The Cardiovascular System: The Heart Flashcards
1
Q
Thoracic cavity between two lungs
A
~2/3 to left of midline
2
Q
surrounded by pericardium: (2 parts)
A
- Fibrous pericardium
- serous pericardium
3
Q
Inelastic and anchors heart in place
A
Fibrous pericardium
4
Q
Inside is ___________ - double layer around heart
A
serous pericardium
5
Q
layer fused to fibrous pericardium
A
Parietal
6
Q
Inner ___________ layer adheres tightly to heart
A
visceral
7
Q
Filled with _____________ - reduces friction during beat.
A
pericardial fluid
8
Q
Heart Wall
A
Epicardium
Myocardium
Endocardium
9
Q
outer layer
A
Epicardium
10
Q
cardiac muscle
A
Myocardium
11
Q
Responsible for the pumping action of the heart
A
Myocardium
12
Q
makes up approximately 95% of the heart wall
A
Myocardium
13
Q
thin layer of endothelium
A
Endocardium
14
Q
provides a smooth lining for the chambers of the
heart and covers the valves of the heart
A
Endocardium
15
Q
“itis”
A
Inflammation
16
Q
is an inflammation of the myocardium that usually occurs as a complication of a viral infection, rheumatic fever, or exposure to radiation or certain chemicals or medications.
A
Myocarditis
17
Q
refers to an inflammation of the endocardium and typically involves the heart valves. Most cases are caused by bacteria (bacterial endocarditis).
A
Endocarditis
18
Q
Tx of Myocarditis and Endocarditis
A
Tx- intravenous antibiotics
19
Q
Chambers of the Heart
A
• 4 chambers
• 2 upper chambers = Atria
• 2 lower chambers = ventricles
• Wall thickness depends on work load
20
Q
receive blood from blood vessels returning blood to the heart, called _______
A
veins
21
Q
eject the blood from the heart into blood vessels called ___________
A
arteries
22
Q
• Atria thinnest
• Right ventricle pumps to lungs & thinner than left
A
Wall thickness depends on work load
23
Q
Forms the right border of the heart and receives blood from three veins:
A
the superior vena cava,
inferior vena cava, and
coronary sinus.
24
Q
thin partition between the right left atrium
A
interatrial septum
25
A prominent feature of this septum is an oval depression called the __________, the remnant of the ________, an opening in the interatrial septum of the fetal heart that normally closes soon after birth
fossa ovalis
foramen ovale
26
blood passes from the right atrium into the right ventricle
tricuspid valve
27
• Forms the right border of the heart and receives blood from three veins: the superior vena cava, inferior vena cava, and coronary sinus.
• interatrial septum - thin partition between the right left atrium
• A prominent feature of this septum is an oval depression called the fossa ovalis, the remnant of the foramen ovale, an opening in the interatrial septum of the fetal heart that normally closes soon after birth
• tricuspid valve - blood passes from the right atrium into the right ventricle
Right Atrium
28
• forms most of the anterior surface of the heart.
• inside of the right ventricle contains a series of ridges formed by raised bundles of cardiac muscle fibers called trabeculae.
• interventricular septum – separate right ventricle from the left ventricle
• blood passes from the right ventricle through the pulmonary valve into a large artery called the pulmonary trunk, which divides into right and left pulmonary arteries and carries blood to the lungs.
Right Ventricle
29
forms most of the anterior surface of the heart.
Right Ventricle
30
inside of the right ventricle contains a series of ridges formed by raised bundles of cardiac muscle fibers called __________
trabeculae.
31
separate right ventricle from the left ventricle
interventricular septum
32
blood passes from the right ventricle through the _________ into a large artery called the ___________, which divides into right and left pulmonary arteries and carries blood to the lungs.
pulmonary valve
pulmonary trunk
33
• receives blood from the lungs through four pulmonary veins.
• Blood passes from the left atrium into the left ventricle through the bicuspid (mitral) valve.
• It is also called the left atrioventricular valve.
Left Atrium
34
receives blood from the lungs through four pulmonary veins.
Left Atrium
35
Blood passes from the left atrium into the left ventricle through the ____________
bicuspid (mitral) valve.
36
It is also called the left atrioventricular valve.
Left Atrium
37
• the thickest chamber of the heart, averaging 10–15 mm
• blood passes from the left ventricle through the aortic valve into the ascending aorta.
