Cardio Flashcards
1
Q
Why do humans require a circulatory system?
A
Transportation of materials to allow exchange between cells of the body and the external environment
2
Q
overall design of cardiovascular system
A
series of tubes (blood vessels), filled with fluid (blood), and connected to a pump (heart)
- closed circuit
- operates by pressure differences
3
Q
pulmonary circulation
A
oxygen depleted blood from right heart to lungs
4
Q
systemic circulation
A
oxygen rich blood from left heart to rest of body
5
Q
arteries
A
take blood away from heart
6
Q
veins
A
return blood to heart
7
Q
two main components of blood
A
plasma and cells
8
Q
blood plasma
A
mostly water
9
Q
red blood cells
A
contain hemoglobin which plays important role in transporting oxygen (erythrocytes)
10
Q
white blood cells
A
immune function (leukocytes)
11
Q
platelets
A
blood clotting
split off from megakaryocytes
12
Q
flow of blood in the cardiovascular system
A
- directly proportional to pressure gradient
- inversely proportional to resistance to flow
13
Q
Pouiselle’s Law
A
resistance is proportional to: length x viscosity x radius^4
-small changes in radius lead to big changes in resistance
14
Q
what part of hemoglobin binds oxygen
A
iron
15
Q
three ways carbon dioxide can be transported
A
1) bind with hemoglobin
2) form bicarbonate ions (what most does)
3) dissolved in plasma
16
Q
erythropoieten
A
hormone produced in the kidneys and can induce RBC production
17
Q
4 chambers of heart
A
R and L atria: receive blood
R and L ventricles: eject blood
18
Q
base of heart
A
the top, round
19
Q
apex of heart
A
bottom, point of cone
20
Q
aorta
A
receives blood from left ventricle to send to systemic arteries
21
Q
pulmonary vein
A
receives blood from veins of the lungs and sends to left atrium
22
Q
vena cavae (superior and inferior)
A
receive blood from systemic veins and send to right atrium
23
Q
pulmonary trunk (artery)
A
receives blood from right ventricle and send to lungs
24
Q
what path does blood take
A
Systemic veins –> RA–> RV–> PA–>Lungs–>PV –>LA–> LV –> Systemic arteries
25
systole
ventricular contraction
- AV valves close to prevent backflow into atria
- semilunar valves open
- pushing blood into aorta
26
diastole
ventricular relaxation
- semilunar valves closed to prevent backflow into ventricles
- mitral valve (bicuspid) open
- allow ventricles to fill with blood
27
electrical signal pathway in heart
SA node --> Atria--> AV Node --> Bundle of His--> Bundle Branches--> Ventricles
28
mechanical contraction
electrical signal is stimulus for coordinated mechanical contraction of atria then ventricles
29
how are electrical signal and mechanical contraction linked?
an increase in cytosolic calcium levels within cardiac contractile cells
30
contractile cells
- sarcomeres
| - generate tension that causes muscle contraction
31
autorhythmic cells
- initiate electrical signal for contraction a SA node
- smaller than contractile cells
- no sarcomeres
32
excitation-contraction coupling
occurs through cytosolic calcium
| -contracts when Ca is high (systole)
33
SA node
- pacemaker of the heart
| - AV node and purkinje fibers can act as pacemaker is SA node not functioning
34
autorhythmic action potentials
- unstable membrane potentials
| - depolarization is due to calcium channels opening
35
Funny channels
allow sodium to enter and depolarize cell
36
calcium channels in autorhythmic cells
T-type open first
| L-type open second
37
contractile cell action potentials
- depolarization due to sodium entry
- repolarization due to potassium exit
- plateaus due to calcium entry in the cell preventing tetanus
38
why do we have long refractory period in cardiac muscle
to prevent tetanus and allow ventricles to refill
39
P wave
atrial depolarization
40
QRS complex
wave of ventricular depolarization
41
T wave
ventricular repolarization
42
atrial repolarization
part of QRS complex, occurs at same time as ventricular depolarization
43
PR segement
corresponds to delay at AV node
44
ST segment
time between ventricular depolarization and repolarization
45
excitation-contraction coupling in contractile cells
1) AP from adjacent cell depolarizes membrane
2) Ca influx triggers more release of Ca from SR
3) Ca binds to troponin to initiate contraction
4) relaxation when Ca unbinds troponin and is pumped back into SR
46
ventricular diastole
```
ventricles filling (includes atrial systole)
LA pressure > LV pressure
```
47
isovolumic contraction
ventricles contract without change in volume
| LA pressure < LV pressure < Aortic pressure
48
ventricular ejection
SL valves open and blood in ejected into PA/aorta
| LV pressure > Aortic pressure
49
isovolumic relaxation
ventricles relax without change in volume
| LA pressure < LV pressure < Aortic pressure
50
S1
"lubb" 1st heart sound
| occurs when AV valves close
51
S2
"dub" 2nd heart sound
| occurs when SL valves close
52
timing of mechanical and electrical events
electrical events followed by mechanical
- depolarization followed by contraction
- repolarization followed by relaxation
53
cardiac ouput
volume of blood ejected by each ventricle in one minute
| -product of heart rate and stroke volume
54
stroke volume
amount of blood ejected from ventricle in each heart beat
| End diastolic volume - End systolic volume
55
ejection fraction
percentage of EDV ejected during each contraction
56
regulation of heart rate
initiated at SA node and modulated by ANS
57
parasympathetic branch
slows heart rate
58
sympathetic branch
increases heart rate
59
parasympathetic neurons
- release ACh that binds to muscarinic receptors
- K out, Ca in
- hyperpolarize cell and decrease rate of depolarization
