Pathophys quiz 2 CV Flashcards
(133 cards)
1
Q
Pressure
A
Force exerted; measured in mmHg
2
Q
Flow
A
Volume moved; measured in mL/min (volume moved in the time)
3
Q
Resistance
A
how difficult it is for the blood to flow between 2 points at any given pressure difference; the measure of the friction that impedes flow
4
Q
3 things that contribute to resistance?
A
- Blood viscosity
- Total blood vessel length (surface area increases resistance)
- Blood vessel diameter (This is the biggest contributor to min-to-min control of resistance in the vascular system)
5
Q
what has the biggest effect on resistance?
A
Radius
6
Q
Flow =
A
change in pressure/ resistance
7
Q
In a system with constant pressure if you increase resistance you _____ flow and if you decrease resistance you _______ flow
A
decrease, increase
8
Q
In a system with constant pressure if you increase pressure it _____ flow
A
increases
9
Q
In a system with constant pressure if you decrease pressure you ____ flow
A
decrease
10
Q
In a system with constant pressure F and R are _______ related
A
inversely
11
Q
Positive chronotropic factors ______ HR
A
increase
12
Q
negative chronotropic factors ______ HR
A
decrease
13
Q
3 systems that regulate the heart
A
Endocrine system, nervous system, kidney
14
Q
How does the endocrine system regulate the heart?
A
Atrial Natriuretic peptide (hearts own endocrine system
15
Q
Atrial Natriuretic peptide
A
- secreted by specialized cells in the atria
- Regulates the concentration of Na+ in extracellular fluid
16
Q
How does the Nervous system regulate the heart?
A
(body talks to the heart through this system)
Sympathetic nervous system (SNS)
Parasympathetic nervous system (PNS)
17
Q
How does SNS regulate the heart?
A
- Increases HR / Increases Stroke volume
- Innervates entire heart muscle and node cells
- Binds the neuroendocrine hormone epinephrine from the adrenal gland
- Beta-adrenergic receptors on the SA node and on Pumping cells
18
Q
SNS releases ______ through thoracic spinal nerves which kicks in first!
A
Norepinephrine (NE)
19
Q
_______ hormone from the adrenal medulla will kick in second
A
Epinephrine
20
Q
How does the PNS regulate the heart?
A
- Slow HR
- innervates just the SA/AV nodes
- Muscarinic Cholinergic receptors on the SA node only
- releases Acetylcholine (hormone) through vagus nerve
21
Q
How do the Kidneys regulate the heart?
A
Control blood volume by retaining or relating fluid (affects stroke volume (SV)
22
Q
arteries and veins both contain what 3 structures, but vary in the amounts of each?
A
smooth muscle
endothelial cells
fibroblasts
23
Q
Structures involved in the vascular system?
A
- Arteries
- Elastiuc arteries (conduit), muscular arteries, arterioles - Capillaries
- veins
- venules
24
Q
Arteries need to be more elastic, while veins are more _____
A
compliant
25
Arteries are responsible for transmitting _____ to the vessels beyond them.
pressure
| they are pressure reservoirs bc of their elastic recoil
26
Veins: the higher the compliance, the more they can _____ without corresponding increase in pressure
stretch out
27
Compliance =
change in volume / change in pressure
28
Veins have _____ walls and _____ compliance
thin, high
29
Pulmonary pressure is always ____ than arterial pressure
lower
30
Pressure ______ the farther it travels down the systemic circuit
decreases
31
does pressure increase or decrease between the arterioles and capillaries?
decreases greatly
32
what controls min - to - min blood flow into the capillaries?
muscular is or arterioles
33
what do veins have to prevent back flow?
valves
34
Respiratory pump
pressure changes in the central cavity due to the negative pressure generated due to breathing. this helps pull blood back to the heart
35
muscle pump
when muscles contract they squeeze the veins, which moves blood forward. valves prevent back flow. the smooth muscle in the veins is under SNS control and contracts when stimulated, similar to arterial smooth muscle.
36
What are the components of the cardiac cycle? (slide 38)
Isovolumetric contraction, ventricular ejection, isovolumetric relaxation, ventricular filling
37
Isovolumetric contraction
the ventricle starts contracting, but no valves are open at first because the pressure hasn't gotten high enough to open them
38
ventricular ejection
ventricular pressure gets high enough to causesemilunar valves to open. when the LV pressure is higher than aortic pressure, the valve opens and the aorta fills
39
Isovolumetric relaxation
the ventricle relaxes, causing the semilunar valves to fall shut. the aortic pressures do high theres a backwards slosh of aortic blood against the aortic valve, creating the dicrotic notch (the blood that sloshes back exits through the coronary Ostia to oxygenate the blood
40
Ventricular filling
the atria are contracting, the ventricles are relaxed. AV valves are open bc atrial pressure is at least equal to ventricular pressure
41
Heart sounds
systole, diastole
42
Systole sounds:
closing of the mitral and tricuspid valves (LUB)
43
diastole sounds:
Closing of the pulmonary and aortic valves (DUB)
44
Why is diastole longer than systole?
