Learning Outcome 3 Cardiovascular System Flashcards
1
Q
Where is the heart located within the mediastinum?
A
The human heart is located within the thoracic cavity, medially between the lungs in the space known as the mediastinum.
2
Q
Where is the base of the heart?
A
The base of the heart is located at the level of the third costal cartilage,
3
Q
The sac around the heart is known as the ______________, and it both protects
the heart and helps to maintain its position within the thorax
A
pericardial sac (Pericardium)
4
Q
known as the visceral pericardium, is the outer layer of
the heart wall
A
(epicardium) – innermost layer, simple squamous epithelium & areolar CT
5
Q
What is responsible for secreting the serous fluid found in the pericardial cavity?
A
Parietal and Visceral Pericardium - reduces friction between the heart and surrounding structures during heart contractions.
6
Q
Heart Wall Layers
A
- Epicardium (Outer)
- Myocardium (middle)
- Endocardium (Inner)
7
Q
The thickest layer of the heart, and the layer that is responsible for pumping is
A
Myocardium
8
Q
Which chamber is more muscular, the left or the right ventricle? Why?
A
The left ventricle is more muscular because it pumps oxygenated blood throughout the entire body at a higher pressure
9
Q
The “ear like” superficial extension of the atria are known as
A
Auricle
10
Q
Deep groove divides atria and ventricles
A
Coronary sulcus
11
Q
Anterior and posterior interventricular sulci
A
Grooves that divide the right and left ventricles anteriorly and posteriorly
12
Q
The upper chambers of the heart are known as the
A
Atrium
13
Q
The ____________ are the lower chambers of the heart, and the primary
pumping chambers
A
Ventricles
14
Q
The pulmonary circuit transports deoxygenated blood to, and oxygenated blood
from the ____________.
A
lungs
15
Q
The ___________ _____________ transports oxygenated blood to the body and
returns deoxygenated blood back to the heart
A
systemic circuit
16
Q
Upon contraction the right ventricle pumps blood into the _________
_________ which bifurcates into the left and right pulmonary arteries.
A
Pulmonary Trunk
17
Q
The pulmonary arteries deliver blood to the lungs, and through gas exchange
this blood gets oxygenated at the ___________ ______________.
A
Pulmonary Capillaries
18
Q
After oxygenation, the blood is returned to the heart through the
A
Pulmonary Veins
19
Q
The pulmonary veins conduct blood into the _______________
A
The pulmonary veins conduct blood into the left atrium, which pumps the blood into the left ventricle, which in turn pumps oxygenated blood into the aorta and on to the many branches of the systemic circuit.
20
Q
Blood returns to the heart, and specifically the right atrium, via the ________
__________ ___________ and __________ __________ _______________.
A
superior vena cava and the inferior vena cava, which return blood to the right atrium then to the right ventricles
21
Q
What structure divides the left and right atria?
A
Interatrial septum
22
Q
What is the fossa ovalis, and why was the foramen ovale necessary in the fetal
heart?
A
Fossa ovalis - A pale colored depression that remains in place of the foramen after birth
Foramen ovale
* Found in fetal heart
* Opening in interatrial septum so blood flows from right atrium to left atrium
23
Q
What structure divides the left and right ventricle?
A
Interventricular septum
24
Q
How is this structure different than the interatrial septum?
A
the interatrial septum bears an oval-shaped depression known as the fossa ovalis,
Between the two ventricles is a second septum known as the interventricular septum. Unlike the interatrial septum, the interventricular septum is normally intact after its formation during fetal development. It is substantially thicker than the interatrial septum, since the ventricles generate far greater pressure when they contract.
25
The atrioventricular septum contains openings to allow blood to flow, but only
in one direction due to the presence of ___________.
