Cardiovascular Flashcards
All lecture content other then Histology, critical numbers and public health
What is the the haemocrit for blood?
45% cellular component of blood.
what is the fluid component of blood?
55%
What lies between the red blood cell and fluid layers on a haemocrit?
it is the white blood cells and platelets.
Where is haemopoesis in utero?
the yolk sac, liver and spleen, and bone marrow.
Where is haemopoesis in children?
in all bones in the bone marrow
Where in adults is haemopoesis?
in the axial skeleton. the spine and skull
What is the name for production of RBCs?
Erythropoeisis?
What is the name for production of which blood cells?
Myelopoiesis
What is the name for the production of Platelets?
Thrombopoesis
What cells does a common myeloid progenitoro lead to?
Megakaryocytes, erythrocytes, mast cells, myeloblasts
What do myeloblasts lead to?
Basophils, neutrophils, eosinophils, and monocytes.
What do common lympnoid proogenitors lead to?
lymphocytes
What growth factor causes RBC production?
Erythropoietin
What growth factor causes white blood cell production?
Granulocyte-macrophage-colony-stimulating factor
Which growth factor stimulates growth of platelets?
Thrombopoietin
Facts about RBCs?
simple cells no nucleus, no mitochondria, Biconcave disk around 7.5um contai haemoglobin and glycolysis enzymes.
Describe the haemoglobin molecule
quaternary structure. 2 alpha chains 2 beta chains. contain Fe2+ in haem group
What are the types of haemoblobin in an adult and proportions?
HbA 2 alpha 2 beta, 96-98%, HbF 2 alpha 2 gamma 0.5-0.8%, HbA2 2 alpha 2 delta 1.5-3.2%
What are the signs and symptoms of anaemia?
signs pallor tachycardia, signs related to underlying cause. symptoms tiredness/lethargy shortness of breath on exertion angina claudications symptoms related to underlying cause.
What changes in acute blood loss?
Volume of blood no change to haemocrit as all components lost equally.
How long do RBCs last for?
120 days aproximately 9 billion in an hour.
Which organs are involved in the removal of RBCs?
Spleen, Liver Bone marrow
Hypoplastic
not enough
Dyshaemopoietic
ineffective production
Haemolytic
breaking of red blood cells
What is hypoplastic anaemia?
Not enough RBC produced causes renal failure endocctine problems can be inherited or idiopathic.
What are causes of iron deficiency anaemia
chronic bleeding poor diet malabsorption or hookworm
Length of life of a neutrophil?
6-10 hours
Length of life of a monocytes?
20-40 hours
Length of life of a lymphocyte?
weeks to years
Length of life of a basophil?
days
Length of life of a eosinophils?
days
Which white blood cells are the most numebrous?
The neutrophils
What is the function of neutrophils?
To phagocytose bacterial and foreign material they also release chemotaxins and cytokines which are important in the inflammatory response
What are macrophages?
They are cells that phagocytose bacteria and foreign material can differentiat to specific ones in tissues
What are macrophages derived from?
Monocytes
What are dendritic cells?
they present antigens to the immune system
What are basophils?
they migrate to tissues and become mast cells and the contain histamine and IgE surface antigens. they are important in immunity and allergic response.
Eosinophils what do they do?
They have a role in inflammation and allergic response especially in protection against parasites.
What are the two types of lymphocytes?
B lymphocytes and T lymphocytes.
What do B lymphocyts do?
mature in bone marrow and generate antibodies becoming plasma cells.
What do T lymphocytes do?
Mature in the thymus and aid B cells and generate cell mediated immunity.
What is Haemostatis?
The balance keeping blood fluid in the vessels and clotting outside the vessels
What acts to cause clotting?
Platelets and proteins of coagulation cascade
What acts to prevent clotting?
Endothelial cells, the anticoagulant pathway and fibrinolytic pathway.
How are platelets produced?
There are megakaryocytes that release platelet precursors from their surface as blebs. they are anucleate and circulate in an inactive state.