bc ventricles which are bigger are filling
45
valve problems
```
stenotic (narrow valve) - turbulent flow
insufficient valve (leaky valve) - turbulent backflow
```
46
What causes a murmur
turbulent flow or back flow
47
systolic pressure =
maximum pressure at systole
48
diastolic pressure =
minimum pressure at diastole
49
pulse pressure=
systolic- diastolic
50
Mean arterial pressure (MAP) =
diastolic + 1/3 of the pulse pressure
51
What is cardiac output?
amount of blood pumped out of each ventricle in one minute
52
Cardiac Output =
HR x SV
53
Stroke Volume (SV) =
EDV - ESV
(fairly constant in a healthy system)
the amount of blood that was pumped out of the heart after contraction
54
End diastolic volume (EDV)
total amount of blood in the ventricle that has the potential to be pumped out
55
End systolic volume (ESV)
the amount of blood left over in the ventricle after the contraction of the heart
56
amount how much blood does the heart pump out during each beat?
60%
57
When SV decrease, the body will increase what to compensate in an unhealthy system?
HR
58
Inotropy
positive or negative things that affect contractility
59
SV can be increased by what?
emptying the ventricles better (increasing ventricular contraction)
-SNS stimulation increases SV
60
What is the most common way of changing CO?
HR
61
Chronotropy
positive (increases HR) or negative (decreases Hr) that affect HR
(HR can also be controlled by the nervous system)
62
Frank-starling Law
- the critical factor controlling stroke volume is preload
- Length/tension relationship (overextension leads to inefficient pumping and under extension limits force)
- Afterload
63
Preload
the degree to which the cardiac muscle cells are stretched (amount of blood in the ventricles) before the contract
64
Amount of blood in the ventricles is controlled by what 2 factors?
venous return and the amount of time between ventricular contractions
65
Anything that increases venous return or slows HR _______ the EDV
increases
| ex. increased SV = Increased EDV
66
Afterload
pressure that the ventricles must overcome to force open the aortic and pulmonary valves
-anything that increases systemic or pulmonary arterial pressure can increase afterload (hypertension)
67
it is easiest for the heart to work with a ____ preload and ____ afterload
high
| low
68
Ejection fraction =
SV / EDV (measures contractility)
- expressed as a percentage (normally between 50-70)
- increased contractility = increased ejection fraction
69
What does the SNS innervate?
SA/AV node and individual cardiac cells by releasing Norepinephrine (NE). It also binds the neuroendocrine hormone epinephrine from the adrenal gland
70
PNS innervates what?
only the SA/AV node and releases Acetylcholine
71
What is BP role in homeostasis of oxygen delivery?
By using sympathetic and parasympathetic stimulation to innervate and suppress the vessels in order to vasodilator and constrict depending on the body need for CO2
72
What is pH role in homeostasis of oxygen delivery?
by using ion channels to facilitate the movement of CO2 and O2 to alter pH within a cell. increased acidity (aka increased CO2) increases oxygen drop off
73
What is Oxygens role in homeostasis of oxygen delivery?
Hypoxic state= increased HR
74
What is ions role in homeostasis of oxygen delivery?
some atria cells secrete atrial natriuretic peptide which regulates Na+
75
what two things keep valves from flying open?
Chordae tendinae and Papillary muscles
76
what valves are open during diastole?
M/T
77
What valves are open during systole?
P/A
78
Hydrostatic pressure:
pressure needed for water to be forced out of the capillaries (filtration)
-over comes osmotic pressure at the beginning of the capillaries
79
Osmotic (oncotic) pressure
pressure causes O2 to flow into the capillary
- it opposes hydrostatic pressure, keeping fluid in the cells.
- Over comes hydrostatic pressure at the end of capillaries
80
arrhythmia
uncoordinated atrial and ventricular contractions caused by a defect in the conduction system
81
defibrillation
application of an electrical stimulation to shock the heart back into normal SA rhythm
82
Heart block
damage to AV node
83
Total heart block
ventricles beat at their intrinsic rate (purkinje fiber rate) = too slow to maintain circulation
84
partial heart block
AV node impulse is slowed but it does get through (pacemaker treats this)
85
Pacemaker
substitues SA and/or AV nodes. for chronic issues. can be single or double lead
86
extrasystoles
```
premature contractions (atrial or ventricular)
-Ventricular (PVC) most problematic
```
87
Extopic focus
abnormal pacemaker that takes over the conducting system
| -can go faster than SA node when it takes over for the damaged SA node
88
Fibrillation
rapid and irregular (usually out of phase) contraction where the SA node is no longer controlling HR
89
Atrial Fibrillation can cause what 2 things?
clotting and inefficient filling of the ventricles
90
Ventricular Fibrillation
- life threatening
| - ventricles pump inefficiently and without filling
91
What does the pulmonary system do?
carries oxygen poop blood to the lungs and then back to the heart
92
why is pressure in the pulmonary pump less?
blood is going to 1 organ at a shorter distance and the capillaries in the lungs are fragile and damage easily
93
What does the systemic system do?
carries blood from the heart to the rest of the body
94
why is pressure in the systemic system higher?