Valve
26
Valves between the atria and ventricles are known as _____________
atrioventricular valves
27
Valves between the ventricles and the pulmonary trunk or aorta are the
semilunar valves
28
Due to the openings present, the atrioventricular septum is reinforced by dense
connective tissue known as the ______________ ________________
cardiac skeleton
29
In addition to the deoxygenated blood supplied by the superior and inferior
vena cavae, the right atrium also receives blood from the coronary circulation
via the _____________ _______________
Coronary Sinus
30
The inferior vena cava drains blood from what part of the body?
Lower Body
31
The _____________ __________ is muscle that lines the auricle and anterior
surface of the right atrium.
pectinate muscle
32
Contains the right atrioventricular valve (tricuspid)
Right Atrium
33
Pectinate muscles
prominent muscular ridges, found in the atrial wall and inner surface of the right auricle (RIGHT ATRIUM)
34
Trabeculae carneae
Muscular ridges on inside of ventricles
35
Contains the left atrioventricular valve (bicuspid or mitral valve)
Left Atrium
36
All vessels entering & leaving right side of the heart contain
Deoxygenated Blood
37
Deoxygenated blood is returned from the body to the RA through 3 vessels:
* Superior vena cava (SVC) – drains blood from upper body
* Inferior vena cava (IVC) – drains blood from lower body
* Coronary sinus – drains blood from myocardium
38
Blood passed through the tricuspid valve from the _______________ and into the ______________
Blood passed through the tricuspid valve from the Right atrium and into the right Ventricles
39
Deoxygenated blood leaves the RV through the pulmonary valve and into the
pulmonary trunk which branches into the left & right pulmonary arteries
which go the lungs
40
Blood is _____________ as it passes through the lungs
oxygenated
41
4 vessels (pulmonary veins) send oxygenated blood from the lungs to the
left atrium (LA)
42
All vessels entering & leaving the left side of the heart contain
oxygenated blood
43
How many Pulmonary veins return oxygenated blood from the lungs to the LA
4
44
Blood passes through the ____________ into the LV
bicuspid (mitral valve)
45
Oxygenated blood leaves the LV through the aortic valve into the ________
Aorta
46
Blood in the ________ delivers oxygenated blood to the body
Aorta
47
3 vessels ____________ return deoxygenated blood from the body back to the RA
* Superior vena cava (SVC) – drains blood from upper body
* Inferior vena cava (IVC) – drains blood from lower body
* Coronary sinus – drains blood from myocardium
48
The right ventricle receives blood from the ___________ __________.
Right Atrium
49
What valve separates the right atrium from the right ventricle?
tricuspid valve
50
What do the chordae tendineae, in conjunction with the papillary muscles,
prevent from happening?
The chordae tendineae and papillary muscles work together to stabilize the AV valves, ensuring one-way blood flow from the atria to the ventricles and preventing backflow during contraction
51
______________ _____________ are the ridges of cardiac muscle found in the
left and right ventricle.
Trabeculae carneae
52
Upon contraction the right ventricle ejects blood into what vessel?
Pulmonary Trunk
53
What vessels return oxygenated blood from the lungs back to the left atrium of
the heart?
pulmonary veins
54
What valve is found between the left atrium and left ventricle?
bicuspid (mitral valve)
55
The right atrioventricular valve is also known as the __________ ________
because it has three flaps
Tricuspid Valve
56
The ______________ semilunar valve is found between the right ventricle and
pulmonary trunk.
Pulmonary
57
Where is the mitral, or bicuspid valve located in the heart?
Located at the opening between the left atrium and left ventricle
58
When the bicuspid and tricuspid valves are open blood flows from the
__________ into the _______________.
Left Atrium into the Left Ventricle
59
When the semilunar valves are open blood flows from the _____________ to
the pulmonary trunk and aorta.
Ventricles
The right ventricle pumps blood through the pulmonary semilunar valve into the pulmonary trunk (to the lungs).
The left ventricle pumps blood through the aortic semilunar valve into the aorta (to the body).
60
What are cardiomyocytes?
61
What circulation supplies cardiomyocytes with blood?