What are the stages of action of platelets?
They bind to collagen via glycoprotein 1a (GP1a) on the platelet membrane. they can also stick to collagen via factors like von Willebrand factor through GP1b GP2a/b.
once the platelets are activated they change shape to help them stick together to make a platelet plug. They release granules. finally GPVI causes stable adhesion and aggregation
What are in electron dense granules of patelets?
Calcium ADP and ATP and serotonin
What are in the alpha granules of platelets?
Platelet derived growth factor fibrinogen, heparin antagonist PF4 and vonWillebrand factor
What is thrombocytopenia?
too few platelets
What is thrombocytosis?
having too many platelets which can lead to thrombosis.
What are some of the components of Plasma?
Proteins- albumin, carrier proteins coagulation proteins and immunoglobulins.
What does albumin do where is it produced?
produced in the liver helps maintain oncotic pressure of the blood to keep fluid in the blood.
What are immunoglobulins?
they are proteins produced by B lymphocytes that are in the blood for immune response.
How many clotting factors are there?
13 but no 3,4,6
What is haemophillia A?
genetic condition males defficiency of clotting factore VII bleeding into muscles and joints
What is haemophillia B
Defficiency in factor IX bleeding into muscles and joints
What is an example of acquired bleeding disorder?
liver disease because of vitamin K deficiecy(found in vegetables.
What is the shape of IgM antibodies?
pentagonal shape
what is the shape of IgA antibodies?
two normal stuck to each end.
What causes a transfusion reaction?
The production of antibodies whcih react with the antigens on the surface of a foreign RBC
What type of antibodies are usually involved with blood reactions?
IgM ones
Which types of antibodies can cross the placenta?
IgG
What is the difference between ABO and RhD antbodies?
RHd is an immune antibody they are warm agglutins while ABO are naturally present and they are cold agglutanins that means they like to react at colder temperatures.
Why is RhD a problem in pregnancy?
When the mother is Rhesus negative so doesn’t have D antigen. If the baby has go D antigens. All pregnant women are tested all who are negative are given antiD antibodies to stop sensitisation Haemolytic disease of the newborn.
What is cross matching in transfusions?
mix donor blood and patient to check for agglutination. could have antibodies from previous transfusions.
What are the early transfusion risks?
ABO incompatability, allergic reactons pyrogenic reactions bacterial contamination. couagulopathy. circulatory overload, transfusion related lung injury. post transfusion purpura
Late transfusion risks
RhD sensitisation, Delayed transfusion reaction, transfusion related iron overload, viral infection, prion infection
What is packed red cells?
less plasma can be given with diuretic usually over 2-3 hours
What product is used for poor clotting?
platelets given over 30mins when have very low platelet count
What is FFP?
Fresh frozen plasma. Frozen in less than 6 hours contains proteins and inhibitors useed fro massive transfusion and dilutional coagulopathy liver disease and
What is cryoprecipitate?
rich in fibrinogen factor 1 used in massive transfusion.
What is HAS?
Human albumin solution plasma expander increases osmotic pressure and reduce oedema.
What layer of the embryo contributes to the arteries and cardiac outflow?
The ectoderm
Which layer of the embryo forms the blood and heart?
mesoderm
What is the shape of the heart fields?
They are sausage shaped sitting on top of each other the first on top of the second the lowest part will form the atria
What does the first heart field give rise to?
the left ventricle
What does the second heart field give rise to?
The future right ventricle the atria and outflows
What does the truncus arteriosis or bulbus cordis do and where is it?
It is at the top of the fused heart tubes and forms the aortic arch and most of the right ventricle
What does the primitive ventricle form?
The left ventricle
Where is the primitive atrium?
it is below the bulbus cordis and primitibve ventricle like carina. it forms the left and right atria
what are the sinus venosis?
they are at the bottom they produce the inferior vena cava and the right atrium
What happens to the heart after the formation of regions?