- slow HR
60
sympathetic neurons
- release NE that binds to beta-1 receptors
- Na and Ca influx
- increase rate of depolarization
- speed up HR
61
stroke volume regulation
- length of muscle fibers at beginning of contraction: increased length as muscles stretch
- contractility: more Ca released and able to bind to troponin to generate greater force of contraction
62
Frank Starling Law of the Heart
- stroke volume is proportional to end diastolic volume
- EDV = "preload" determines length of muscle fibers prior to contraction
- "the heart pumps the blood it receives"
63
EDV is determined by
Venous return:
- skeletal muscle pump
- respiratory pump
- constriction of veins
64
ionotropic agent
any chemical that affects contractility
65
positive ionotropic effect
epinephrine and norepinephrine
66
negative ionotropic effect
beta blockers and calcium channel blockers
67
phospholamban
regulates activity of sarcoplasmic ATPase pump
68
arteries and arterioles
take blood away from heart
- elastic walls
- thick layers of vascular smooth muscle
- constriction and relaxation to influence blood distribution
69
capillaries
facilitate exchange of materials between blood and tissue
70
venules and veins
take blood back to heart
- thin walls of vascular smooth muscle
- constriction can increase venous return
71
determinant of blood flow
blood flows if there is a pressure gradient
| high to low pressure
72
determinants of blood pressure
flow x resistance
blood flow follows a pressure gradient that is highest in the aorta/large arteries and moving to arterioles and lowest in the veins
73
resistance
inversely proportionally to radius^4
| proportional to length and viscosity (usually stay same)
74
what regulates arteriole diameter
vascular smooth muscle
- vasoconstriction
- vasodilation
75
small changes in radius have big changes in resistance
decrease radius --> decrease flow
| increase radius --> increase flow
76
local control
matches tissue blood flow with the metabolic needs of a given tissue
ex) adenosine in hypoxic cells can increase blood flow to match metabolism
77
sympathetic reflexes
to maintain arterial pressure and regulate blood distribution for homeostatic needs
ex) NE release on alpha receptors
78
hormones
either directly or by altering ANS
79
ANS regulating HR
SNS and PNS innervation influence rate of SA node depolarization
- SNS release NE to increase HR
- PNS release ACh to decrease HR
80
ANS regulating stroke volume
SNS innervation
- NE and E from adrenal medulla influence contractility
- SNS mediated venoconstriction
81
SNS influences arteriolar resistance
-tonic release of NE maintains muscle tone
alpha: vasoconstriction of GI and kidneys
beta 1: pos. ionotropy and increased HR
-Epi release from adrenal medulla
beta 1: pos. ionotropy and increased HR
beta 2: vasodilation
82
baroreceptor reflex
ensure adequate perfusion of the brain and heart by maintaining sufficient mean arterial blood pressure
83
mean arterial blood pressure determinants
blood volume, effectiveness of heart as a pump, resistance, and relative distribution of blood (between arteries and veins)
84
drop in BP
increased SNS/decreased PNS
increased HR and SV
vasoconstriction
85
elevated BP
increased PNS/decreased SNS
decreased HR and SV
vasodilation
86
continuous capillaries
endothelial cells form continuous lining with leaky junctions; muscle, connective tissue, neural tissue (most common type)
87
fenestrated capillaries
large pores between endothelial cells; kidneys and intestines
88
velocity of blood flow
slowest at capillaries, but they have greatest surface area
89
capillary exchange
diffusion: small dissolves gases and solutes
bulk flow (paracellular pathway)
vesicles: larger solutes
90
bulk flow
mass movement as a result of hydrostatic or osmotic pressure gradients
91
absorption
fluid movement into capillaries
- net absorption at venous end
- caused by colloid osmotic pressure
92
filtration
fluid movement out of capillaries
- net filtration at arterial end
- caused by hydrostatic pressure
93
lymphatic system
returns fluids and proteins filtered out of the capillaries to circulatory system
94
edema
excess fluid in the interstitial space
95
causes of edema
1) inadequate drainage of lymph
| 2) blood capillary filtration exceeds absorption
96
adjustments of cardiovascular system during exercise
- increased cardiac output
- increased central venous pressure (venous return)
- decreased systematic vascular resistance
97
baroreceptor reflex during exercise
CNS modifies and resets to a higher control point to avoid bradycardia
98
adjustments to cardiovascular system during hypotension caused by an abrupt change in body posture or blood loss
sudden change to standing can cause hypotension (which triggers baroreceptor reflex)
-short term response by baroreceptor and long term response by hormones
99
stenotic valves
-narrowing of valve opening
-increased resistance to flow
-increased velocity of flow
heart murmur when valves should be open
100
insufficient valves
-valve leaflets do not completely seal when valve should be closed
-causes regurgitation of blood
heart murmur when valves should be closed
101
heart failure
diminished contractility
- rightward shift on SV vs. EDV curve (to maintain SV)
- Poor pump function can ultimately cause pulmonary/systemic edema
102
Atherosclerotic Vascular Disease
causes: stenosis of artery
consequences: increased vascular resistance
treatment: bypass surgery or angioplasty
103
hypertension
causes: any factor that increases blood volume, CO, or TPR
consequences: Kidneys are complicit in ”allowing” chronic elevation in BP
treatment: target reductions in blood volume or TPR