Coronary arteries
62
What is the purpose of coronary arteries?
supply blood to the myocardium and other components of the heart.
63
Where are epicardial coronary arteries found?
Coronary vessel branches that remain on the surface of the artery and follow the sulci
64
Where is the circumflex artery located?
arises from the left coronary artery and follows the coronary sulcus to the left.
65
What does the name anterior interventricular artery tell you about its location?
also known as the left anterior descending artery (LAD), is the second major branch arising from the left coronary artery. It follows the anterior interventricular sulcus around the pulmonary trunk.
66
What is an anastomosis? When would an anastomosis be beneficial?
an area where vessels unite to form interconnections that normally allow blood to circulate to a region even if there may be partial blockage in another branch. The anastomoses in the heart are very small. Therefore, this ability is somewhat restricted in the heart so a coronary artery blockage often results in death of the cells (myocardial infarction) supplied by the particular vessel.
67
What part of the heart is supplied with blood by the marginal arteries?
supply blood to the superficial portions of the right ventricle.
68
What purpose do coronary veins serve?
drain the heart and generally parallel the large surface arteries
69
Blood from the great, middle, small, and anterior cardiac veins all return their
deoxygenated blood to what chamber of the heart?
Right Atrium
70
Drains blood from the cardiac veins into the RA
Coronary Sinus
71
Carry blood away from capillaries in the heart tissue
Cardiac Veins
72
The two types of cardiac muscle cells
1. Myocardial contractile cells (99%)
* Produce contractions to propel blood
2. Myocardial conducting cells (1%)
- form the conduction system of the heart.
73
Autorhythmicity
Cardiac muscles contract automatically without neural or hormonal stimulation
74
Cardiac Muscle Cells
* Shorter, branched fibers, involuntarily controlled
* Typically, 1 nucleus/cell, many mitochondria
* Striated (sarcomeres)
* Cells joined by intercalated discs:
* Desmosomes, tight junctions and gap junctions
* Synchronize contractions
* Hold cells together during the strong muscle contractions
* Metabolism is entirrely aerobic using glucose and fatty acids to produce ATP
75
Intercalated discs
A junction between two adjoining cells is marked by a critical structure called an intercalated disc, which helps support the synchronized contraction of the muscle
- The sarcolemmas from adjacent cells bind together at the intercalated discs.
76
What are the components of the conduction system of the heart?
* Sinoatrial Node (SA Node) (aka pacemaker)
* Atrioventricular Node (AV Node)
* Atrioventricular Bundle (AV bundle of His)
* Right and left bundle Branches
* Purkinje Fibers
77
Where is the sinoatrial node found within the heart?
* Found in the posterior wall of the right atrium near the opening of the SVC
- It initiates the sinus rhythm
- * Fibers are continuous with the conducting cells (internodal
pathways)
78
The sinoatrial node is the pacemaker of the heart, and as such it initiates the
__________ ___________ or the electrical pattern that leads to contraction of
the heart.
Cardiac Impulses
79
What role does the atrioventricular septum play in the conduction pathway? In
other words, what does it prevent?
The septum prevents the impulse from spreading directly to the ventricles without passing through the AV node.
80
Where is the AV node located in the heart?
located in the inferior portion of the right atrium within the atrioventricular septum.
81
AV Node
* Provides the only pathway between atrial and ventricular conducting cells
* Impulse is delayed by junctional fibers & AV node itself which allows
time for complete atrial systole (contraction) and ventricular filling
82
atrioventricular bundle also known as
AV Bundle of His
83
The atrioventricular bundle passes through which septum of the heart?
proceeds through the interventricular septum before dividing into two atrioventricular bundle branches
84
What part of the heart do the different atrioventricular bundle branches supply?
Which is larger, and why?
Left and Right Ventricles
- the left ventricle is much larger than the right,
85
What is the role of the Purkinje fibers?
* Carry impulses to all parts of the ventricular myocardial cells
* Allows for complete ventricular systole (contraction)
86
What structure controls the heartbeat?