Dextro rotation to the right. the cordis and primitive ventricle moves down and to the front the primitive atrium moves up the back
What is cardiac septation?
formation of septum from the primus
what are the endocardial cushions?
they grow up and down to form the separation of the AV canal.
Describe the formation of the interatrial septum.
First There is the growth of the septum primum to join with the endocardial cussion making a hole the foramum primum at the bottome, then the foramen primum dissapears then forms foramen secundum at top.
then the septum secundum which is thicker and more muscular than the septum secundum contains the foramen ovale. the septum primum acts a valve flap for the atria.
Where is most of the blood in the body?
In veins
Where are the elastic arteries?
main ones like aorta brachiocephalic carotids subclavian and pulmonary.
What are the three types of capillaries?
Continuous which are most common, fenestrated in kidney small intestine and endocrine glands and discontinuous in the liver sinusoids
What advantage does valves give veins?
Muscular return of blood can take places.
When does vasculargenesis commence?
day 18
Which part of the primitive heart makes the aortic arch?
the truncus arteriosis/bulbus cordis
how many arches of the aorta are there?
6 main ones but there is no 5th
What does the 1st arch become?
part of the maxillary artery
What does the 2nd arch become?
the stapedial artery
what does the 3rd arch become?
the left or right internal and external carotid
What does the 4th arch become?
on left part of the aortic arch on the right the right subclavian.
What does the 6th arch develop into?
left the pulmonary artery and ductus arteriosis, on the right the right pulmonary artery
What does the 7th segmental artery become?
the left subclavian artery and part of the right subclavian artery
what does the dorsal aorta do?
It becomes the decending thoracic aorta on the left and regresees to be part of the right subcavian on the right.
What does the aortic sac become?
ascending aorta and part of brachiocephalic trunk.
What is the importance of platelets in disease?
Thrombosis
Describe the stages of Thrombosis
A fatty streak builds up on lining, becomes a fibrous plaque, artherosclerotic plaque then this can rupture or fissure and cause the clot to block that artery or pass to a critial area like the heart or brian.
What happens when a platelet it activated?
It changes shape from smooth to spiculates and pseudopodia (legs). increasing SA so increased interactions. more receptors and increased affinity to fibrinogen
Which receptors are used to cause adhesion?
attachement via GPIIb/IIIa integrin alphaIIb beta3
What can activate platelets?
Thrombin- also cleavs fibrinogen into fibrin. by PAR1 and PAR4
Thromboxane A2- comes from platelets when its bound to collagen, asprin stops this.
Collagen GPVI receptor
ADP- P2Y1
What biochemical changes occur at activation of platelets?
Causes more GPIIb/IIIa receptors,
Describe the action of COX1 and 2
Cyclooxygenases. both convert arachidonic acid into prostaglandin H2
COX-1 turns into thromboxane A2 in plateletsand COX-1 and COX-2 in endothelial cells convert prostaglandin H2 into prostacyclin
What is the effect of thromboxane A2?
causes platelet aggregation, and vasoconstriction.
What is the effect of prostacyclin?
Inhibits platelet aggregation and vasoconstriction. it mediates inflamation
What do NSAIDs do?
Block COX-1 and 2 to stop prostacyclin being formed meaning a clot is more likely.
What does low dose asprin do?
it inhibits COX-1 in platelets which stops thromboxane A2 production which leads to less clotting
What does high dose asprin do?
Block COX-1 and 2 to stop prostacyclin being formed meaning a clot is more likely.
What does high dose asprin do?
Block COX-1 and 2 to stop prostacyclin being formed meaning a clot is more likely.
What are P2y1 and P2y12?
both ADP receptors, P2y1 is linked to Gq which mobilises Ca and initates platelet activation. P2y12 which is linked to a G protein Gi which causes cAMP giving amplification of activation and dense granule release with ADP.
What are amplification pathways on the platelet?
P2y12 activated by ADP releases dense granules to re stimulate itself. GPIIb/IIIa causes granule release. Collagen binding to GPVI causes release of thromboxane A2.
