Lecture: The Cardiac System Flashcards
1
Q
What are the two layers of pericardium?
A
Parietal (inner) and Visceral (outer)
2
Q
What is the role of the pulmonary circuit?
A
Carries blood to and from gas exchange surfaces of lungs
3
Q
What is the role of the Systemic Circuit?
A
Carries blood to and from the body
4
Q
Blood alternates between which 2 circuits?
A
The pulmonary and the Systemic
5
Q
What are the 3 types of blood vessels?
A
- Arteries 2. Veins 3. Capillaries
6
Q
What is the role of arteries?
A
Carry blood away from the heart
7
Q
What is the role of veins?
A
Carry blood to the heart
8
Q
What is the role of capillaries
A
Networks between veins and arteries
9
Q
Capillaries exchange materials between what two things?
A
Blood and Tissues
10
Q
What materials do capillaries carry between blood and tissues?
A
dissolved gases, nutrients, wastes
11
Q
What are the 4 chambers of the heart?
A
The Right and Left atria, The Right and Left ventricle
12
Q
What occurs in the Right atrium?
A
Collects blood from the systemic circuit
13
Q
What occurs in the Right ventricle?
A
Pumps blood to the pulmonary circuit
14
Q
What occurs in the Left atrium?
A
Collects blood from the pulmonary circuit
15
Q
What occurs in the Left ventricle?
A
Pumps blood to the systemic circuit
16
Q
Where do the great veins and arteries gather?
A
The base of the heart
17
Q
What is the ‘pointed tip’ of the heart
A
The apex
18
Q
What surrounds the heart?
A
The pericardial sac
19
Q
Where does the heart ‘sit’
A
Between two pleural cavities in the mediastinum
20
Q
What is the ‘outer’ layer of the pericardium?
A
The parietal pericardium
21
Q
What is the ‘inner’ layer of the pericardium?
A
The Visceral pericardium
22
Q
Where is the pericardial cavity?
A
Between the visceral layers
23
Q
Where is the pericardial fluid?
A
Inside the pericardial cavity
24
Q
What is the purpose of pericardial fluid?
A
To prevent friction on the heart as it pumps
25
What is the pericardial sac made of?
Fibrous Sac
26
What qualities differentiate the cardiac muscle?
1. It is branched 2. It contains intercalated disks 3.
27
Which part of the heart has THIN walls?
The Atria
28
Which part of the wall is flexible and expandable?
The outer auricle
29
What is the coronary sulcus?
Divides the atria and the ventricles
30
What part of the heart separates the right and left ventricles?
Anterior inter ventricular sulcus and posterior interventricular sulcus
31
What contains the blood vessels of cardiac muscle?
Anterior inter ventricular sulcus and posterior interventricular sulcus
32
Between which ribs does the heart ‘sit’?
Approx between 2-6
33
What 3 parts make up the heart wall?
The epicardium, the myocardium, and the endocardium.
34
Which layer of the heart is the muscular wall?
The myocardium (middle layer)
35
The atrial myocardium wraps around what?
The great vessels
36
Which layer of the heart is made of simple squamous epithelium?
The Endocardium or inner layer
37
What connects cardiac muscle cells?
Intercalated disks
38
What is secured by desmosomes?
Intercalated disks
39
What conveys the FORCE of contraction in cardiac muscle?
Intercalated disks
40
Intercalated disks are linked by what?
Gap junctions
41
Describe the nucleus of a cardiac muscle cell:
Single and central
42
Muscle cells are abundant in what?
Mitochondria (25% of total cell volume)
43
What is the role of the Interatrial septum?
Separates the atria
44
What is the role of the Interventricular septum?
Separates ventricles
45
What valves connect the right atrium to the right ventricle and the left atrium to the left ventricle?
The AV valves
46
Which valves contain the bicuspid and tricuspid valves?
The AV valves
47
Which valves permit blood flow from atria to the ventricles?
The AV valves
48
Where do the Superior and Inferior Vena Cava open to?
The right atrium
49
The right atrium receives blood from the head neck and upper limbs and chest via what valve?
The Superior vena cava
50
The right atrium receives blood from the trunk viscera and lower limbs via what valve?
The Inferior vena cava
51
Other than the vena cava, how does blood enter the right atrium?
Via the coronary sinus
52
What returns blood to the coronary sinus?
Cardiac veins
53
Where is the foramen ovale?
The right atrium
54
What happens to the foramen ovale after birth?
It closes and becomes the fossa ovalis.
55
What does the foramen ovale connect?
The two atria
56
Where are the pectinate muscles located?
The right atrium
57
What do chordae tendinae attach?
Papillary muscles to the right ventricle
58
What is the role of the chordae tendinae?
Prevents the valve from opening backwards.
59
Which valve is the RIGHT AV valve
The tricuspid valve
60
The tricuspid valve opens from ____ to _____
Right Atrium to Right Ventricle
61
What is the role of the tricuspid valve?
To prevent back flow
62
What is Trabeculae carneae?
Muscular ridges on internal surface of right and left ventricle
63
What is the role of the motor band on the Trabeculae carnae?
coordinates contractions of cardiac muscle cells
64
Where is the Conus arteriosus and where does it lead?
Superior end of right ventricle. Leads to pulmonary trunk
65
Pulmonary trunk divides into what?
2 left and right pulmonary arteries
66
Blood passes through what when passing from the right ventricle to the pulmonary trunk?
Through the pulmonary valve
67
Which valve has 3 semilunar cusps?
