cardiovascular system L5-10 Flashcards
1
Q
functions of CVS
A
controlled/ continuous transfer
hormone transport
homeostasis
2
Q
CVS structure
A
2 circulations in series (systemic> high and pulmonary> low)
unidirectional flow
equal blood vol in each circulation
3
Q
which vessels carry blood away from heart?
A
aorta
pulmonary artery
4
Q
which vessels carry blood into heart?
A
vena cava
pulmonary vein
5
Q
atrioventricular valves
A
R - tricuspid
L- mitral/ bicuspid
6
Q
semilunar valves
A
R- pulmonary
L- aortic
7
Q
stroke volume
A
volume of blood pumped by 1 ventricle
8
Q
average stroke volume
A
~75ml at rest
9
Q
cardiac output
A
volume of blood pumped per ventricle per minute
10
Q
cardiac output formula
A
heart rate * stroke volume
11
Q
venous return
A
amount of blood returning to heart
at steady state VR=CO
12
Q
arteries properties
A
high pressure
elastic
function for distribution
13
Q
arterioles properties
A
high resistance
blood flow control to tissues
14
Q
capillaries function
A
thin wall
arranged in parallel
exchange function
15
Q
veins properties
A
decreasing pressure
one-way valves
capacitance/ collection function
16
Q
pressure of fluid in motion rule
A
decreases with distance due to friction
17
Q
pulse pressure
A
systolic pressure - diastolic pressure
18
Q
biggest drop in pressure
A
from arterioles
19
Q
mean arterial pressure
A
pressure averaged over time
20
Q
blood flow relation to resistance
A
blood flow proportional to 1/ resistance
21
Q
Darcy’s law
A
flow = change in pressure/ resistance
22
Q
resistance factors
A
distance
vessel radius
blood viscosity
23
Q
poiseuille’s law
A
flow proportional to change in pressure * radius^4
24
Q
blood flow
A
volume/ minute
25
blood velocity
distance travelled / minute
26
blood velocity factors
flow
cross-sectional area
27
cardiac muscle cells
striated with T-tubules > SR
actin/ myosin/ troponin sarcomere
a.p generation to elevate cytoplasmic Ca2+ for contraction in excitation-contraction coupling
28
autorythmic
nerve supply regulated HR
29
2 groups of myocytes
conducting > fast spread of a.p's
work> generate atrial/ ventricular force
30
heart beat initiation location
sino atrial node in right atrium
31
synctium
work cells interlinked by intercalated discs
32
spread of excitation from SAN
conducting fibres in atria/ ventricles
cell-cell via gap junctions
33
pacemaker potential function
spontaneously depolarizes to threshold so AP is generated, setting HR
34
ionic basis of electrical activity of SAN
1. slow initial depolarization
2. full depolarization
3. repolarization
4. minimum potential phase
35
slow initial depolarization of SAN
cation leak via non-spec cation leak channels in PM
36
full depolarization of SAN
at threshold, v-gated Ca2+ channels open and Ca2+ enters cell
37
repolarization of SAN
Ca2+ channels close and K+ open
38
minimum potential phase of SAN
K+ remains open
membrane hyperpolarization and non-specific cation channels open, repeating cycle
39
ionic basis of electrical activity in ventricular muscle cell
1. rapid depolarization
2. initial repolarization
3. plateau
4. repolarization
40
rapid depolarization of ventricular muscle cell
v-gated Na+ channels open and Na+ enters
41
initial repolarization of ventricular muscle cell
Na+ channels inactivated and K+ leak
42
plateau of ventricular muscle cell
Ca2+ channels open as K+ leave , prolonging depolarization
43
repolarization of ventricular muscle cell
Na+/ Ca2+ channels close and K+ exits
44
trigger Ca2+
v-gated Ca2+ channels in plateau phase lead to muscle contraction > Calcium induced Calcium release
45
factors affecting force of contraction
sarcomere length
no. active cross-bridges (how much Ca2+ bound to troponin-C, depending on CICR amount)
46
refractory period of heart
outlasts contraction period to prevent tetanus
47
ECG
measures electrical signals conducted to body surface for depolarization/ repolarization/ disturbance recording