Thrombin activates dense granule release.
thrombin produced on membrane
Describe the changes to lipid bilayer in platelets that faciltate production of thrombin
usually has amiophospholibids that are kept on inner layer of plasma membrane by translocase. when activated Ca released which scramblase is activated and translocase inhibited which means amino phospholibids allows prothrombinase can bind to the membrane and convert prothrombin to thrombin factor 2 and 2a
Describe the fibrinolytic system
the endothelium releases tPA tissue plasminogen activator. converts plasminogin into plasmin which converts fibrin into degreded products
there are inhibitors are PAI-1 and antiplasmin
What is the significance of platelete alpha granules?
release coagulation factors and inflammatory mediators which help the wound healing with WBCs
allow monocytes to bind.
What lies on the right heart border?
Superior vena cava, right atrium
Where does the right heart border lie?
It is to the right of the sternum
Where is the inferior border of the heart.
Sits on the diaphragm and below the xiphoid sternum.
Where is the let heart border?
left mid clavicular line
Where is the apex beat?
left midclavicular line 5th intercostal space.
What is the pleural refelction?
it is an area below the xiphoid sternum it is an area on inferior surface of the heart and is a gap in pleural membrane used to drain fluid from the heart without openning the pleural.
What lies on the left heart border
aorta left atrial appendage and most is left ventricle.
what makes the anterior border of the heart?
right ventricle and left ventricle
What is the posterior border of the heart?
the left atrium.
What is the importance of the sternal angle?
2nd costal cartilage, defines the superior and inferior mediastinum. T4/5 level
What is in the anterior mediastinum?
the thymus
What is in the middle mediastinum?
pericardium and heart
What is in the posterior mediastinum?
oesophagus the aorta intercostal arteris bronchial arteries the throacic duct azygous veins and hemiazygous vein sympathetic trunks
What is the pericardium like?
Fibrous layer parietal and visceral on the surface of the heart.
which great vessels are at the front of the heart
aorta and pulmonary artery.
What are the two areas of the right atrium?
the smooth parts and the trabeculated part(with ridges) they are separated by the crista terminalis
Where is the coronary sinus?
it drains into the right atrium directly runs in the atrioventricular goove
What is the aortomitral continuity?
the aortic and mitral valves are connected by a fibrous area.
What are the branches of the right coronary artery?
it runs through the atriventricular sinus then at edge gives right marginal artery, continues to the back potentally giving posterior interventricular artery.
What are the first branches of the aorta?
the coronary arteries
describe the branches of the left coronary artery.
The circumflect comes off to go in atrioventricular groove to back to give posterior interventricular also gives obtuse marginal artery. the LAD runs between the ventricles. it gives the septal arteries that go into the septum and diagonal across the front.
Explain dominance in terms of coronary arteries
what artery suplies the posterior descending. 70% right dominant 20% left dominant 10% co-dominant
How many electrodes are there on an ECG?
- left arm right arm left leg right leg. then V1-6 V1 on Rhs of sternum 4th intercostal space. V2 right ternal border 4th intercostal space. V3 between V2V4 V4 5th iCS mid clavicular line V5 anterior axillary V6 mid auxillary
What does each small square represent on an ECG?
40ms
What does each big square represent?
0.2s
Why are there 12 leads but 10 electrodes?
different views between them
how many bipolar leads are there?
3
how many unipolar leads are there?
3 arm 6 chest
Which leads give lateral view?
Lead 1 avL V5 V6
which give inferior view?
lead 2 lead3 avF
which give septal view?
V1
Which ECG lead gives anterior view?
V2 V3 V4
Which lead(s) are P waves negative?
aVR
What does a P wave represent?
atrial depolarisation(not systole)
How to interpret an ECG?
Rate Rhythm Axis P PR interval QRS ST segment T waves QT interval
How can you calculate ventricular rate?
