Lab 2: Blood Circulation

Question 1

Blood Pressure: Definition

Answer 1

Question 2

Normal Blood Pressure Range

Answer 2

“will you be so kind to specify under which conditions and where?”

question:

“What is the blood pressure in the temporal artery?”

Answer:

“I can not say specifaclly because i do not know your systemic pressure. i can make an estimaion based on the fact that you look healthy and by using the approximite distance of the temporal artery from your heart.”

Question 3

Systolic BP definition

Answer 3

Systolic: The highest pressure anywhere (where there is a pulsation) during the cardiac cycle

Question 4

Siastolic BP Definition

Answer 4

Diastolic: The lowest arterial pressure during the relaxation of the left ventricle

Question 5

Cardiac Output Definition

Answer 5

Volume of blood pumped from each ventricle per minute

Question 6

CO equations

Answer 6

Question 7

Stroke Volume: definition, equations, factor that affect it

Answer 7

Question 8

What factors influence blood pressure (scheme)?

Answer 8

Question 9

Preload definition:

Answer 9

• The extent to which heart muscle fibers are stretched before the onset of systole
• This depends greatly on the end-diastolic ventricular volume (EDV): volume load created by blood entering ventricles at end of diastole before contraction
• It is not possible to measure preload in vivo, but we can use the EDV as an indicator

Question 10

Factors affecting Preload

Answer 10

**add

Question 11

Afterload Definition

Answer 11

•The extent to which heart muscle fibers are stretched during systole/ejections

…The ressistance ventricles must overcome during systole

Question 12

Factors affecting Afterload

Answer 12

Question 13

Frank-Starling Law: definition

Answer 13

Definition: a law that describes the relationship between end-diastolic volume and cardiac stroke volume

• Cardiac contractility is directly related to the wall tension of the myocardium.

An increase in end-diastolic volume (preload) will cause the myocardium to stretch (↑ end-diastolic length of cardiac muscle fibers), which increases contractility (↑ force of contraction) and results in increased stroke volume in order to maintain cardiac output.

This relationship between end-diastolic volume and stroke volume is shown in the Frank-Starling curve.

Aim: maintain CO by modulating contractility and SV

↑EDV= ↑STRECH= ↑CONTRACTILITY= ↑SV= ↑CO

Question 14

Diffrence in systemic and pulmonary circulation: pressure, resistance, compliance

Answer 14

Question 15

Compliance Deffinintion:

Answer 15

?

Question 16

Geeral stages of the cardiac cycle

Answer 16

Question 17

When and why do the hears valves open?

Answer 17

Question 18

Relative proportion of blood volume throughout the cardiovascular system:

Answer 18

Question 19

What is Pressure Pulse:

Answer 19

is the difference between the systolic and diastolic pressures.

Pulse pressure = P(systolic) - P(diastolic)

■   The most important determinant of pulse pressure is stroke volume. As blood is ejected

from the left ventricle into the arterial system, arterial pressure increases because

of the relatively low capacitance of the arteries. Because diastolic pressure remains

unchanged during ventricular systole, the pulse pressure increases to the same extent

as the systolic pressure.

■■   Decreases in capacitance, such as those that occur with the aging process, cause

increases in pulse pressure

Question 20

Mean Arterial Pressure

Answer 20

■■   is the average arterial pressure with respect to time.

■■   is not the simple average of diastolic and systolic pressures (because a greater fraction

of the cardiac cycle is spent in diastole).

■■   can be calculated approximately as diastolic pressure plus one-third of pulse pressure.

* to know the exact vaule we must do an integral of the graph (area under the graph)

Question 21

Ejection Fraction deffinition:

Answer 21

Question 22

What is arterial compliance?

Answer 22

Compliance is the ability of a hollow organ (vessel) to distend and increase volume with increasing transmural pressure

* In compliance, an increase in volume occurs in a vessel when the pressure in that vessel is increased. The tendency of the arteries and veins to stretch in response to pressure has a large effect on perfusion and blood pressure. This physically means that blood vessels with a higher compliance deform easier than lower compliance blood vessels under the same pressure and volume conditions.[1] Venous compliance is approximately 30 times larger than arterial compliance.[2] Compliance is calculated using the following equation, where ΔV is the change in volume (mL), and ΔP is the change in pressure (mmHg):

Question 23

Windkessel effect

Answer 23

Windkessel effect is a term used in medicine to account for the shape of the arterial blood pressure waveform in terms of the interaction between the stroke volume and the compliance of the aorta and large elastic arteries (Windkessel vessels) and the resistance of the smaller arteries and arterioles.