(summed electrical activity generated by all working cells of heart)
48
P wave
atrial depolarization
49
QRS complex
ventricular depolarization
50
T wave
ventricular repolarization
51
arrythmia
abnormal heart rythmns
1. impulse propagation
2. impulse initiation
52
cardiac cycle
cycle of pressure and volume changes in the heart chambers w contraction and relaxation
53
cardiac cycle stages
1.ventricular filling/ late diastole
- atrial systole
2. isovolumetric ventricular contraction
- AV valves close
3. ventricular ejection
- semilunar valves open
4. isovolumetric ventricular relaxation
cycle repeat
54
systole
contraction
55
diastole
relaxation
56
end-diastolic volume
most blood in ventricles
57
end-systolic volume
minimum blood in ventricles
58
lubb
S1-AV valve closure
59
dupp
S2-SL valve closure
60
phonocardiogram
measure pressure over time
- all 4 valves can be individually listened to for functional abnormalities
61
valve diseases
stenosis
incompetence (regurgitation/ leaky)
62
arterial pressure wave
diastolic pessure
systolic pressure
dichrotic notch
aortic valve closure
63
MAP formulae
diastolic pressure + 1/3 pulse pressure
64
pulse pressure formulae
SP-DP
65
systemic arterial blood pressure
measured at heart level on upper arm
systolic/ diastolic measurement
~120/80mmHg
66
auscultation
2 types of flow?
measures systolic/ diastolic flow
laminar
turbulent
67
laminar flow
silent flow w no compression
68
turbulent flow
korotkoff sounds
pulsatile blood through artery
69
cardiac output formula
stroke volume * Heart rate
70
total peripheral resistance
sum of individual vessel resistance to flow
71
mean arterial blood pressure formula
cardiac output * total peripheral resistance
72
average cardiac output/ heart rate/ tidal volume at rest
4.9 L/min
70ml
70bpm
73
parasympathetic neural control of heart
ACh
muscarinic ACh receptor activation
74
sympathetic neural control of heart
NA
B1-adrenergic receptor activation
75
sympathetic stimulation with SAN pacemaker
tachycardia
76
tachycardia
increased HR due to steeper potential slope/ quicker threshold time
77
parasympathetic stimulation w SAN pacemaker
bradycardia
78
bradycardia
decreased HR
longer threshold time
79
chronotropic effects
changes in HR
80
2 mechanisms for stroke volume regulation
intrinsic
extrinsic
81
Starling's law of the heart
force of contraction proportional to initial muscle fibre length in diastole
82
intrinsic neural regulation
VR^ ^EDV in diastole (stretching cardiac muscle) ^ force of contraction and stroke volume
intracellular Ca2+ lowers tension/ matches R/L input of heart/ heart adaptation when pumping/ prevents lung oedema
83
extrinisic neural regulation
^sympathetic activity
enhances contractility/ NA/ binds to B1 adrenergic receptors
enhances SV
+inotropic effect
84
lusitropic effect
changes in rate of muscle relaxation
85
catecholamines
^ contractility by triggering more Ca2+
86
what's venous return maintained by?
venous-atrial pressure difference
skeletal muscle contraction
venometer tone
respiration
87
arterioles function
control TPR
match local blood flow to local metabolic need (decreases tone w ^ need/ radius)
88
arteriole radius control
local
hormonal
neural
89
autoregulation of tissue blood flow
constant flow w ^pressure
intrinsic / myogenic smooth muscle activity
safety mechanism preventing damage to vessels
90
flow formula
MAP/R
91
metabolic control of tissue blood flow
*can override myogenic
metabolism-derived vasodilators >> ^CO2/ ^H+ ^temp ^adenosine ^K+ / decreasing O2
92
vasodilators
kinins
histamine
adrenaline
93
vasoconstrictors
angiotensin II
vasopressin
adrenaline
94
sympathetic vasoconstriction fibres
release NA
bind to a1-adrenergic receptor for vasoconstriction
95
B-receptor vasodilation
epinephrine from B-receptor
96
a-receptor vasoconstriction
norepinephrine from a-receptor