300 divided by big squares between 2 QRS complexes
How can you tell if it is sinus rhythm?
Pwave morphology suggest its from SA node eg positive in all but aVR and that its followed by a QRS complex
name sone other rhythms?
sinus, supraventricular, ventricular heart block
What is a normal cardiav axis?
-30 to 90 degrees
How long should the P wave be?
3 small squares.
What kind of abnormalities can be present in P waves?
Tall peaks, right atrial enlargment. bifid p wave left atrial enlargement. inverted non sinus origin
PR interval should be how long?
3 to 5 squares long can show poor conduction.
How long should the QRS complex be?
3 small squares or 120msec
What does the QRS complex represent?
Verntricular depolarisation (not systole)
What are some common QRS comples abnormalities?
Broad complex- Ventricular origin, BBB, hyperkalemia, ventricular pacing.
High voltage QRS-ventricular hypertrophy
What does the ST segment show?
Interval between depolarisation and repolarisation.
What does T wave show?
Ventricular repolarisation
What is a common ST abnormalities?
ST segment depression often due to ischemia or digitoxin toxicity hypokalemia ventricular hypertrophy
T wave inversion is caused by what?
ischemis pulmonary embolism, ventricuar hypertrophy, often normal like this in children.
What is the QT interval? how long is too long?
Time of depolarisation and repolarisation. 440 for men 460 for women
Which organs of the body use the most blood(in order)>
Liver Kidneys, muscle, brain
Where does blood flow the fastest in the circulatory system?
in the aorta and vena cava
What are the adaptations of the arteries?
Elastic to cushion systole and maintain blood flow to organs during diastole.
Which blood vessel is the principal site of resistance tovascular flow?
the arterioles
What is TPR?
Total peripheral resistance = total arteriola resistance it can be varied and plays a major role in detrmining arterial pressure and distribution of flow to organs
what happens when vascular smooth muscle constricts?
radius decreases and resistance increases and flow decreases.
Is vascular smooth muscle ever completely relaxed?
No this is called the myogenic tone
What happens to blood in capillaries?
it slows down to allow for blood do drop off nutrients.
What is the average pressure of a vein?
10mmHg
What mediates vasoconstriction?
the sympathetic nervous system
What is the purpose of lymphatics?
To drain excess filtered fluid from capillaries and the tissues
Where is the return of the interstitial fluid?
The throacic duct at the left subclavian vein.
What aids the flow of lymph?
respiratory pump skeletal muscle pup smooth muscle in lymphatic vessels?
What is cardia output?
heart rate x stroke volume
Equation for blood pressure?
cardiac output x total peripheral resistance
What is pulse pressue?
systolic- diastolic pressure
what is the mean arterial pressure?
diastolic +1/3 of the pulse pressure
What changes the flow?
the pressue and resistance flow= pressure gradient/resistance Ohm’s law
Which is poiseullie’s equation?
Flow = radius to the power of 4
What is the frank starling mechanism?
more stretch in ventricle or of muscle the sronger it contracts causing a higher pressure and larger cardiac output
What happens whe venous return is higher?
end disastolic volume is higher stroke volume is therefore higher and then the cardiac output is higher
What is an important factor in long term blood pressure?
Blood volume
Which systems change blood volume?
Renin-angiotensin-Aldosteroe System and ADH
why does the circulation need controlling?
maintain the flow of blood, maintain pressure
What is systolic and diastolic blood pressure?
systolic is the highest blood pressure when the ventricles contract. the diastolic is the lowest when the ventricles relax
Why do you measure blood pressure using the brachial artery?
convenient to compress and it is at the level of the heart.
which Korotkoff sounds are important for measuring BP?
1 and 5
What is myogenic autoregulation?
the innate response of a vessel to contract against an expansion.
Which organs have good autoregulation which have bad?
renal cerebral coronary are very good. skeletal and splanchic are moderate ans cutaneous is poor
What is intrinsic control?
dominant in the brain and heart sometimes in the muscle when exercising.