Question 24

Distribution of blood flow ( as a % of CO)

Answer 24

..

Question 25

Blooc pressure values inside the heart chambers

Answer 25

Question 26

Blood pressure regulation: classifications

Answer 26

* Myogenic —\> stretch reflex of the smooth muscles in the vessel walls * Neural (Short Term) * Humoral (Long Term - RAAS)

Question 27

Heart Sounds

Answer 27

Question 28

Pulse wave velocity (PWV)

Answer 28

* Pulse: alternate expansion and recoil of elastic arteries due to a travelling pressure wave after each ventricular systole * PWV: The velocity at which bp pulse propagates through the an artery or combined length of arteries * Clinical: Measure of arterial stiffness (due to biological ageing and arteriosclerosis) —\> arteries become less compliant * Gold Standard: Palpation of carotid artery and femoral artery at the same time —\> femoral will cause a pulse pressure wave later that the carotid artery

Question 29

Measurments of blood pressure: Classifications

Answer 29

a) Indirect = Non-invasive • Auscultation • Palpation • Oscillatory b) Direct = Invasive • Catheterisation

Question 30

BP measurment: Auscultatory Method

Answer 30

Question 31

BP measurment: Palpation and Oscillatory meathod

Answer 31

Question 32

Influence of gravity on blood content in blood vessels

Answer 32

?

Question 34

What is the effect of body position on heart rate?

Answer 34

?

Question 35

central venous pressure

Answer 35

Central venous pressure (CVP) is the blood pressure in the venae cavae, near the right atrium of the heart. CVP reflects the amount of blood returning to the heart and the ability of the heart to pump the blood back into the arterial system. CVP is often a good approximation of right atrial pressure (RAP),[1] although the two terms are not identical, as a pressure differential can sometimes exist between the venae cavae and the right atrium. CVP and RAP can differ when arterial tone is altered.

Question 36

Determination of central venous pressure

Answer 36

Question 37

How does HR and BP change after exercise:

Answer 37

you need to ask: - What type of excersize? what happens to the bp: when? during the beggining? middle? end? - where are we measuring the BP? During what part? The diastolic pressure can decrease a little bit (due to vasodilationin the muscle- increased metabolic request)

Question 38

Important equations: Blood flow Resistance CO SV Ejection fractions PP MAP

Answer 38

Question 39

Important Pressure Values

Answer 39

Question 40

Pressure Value: Pulmonary Vein

Answer 40

Pulmonary Vein = 2-15mmHg

Question 41

Pressure value: Left Atria

Answer 41

Left Atria = 0-10mmHg

Question 42

Pressure Value: Left Ventricles

Answer 42

Left Ventricles = 0-120mmHg | (250/unchanged during excersize)

Question 43

Pressure Values: Aorta

Answer 43

Aorta = 80-120mmHg

Question 44

Pressure Values: Systemic Capillaries

Answer 44

Systemic Capillaries = 15-35mmHg (μ = 17mHg) (Note: exception is Renal capillary) * Venule side = 10-15mmHg * Arteriole Side = 35mmHg

Question 45

Pressure Values: Vena Cava

Answer 45

Vena Cava = 0-5mmHg

Question 46

Pressure Values: Right Atria

Answer 46

Right Atria = 0-5mmHg

Question 47

Pressure Values: Right Ventricle

Answer 47

Right Ventricle = 0-25mmHg

Question 48

Pressure Values: Pulmonary Artery

Answer 48

Pulmonary Artery = 8-25mmHg

Question 49

Pressure Values: Pulmonary Capillaries

Answer 49

Pulmonary Capillaries = 7mmHg

Question 50

Pressure Values: Renal Capillaries

Answer 50

Renal Capillaries = 55mmHg

Question 51

Pressure Values: Renal Vein

Answer 51

Renal Vein = 10-15mmHg

Question 52

Pressure Values: Hepatic Artery

Answer 52

Hepatic Artery = 90mmHg

Question 53

Pressure Values: Portal Vein

Answer 53

Portal Vein = 5-10mmHg (Note this is close to 0mmHg as venous system)

Question 54

Length–tension relationship in the ventricles

Answer 54

■   describes the effect of ventricular muscle cell length on the force of contraction. ■   is analogous to the relationship in skeletal muscle. 1. Preload ■■   is end-diastolic volume, which is related to right atrial pressure. ■■   When venous return increases, end-diastolic volume increases and stretches or lengthens the ventricular muscle fibers (see Frank-Starling relationship, IV D 5). 2. Afterload ■■   for the left ventricle is aortic pressure. Increases in aortic pressure cause an increase in afterload on the left ventricle. ■■   for the right ventricle is pulmonary artery pressure. Increases in pulmonary artery pressure cause an increase in afterload on the right ventricle.

