Cardiovascular Exam Flashcards
1
Q
where in the chest is the heart located?
A
sits posterior to sternum and left of midline between the lungs in the mediastinum
2
Q
what are the layers of the pericardium
A
- fibrous pericardium
- parietal layer of serous pericardium
- visceral layer of serous pericardium
3
Q
What is the function of the fibrous pericardium?
A
dense irregular CT that is outermost covering that anchors heart and prevents overfilling
4
Q
What is the coronary sulcus?
A
external groove extending around circumference of heart that separates atria from ventricles
5
Q
what superficial feature separates the left from right ventricles?
A
interventricular sulci
6
Q
what is the wrinkled extension of the atrium called?
A
the auricle
7
Q
what are the three layers of the heart wall?
A
- epicardium,
- myocardium
- endocardium
8
Q
what is the thickest layer of the heart wall?
A
myocardium
9
Q
what is the function of atrioventricular valves?
A
prevent back flow to atria
- close when ventricles contract
10
Q
what is the function of the semilunar valves?
A
prevent back flow to ventricles
- open when ventricles contract and blood goes to arteries
- close when ventricles relax
11
Q
how many cusps does each semilunar valve have?
A
3
12
Q
what do the two sounds of the heart indicate
A
s1: closing of AV valves
s2: closing of semilunar valves
13
Q
what is a heart murmur?
A
an abnormal heart sound that is the result of turbulence of blood passing through heart
14
Q
what are the two types of heart murmurs?
A
valvular insufficiency and valvular stenosis
15
Q
what is occurring in valvular insufficiency?
A
cardiac valves are leaking because cusps are not closing tightly, causing blood to regurgitate back through valve
16
Q
what is occurring during valvular stenosis?
A
valve cusps are scarred and cannot open completely which causes reduced cardiac chamber output
17
Q
what are some characteristics of cardiac muscle tissue?
A
- one or two central nuclei
- supported by areolar CT (endomysium)
- myofilaments arranged in sarcomeres
- cells are connected with intercalated discs
18
Q
What is the fibrous skeleton of the heart?
A
a network of dense irregular CT that provides support at boundry of atria and ventricles, forms fibrous rings to anchor valves, and acts as electrical insulator preventing ventricles from contracting at the same time as atria
19
Q
how does the cardiac muscle relate to the fibrous skeleton?
A
cardiac muscle cells are attached to fibrous skeleton and arranged in spiral bundles
20
Q
how does coronary flow coincide with heart contractions?
A
vessels are patent when heart is relaxed and compressed when heart contracts
21
Q
what is atherosclerosis?
A
plaques narrow coronary arteries
22
Q
what is a coronary spasm?
A
sudden narrowing of vessles
23
Q
what is angina pectoris?
A
chest pain that may also include referred pain in left arm or jaw
24
Q
what is a myocardial infarction?
A
a sudden and complete occlusion of coronary artery that causes myocardium to be deprived of oxygen
25
what is the function of the sinoatrial (SA) node?
initiates heart beat (pacemaker)
26
what is another name for the atrioventricular bundle?
the bundle of his
27
where are the purkinje fibers located
extend from right and left bundles at apex and course through walls of ventricles
28
where is the cardiac center located?
medulla oblongata
29
what is the function of the cardiac center?
- receives signals from baroreceptors and chemoreceptors in cardiovascular system
- sends signals via sympathetic and parasympathetic pathways
- modifies, but does not initiate, cardiac activity
30
how does parasympathetic innervation occur?
- starts at cardioinhibitory center in medulla
- relayed via vagus nerves and heart rate decreases
31
how does sympathetic innervation occur?
- Starts at cardioacceleratory center
- relayed via nuerons from T1-T5 segment of spinal cord
32
what are the two events involved in heart contraction?
- the conduction system initiates and propagates an action potential
- cardiac muscle cells fire action potentials and contract
33
what are the cells that initiate heartbeat in the SA Node?
nodal cells
- spontaneously depolarize and generate action potential
34
what kind of voltage gated channels are present in nodal cells?