What are the local humoral factors for vasoconstriction?
Endothelin-1 and internal blood pressure
What are the local humoral factors of vasodilation?
Hypoxia Adenosine Bradykinin NO potassium CO2 Hydrogen ions tissue breakdown and prostacyclin
What is the role of the endothelium in control of the circulation?
Produces NO, prostacyclin and endothelin.
What are circulating(hormonal) vasoconstrictors?
nor-Epinephrine, Angiiotensin 2, vasopressin(ADH).
what are circulating (hormonal) vasodilators?
Epinephrine, Atrial natriuretic peptide
Where are the primary baroreceptors of the body?
Carotid sinus and aortic arch
Where are the secondary baroreceptors?
in the veins myocardium and pulmonary vessels
What are the afferent nerves for baroreceptors?
Glossopharengeal 9th
What are the efferent nerves for baroreceptors?
Sympathetic and Vagus 10th
How do arterial baroreceptors affect central control?
If pessure increases then they fire more which decreases sympathedic coutflow to the heart and arterioles but increases parasympathetic outflow to the heart
Where are the cardiopulmonary baroreceptors found?
in the atria and verticals and pulmonary artery. if they are stimulated they the vasoconstriction centres in the brain to reduce BP. these oens stimulate angiotensin aldosterone and vasopressin
What are the main neural influences on the medulla?
Baroreceptors, chemoreceptors, hypothalamus, cerebral cortex, skin, canges in O2 and CO2
What does stimulation of the hypothalamus do?
reduce blood pressure. it can regulate skin blood flow
Where are the central chemo receptors?
in the medulla.
What is excitation- contraction coupling?
When the membrane is stimulated it releases calcium which leads to the contraction of the muscle.
What type of process does calcium use to move into the muscle cytosol?
passie diffusion
How is relaxation of the heart initiated?
When calcium is pumped out of the cells.
What does the heart use for energy?
Free fatty acids as this is the most efficient. it can use glucose anaerobically if required.
What is the A band?
a reigone of the sarcomere that has thick filaments and is dark
What is the I band?
It is light and is only occupied by thin filaments that extend toward the centre of the sarcomere from the z lines it also contains tropomyosin and troponin
Where is the Zline?
In the middle of each I band
How does the contraction happen?
Sliding of actin over mysosin by ATP hydrolysis by ATP ase in the myosin heads
Describe the structure of myosin
2 heavy chains that are responsible for the dual heads and 4 light chains the heads are perpendicular at rest and bend towerds the middle.
Describe the structure of actin
It is a globular protein with a double stranded macromolecular helix and form F actin
Describe the structure of tropomyosin.
it is an elongated molecule made of two helical peptide chains. it is in the grooves of the actin strands and regulates the interaction with the other strands
What are the components of troponin?
I T C
What do the components of troponin do?
I with tropomyosin inhibit actin and myosin interaction
T binds troponin complex to the tropomyosin C has a high affinity for calcium. this allows the Tn I to move away from actin allowing interaction.
At what angle are all the heads of myosin?
120 degrees to each other. and 43nm apart.
What is the ventricular contraction of the heart cycle?
LV contraction there is isovolumic contraction where the volume doesn’t change and pressure increases. then maximal ejection where it actually ejects. at the start of relaxation there is reduced ejection. then isovolumic relaxation and it fills passively
What is the atrial booster?
when the atria contract to fill the ventricle .
What is the first heart sound made from?
After the atrial booster which closes the mitral valve
What is the second heart sound?
After the aortic valve closes after relaxation of the ventricle
What is the 3th heart sound
when the ventricle jitters which coincides with early filling passively of ventricle
What is the 4th heart sound
Just before mitral valve closes it is pathogenic stenosis.
What is diastasis?
when the ventricle rises to same pressure as the atrium just before the ventricle contracts again.
Where should you feel a pulse for the timing of heart sounds?
the carotid pulse pressing against transverse process of C6
