Lesson 2

Question 1

Blood flow

Answer 1

The volume of blood flowing through a vessel, organ or entire circulation in a given period of time (ml/min)

Question 2

Cardiac output formulation

Answer 2

CO= Stroke Volume x Heart Rate

Question 3

Stroke volume

Answer 3

Volume of blood pumped out of one ventricle with each beat (contraction)

Question 4

How much ml of blood is pumped out of ventricle with each contraction

Answer 4

70ml

Question 5

End diastolic Volume

Answer 5

The amount of blood in the left ventricle after filling

Question 6

End Systolic Volume (ESV)

Answer 6

Not all the blood leaves the left ventricle, the amount still in the left ventricle after contraction

Question 7

Stroke Volume Formula

Answer 7

Stroke Volume = EDV - ESV

Question 8

What is the three factors SV is influenced by

Answer 8

1. Preload
2. Contractility
3. Afterload

Question 9

Preload

Answer 9

The volume of blood entering the left/right atrium

Question 10

What will happen if preload invrease

Answer 10

EDV increase which increases the SV

Question 11

Contractility

Answer 11

The strength of the contraction of the ventricle. As contractility increase the ventricle forces more blood out per stroke, reducing the ESV and increasing SV

Question 12

Starling‘s Law

Answer 12

Increased contraction strength with increased myocardial stretching

Question 13

Afterload

Answer 13

Is the amount of preassure in the aorta which left ventricle must overcome to push the blood out of the left ventricle into the aorta

Question 14

Chemicals that influence contractility

Answer 14

Intropes (or intropic chemicals) increase cardiac muscle contractility
- Hormones such as adrenaline
- Neurotransmitters such as noradrenaline released from sympathetic nerves
- Caffeine
- Digoxin- strong “poison” used to treat heart failure

Question 15

What happens if afterload increases

Answer 15

The left Ventricle cannot push out much blood. ESV increase which decrease SV

Question 16

What is afterload also called

Answer 16

Peripheral resistance

Question 17

With what must HR increase to increase SV

Answer 17

Increased contractility

Question 18

Outcomes

Answer 18

An increase in the preload or increase in contractility will proportionally increase SV and CO.
An increase in the afterload will decrease SV thus will decrease the SV and CO
Body must compensate for this reduction in CO - cardiac muscle hypertrophy

Question 19

Blood Pressure (BP)

Answer 19

Force per unit of area exerted on a vessel wall by the contained blood
Measured in mm Hg

Question 20

On what arteries in BP messured

Answer 20

Largest arteries closes to the heart

Question 21

What energy conversion is at BP

Answer 21

Potential energy that becomes kinetic energy to move the blood
Blood moves due to pressure gradient: high pressure to low pressure

Question 22

Fun fact

Answer 22

Stroke Volumes creates the bolus of blood in the aorta. BP is the measurement of that bolus of blood. Difference of high pressure in aorta and low pressure in right atrium leads to blood flow

Question 23

Mean Arterial Pressure (MAP) formular

Answer 23

Map= diastolic pressure + ( pulse pressure/3)

Pulse pressure= (systolic - diastolic pressure)

MAP = Diastolic pressure + ( systolic pressure - diastolic pressure]3)

Question 24

What is the three terms to define resistance (afterload)

Answer 24

1- blood viscosity
2- total blood vessel length
3- blood vessel diameter

Question 25

Blood viscosity

Answer 25

Described the thickness or stickiness of a fluid The higher the viscosity the slower the movement of the fluid Creates internal resistance to flow- constant

Question 26

What can influence blood viscosity

Answer 26

The number of red blood cells: medical conditions Polycythemia vs Anaemia

Question 27

Which will increase blood viscosity: Polycythemia or Anaemis

Answer 27

Polycythemia because it is an increased red blood cells.

Question 28

When could you hear a flow murmur due to increased blood flow in the valves of the heart

Answer 28

When there is increased cardiac output or increased velocity of blood

Question 29

Total blood vessel length

Answer 29

Longer the vessel the greater the resistance Childs blood vessel length increases as the grow bigger - resistance increases this BP increases as we age to adulthood Once reached adulthood this factor is constant and vessels no longer grow in length

Question 30

Blood vessel diameter

Answer 30

This is the greatest influence over resistance The larger the diameter of the blood vessel the less resistance is encountered on the side of the vessel wall. The more room is in the centre for the liquid to flow fast The opposite is true for narrow vessel: all the fluid is encountering the vessel walls thus increase in resistance and slowing down blood flow

Question 31

Laminar Flow

Answer 31

Fluid meets resistance in a tube - fluid rubs up against the side walls of the tube, resistance is created. Sides flow slower, centre fast

Question 33

Vessel radius (fourth power of resistance)

Answer 33

Radius is half the diameter of a circle

Question 34

Radius formula

Answer 34

Resistance = 1/r to power of 4 Therefore larger diameter = decreased resistance will increase flow

Question 36

Primary (essential) hypertension

Answer 36

Hugh blood pressure with no identifiable underlying cause. Accounts for 90-95% of cases Likely due to genetics, environment and lifestyle factors

Question 37

Secondary hypertension

Answer 37

Hugh blood pressure that results from an identifiable underlying condition Accounts for 5-10% of cases