CV important Flashcards
1
Q
what is the percentage of plasma in the blood
A
55%
2
Q
what is in the buffy coat of the blood
A
1%
platelets and leukocytes
3
Q
what is the percentage of red blood cells in the blood
A
45%
4
Q
what are the components of the plasma
A
water
electrolytes
hormones
proteins (carrier, immunogloblins, clotting factors)
5
Q
where are Erythrocytes (RBC’s) made and with what hormone
A
liver in foetus, bone marrow in adults
hormone: erythropoietin
6
Q
describe the structure of RBC’s
A
biconcave, anucleate
7
Q
lifespan of RBC’s
A
120 days
8
Q
what is a haematocrit
A
percentage of blood occupied by RBC’s
9
Q
what are the 3 sites of haemolysis
A
spleen
bone marrow
lymph nodes
10
Q
what causes a high haematocrit
A
excessive RBC production and dehydration
11
Q
what causes a low haematocrit
A
anaemia
12
Q
what is anaemia and what are the 2 types
A
haemoglobin deficiency
types:
impaired production
increased haemolysis
13
Q
what are the 2 categories of leukocytes
A
agranulocytes
granulocytes
14
Q
what are the 3 subtypes of granulocytes
A
basophils
eosinophils
neutrophils
15
Q
what are the 2 subtypes of agranulocytes
A
monocytes
lymphocytes
16
Q
what is the role of neutrophils
A
phagocytosis
front-line defence during acute inflammation
17
Q
what is the role of eosinophils
A
combats parasite infections
neutralises histamine
18
Q
what is the role of basophils
A
responsible for anaphylaxis
produces histamine
19
Q
what is the role of monocytes
A
only monocytes when in blood
differentiate into macrophages inside tissue
phagocytoses foreign material
e.g. Kupffer cells
20
Q
what are the 3 types of lymphocytes
A
T-cells
B-cells
Natural killer cells
21
Q
how does the structure of platelets change
A
Anucleate & discoid -> become spiculated with pseudopodia once activated
22
Q
what is the function of platelets
A
haemostasis
23
Q
how and where are platelets produced
A
liver & kidneys
thrombopoietin
derived from megakaryocytes
24
Q
what is haemostasis
A
the process to prevent & stop bleeding
25
describe the stages of primary haemostasis
```
Platelet plug formation
4 steps (Vessel injury -> Adhesion -> Activation -> Granule release -> Aggregation
```
26
what is involved in secondary haemostasis
coagulation cascade
| fibrin clot formation
27
how to platelets bind to collagen
via vWF using their receptor GP1B
28
describe the activation stage of haemostasis
Once bound to the subendothelium, platelets change shape
| Platelets release alpha and electron dense granules, to escalate haemostasis process
29
name examples of Alpha granules
vWF, Thromboxane, fibrinogen
30
name examples of electron-dense granules
ADP, Ca2+, Serotonin
31
what happens during the aggregation stage of haemostasis
Lots of platelets join the party and bind to each other using GP2b/3a receptors and fibrinogen
32
name 4 important factors in the coagulation cascade
IIa: Thrombin
Ia: Fibrin
XIIIa: Fibrin-stabilizing factor
IV: Ca2+
33
what are the Vitamin-K dependent factors in the coagulation cascade
X, IX, VII, II
| 1972
34
what are the stages of the fibrinolytic pathway
plasminogen -> plasmin -> fibrin breakdown
35
what are the 2 types of blood transfusion
Homologous (emergency transfusion)
| Autologous (self-transfusion)
36
Rh+ facts
contains D-antigen, no antibodies
can receive from both Rh+ and Rh-
only donates to Rh+
37
Rh- facts
contains no antigens, and anti-D antibodies
can donate to both Rh- and Rh+
only receives from Rh-
38
describe week 3/4 formation of the primitive heart tube
Visceral Mesoderm -> 2x Heart Tubes -> Fuse (Lateral folding) -> Craniocaudal folding (“Shrimp”) -> Heart tube has divisions now
39
what are the divisions of the primitive heart tube
```
truncus arteriosus
bulbus cordis
primitive ventricle
primitive atrium
sinus venosus
```
40
what does the truncus arteriosus become
> Ascending aorta
| > Pulmonary trunk
41
what does the bulbus cordus become
> Smooth (outflow) parts of L & R ventricles
42
what does the primitive atrium become
> both auricular appendages
> Entire L atrium
> Anterior part of R atrium
43
what does the primitive ventricle become
> Forms majority of ventricles
44
what does the sinus venosus become
> Smooth part of R atrium
> Vena cavae
> Coronary sinus
45
what does the 1st aortic arch become
maxillary
46
what does the 2nd aortic arch become
stapedial
47
what does the 3rd aortic arch become
common carotids (part of internal carotids)
48
what does the 4th aortic arch become
left -> aortic arch
| right -> right subclavian
49
what does the 6th aortic arch become
pulmonary arteries
| left -> ductus arteriosus
50
when does the heart appear and start beating
3rd week
| beating = day 23
51
what is obstetrical climbing
constriction of umbilical vein > ligamentum teres
52
what are the 3 layers of the heart
Epicardium – adipose tissue, vessels & nerves underlying the pericardium
Myocardium – thickest layer that contracts
Endocardium – inner layer of the heart, made of endothelial cells
53
what are the 3 layers (tunics) of blood vessels
```
Tunica intima (endothelial layer)
Tunica media (muscle layer)
Tunica adventitia (connective tissue)
```
54
what is myosin comprised of
2x heavy chains
| 4x light chains
55
what is actin
polymerised globular protein with troponin and tropomyosin incorporated
56
what is Titin
elastic filaments that maintain alignment of sarcomere
57
what is tropomyosin
Binds to Actin and blocks its Myosin binding site
58
what is troponin
Binds to Tropomyosin, unlocked by calcium
59
describe excitation-contraction coupling