Question 55

Changes in the Ventricular-volume loop during increased: preload/afterload/contractility

Answer 55

Question 56

Velocity of Blood flow

Answer 56

• The velocity of blood flow is the rate of displacement of blood per unit time. (Linear velocity)

Question 57

Blood flow

Answer 57

Question 58

Vascular resistance

Answer 58

Definition: resistance offered by the circulatory system that must be overcome to create blood flow (R = ΔP / Q)

Question 59

Poiseuille equation

Answer 59

Question 60

Resistance of vessels in parallel

Answer 60

Question 61

Resistance of vessels in series

Answer 61

Question 62

Laminar flow versus turbulent flow

Answer 62

Question 63

Shear

Answer 63

Question 64

Compliance

Answer 64

Question 65

Windkessel Effect

Answer 65

Question 66

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Question 67

What does blood pressure of value 0 mean?

Answer 67

0= pressure that is equal to the atmospheric pressure

Question 68

Where can we find blood pressure that is equal to 0?

Answer 68

RA= LA= LV= diastol Majority of the venous system

Question 69

Why arent we measuring the flow of blood instead of blood pressure?

Answer 69

* Its hard and expensive to measure (example: dopler system) * need a qualidied technishion BP: cheap, non invasive, easy

Question 70

What is the BP of the glomerulus?

Answer 70

=55mmHg The glomerular filtration rate The rate at which kidneys filter blood is called the glomerular filtration rate. The main driving force for the filtering process, or outward pressure is the blood pressure as it enters the glomerulus. This is counteracted to some extent by inward pressure due to the hydrostatic pressure of the fluid within the urinary space, and the pressure generated by the proteins left in the capillaries that tend to pull water back into the circulatory system (colloidal osmotic pressure). The net filtration pressure is the outward pressure minus the inward pressure.

Question 71

BP Vasa recta?

Question 72

How to regard BP with relation to gravity at the level blow and above the heart?

Answer 72

* hydrostatic pressure and gravity * murcury is 13 time more dense than blood.... * What are the claculations? * for 1 cm below the heart there is a 0.77nnHg rise in BP

Question 73

Blood groups: defintion

Answer 73

* Definition: Categorisation of blood types by presence or absence of specific antigens * Antigens found = Agglutinogens * Antibody to agglutinogens = Agglutinins

Question 74

Importance of knowing blood types:

Answer 74

; transfusion, organ transplantation and certain pregnancies

Question 75

ABO Blood groups:

Answer 75

Question 76

Rh blood group + incompability

Answer 76

* There are six common types of Rh antigens, each of which is called an Rh factor: * C D E, c d e * A person with C antigen won't have c antigen, and person without C antigen will surely have c antigen (same for D-d and E-e). * The type D antigen is widely prevalent in the population and considerable more antigenic than the other Rh antigens. * Anyone who has this type of antigen is said to be Rh positive, whereas a person who doesn't have type D antigen is said to be Rh negative. * 85% of white people are Rh positive (D), 15% Rh negative (d). * Antibodies do not occur naturally in the Rh system (unlike the AB0 system). * This means that there are no antibodies to the D antigen in the body of an Rh-negative individual. * They can form in the body in the event of prolonged contact with Rh-positive blood. Rh incompatibility blood transfusion * When RBCs containing Rh factor (D) are injected into a person whose blood doesn't contain the Rh factor (into a Rh negative person) anti-Rh agglutinins develop slowly * If a Rh-negative person has never before been exposed to Rh-positive blood, transfusion of Rh+ blood into this person likely cause no immediate reaction, but anti-Rh antibodies can develop in sufficient quantities during the next 2-4 weeks to cause agglutination of the transfused cells which will then hemolyzed by the macrophage system. * Thus, a delayed transfusion reaction occurs, usually mild. * Upon subsequent transfusion of Rh-positive blood into the same person, the transfusion reaction is greatly enhanced and can be immediate and severe.