The pulmonary valve
68
What veins deliver blood to the left atrium?
Left and right pulmonary veins
69
Through what valve does blood pass from the left atrium to the left ventricle?
The LEFT AV valve (mitral, biscupid)
70
Which chamber of the heart is the most powerful?
The left ventricle
71
Which ventricle lacks a moderator band?
The left ventricle
72
The aortic valve connects which chamber to what?
The left ventricle to the ascending aorta
73
What are the 3 parts of the aorta?
The ascending aorta the aortic arch and the descending aorta
74
Which ventricle is pouch shaped and which ventricle is round?
Right: pouch shaped Left: round
75
Which valves close due to blood pressure during ventricular contraction
Atrioventricular Valves (AV)
76
What prevents the valves from swinging into atria
Papillary muscles tensing the chordae tendineae
77
Which 2 valves make up the semi lunar valves?
Pulmonary and aortic tricuspid valves
78
Which valves receive no muscular support?
The semi lunar valves
79
The semi-lunar valves prevent back flow from where?
The pulmonary trunk (pulmonary) and aorta (aortic) into ventricles.
80
What are the aortic sinuses?
They are sacs that prevent valve cusps from sticking to the aorta
81
Where are the aortic sinuses?
At the base of the ascending aorta.
82
What causes the semilunar valves to close?
The cusps fill with blood
83
What structure provides physical support cardiac muscle fibers?
the Cardiac (Fibrous) Skeleton
84
What supplies the heart itself with blood?
Left and right coronary arteries and cardiac veins
85
Where do the coronary arteries orginate?
The aortic sinuses.
86
2 main branches of the coronary artery are?
The circumflex artery and the Anterior interventricular artery
87
What is the role of the Great cardiac vein?
Drains blood from area of anterior interventricular artery into coronary sinus
88
What is the role of the Anterior cardiac veins
Empties blood into the right atrium
89
What is the role of the posterior middle and small cardiac vein?
Empty into great cardiac vein or coronary sinus
90
In what order to the parts of the heart contract when beating?
The atria, followed by the ventricles.
91
What are the 2 types of cardiac muscle cells?
1. Conducting system (coordinates heartbeat) 2. Contractile cells (produces contractions that propel blood)
92
What stimulates the contraction of the heart?
Electrical impulses
93
What is Automaticity?
Automatic muscle contractions
94
What are the 3 structures of the conducting system?
1. Sinoatrual (SA) node 2. Atrioventricular (AV) node 3. Conducting cells (throughout myocardium)
95
What is prepotenial?
Resting potential of conducting cells.
96
What node establishes the heart rate?
SA node depolarizes, establishing heart rate.
97
How many action potentials are generated by the SA Node per minute?
80-100
98
What slows the heart rate?
Parasympathetic stimulation
99
How many action potentials are generated by the AV node per minute?
40-60
100
Which node is in the posterior wall of the right atrium?
The SA node
101
Which node contains pacemaker cells?
The SA node
102
Where is the AV node located?
The floor of the right atrium
103
Which node receives impulses from the SA Node?
The AV node
104
Where does atrial contraction begin?
The AV node
105
How long is the delay at the AV node?
100 msec
106
Where is the AV bundle?
The septum
107
Where does the AV bundle lead impulses?
The moderator band and left and right bundle branches
108
Where do Purkinje fibers receive impulses from?
The AV bundle
109
How does ventricular contract begin?
The purkinje fibers distribute impulse through the ventriclular myocardium as the atrial contraction completes.
110
What is Bradycardia?
Abnormally slow heart rate
111
What is Tachycardia?
Abnormally high heart rate
112
What is Electrocardiogram?
A device that uses electrodes to record of electrical events in the heart and detect Abnormal patterns and diagnose damage
113
What is ectopic pacemaker?
An excitable group of cells that causes premature heart beat outside the normally functioning SA node of the heart.
114
What is denoted by the P wave on an EKG?
Atria depolarizes
115
What is denoted by the QRS complex on an EKG?
Ventricles depolarize
116
What is denoted by the T wave on an EKG?
Ventricles depolarize
117
Where does the P-R interval start and end on an EKG?
Starts at atrial depolarization and ends at the start of the QRS complex
118
Where does the Q-T interval start and end on an EKG?
Starts and ventricular depolarization and ends at ventricular repolarization.
119
What is the resting potential of a ventricular cell?
About 90mV
120
What is the resting potential of an atrial cell?
About 80mV
121
What is the difference between Absolute refractory period and Relative refractory period?
1. Long, cardiac muscle cells can NOT respond 2. Short, response depends on degree of stimulus
122
Length of cardiac action potential in ventricular cell?
250-300 msecs
123
What ion increases to produce contraction of cardiac muscle?
Calcium Ions
124
What 3 steps provide aerobic energy for the heart?
1. Mitochondrial breakdown of fatty acids and glucose 2. Oxygen from hemoglobin 3. Cardiac muscles store oxygen in myoglobin
125
What is a cardiac cycle?
Includes contraction and relaxation of 1 heartbeat
126
What is systole?
Contraction of the heart
127
What is Diastole?
Relaxation of the heart
128
Blood pressure does what during systole?
Rises
129
Blood pressure does what during diastole?
Falls
130
How long is the cardiac cycle and what bpm does it produce?
800 msecs, 75 bpm
131
What parts of the cardiac cycle shorten when the heart rate increases?
All parts but especially diastole.