- slow voltage gated Na + channels
- fast voltage gated Ca2+ channels
- voltage gated K+ channels
35
what are the steps of autorhythmicity?
1. reaching threshold
- slow V gated Na+ channels open and membrane potential changes from -60 to -40 mV
2. depolarization
- fast V gated Ca2+ channels open
- membrane potential increases to just above 0
3. repolarization
- calcium channels close and V gated K+ channels open
- membrane potential returns to -60
- voltage gated Na+ channels open at -60 and process repeats
36
how long of a gap is there between SA node action potentials at rest?
0.8 sec after the last
37
what prevents SA node from firing faster like it wants to?
vagal tone keeps resting heart rate slower
38
How do nodal cells and neurons compare and contrast?
- while both can fire action potentials, neurons require stimulation to fire unlike nodals cells.
- nodal cells do not have a stable RMP
- nuerons depolarize from Na+ entry while nodal cells use Ca2+ entry
39
how does the action potential spread after starting at SA node?
1. AP is distributed through atria and reaches AV node
2. AP is delayed at AV node
3. AP travels through AV bundle to bundle branches to purkinje fibers
4. AP spreads through ventricles
40
what causes the delay of the AP at the AV node?
AV nodal cells are slow due to small diameter and few gap junctions, insulation of fibrous skeleton also means AV node is bottleneck
41
How do purkinje fibers differ from other cardiac fibers?
large in diameter to ensure AP is extremely rapid and ventricles contract at same time
42
how do papillary muscles aid with ventricular contraction?
- anchor chordae tendinae of AV cusps and starts to pull on cusps just prior to increase in pressure in ventricles
43
What occurs during depolarization of cardiac muscle cells?
- impulse from conduction system opens fast voltage gated Na+ channels
- Na+ enters cell changing RMP from -90 to +30
- voltage gated Na+ channels start to inactivate
44
what occurs during plateau of cardiac muscle cells?
- depolarization opens V gated K+ channels and slow V gated Ca2+ channels
- K+ leaves as Ca2+ enters
- membrane remains depolarized
45
What occurs during repolarization of cardiac muscle cells?
- voltage gated Ca2+ channels close while K+ channels remain open
- membrane potential returns to -90 mV
46
True or false, cardiac muscle cannot exhibit tetany
true, unlike skeletal muscle, cardiac cells have a long refractory period and the heart must contract and relax before it can be stimulated again
47
What are the major waves in an EKG?
P wave, QRS complex, T wave
48
what are the major segments in an EKG?
P-Q segment and S-T segment
49
What does the P wave reflect?
shows electrical changes of atrial depolarization
50
What changes are seen in the QRS complex?
shows eletrical changes associated with ventricular depolarization (atrial repolarization is also occurring simultaneously)
51
What is reflected in the T wave?
shows electrical changes that occur with ventricular repolarization
52
What do segments between waves represent?
the plateau phase where there is no electrical change
53
what occurs during the P-Q segment?
atrial cells plateau (atria are contracting)
54
what occurs during the S-T segment?
ventricular plateau (ventricles are contracting)
55
What happens in a first degree AV block?
PR prolongation; slow conduction between atria and ventricles
56
What happens in a second degree AV block?
failure of some atrial action potentials to reach ventricles
57
What happens in a third degree AV block?
complete blockage, failure of all action potentials to reach ventricles
58
What is atrial fibrillation?
chaotic timing of atrial action potentials
59
What is the cardiac cycle?
all events in heart from the start of one heart beat to the start of the next
60
what is the driving force behind the cardiac cycle?
ventricular activity
61
what occurs during ventricular contraction?
ventricular pressure is raised
- AV valves pushed closed
- semilunar valves pushed open and blood ejected to artery
62
what occurs during ventricular relaxation?
ventricular pressure is lowered
- semilunar valves close due to no pressure from below to keep them open
- AV valves open due to no pressure pushing them closed
63
What is happening during atrial contraction?
