Cardio Flashcards
What is serum
plasma sans clotting factor
what is haematocrit?
proportion of blood that is RBC
types of leukocytes
monocytes lymphocytes basophils eosinophils neutrophils
types of granulocytes
basophils
eosinophils
neutrophils
types of agranulocytes
monocytes
lymphocytes
What leukocyte produces histamine and is responsible for anaphylaxis
basophils
name 2 phagocytosing leukocytes
monocytes and neutrophils
do platelets have a nucleus?
no
what induces platelet production?
thrombopoietin
what cells produce platelets
megakaryocytes
what is haemostasis
prevention and stopping of bleeding
what occurs in primary haemostasis
formation of platelet plug
injury>adhesion>activation>aggregation
what is secondary haemostasis?
coagulation cascade
fibrin clot formation
what occurs at the site of intravascular endothelium damage?
endothelin mediated vasoconstriction at injury site to limit blood loss
what occurs during platelet adhesion?
platelet GP1B receptor binds von willebrand’s factor on exposed basement membrane collagen
what is platelet activation?
after binding to subendothelium platelets:
- Change shape to increase surface area
- Release alpha and electron dense granules
What factors are in platelet alpha granules
Thromboxane A2
Fibrinogen
Fibrin stabilising factor
what is in the electron-dense granules released by activated platelets?
ADP
Ca2+
Serotonin
What occurs during platelet aggregation phase?
platelets bind together using GP2b/3a receptors and fibrinogen
that is an autologous blood transfusion?
transfusion of patients own blood
How is cross matching performed in blood transfusion?
mix donor blood with patient serum and observe if there is a reaction
what is rhesus factor
blood factor eg O+ vs O-
what embryologic structures gives rise to the ventricles?
bulbus cordis
primordial ventricle
what does the truncus arteriosus give rise to?
ascending aorta and pulmonary trunk
in development what is the order of the primitive heart tube compartments
truncus arteriosus bulbus cordis primitive ventricle primitive atrium sinus venosus
what is septation
formation of the heart septum and folding to look more like heart
when do aortic arches appear
weeks 4-6
which aortic arch becomes carotid arteries
3
which aortic arch becomes the pulmonary artery and which becomes the aortic arch
6 - pulmonary
4 - aortic arch
how does sympathetic stimulation effect pacemaker cells
noradrenaline - increases Ca2+ channel opening = faster depolarization
how does vagal stimulation of pace maker cells effect the heart
ACh causes hyperpolarization by activating potassium channels.
delays reaching threshold for calcium channel opening.
which ECG lead gives the standard wave pattern
lead 2
right arm to left leg
what is afterload
force the ventricle must overcome to pump blood - closely related to aortic pressure
how does afterload effect stroke volume
indirectly proportional
high afterload = low stroke volume
what is preload
ventricular wall stress at the start of systole
how are preload and afterload related
increased afterload with subsequently increase preload as a high afterload will lower the proportion of blood ejected increasing the end systolic volume causing ^blood volume in the ventricles.
how can you calculate MAP
1/3 pulse pressure + diastolic pressure
how do you calculate TPR
radius^4
how is BP controlled intrinsically
local constriction based on stretch of smooth muscle
local vasoconstrictor and dilator release
nervous input
how is BP controlled extrinsically
hormones eg RASS, adrenaline, ADH
Carotid sinus baroreceptors
what is the carotid sinus and carotid body
sinus is for pressure
body is for chemicals
what innervates the carotid sinus
glossopharyngeal IX
what are the layers of the pericardium
fibrous outer and serous inner
serous = parietal and visceral layers
visceral layers always on organs
what arises from the right coronary artery
right marginal
posterior interventricular
what does the posterior interventricular artery supply
posterior 1/3 of septum and AVN
name the branches of the left coronary artery
left coronary > left anterior descending > diagonal
left coronary > circumflex > marginal
what is the blood supply to the SAN
60% right coronary
40% left coronary
what is the origin of the phrenic nerve
c3-5
what are the layers of an artery
out to in adventitia external elastic lamina media internal elastic lamia intima basement membrane endothelium
differences between large arteries and veins?
arteries have a thick tunica media with 40-70 layers of elastic membranes with smooth muscle
large veins have thicker tunica intima and well developed longitudinal smooth muscle
what vessels have valves?
veins
venules
lymphatic vessels
standard right heart and pulmonary circulation pressure
20/8 mmHg
cardiac output calculated by?
Stroke volume X Heart rate
What effects stroke volume
preload
afterload
contractility
heart rate
what units are preload and afterload measured
mmHg
What is inotropy
force of heart contraction
name a positive inotropic factor
adrenaline
thyroxine
digoxin
name a negatively inotropic drug
beta blockers
normal HR
60-100
is an increase in HR proportional to an increase in CO?
no as diastole shortens so less preload
what is the basis of frank starlings law
stretch of muscle causes stretch mediated calcium channels to open increasing contraction force
how do pacemaker cells fire spontaneously
- sodium channels that open due to hyperpolarization (neg charge)
- voltage gated calcium t channels open at threshold
- influx of Ca2+ causes depolarization
- restored by K+ efflux
What does beta 1 receptor stimulation in the heart do? what stimulates them?
Noradrenaline causes increase Ca2+ channel opening increasing depolarization rate
What does muscarinic (M2) receptor stimulation in the heart do? what stimulates them?
ACh causes K+ channels to promote hyperpolarization, making it harder to reach threshold for depolarization
what electrically insulates atria from ventricles
fibro-granular rings around AV valve
What does atrial repolarization look like on an ECG
can’t see it as it is too small