SA Node
87
Parasympathetic innervation
* Cardioinhibitory center via vagus nerve (CN X)
* Decreases HR but not force of contraction
88
Sympathetic innervation
* Cardioacceleratory center via spinal nerves (T1-T5)
* Increases HR and force of contraction
89
Homeostatic Mechanism
Sensory input
* Baroreceptors (monitor blood pressure) and chemoreceptors (monitor, pH, pCO2, pO2)
Control center
* Cardiac center in medulla oblongata
* contains cardioinhibitory & cardioacceleratory centers
Cardiac activity modified
* Heart rate and force of contraction
90
The homeostatic mechanism which controls heart rate and force of
contraction.
Cardiac activity modified
91
What causes the SA node to have an unstable resting membrane potential?
* Na+ tends to leak into SA node between heartbeats causing spontaneous depolarization
92
What is the resting potential of the SA node?
-60mV
93
What is the threshold value of the SA node?
-40mV
94
Once threshold (-40mV) is reached:
* Depolarization:
* Calcium channels open, allows for rapid entry of Ca2+
depolarizing the cell to approximately +15mV
95
Repolarization:
* At +15mV - Calcium channels close, K+ channels open, K+
rushes out, stops the AP
96
hyperpolarization
Resting potential drops from –60mV to –70mV
97
Compare which ions move and their direction of movement during
depolarization and repolarization of an action potential in the SA node.
Na+ Into the cell −60 mV up to about –40 mV.
Ca+ Into the Cell Depolarization
K+ move out Repolarization until -60mV and then Na+ channels open and it starts over
98
What is the resting membrane potential of atrial cells? Of ventricular cells?
* Resting potential of atrial cells -80 mV
* Resting potential of ventricular cells -90 mV
99
Describe what is happening in each of the phases of the action potential
(depolarization, plateau, repolarization) in cardiac muscle cells
* Threshold value for ventricular muscle cells -75 mV
Rapid depolarization:
* Fast Na+ channels open at -75 mV (threshold), Na+ rushes into cell
* Cell depolarizes to +30 mV
Plateau:
* At +30 mV Na+ channels close, Ca2+ channels open, Ca2+ enters sarcoplasm
* A few K+ channels open, some K+ exits the cell
* At 0 mV, Ca2+ channels close
Repolarization:
* At 0 mV, Ca2+ channels close
* K+ channels open and K+ rushes out of the cell
* Cell returns to -90 mV
Refractory periods:
* Absolute ~200 msec
* Relative ~50 msec
100
What does the long refractory period in cardiac muscle cells allow time for?
since the heart muscle must contract to pump blood effectively and the contraction must follow the electrical events. Without extended refractory periods, premature contractions would occur in the heart and would not be compatible with life.
101
What ion movement allows for the plateau phase seen in cardiac contractile
cells?
ca2+
102
P wave represents
Depolarization of the atria
103
QRS complex represents
the depolarization of the ventricles,
104
T wave represents
the repolarization of the ventricles.
105
How long is the cardiac cycle?
* One complete heartbeat
* atria contract, atria relax, ventricles contract, ventricles relax
-The period of time that begins with contraction of the atria and ends with ventricular relaxation is known as the
106
What is systole? What is diastole?
Systole
* Contraction of the heart chamber (ejecting blood)
Diastole
* Relaxation of the heart chamber (filling with blood)
107
CARDIAC CYCLE
108
During atrial systole blood flows from what chamber to what chamber in the
heart?
Right atrium → Right ventricle (through the tricuspid valve)
Left atrium → Left ventricle (through the bicuspid/mitral valve)
109
What valves are open and/or closed during isovolumetric contraction?
Cuspid and semilunar valves CLOSED
110
What valves are open and/or closed during isovolumetric relaxation?
* Cuspid and semilunar valves CLOSED
111
What causes heart sounds?
Produced by the closing of heart valves
112
What is the difference between lub (S1) and dub (S2)?