- SA node starts atrial excitation
- atria contract and push blood into ventricles until ventricles reach EDV
- AV valves open and SL valves closed due to arterial trunk pressure>ventricular pressure
64
what is happening during ventricular ejection?
- ventricles continue to contract so that ventricular pressure rises above arterial pressure
- semilunar valves forced open as blood moves from ventricles to arterial trunks
65
what is stroke volume
amount of blood ejected by ventricle
66
what is end systolic volume
amount of blood remaining in ventricle after contraction finishes
67
what occurs during isovolumetric relaxation
- ventricles relax and start to expand, lowering pressure
- arterial pressure greater than ventricular pressure
- SL valves shut and AV valves remain closed
- when all valves are closed, blood neither enters nor leaves and the time is called isovolumetric
68
what is ventricular balance?
equal amounts of blood are pumped by left and right sides of heart
69
What is cardiac output?
amount of blood pumped by a single ventricle in one minute
- HR x SV
70
how does heart size affect cardiac output
individuals with smaller hearts have smaller stroke volume and faster heart rate and vice versa
71
what is cardiac reserve?
capacity to increase output above rest level, ex: CO increases during exercise
72
what are the two types of edema?
systemic edema and pulmonary edema
73
what is occurring in systemic edema?
may occur if right ventricle is impaired, results in more blood in systemic circulation and additional fluid entering interstitial space
74
what is occurring in pulmonary edema?
ay occur if left ventricle is impaired, results in more blood remaining in pulmonary circulation, swelling and fluid accumulation in lungs, and dyspnea
75
What are chronotropic agents?
change heart rate by altering the activity of nodal cells
76
what affect do positive chronotropic agents have?
- sympathetic nerve stimulation that cause NE release on heart
- cause adrenal gland to release EPI and NE
- EPI and NE bind to nodal cells and increase their firing rate
77
what are some examples of positive chronotropic agents?
thyroid hormone, caffeine, nicotine, and cocaine
78
what affect do negative chronotropic agents have?
- parasympathetic axons release ACh onto nodal cells which open K+ channels and make cell more negative
- longer time for nodal cel to reach threshold, slower heart rate
79
what affect do beta blockers have?
interfere with EPI and NE binding to beta receptors
80
what is the atrial reflex?
protects heart from overfilling
- baroreceptors in atrial walls stimulated by increased venous return
- HR increases to move blood through quickly
81
What three factors influence stroke volume
venous return, inotropic agents, and afterload
82
how does venous return infleunce stroke volume?
determines amount of ventricular blood prior to contract; volume determines preload
83
what is the Frank-Starling law?
as EDV increases, the greater stretch of heart wall results in more optimal overlap of thick and thin filaments
- heart contracts more forcefully when filled with more blood so SV increases
84
what are inotropic agents?
factors that change stroke volume by altering contractility
85
what affect do positive inotropic agents have?
- EPI and NE work via beta one receptors to increase Ca2+
86
what affect do negative inotropic agents have?
decrease available Ca2+ and thus lower contractility
87
what is afterload?
resistance in arteries to ejection of blood by ventricles, pressure must be exceeded before blood is ejected
88
what factors contribute to cardiac output?
- chronotropic agents
- venous return
- inotropic agents
- increased afterload
89
define systole and diastole
systole: contraction
diastole: relaxation
90
what are some secondary factors that can influence heart rate?
age, gender, exercise, body temperature
91
what is the space inside a blood vessel called?
lumen
92
what are the layers of the vessel wall called?
tunics
93
what are the tunics of vessel walls?
- tunica intima
- tunica media
- tunica externa
94
what is the tunica intima composed of?