bloody has to be sent out a further distance to the entire body
95
4 advantages to having a closed system with 2 parallel loops
- more bang for you buck (stronger contractions)
- easy to create force when pushing against each other (shared wall, atrioventricular septum)
- Lungs are close by
- More efficient, blood is being oxygenated and delivered to the rest of the body simultaneously
96
Disadvantages to having a closed system with 2 parallel loops
A small imbalance in one side affects the other side
- if the right side doesn't deliver/fill properly, the left side has nothing to pump out (atrial dysfunction)
- if the left side doesn't pump fast enough, it backs up into the right (systolic dysfunction)
97
Describe portal systems
- 2 systems that have 2 sets of capillaries that exchange with their surroundings, found chained together in one-two fashion
- ensure all parts of the organ receive what they need
- 2 drop-off points
98
Hepatic portal system
vein-capillary-vein
-directs blood from parts of the GI tract to the liver. substances absorbed in the small intestine travel first to the liver for processing before continuing to the heart
99
Hypothalamic portal system
vein-capillary-vein
- picks up hormones at the hypothalamus and drops them off in high concentration at the pituitary
- not a lot of releasing hormone is needed because it is not being diluted by the entire blood stream
100
Nephron portal system
artery-capillary-artery
| -water is filtered out at one capillary bed, reabsorbed at another
101
order of blood through the body
arteries-arterioles-capillaries-venules-veins-heart
102
arteries =
away (normally oxygenated)
103
arterioles =
smallest arteries. their fx in controlled by neural, hormonal, and local chemicals (see study guide for more info)
104
autoregulation
dynamic process of constant changing diameter in the arterioles
105
paracrine signaling:
endothelial cells secrete paracrine agents (affect smooth muscle) and induce a relaxation or contraction
106
NO is one of the most important paracrine signals because...
its causes vasodilation for proper vessel tone.
| -sns / pos make arterioles more sensitive to NO
107
Continuous capillaries are...
most common and allow passage of fluids and small solutes (skin and muscle)
108
fenestrated capillaries
more permeable to fluids and solutes than continuous capillaries- allowing for more rapid transfer of substances into/out of the capillary (kidneys, intestines, endocrine (hormone) tissue)
109
Sinusoidal capillaries
leaky capillaries that allow large molecules to pass between blood and surrounding tissues (liver, bone marrow, lymphatics)
110
Filtration
flow of fluid leaving the plasma to the interstitial fluid through the capillaries
111
absorption
flow of fluid from the interstitial fluid to the plasma through the capillaries
112
Colloid osmotic (oncotic) pressure remains _______through the entire capillary
constant
113
Hydrostatic pressure is _____ at the arteriole end of the capillary and _____ at the venous end of the capillary
Higher, lower
114
3 layers of the veins:
Tunics: interna-media-externa (less smooth muscle and elastin than arteries
115
varicose veins are caused by what
leaky valves
116
4 determinants of venous pressure
- Nervous sytem (sympathetic increases BP by increasing central blood volume)\
- Skeletal muscle "pump" of the legs
- Inspiratory effort (creates negative pressure in the thorax)
- blood volume (more volume = higher pressure)
117
Pulmonary artery
carries deoxygenated blood to the lungs
118
pulmonary vein
carries oxygenated blood to the heart
119
umbilical artery
carries deoxygenated blood away from the fetus to the mom
120
how much blood is in our veins at any given time?
60%
121
how many more veins do we have than arteries?
3x as many
122
Why are arteries stiffer?
accommodate larger volumes of blood and pressure
123
what percent of your capillaries are open at any given time?
5-10%
124
What would happen if all of your capillaries were open at the same time?
BP drops, not enough blood goes back to your heart, and SHOCK
125
Hematocrit
Percentage of blood made up by RBC
- 45% men
- 38-42% women
- measured by separating components of blood via centrifuge
126
3 layers of the heart
Epicardium, myocardium, endocardium
127
epicardium
superficial outer layer of the heart
128
Myocardium
- bulk
- cardiac muscle
- middle layer
129
endocardium
inner layer
- made of endothelium resting on a thin layer of connective tissue
- continuous with lining of blood vessels (this is important bc it reduces "roadblocks", less resistance)
130
Progression of blood through circulatory system
1. Superior and inferior venacava
2. Right atrium
3. Tricuspid valve (right atrioventricular)
4. Right ventricle
5. Pulmonary valve(semilunar)
6. pulmonary artery
7. lungs
8. pulmonary vein
9. Left atria
10. Bicuspid (mitral) (left atrioventricular) valve
11. Left ventricle
12. Aortic valve (semilunar)
13. Aorta
14. Systemic
131
Where does the pause occur during conduction of the heart and why does it occur?
- Occurs at the bundle of His
| - allows for atria emptying and ventricle filling
132
What are the 2 reasons why the refractory period is needed?
- allows for ventricular emptying
- prevents cardiac tetani
- T wave= ventricular reporlarization
133
how does the percentage of blood change in the brain, heart, skeletal muscle, skin, kidneys, abdominal organs, and other from resting to exercise?
```
Brain: less
Heart: same
Skeletal muscle: more
Skin: more
Kidneys: less
abdominal organs: less
Other: less
```