First heart sound:
* ‘lub’ or S1
* Produced by the closing of the atrioventricular valves
Second heart sound:
* ‘dub’ or S2
* Produced by the closing of the aortic and pulmonary semilunar valves
113
What is cardiac output and how is It calculated?
* CO = amount of blood pumped by a single ventricle in one minute
* CO = HR x SV
114
What is the amount of blood pumped by each ventricle per beat?
Stroke Volume - Normal range for SV would be 55–100 mL.
115
What are the factors affecting heart rate? How does each factor alter heart rate
specifically?
Excercise, Age, Hormones
116
What are the factors affecting stroke volume? How does each factor alter stroke
volume specifically? How does each factor affect the preload, contractility of the
heart and the afterload?
117
What is the average stroke volume in ml?
SV = ~ 70 ml
118
What happens to heart rate and stroke volume during exercise?
Increases
119
What is autonomic tone?
During rest, both centers provide slight stimulation to the heart,
120
What is a cardiac reflex?
A cardiac reflex is an automatic heart response to changes in blood pressure, oxygen levels, or venous return
121
According to the atrial or Bainbridge reflex, if increased venous return stretches
the atria what will reflexively happen to heart rate?
Increase HR
122
Which blood vessels carry blood away from the heart under high pressure?
Arteries
123
* Drain blood from capillaries, have valves
* Carry blood under relatively low pressure back to the heart
Veins
124
Chemical and gaseous exchange between blood and tissues
Capillaries
125
What are the three types of blood vessels and why is each type important?
1. Arteries
2. Capillaries
3. Veins
126
Lumen
Space inside vessel
127
What are the three layers (tunics) found in the walls of blood vessels?
* tunica intima – inside layer
* tunica media – middle layer, contains smooth muscle
* tunica externa – outer layer
128
* Smaller lumen
* Thicker middle layer
* No valves
Arteries
129
* Contain only the tunica interna (simple squamous epithelium)
Capillaries
130
* Larger lumen
* Thinner middle layer, thicker outer layer
* Have valves
Veins
131
What is the vasa vasorum?
* “Vessels of vessels”
* Walls of large blood vessels contain small arteries and veins to supply the smooth muscle cells and fibroblasts of the tunica media and tunica externa
132
What are the three types of arteries in the body and what is the function of each type?
1. Elastic arteries (Conducting)
2. Muscular arteries (Distribution)
3. Arterioles (Resistance vessels)
133
Elastic Arteries (Conducting)
* Largest arteries located close to the heart
* Transport large volumes of blood AWAY from heart
* Large amounts of elastic fibers in all tunics, especially tunica media, allow the vessels to tolerate pressure changes to keep blood flow continuous
* Examples - pulmonary trunk, aorta, brachiocephalic, common carotid arteries, subclavian arteries, common iliac arteries
134
Muscular arteries (Distribution)
* Medium sized arteries
* More smooth muscle cells than elastic fibers which allows for better vasoconstriction/vasodilation
* Distribute blood to body regions and organs
* Examples - brachial arteries, anterior tibial arteries, coronary arteries, inferior mesenteric arteries
135
Arterioles (Resistance vessels)
* Smallest arteries that branch off an artery & decrease in size to become capillaries
* Create the force opposing blood flow
* Diameter changes due to:
* Local conditions
* Endocrine stimulation
* Sympathetic stimulation
136
ONLY blood vessels that allow exchange between blood and
surrounding interstitial fluids (2 way exchange)
Capillaries
137
What are the three types of capillaries? What is the function of each type?
* Continuous
* Fenestrated
* Sinusoids
138
What is a metarteriole? What is a capillary bed?
- One arteriole (metarteriole) branches into dozens of capillaries
- Capillaries function together as a group, forming capillary beds
139
What is the difference between veins and venules?
Venules
* Thin walled vessels that drain blood from capillaries to veins
Veins
* Take blood to the heart under relatively low pressure
140
