body??
A
- Slit-like space lined by serous membranes
- Parts of the body that do not contain air, but a thin layer of serous fluid that is produced by both the parietal and visceral serous membranes.
21
Q
What does serous fluid do?
A
The slippery serous fluid allows the visceral organs to slide with minimal friction across the cavity wall as they carry out their routine functions
22
Q
What is the parietal serosa?
A
Outer wall of the cavity
23
Q
What is the visceral serosa?
A
Covers the visceral organs
24
Q
What are the two primary layers of the pericardium?
A
Fibrous pericardium and serous pericardium
25
What is the fibrous pericardium?
Strong layer of dense connective tissue
26
What 2 layers is the serous pericardium formed by?
Parietal layer and visceral layer
27
What are the 3 layers of the heart wall?
Epicardium, myocardium, and endocardium
28
What is the epicardium?
Visceral layer of the serous pericardium
29
What is the myocardium?
Consists of cardiac muscle and forms bulk of heart
Surrounding the cardiac muscle cells in the myocardium are connective tissues that form the fibrous skeleton of the heartwhich binds these muscle cells together arranged in elongated circular and spiral patterns
30
What is the endocarium
Endothelium (sheet of simple squamous epithelium) on a layer of connective tissue
Lines the internal walls of the heart chambers & valves
31
What are the three types of heart inflammation and what do they mean?
Endocarditis: inflammation of the endocardium
Myocarditis: inflammation of the myocardium
Pericarditis: inflammation of the pericardium
32
What are the heart chambers?
Right and left atria (superior chambers), interatrial septa, right and left ventricles (inferior chambers), interventricular septa
33
What are the 3 parts of the Right atrium?
Pectinate muscles, fossa ovalis, and crista terminalis
34
What is the pectinate muscles (of the right atrium)?
Ridges inside anterior of right atrium
35
What is the fossa ovalis (of the right atrium)?
Depression in inreratrial septum, remnant of foramen ovale
36
What is the crista terminalis (of the right atrium)?
C-shaped ridge landmark used to locate veins entering right atrium
37
What and from where does the Right Atrium receive blood?
Receives de-oxygenated blood from systemic circuit via the superior and
inferior vena cava and via the coronary sinus (large vein) in posterior part of coronary sulcus
38
What are the 3 internal walls of the right ventricle?
Trabeculae carneae, papillary muscles, chordae tendineae
39
What are the trabeculae carneae?
irregular ridges of muscles along inner surface of ventricle
40
What are the papillary muscles?
Cone shaped muscle projections
41
What are the chordae tendineae?
strong thin bands which
project superiorly from the papillary muscles
to the cusps of the tricuspid AV valve
42
What and from where does the Right ventricle receive blood?
- Receives blood from right atrium through the atrioventricular (tricuspid) valve
- Pumps blood through pulmonary semilunar valve into pulmonary trunk which branches into the right and left pulmonary arteries
43
What and from where does the Left atrium receive blood?
- Receives oxygen-rich blood from lungs through two right and two left pulmonary veins
- Opens into the left ventricle through mitral valve (left atrioventricular valve)
44
What are the internal walls of the left ventricle? (3)
Trabeculae carneae, papillary muscles, and chordae tendineae
45
What does the left ventricle pump blood through and what does it form in the heart?
Pumps blood through systemic circuit via aortic semilunar valve (aortic valve), Forms apex of the heart
46
What is the heart valve structure?
Each valve composed of two to three cusps made of endocardium with connective tissue core
47
Where are the right atrioventricular and left atrioventricular/mitral valve located?
Right atrioventricular (tricuspid/3 cusps) valve and left atrioventricular/mitral (bicuspid/2 cusps) valve between atria and ventricles
48
Aortic and pulmonary valves have how many cusps, where are the cusps?
Aortic and pulmonary valves each have 3 cusps and are at junction of ventricles and great arteries
49
What are the aortic and pulmonary valves called and why?
Semilunar because each of the 3 cusps looks like a crescent moon
50
1 Where is the fibrous skeleton located?
2 What is the fibrous skeleton composed of?
3 What does the fibrous skeleton do?
1 Lies in the plane between the atria and ventricles and surrounds and reinforces all four valves
2 Composed of dense connective tissue
3 Anchors valve cusps
3 Prevents overdilation of valve openings
3 Main point of insertion for bundles of cardiac muscle in the atria and ventricles
3 Supports proper coordination of atrial and ventricular contractions by blocking direct spread of electrical impulses from atria to ventricles
51
What are the steps of blood returning to the heart?
1) Blood returning to the heart fills atria, putting pressure against atrioventricular valves; atrioventricular valves are forced open.
2) As ventricles fill, atrioventricular valve flaps hang limply into ventricles.