AP spreads into myocytes via T-Tubules -> Ca2+ channels open , enters muscle cell -> binds with troponin -> uncovers active site on tropomyosin
60
what is the force of contraction directly proportional too
levels of cytosolic Ca2+
61
what do drugs which increase myocardial contractility do
increase cytosolic calcium levels e.g. adrenaline
62
what is the first stage of the cardiac cycle (ventricular systole)
isovolumetric contraction
ventricular p > atrial p so AV valves close
arterial p>Ventricular p so SL valves closed
63
what is the 2nd stage of the cardiac cycle (ventricular systole)
Ejection
ventricular p> arterial p so SL valves open and blood ejected out
atria begin to fill with blood
64
what is the 3rd stage of the cardiac cycle (diastole)
isovolumetric relaxation
| ventricular p
65
what is the 4th stage of the cardiac cycle (diastole)
passive blood flow
atrial p> ventricular so AV valves open
70-80% of blood passively fills the ventricles
66
what is the 5th stage of the cardiac cycle (diastole)
atrial booster
Extra kick to move the remaining blood out of the atria
PR interval
67
what are the 3 factors affecting stroke volume
preload
afterload
contractility
68
what is the Frank-Sterling law
States that stroke volume depends on force of contraction
Increased EDV -> increase stretch of the myocardium -> increase sarcomere length -> increase length of overlapping filaments -> increased force of contraction -> increased stroke volume
69
5 factors that affect preload
```
atrial contractility
venous return
ventricular compliance
valvular resistance
heart rate
```
70
increased contractility
```
Increases FoC -> increases SV
Positive inotropic agents:
Sympathethic nervous system
Hormones: adrenaline, thyroxine
Drugs: e.g. Digoxin
```
71
decreased contractility
Decreases FoC Decreases SV
Negative inotropic agents:
Parasympathetic nervous system
Drugs: e.g. β-blockers
72
what is afterload
Ventricular wall stress during systole
The amount of resistance the ventricles must overcome during systole
Basically the same as systolic blood pressure
Indirectly proportional to SV (unlike preload)
73
what 3 factors affect afterload
valvular diseases
aortic pressure
SVR/TPR
74
what is the pacemaker potential generated by
Nodal cells 1%
primary pacemaker - SA node
latent pacemakers - AV node, bundle of His, Purkinje
75
what is the sympathetic stimulation of the pacemaker potential
Noradrenaline = increases Ca2+ channel opening = faster depo.
Steeper Phase 0
Increases heart rate and force of contraction
76
what is the parasympathetic stimulation of the pacemaker potential
Decreases heart rate
ACh activates potassium channels = Hyperpolarizes membrane = longer to reach TP
Also decreases calcium influx= decreases slope of pacemaker potential
77
what is the absolute refractory period?
Period where the cell is completely unexcitable
| Longer for cardiomyocytes
78
what is the relative refractory period?
when a greater than normal stimulus can depolarise the cell
79
describe the path of action potential
SAN → Bachmann’s Bundle (left atria) + RA cardiomyocytes → AVN (only A-V connection) → Bundle of His → Purkinje fibres (R/L)
80
what is AV nodal delay
0.1 ms
| Allows atrium to fully contract/ventricular filling
81
p wave
atrial depolarisation
82
PR segment
AVN delay & atrial contraction
83
QRS complex
ventricular depolarisation
84
ST segment
space between Ventricular depo. and repo.
85
T wave
Ventricular repo.
86
mean arterial pressure =
CO x TPR
87
what is systolic pressure
point when LV pressure during ejection = aortic pressure during ejection
88
what is diastolic pressure
Pressure caused by recoiling of arteries during diastole
89
pulse pressure =
SP - DP
90
velocity of blood flow =
blood flow/area of vessel
91
factors affecting resistance
Viscosity
Vessel length
Vessel radius
92
blood pressure =
CO x TPR
93
role of baroreceptors
```
sense changes in BP
Aortic body = increase
Carotid body = both
Signal via CNs to Nucleus tractus Solitarius to CV control centres in Medulla
Negative feedback
```
94
how changes in CO2 control BP
chemical chemoreceptors
Increase CO2 -> diffuses into CSF (react w/ H2O)
H2CO3 > H+ and HCO3-
Decrease pH of CSF
Activation of vasomotor region of medulla (CV control centre)
95
name some major vasoconstrictors
```
local = endothelin-1
hormonal = adrenaline, ADH, angiotensin 2
neural= cardiovascular control centre
```
96
name some major vasodilators
local= NO, Lactic acid
Hormonal=Adrenaline, ANP
Neural = CV control centres
97
where can the aortic valve be heard
2nd intercostal space, right sternal border
98
where can the tricuspid valve be heard
5th intercostal space, left sternal border
99
where can the mitral valve be heard
5th intercostal space, mid-clavicular line
100
where can the pulmonary valve be heard
2nd intercostal space, left sternal border
101
Cardiac output
The amount of blood ejected by each ventricle per minute. CO = SV * HR. ~5-6 L/min.
102
stroke volume
The volume of blood ejected by each ventricle with each beat ~70 mL.
103
heart rate
The number of times the heart beats per minute. 60-100 per minute
104
end-diastolic volume
Volume of blood in each ventricle at the end of diastole ~130 mL.
105
ejection fraction
Percentage of end-diastolic volume ejected with each beat. SV/EDV. 65%.
106
end-systolic volume
Volume of blood remaining in each ventricle at the end of systole ~50 mL.
107
mean arteriole pressure =
diastolic pressure + 1/3 PP
108
stroke volume =
EDV - ESV
109
Poiseuille's equation:
radius to the power of 4