Left Ventricle
38
the thickest chamber of the heart, averaging 10–15 mm
Left Ventricle
39
blood passes from the left ventricle through the _________ into the ascending aorta.
aortic valve
40
• Superior & inferior Vena Cavae
— Delivers deoxygenated blood to R. atrium
from body
— Coronary sinus drains heart muscle veins
• R. Atrium -> R. Ventricle
• pumps through Pulmonary Trunk
• -> R & L pulmonary arteries
• -> lungs
Great Vessels Of Heart-Right
41
• Pulmonary Veins from lungs
— oxygenated blood
• -> L. atriumè Left ventricle
• -> ascending aorta -> body
• Between pulmonary trunk & aortic arch is ligamentum arteriosum (fetal ductus arteriosum remnant) - which connects the arch of the aorta and pulmonary trunk.
Great Vessels Of Heart-Left
42
Pulmonary Veins from lungs
oxygenated blood
43
Between pulmonary trunk & aortic arch is _____________(fetal ductus arteriosum remnant) - which connects the arch of the aorta and pulmonary trunk.
ligamentum arteriosum
44
Designed to prevent back flow in response to pressure changes
Valves
45
Between atria and ventricles
Atrioventricular (AV) valves
46
Right
tricuspid valve (3 cusps)
47
Left
bicuspid or mitral valve
48
near origin of aorta & pulmonary trunk
Semilunar valves
49
valves respectively
Aortic & pulmonary
50
• Designed to prevent back flow in response to pressure changes
• Atrioventricular (AV) valves
— Between atria and ventricles
• Right = tricuspid valve (3 cusps)
• Left = bicuspid or mitral valve
• Semilunar valves near origin of aorta & pulmonary trunk
• Aortic & pulmonary valves respectively
Valves
51
• narrowing of a heart valve opening that restricts blood flow is known as stenosis.
• mitral stenosis - scar formation or a congenital defect causes narrowing of the mitral valve.
• Mitral valve prolapse (MVP) backflow of blood from the left ventricle into the left atrium
• aortic stenosis - aortic valve is narrowed, and in aortic insufficiency there is backflow of blood from the aorta into the left ventricle.
• Rheumatic fever - acute systemic inflammatory disease that usually occurs after a streptococcal infection of the throat.
Heart Valve Disorders
52
• Blood flow through vessels in myocardium = coronary circulation
• Left & right coronary arteries
— Branch from the ascending aorta and supply
oxygenated blood to the myocardium
• Most of the deoxygenated blood from the myocardium drains into a large vascular sinus in the coronary sulcus on the posterior surface of the heart, called the coronary sinus
• Empties into right atrium
Blood Supply Of Heart
53
Blood flow through vessels in myocardium =
coronary circulation
54
Branch from the ascending aorta and supply
oxygenated blood to the myocardium
Left & right coronary arteries
55
Most of the deoxygenated blood from the myocardium drains into a large vascular sinus in the coronary sulcus on the posterior surface of the heart, called the
coronary sinus
56
Empties into right atrium
Blood Supply Of Heart
57
only 1% of the cardiac muscle fibers become autorhythmic fibers
Conduction System
58
• only 1% of the cardiac muscle fibers become autorhythmic fibers;
• Two important functions:
1. They act as a pacemaker, setting the rhythm of electrical excitation that causes contraction of the heart.
2. they form the cardiac conduction system, a network of specialized cardiac muscle fibers that provide a path for each cycle of cardiac excitation to progress through the heart.
Conduction System
59
setting the rhythm of electrical excitation that causes contraction of the heart.
pacemaker
60
a network of specialized cardiac muscle fibers that provide a path for each cycle of cardiac excitation to progress through the heart.
cardiac conduction system
61
Two important functions of Conduction System
1. pacemaker
2. cardiac conduction system (CCS)
62
• Normally begins at sinoatrial (SA) node
• -> Atria & atria contract
• -> AV node - slows
• -> AV bundle (Bundle of His)
• -> bundle branches -> Purkinje fibers
• -> apex and up- then ventricles contract pushing the blood upward toward semilunar valve.
