Test 5 Cardiology, Blood Vessels and Blood Flashcards
0
Q
what is the muscular layer of the heart called?
A
myocardium
1
Q
What is the outermost layer of the heart called?
A
Epicardium or visceral pericardium
2
Q
which side of the heart holds deoxygenated blood?
A
right
3
Q
which side of the heart holds oxygenated blood?
A
left
4
Q
when the ventricles are filling what valves are open?
A
atrioventricular (AV) valves
5
Q
when the ventricles are emptying what valves are open?
A
semilunar valves
6
Q
what percent of heart muscle cells can cause contractions?
A
about 1%
7
Q
what do modified myocardial cells do?
A
provide a specific pathway for depolarization of myocardium
8
Q
what system allows the heart to continue beating even if the nerves are damaged?
A
intrinsic conduction system
9
Q
what is the importance of coordinated contractions of the heart?
A
forces blood to move in only one direction
10
Q
where does the intrinsic conduction system start?
A
right superior atrium (sinoatrial node)
11
Q
what are specialized cells of SA node called?
A
pacemaker cells
12
Q
what follows from the action potential of SA node?
A
Atria contracts
13
Q
What allows atria to finish contracting before ventricles begin contraction?
A
atrioventricular node conducts impulses slower than other cells which causes AV delay
14
Q
What are the names of the ECG peaks and troughs in order from left to right
A
PQRST
15
Q
What does the P wave of an ECG indicate?
A
depolarization and subsequent contraction of atria
16
Q
what does the QRS complex of an ECG indicate?
A
depolarization and subsequent contraction of ventricles as well as repolarization and subsequent relaxation of atria
17
Q
What does the T wave of an ECG indicate?
A
repolarization and subsequent relaxation of ventricles
18
Q
What does the P-R interval of an ECG indicate
A
atrial depolarization to ventricle depolarization
19
Q
what does Q-T interval of an ECG indicate?
A
ventricular depolarization through ventricular repolarization
20
Q
what does S-T segment of ECG indicate?
A
ventricles are depolarized
21
Q
What does a large R wave on an ECG indicate?
A
enlarged ventricles
22
Q
what does a Flat T Wave on an ECG indicate?
A
ventricular ischemia
23
Q
what does a prolonged Q-T interval on an ECG indicate?
A
increased risk of ventricular arrhythmias
24
what are the two heart sounds?
1. Lub
| 2. Dup
25
What does the Lub heart sound indicate?
AV valves are closing
26
What does the Dup heart sound indicate?
Semilunar valves are closing
27
what causes a heart murmur?
a leaky valve in the heart
28
what is a valve stenosis?
a small opening that causes a high pitched click (heart murmur)
29
what occurs during systole?
contraction
30
what occurs during diastole?
relaxation
31
what is end diastolic volume (EDV)?
maximum ventricular volume at end of relaxation
32
What keeps AV valves shut?
papillary muscles and chordaea tendinae
33
what is the ductis arteriosus?
a blood vessel in fetal pulmonary artery that allows blood to bypass nonfunctioning lungs and enter descending aorta
34
what is ligamentum arteriosum?
the remnant of ductus arteriosus after birth
35
what is the foramen ovale?
a hole in fetal heart that allows blood to enter left atrium from right atrium
36
what is the fossa ovalis?
remnant of foramen ovale after birth
37
where are impulses conducted to after SA node?
to atrioventricular node
38
where is AV mode located?
inferior right atrium
39
where does AV node conduct impulses to?
atrioventricular bundle (Bundle of His)
40
where is Bundle of His located
interventricular septum
41
where does bundle of His conduct impulses to?
left and right bundle branches
42
where are purkinje fibers located?
branches off of left and right bundle branches, originating at apex and going through ventricular myocardium
43
where is subendocardial conducting network most elaborate?
on left side
44
why is tetany of the heart bad?
myocardium must relax for blood to fill chambers
45
how does cardiac muscle prevent tetany?
longer absolute refractory period gives chamber time to refill
46
what allows SA node to develop its own rhythm
funny current of sodium ions responds to hyperpolarization and brings resting membrane potential to threshold
47
what ion channel causes depolarization of pace maker cells at threshold?
calcium channels
48
what is arrhythmia?
abnormal heart rhythm
49
what is fibrillation?
rapid and irregular contractions in the atria and/or ventricles
50
what is ectopic focus?
pacemaker is not SA node
51
how does fibrillation cause clots?
blood becomes turbulent and is more likely to clump together
52
what happens at the beginning of atrial systole?
atrial contraction begins
53
what happens during atrial systole?
blood is ejected into ventricles
54
what happens at the end of atrial systole?