3) Atria contract, forcing additional blood into ventricles.
Bottom line: AV valves open, atrial pressure > ventricular pressure
52
What happens when the atrial pressure < ventricular pressure? And what are the steps of this happening?
1) Ventrlcles cicontract, forcing blood against atrioventricular valve cusps.
2) Atrioventricular valves close.
3) Papillary muscles contract and chordae tendineae tighten, preventing valve flaps from everting into atria.
Bottom line: AV valves close, atrial pressure < ventricular pressure
53
What happens when the semilunar valves open?
As ventricles contract and intraventricular pressure rises, blood is pushed up against semilunar valves, forcing them open.
54
What happens when semilunar valves close?
As ventricles relax and intraventricular pressure falls, blood flows back from arteries, filling the cusps of semilunar valves and forcing them to close.
55
What are the heart sounds and what do they mean? "Lub-Dup"
1st sound: "lub" is the closure of the AV valves
| 2nd sound: "dup" is the closure of the semilunar valves
56
What is heart murmur?
Heart sounds produced when blood flows across one of the heart valves that is loud enough to be heart with a stethoscope
57
What is the different between functional vs. pathological heart murmurs?
* A functional murmur or "physiologic murmur" is a benign heart murmur that is primarily due to physiologic conditions outside the heart.
* Pathologic murmurs result from various structural problems, such as narrowing or leaking of valves, or the presence of abnormal passages through which blood flows in or near the heart.
58
What murmur is associated with the pulmonary valve?
Superior left corner
59
What murmur is associated with the aortic valve?
Superior right corner
60
What murmur is associated with the mitral (bicuspid) valve?
Apex
61
What murmur is associated with the tricuspid valve?
Inferior right corner
62
How many heart beats per minute at rest
60-80
63
What is systole?
The higher number of blood pressure. Contraction of a ventricles pushes blood out through aorta and pulmonary trunk arteries (the pulse that is palpable from the radial artery of the wrist is a reflection of the ventricular systole pushing blood through the aorta and downstream arteries)
64
What is diastole?
The lower number of blood pressure. Relaxation of the heart muscle results in expansion of a heart chamber volume as atria and ventricles fill up with blood
65
What is the pathway of blood through the heart?
* Beginning with oxygen-poor blood in the superior and inferior vena cava
* Through right atrium, right ventricle, and pulmonary circuit
* Through left atrium, left ventricle, and systemic circuits
* As blood passes through all structures sequentially (atria contract together, ventricles contract together)
66
What are three types of heart valve abnormalities?
Valve insufficiency or incompetence, Mitral valve prolapse, and valve stenosis
67
What is valve insufficiency of incompetence?
Valves leak because they fail to close properly
68
What is mitral valve prolapse?
Weakness of collagen in valve and/or the chordae tendinae allow one of both cusps to flop into the left atrium during ventricular systole causing some blood to flow back from left ventrical into left atrium, THIS IS MOST COMMON ONE
69
What is valve stenosis?
Valves w narrow openings due to fused or stiffened cusps; the constricted opening does not open maximally causing less blood to flow through the valve
70
Do atria have think or thick walls?
Thin
71
Do ventricles have thick or thin walls?
Thick
72
Are the left ventricular walls thicker or the right ventricular walls? By how much thicker?
Left ventricular walls (bc systemic circuit is longer than pulmonary circuit and offers greater resistance to blood flow). 3x thicker.
73
What does myocardium contain and what surrounds it?
Contains: cardiac muscle cells
| Surrounded by: Connective Tissue
74
How does myocardium contract?
By sliding filament mechanism
75
What are characteristics of cardiac muscle cells?
* Short compared to skeletal muscle fibers
* Branching
* Have one or two nuclei
76
What does cardiac muscle cells contain?
Contain myofibrils with sarcomeres composed of A bands, I bands, H zones, Z discs, M lines, and titin
77
What is endomysium composed of?
Loose fibrous connective tissue
78
What does endomysium do?
Binds adjacent cardiac fibers, Merges with the fibrous skeleton of the heart and thus functions to anchor the muscle cells and facilitate the transmission of contractile forces by muscle cells
79
What are intercalated discs?
complex junctions that join cardiac muscle cells enabling adjacent sarcolemmas to interlock through meshing "fingers"
80
Where are fasciae adherans contained?
Contained in transverse regions and are long desmosome-like junctions that bind adjacent cells together, transmitting the contractile signal to adjacent cells
81
Where are gap junctions contained?
Contained in longitudinal regions and allow ions to pass between cells, transmitting the contractile signal to adjacent cells
82
What is cardiac muscle contraction triggered by?