Sequence of AP propagate through the conduction system
63
• Depolarize spontaneously
• sinoatrial node ~100times /min
• also AV node ~40-60 times/min
• in ventricle ~20-35 /min
• Fastest one run runs the heart = pacemaker
• Normally the sinoatrial node
Pacemaker
64
Depolarize spontaneously
Pacemaker
65
sinoatrial node
~100times /min
66
also AV node
40-60 times/min
67
in ventricle
20-35 /min
68
Fastest one run runs the heart
pacemaker
69
Normally the sinoatrial node
pacemaker
70
• if the pacing rate is so slow (20–35 bpm) that blood flow to the brain is inadequate.
• artificial pacemaker - a device that sends out small electrical currents to stimulate the heart to contract.
• A pacemaker consists of a battery and impulse generator and is usually implanted beneath the skin just inferior to the clavicle.
• Many of the newer pacemakers, referred to as activity-adjusted pacemakers, automatically speed up the heartbeat during exercise.
Artificial Pacemakers
71
if the pacing rate is so slow (20–35 bpm) that blood flow to the brain is ________
inadequate
72
a device that sends out small electrical currents to stimulate the heart to contract.
artificial pacemaker
73
A pacemaker consists of a battery and impulse generator and is usually implanted beneath the skin just inferior to the __________.
clavicle
74
Many of the newer pacemakers, referred to as ____________, automatically speed up the heartbeat during exercise.
activity-adjusted pacemakers
75
Recording of currents from cardiac conduction on skin
electrocardiogram (EKG or ECG)
76
is a composite record of action potentials produced by all the heart muscle fibers during each heartbeat.
ECG
77
3 waves
P wave
QRS complex
T-wave
78
represents atrial depolarization
P wave
79
• Contraction begins right after peak
• Repolarization is masked in QRS
P wave
80
• rapid ventricular depolarization
• Contraction of ventricle
QRS complex
81
• ventricular repolarization
• Just after ventricles relax
T-wave
82
indicate enlargement of an atrium;
Larger P waves
83
may indicate a myocardial infarction
Enlarged Q wave
84
generally indicates enlarged ventricles
Enlarged R wave
85
If ______ is flatter than normal = heart muscle is receiving insufficient oxygen—exp, in coronary artery disease.
T wave
86
The _______ in hyperkalemia (high blood K level).
T wave may be elevated
87
in coronary artery disease and rheumatic fever.
P–Q interval lengthens
88
_______ in acute myocardial infarction and depressed when the heart muscle receives insufficient oxygen.
S–T segment is elevated
89
________ by myocardial damage, myocardial ischemia (decreased blood flow), or conduction abnormalities.
Q–T interval may be lengthened
90
A single ______ includes all the events associated with one heartbeat.
cardiac cycle
91
cardiac cycle consists of :
systole and diastole of the atria PLUS
systole and diastole of the ventricles
92
lasts about 0.1 sec, the atria are contracting
(P -wave). The ventricles are relaxed (diastole).
atrial systole
93
which lasts about 0.3 sec, the ventricles are contracting. The atria are relaxed in (atrial diastole).
ventricular systole
94
Ventricular pressure drops below atrial pressure & AV valves open -> ventricular filling occurs
after T-wave -> ventricular diastole
95
Finishes filling ventricle (25mL)
After P-wave -> atrial systole
96
• Pressure pushes AV valves closed
• Pushes semilunar valves open and ejection occurs
• Ejection until ventricle relaxes enough for arterial pressure to close semilunar valves
After QRS -> ventricular systole
97
Cardiac cycle
1. Relaxation period
2. Atrial systole
3. Ventricular systole
98
the volume ejected per beat from each ventricle, equals end-diastolic volume minus end-systolic volume
Stroke volume (SV = EDV - ESV)
99
At rest, the stroke volume is about _____
130 mL - 60mL = 70 mL (a little more than 2 oz).
100
is the volume of blood ejected from the left ventricle (or the right ventricle) into the aorta (or pulmonary trunk) each minute.
Cardiac output (CO)
101
Cardiac output equals the Stroke volume, multiplied by the Heart rate (HR)
CO(mL/min) = SV(mL/beat) • HR (beats/min)
102
Three factors regulate SV and ensure that the left and right ventricles pump equal volumes of blood:
Preload
Contractility
Afterload
103
the degree of stretch on the heart before it contracts
preload
104
the forcefulness of contraction of individual ventricular muscle fibers
contractility
105
the pressure that must be exceeded before ejection of blood from the ventricles can occur.
afterload
106
• Degree of stretch = Frank-Starling law
— Increase diastolic Volume increases strength of contraction -> increased S.V.
— Increased venous return -> increased S.V.