- endothelium of simple squamous epithelium
- subendothelium layer of areolar CT
95
What is middle layer of the vessel wall?
tunica media
96
what is the function of the tunica media
contains circularly arranged layers of smooth muscle cells with elastic fibers that control vasoconstriction/dilation
97
what is the outermost layer of the vessel wall?
tunica externa
98
what is the function of the tunica externa?
helps anchor vessel to other structures
99
what are vasa vasorum?
small arteries found in some tunica externa required to supply very large vessels
100
what are companion vessels?
vessels that lie next to each other (arteries and veins serving same body region)
101
what type of blood vessel has the thickest tunica media?
arteries
102
how does the composition of arteries aid their function?
have more elastic and collagen fibers, which are more resilient and resistant to changes in blood pressure
103
what vessel has the largest lumen?
veins
104
what tunics are found in the capillaries?
only tunica intima ( no subendothelial layer)
105
as arteries branch how do they change?
- decrease in lumen diameter and elastic fibers
- increase in relative amount of smooth muscle
106
what are the three types of arteries?
- elastic arteries
- muscular arteries
- arterioles
107
what is the largest type of artery?
elastic arteries
108
what is the function of elastic arteries
conduct blood from heart to muscular arteries
- have large proportion of elastic fibers allowing stretch and recoil and help propel blood through arteries during diastole
109
what is the function of muscular arteries?
distribute blood to specific body regions, muscle allows for vasoconstriction/dilation
110
what are the two layers of elastic tissue found in muscular arteries
- internal elastic lamina: between tunica intima and tunica media
- external elastic lamina: between tunica media and tunica externa
111
what are the smallest type of arteries?
arterioles
112
how many tunics do arterioles have?
larger ones have 3 and smaller arterioles only have thin endothelium and single layer of smooth muscle
113
what is atherosclerosis
progressive disease of elastic arteries which includes the presence of atheroma which can cause the thickening of tunica intima and narrowing of arterial lumen
114
what causes atherosclerosis?
may be due to response to injury to endothelium caused by infection, trauma, or hypertension
115
how is atherosclerosis treated
stent with balloon angioplasty or coronary bypass surgery
116
how do RBCs pass through capillaries?
travel single file (rouleau)
117
what are the three types of capillaries
continuous, fenestrated, and sinusoid
118
what features are unique to continuous capillaries?
- endothelial cells form a continuous lining
- tight junctions connect cells but don't form a complete seal
119
where are continuous capillaries typically found?
muscle, skin, lungs, CNS
120
what features are unique to fenestrated capillaries
endothelial cells form a continuous lining but the cells have fenestrations (pores that allow movement of smaller proteins)
121
where are fenestrated capillaries found?
found in areas where a lot of fluid transport occurs (intestine, kidneys)
122
what features are unique to sinusoids?
- endothelial cells form an incomplete lining with large gaps
- basement membrane incomplete/absent
- openings allow transport of large substances
123
Where are sinusoids found?
bone marrow, spleen, some endocrine glands
124
what are capillary beds?
groups of capillaries functioning together
125
what feeds into capillary beds?
metarterioles
126
what side of a capillary bed contains smooth muscle cells?
proximal part
127
what is the precapillary sphincter?
smooth muscle ring at true capillary origin that permits entry into capillaries
128
at one time, how many of the bodies capillary beds are open?
one quarter
129
what is perfusion?
amount of blood entering capillaries per unit time per gram of tissue
130
what are the smallest type of vein?
venules
131
what is the function of the valves found in veins
prevent blood from pooling in the limbs, ensure flow toward heart
132
What are vein valves made of?
tunica intima and elastic and collegen fibers
133
what % of blood is in systemic circulation at rest?
70%
- systemic veins: 55%
- systemic arteries: 10%
- systemic capillaries: 5%
134
what is an end artery?
one that provides only one path for blood to reach organ/region
135
what is arterial anastomosis?
two or more arteries converge to supply same region
136
what is venous anastomosis?
two or more veins drain same body region
137
what is arteriovenous anastomosis?
transports blood from artery directly to vein
138
what is portal system?
two capillary beds in sequence
139
what is the cross sectional area of a vessel?
lumen diameter
140
what is total cross sectional area?
sum of diameters of all vessels of a certain type
141
what type of vessel has the largest total cross sectional area
capillaries
142
how does blood flow velocity relate to total cross sectional area?
inversely proportional
143
how do substances enter/leave the blood
leave or enter blood based on their concentration gradient
- high to low concentration
144
what is vesicular transport?