AV valves close
55
what happens at the beginning of ventricular systole?
isovolumetric contraction
56
what is the result of isovolumetric contraction?
pressure increases rapidly without a change in volume
57
what happens after isovolumetric contraction?
SL valves open and ventricular ejection occurs
58
what happens at the end of ventricular systole?
semilunar valves close
59
what happens at the beginning of ventricular diastole?
isovolumetric relaxation occurs
60
what is the result of isovolumetric relaxation?
pressure decreases rapidly but volume of blood stays the same
61
what happens after isovolumetric relaxation?
AC valves open and passive ventricular filling occurs
62
what is the purpose of papillary muscle during isovolumetric contraction
prevent high pressure blood from flowing back into atrium by closing AV valve
63
what forces must the ventricles over come for the ejection phase to occur?
aortic pressure and pulmonary trunk pressure
64
what drives direction of blood through heart?
pressure gradient
65
what is preload?
how much blood is coming into the heart
66
what is the frank-starling law of the heart
increased stretch (preload), increased stroke volume
67
how does increase in contractility affect end systolic volume? stroke volume?
decreases it, therefore increasing stroke volume
68
what is afterload?
back pressure on SL valves
69
how does afterload effect cardiac output?
must work harder to eject blood which increases end systolic volume
70
how does autonomic nervous system effect heart rate?
increase
71
how does parasympathetic nervous system affect heart rate?
decreases
72
where is SNS control center?
cardioaccelatory center in medulla onlongata
73
how does epinephrine/norepinephrine increase heart rate?
reach threshold quicker by increasing calcium entry into cell
74
how does acetylcholine decrease heart rate?
hyperpolarizes sarcolemma which means it takes longer for cell to depolarize
75
what do baroreceptors respond to
increase stretch of aortic arch, carotid sinus and elsewhere
76
what is the baroreceptor reflex
baroreceptors send signal that are responded to by both branches of autonomic nervous system
77
how does thyroxine affect heart rate
increase metabolism, increase heart rate
78
how does hypocalcemia affect heart rate
decrease heart rate
79
how does hypercalcemia affect heart rate
increase heart rate
80
how does hypernatremia affect heart rate
inhibits calcium influx, decreases heart rate
81
how does hyperkalemia affect heart rate
hyperpolarizes cardiac muscle, decreases heart rate
82
how does hypokalemia affect heart rate
causes cardiac arrythmias
83
what is tachycardia
HR greater than 100
84
what is possible danger of tachycardia
fibrillation
85
what is bradycardia
less than 60 bpm
86
what is an issue of bradycardia
inadequate blood circulation
87
what is ishemia
low blood supply
88
what is angina pectoris
chest pain caused by ischemia
89
what is myocardial infarction
dead myocardial tissue from ischemia
90
what are congenital septal defects
holes in heart that mix systemic and pulmonary blood
91
what is hypertension
continual high blood pressure causes weakness in myocardium
92
what is coronary atherosclerosis
clogging of coronary artery
93
what is congestive heart failure
heart doesn't pump enough blood for needs so it tries to grow but it progressively gets worse
94
what are arteries
carry blood away from heart
95
what are arterioles
small arteries
96
what are capillaries
site of exchange of nutrients and waste
97
what are venules
small veins
98
what are veins
carry blood towards heart
99
what is lumen of blood vessel
central canal that carries blood
100
what type of tissue composes tunica internal
1. slippery simple squamous
| 2. subendothelial connective tissue
101
what tissues are in tunica media
1. circular smooth muscle
| 2. sheets of elastin
102
what three types of tissues are in tunica externa
1. loose collagen fibers
2. nerve endings
3. lymphatics
103
what are elastic arteries
withstand fluctuations in pressure
104
where are elastic arteries located
Aorta, brachiocephalic, subclavian, other major arteries
105
what do muscular arteries do
deliver blood to organs
106
which type of arteries are more active in vasoconstriction
muscular arteries
107
how many RBC fit in capillary lumen
one
108
what are continuous capillaries
no holes
109
which capillary type is most abundant
continuous
110
what are fenestrated capillaries
small holes
111
where are fenestrated capillaries located
where absorption or filtration is needed; kidneys and intestines
112
what characterizes sinusoidal capillaries
large lumens and holes that allow large molecules to enter bloodstream
113
where are sinusoidal capillaries located
liver, lymph, bone marrow and endocrine glands
114
what are capillary beds
site of gas and nutrient exchange
115
how do the tunics of veins compare to arteries
smaller
116
what percent of blood can veins hold up to
65%
117
how does exercise increase venous return
contracting muscles squeeze against veins and increase blood flow
118
what are anastomoses
branches formed between adjacent blood vessels
119
are anastomoses more common in arteries or veins?