• When HR exceeds about 160 beats/min, SV usually declines due to the short filling time
• High back pressure in artery -> decreased S.V. — Slows semilunar valve opening
Control of Stroke Volume (S.V.) Preload
107
Degree of stretch
Frank-Starling law
108
When HR exceeds about 160 beats/min, _________ due to the short filling time
SV usually declines
109
• positive inotropic agents - substances that increase contractility
— Ex. stimulation of the sympathetic div of ANS, hormones such as Epi & NE increase Ca2+ level and drug digitalis.
• negative inotropic agents - decrease contractility
— Ex. inhibition of the sympathetic div of the ANS, anoxia, acidosis, some anesthetics, and increased K level in the interstitial fluid have negative inotropic effects.
• Calcium channel blockers - reduce Ca2+ inflow
Control of Stroke Volume (S.V.)
Contraction
110
- substances that increase contractility
Ex. stimulation of the sympathetic div of ANS, hormones such as Epi & NE increase Ca2+ level and drug digitalis.
positive inotropic agents
111
- decrease contractility
Ex. inhibition of the sympathetic div of the ANS, anoxia, acidosis, some anesthetics, and increased K level in the interstitial fluid have negative inotropic effects.
negative inotropic agents
112
reduce Ca2+ inflow
Calcium channel blockers
113
• pressure that must be overcome before a semilunar valve can open.
• increase in afterload causes stroke volume to decrease,
• More blood remains in the ventricles at the end of systole.
• Conditions that can increase afterload include hypertension and narrowing of arteries by atherosclerosis
Control of Stroke Volume (S.V.) Afterload
114
___________ causes stroke volume to decrease
increase in afterload
115
• loss of pumping efficiency by the heart.
• Causes: coronary artery disease, congenital defects, long-term high blood pressure, myocardial infarctions, and valve disorders.
• As a result, blood backs up in the lungs and causes pulmonary edema, that can cause suffocation if left untreated.
• If right ventricle fails first, blood backs up in the systemic veins and, over time, the kidneys cause an increase in blood volume. Resulting peripheral edema - most noticeable in the feet and ankles.
Congestive Heart Failure
116
loss of pumping efficiency by the heart.
Congestive Heart Failure
117
As a result, blood backs up in the lungs and causes ________, that can cause suffocation if left untreated.
pulmonary edema
118
If right ventricle fails first, blood backs up in the systemic veins and, over time, the kidneys cause an increase in blood volume. Resulting ___________- most noticeable in the feet and ankles.
peripheral edema
119
• Pacemaker adjusted by nerves
— Cardiovascular center in Medulla
• Parasympathetic- ACh slows
— via vagus nerve (CN X)
• Sympathetic - Norepinephrine speeds
• Sensory input for control:
— Baroreceptors (aortic arch & carotid sinus)-monitor the stretching of major arteries and veins caused by the pressure of the blood flowing.
— Chemoreceptors- O2, CO2, pH
Controls- Heart Rate
120
adjusted by nerves
Pacemaker
121
ACh slows
Parasympathetic
122
Norepinephrine speeds
Sympathetic
123
Sensory input for control
• Baroreceptors (aortic arch & carotid sinus)
• Chemoreceptors
124
monitor the stretching of major arteries and veins caused by the pressure of the blood flowing.
Baroreceptors (aortic arch & carotid sinus)
125
O2, CO2, pH
Chemoreceptors
126
• Epinephrine & norepinephrine increase
H.R.
• Thyroid hormones stimulate H.R.
• Hyperthyroidism causes tachycardia
Hormones
127
Hyperthyroidism causes
tachycardia
128
• Increased Na+ or K+ decrease H.R. &
contraction force
• Increased Ca2+ increases H.R. &
contraction force
Ions
129
Increased ______ decrease H.R. &
contraction force
Na+ or K+
130
Increased ______ increases H.R. &
contraction force
Ca2+
131
• Aerobic exercise (longer than 20 min) strengthens cardiovascular system:
• Brisk walking, running, bicycling, cross-country skiing, and swimming are examples of aerobic activities.
• Well trained athlete -> doubles maximum C.O.
• Resting C.O. about the same but resting H.R.
decreased (40–60 bpm)
• Regular exercise also helps to reduce blood pressure, anxiety, and depression; control weight; and increase the body’s ability to dissolve blood clots.
Exercise and the Heart