Ca2+ entering the sarcoplasm (muscle cell cytoplasm)
83
What are the steps of cardiac muscle contraction?
* Small amount of Ca2+ ions from extracellular fluid enter cardiac muscle sarcoplasm through the sarcolemma (muscle cell plasma membrane)
* Signals T tubules and sarcoplasmic reticulum to release stored Ca2+ ions
* Ca2+ ions diffuse into sarcomeres (part of myofibril between two Z discs) which triggers a sliding filament mechanism
84
What is the conducting system?
• Cardiac muscle tissue has intrinsic ability to generate and conduct electrical impulses to signal these same cells to contract rhythmically
• Even if all the extrinsic nerve connections to the heart are severed, the heart continues to
beat rhythmically
85
What is the intrinsic conducting system?
* Consists of a series of specialized cardiac muscle cells (not nervous tissue) that transmit impulses throughout the cardiac musculature
* Sinoatrial (SA) node sets the inherent rate of contraction
86
What consists of the cardiac conducted system?
* SA (sinoatrial) node
* AV (atrioventricular) node
* AV bundle
* Bundle branches
* Subendocardial branches (Purkinje fibers)
87
What does the SA node do?
- SA (sinoatrial) node (pacemaker, which generates impulses)
| - Impulses from SA node transmitted to AV node in inferior part o interatrial septum and pause for 0.1 second
88
What does the AV node do?
AV (atrioventricular) node (Impulse pause at the AV node)
89
What does the AV bundle do?
AV bundle (Connects atria to ventricles)
90
What does the bundle branches do?
Bundle branches (conduct impulses through the interventricular septum)
91
What does the Purkinje fibers do?
Subendocardial branches (Purkinje fibers) (stimulate the contractile cells of bothe ventricles)
92
Overall, What are the conducting system steps in the atria? (Just for reference)
* Sino-atrial (SA) node in wall of right atrium generates impulses and is the heart’s pacemaker
* Impulses from SA node spread in wave through atrial muscle fibers signaling the atria to contract
* Impulses from SA node are also transmitted to the atrial-ventricular (AV) node in inferior part of the interatrial septum and pause for 0.1 second
93
What do impulses from the AV node go through?
Impulses from AV node are rapidly transmitted through the atrioventricular (AV) bundle which connects atria to ventricles
94
What is the conducting system in ventricles?
* Impulses from AV node are rapidly transmitted through the atrioventricular (AV) bundle which connects atria to ventricles
* AV bundle enters the interventricular septum and divides into right and left bundle branches which conduct impulses through the interventricular septum
* Halfway down the septum the bundle branches become subendocardial branches (Purkinje fibers) which extend down to the heart wall apex and up into the ventricular walls
95
What is heart rate altered by?
External controls
96
What can visceral sensory fibers do?
They can perceive cardiac muscle stress in person with ischemic heart disease
97
What decreases heart rate?
Parasympathetic motor branches of vagus nerve
98
What increases heart rate?
Sympathetic motor fibers—from cervical and upper thoracic chain ganglia
99
What controls the autonomic input into the heart rate?
cardiac centers in the reticular formation of the medulla oblongata of the brainstem
100
What does the cardioinhibitory center influence?
Parasympathetic
101
What does the cardioacceleratory center influence?
Sympathetic
102
What do the coronary arteries do?
Provide blood supply to the heart
103
Where do the coronary arteries arise?
Arise from the base of the aorta
104
What are the main branches of the coronary arteries, and what do the branches branch into?
left coronary artery and right coronary artery
• Left coronary artery branches into circumflex artery and anterior interventricular artery
• Right coronary artery branches into marginal artery and posterior interventricular artery
105
What are the treamtnet of artherosclerosis of coronary arteries?
(a) Angioplasty and placement of stent
| (b) Coronary artery bypass graft (CABG) performed on two vessels; double bypass surgery
106
What is heart failure including CHF (conjestive heart failure)?
Progressive weakening of the heart muscle, cannot meet the body's demands for oxygenated blood
107
What is pulmonary arterial hypertension?
Enlargement and potential failure of right ventricle from the elevated pressure in the pulmonary circuit
108
What is a Arrythmias?
Arrythmias = variation from normal heart rate and/or rhythm e.g., fibrillation with has an abnormally fast heart rate (>200) = tachycardia.
Atrial fibrillation and Ventricular fibrillation
109
What is atrial fibrillation?
Impulses circle within atrial myocardium, randomly stimulating AV node, which signals the ventricles to contract irregularly and quickly that causes blood to move irregularly and sluggishly through the heart
110
What is ventricular fibrillation?
* Rapid, random firing of electrical impulses in the ventricle prevents coordinated contraction of the ventricle
* Results from damaged conducting system
* Common cause of cardiac arrest