- substances are taken in by pinocytosis (form fluid filled vesicles)
- transport vesicle across cell
- secrete substance from other side by exocytosis
- used in both directions
145
what is bulk flow?
- fluids flow doe pressure gradient
- large amounts of fluids and dissolves substances move in direction that depends on net pressure of opposing forces
146
what are the two types of bulk flow
- filtration (fluid moves out of blood)
- reabsorption (fluid moves back into blood)
147
what is hydrostatic pressure?
force exerted by a fluid
148
what are the types of hydrostatic pressure?
- blood hydrostatic pressure: force exerted per unit are by blood on vessel wall
- interstitial fluid hydrostatic pressure: force of interstitial fluid on outside of blood vessel
149
what is colloid osmotic pressure?
the pull on water due to the presence of protein solutes
150
what are the types of colloid osmotic pressure?
- blood colloid osmotic pressure: draws fluid into blood due to blood proteins, promotes reabsorption
- interstitial fluid colloid osmotic pressure: draws fluid into interstitial fluid
151
what is net filtration pressure?
the difference between net hydrostatic pressure and net colloid osmotic pressure
152
how does net filtration pressure change across a capillary?
- at arterial end: NFP favors filtration
- at venous end, NFP favors reabsorption
153
what is local blood flow dependent on
- degree of tissue vascularity
- myogenic response
- local regulatory factors
- total blood flow
154
what is blood pressure gradient?
change in pressure from one end of vessel to other
155
what is pulse pressure
pressure in arteries added by heart contraction
156
what is mean arterial pressure?
average arterial blood pressure across entire cardiac cycle
- MAP = diastolic + 1/3(pulse pressure)
157
what is capillary blood pressure?
pressure no longer fluctuates between systolic and diastolic
158
what is venous return dependent on?
pressure gradient, skeletal muscle pump, and respiratory pump
159
what is the function of the skeletal muscle pump
assists venous return from limbs
- as muscle contracts, veins are squeezed moving blood towards heart
160
what is the function of the respiratory pump?
assists venous return in the thorax
- in inspiration: diaphragm contracts, abdominal pressure increases and thoracic pressure decreases
- in expiration: diaphragm relaxes, so thoracic pressure increase while abdominal pressure decreases
161
what is resistance?
the friction blood encounters due to contact between blood and vessel wall
162
what affects peripheral resistance?
viscosity, vessel length, lumen size
163
how does the length of a vessel affect resistance?
longer vessels create more resistance
164
what is laminar flow?
different flow rate within vessel (faster in center of lumen slower near wall)
165
what is total blood flow?
amount of blood moving through the system per unit time
166
what is blood pressure dependent on?
cardiac output, resistance, blood volume
167
what regulate bp short term?
autonomic reflexes
168
what are the two divisions of the cardiovascular center and their functions?
- cardiac center: influences bp by influencing cardiac output
- vasomotor center: influences bp by influencing vessel diameter
169
what are the two nuclei housed in the cardiac center?
- cardioacceleratory center: origin of sympathetic pathways
- cardioinhibitory center: origin of parasympathetic pathways
170
what are baroreceptors?
nerve endings that respond to stretch of vessel wall
171
what hormones work w/ the sympathetic nervous system to regulate bp?
epinephrine and norepinephrine
- angiotensin II, ADH, aldosterone also have effects
172
how does ADH regulate bp?
- increases water reabsorption in kidneys
- stimulates thirst center to increase fluid intake
- in large amounts causes vasoconstriction
173
how does aldosterone regulate bp?
increases absorption of sodium ions and water in the kidney
174
what effect does atrial natriuretic peptide have on bp?
decreases bp by stimulating vasodilation and increasing urine output
175
how does blood flow distribution change during exercise?
total blood flow increases
- heart beats faster/stronger
- blood is removed from venous reservoirs
- blood is redistributed so that more goes to active tissues