veins
120
what is collateral circulation
redundancy in blood vessels
121
what is blood flow
volume of blood through vessel per unit time
122
what is blood pressure
force exerted on vessel wall by blood inside
123
what is peripheral resistance
opposition to blood flow
124
what are three factors of resistance
1. blood viscosity
2. vessel length
3. vessel diameter
125
what blood vessel is blood pressure the lowest
capillary
126
what provides blood flow?
heart working as a pump
127
when flow is opposed by resistance what results?
blood pressure
128
what is systolic pressure
pressure within arteries during ventricular contraction
129
what is diastolic pressure
pressure within arteries when ventricles are relaxing
130
what is pulse pressure
difference between systolic pressure and diastolic pressure
131
what happens to pulse pressure as you approach capillaries
reaches nearly zero
132
what two pumps affect venous return
respiratory pump and muscle pump
133
how does respiratory pump affect venous return
breathing causes change in pressure which moves blood toward heart
134
how does venous blood stay flowing in one direction with such low pressure
use of venous valves and skeletal muscles
135
what is mean arterial pressure
pressure that moves blood to tissues
136
what are two short term blood pressure regulation systems
1. cardiac output
| 2. vessel diameter
137
is the long term blood pressure regulating system
blood volume
138
how does vasomotor center affect blood pressure
vasoconstriction by sympathetic nervous system
139
what 4 things stimulate vasomotor center
1. baroreceptors
2. chemoreceptors
3. cerebral cortex
4. hormones
140
what causes venous reservoirs to dilate?
baroceptor reflex resulting in increased parasympathetic tone
141
what are two major control mechanisms of autoregulation
1. metabolic (what is demanded by cells)
| 2. myogenic (vasoconstriction and vadodilation)
142
how does ADH affect blood volume and pressure?
increase volume increase pressure
143
how does aldosterone affect blood volume and pressure?
retain more water, increase volume and pressure
144
how does atrial natriuretic peptide affect blood volume and pressure?
kidneys excrete more sodium and water, decrease volume decrease pressure
145
three places diffusion occurs in capillaries
1. through cell
2. intercellular cleft
3. fenestrations
146
what is capillary hydrostatic pressure
movement of solutes from blood into interstitial fluid
147
what is interstitial fluid hydrostatic pressure
movement of solutes from interstitial fluid into blood (very little)
148
what is capillary osmotic pressure
non-diffusible molecules pull water into capillary
149
what is interstitial fluid osmotic pressure
non-diffusible molecules in interstitial fluid pull water out of capillary (very little)
150
what is net filtration pressure
difference between net hydrostatic pressure and net osmotic pressure
151
which capillary dynamics force is strong at arterial end?
hydrostatic force
152
which capillary dynamics force is stronger at venous end?
osmotic force
153
what happens to excess fluid leaving capillary in capillary bed?
absorbed by lymphatic system
154
what causes anaphylactic shock
histamine release results in vasodilation
155
what causes neurogenic shock
failure of sympathetic nervous system causes vasodilation
156
what causes septic shock?
immune responses cause vasodilation
157
what causes hypovolemic shock
large blood loss