Question 77

Rh incompatibility of mother and fetus

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Bleeding time: Clotting time: Prothrombin time: Activated partial thrombin time:

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Rh vs ABO

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aggulation test:

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I think it is yellow, but not suree

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Question 160

Formed Blood Elements Number per μL

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Question 161

Hemoglobin general characteristics

Answer 161

1% of oxygen is dissolved in the blood. Each hemoglobin molecule is not strictly bound to 4 molecules of oxygen. Concentration of hemoglobin is 150g/L in women and 160g/L in men. It is less in females due to monthly blood loss through menstruation Always give a range for Hb 130-150g/L and 160-170g/L – BUT CHECK THESE VALUES every book is different Hb storage of Oxygen (1L) Talk about 75% deoxygenated blood Variable in the case of fetal hemoglobin, embryonic hemoglobin and some pathological states such as Sickle cell anemia, HbE etc. FETAL Hb à (37 AAs residues different from those of Beta chains.) CO2 binds to the amine group in the chain Whereas O2 binds to the iron along with CO, compete

Question 162

Types of Hemoglobin

Answer 162

Question 163

\> Oxygen- Hemoglobin dissociation curve

Answer 163

* Saturation in arterial blood is around 100% (97.5% Guyton) * Saturation in venous blood is around 75% * Not a straight line as initial oxygenation of one of the hemoglobin subunits will cause an increased affinity for oxygen in the other hemoglobin subunits (T configuration à R configuration) * Sigmoidal shape: COOPERATIVE BINDING * Cooperative bind is the binding of the first molecule of oxygen increases the chances of binding/ affinity for the next molecules of oxygen due to a conformational change in the Hb molecule. * Hence Hb affinity for oxygen increases as more molecules of oxygen bind. More molecules of oxygen bind as the partial pressure of oxygen increases until a maximum value is obtained (i.e. when Hb is fully saturated). * When this value is obtained the curve flattens out (plateaus) as very little additional oxygen is able to bind. * The plateau portion of the curve exists in the pulmonary capillaries. * At higher partial pressures (towards the right side of the curve) the curve is not as steep which means the oxygen content (Hb saturation) does not change drastically despite large changes in oxygen partial pressure. * In the middle part of the curve (steepest area) this is where gaseous exchange takes place in the systemic capillaries. At this point on the graph the oxygen is being unloaded to respiring tissues and as a result hemoglobins affinity to oxygen decreases. A small change in oxygen partial pressure leads to a large difference in the hemoglobin saturation hence a release in large amounts of oxygen for respiring cells. * P50: the conventional measure of heamoglobin affinity for oxygen. It is calculated using the graph as you simply just record what the oxygen partial pressure is at 50% heamoglobin saturation. * Left shift? Increased affinity for oxygen à more loading of oxygen à Fetal Hb * Right shift? Decreased affinity for oxygen à more unloading of oxygen à Exercise * CADET = CO2, acidity, 2,3 DPG, exercise & temperature * FETAL HB: They don’t have beta-chains therefore pockets wide therefore o2 retained by Hb/ can be caught more easily, which is important so it can take up o2 from placental circulation. * Temperature= increased temperature is able to weaken/denature the bond between the Ferrous iron and the O2 molecule (only really evident with extreme changes in temperature) * pH= Bohr effect, it is observed that deoxygenated hemoglobin is better at buffering (binding H+ ) therefore there is a shift towards this form * 2,3 biphosphoglycerate= glycolysis by-product of erythrocytes (anaerobic respiration), it promotes the release of oxygen to the tissue, in hypoxic conditions there is an overall increase in 2,3 BPG production. It holds the 2 beta globin chains and cross links them therefore pockets become narrower and o2 jumps out of Hb. * CO2 = Haldane Effect, deoxygenated hemoglobin is better at binding CO2 than oxygenated hemoglobin, this normally occurs at the same time as the Bohr effect as increased CO2 will lead to a decrease in pH too

Question 164

Bohr Effect

Answer 164

Question 165

Hemoglobinometry

Answer 165

Question 166

Colorimetry

Answer 166

Question 168

The principle of Drabkin's solution:

Answer 168

Drabkin's Reagent is used for the quantitative, colorimetric determination of hemoglobin concentration in whole blood at 540 nm. Drabkin's Solution reacts with all forms of hemoglobin except sulfhemoglobin, a pigment that normally occurs in only minute concentrations in blood. * Drabkin′s reagent is used in measuring haemoglobin from blood samples. * It comprises potassium ferricyanide, potassium cyanide and potassium dihydrogen phosphate as components. * Potassium ferricyanide **oxidizes** haemoglobin to methemoglobin and then to cyanmethemoglobin.