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BDS Stage 1 > Cardiovascular System > Flashcards

Cardiovascular System Flashcards

1
Q

Main function and structure of Resistance/Muscular artery

A

Muscular element is most significant, plays major role in regulation of blood pressure

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2
Q

Main function and structure of arteriole

A

Muscular tissue is most significant (although smaller amount than resistance artery), plays major role in regulation of blood pressure

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3
Q

Main function and structure of Capillary

A

Assembled of only endothelium and basal tissue, slows rate of blood flow to maximise exchange

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4
Q

Structure of Venules

A

Muscle tissue is less significant, larger lumen

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5
Q

Structure of Veins

A

Large proportion of fibrous tissue, large lumen and relatively large smooth muscle layer

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6
Q

Functions of Heart

A

Pumping blood around the body and generating blood
pressure

Sending deoxygenated blood to the lungs to be oxygenated

Sending oxygenated blood to the whole body

Separates pulmonary and systemic circulation

Provides unidirectional (one-way) blood flow and prevents
back flow (valves)
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7
Q

Which part of the heart is more muscular

A

Left part (Ventricle)

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8
Q

Why is the left ventricle more powerful

A

As the systemic circuit comprises of many parallel circuits therefore requires greater pressure

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9
Q

Functions of CVS

A
  • Oxygen and CO2 transport
  • Nutrient and waste product transport
  • Disease protection and healing
  • hormone delivery
  • body temperature regulation
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10
Q

What is the adaptation of Ohm’s law used for calculation of cardiac output.

A

Q = ΔP/R

ΔP - Mean Arterial Pressure Q - Cardiac Output
R - Total Peripheral Resistance

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11
Q

What is Polycythaemia?

A

Elevated red blood cell count in Haematocrit

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12
Q

Describe the main function and structure of Conduit/Elastic Arteries

A

Large Proportion of elastic tissue and smooth muscle. Main function is to conduct blood under High pressure

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13
Q

What is starling’s law?

A

the stroke volume of the heart increases in response to an increase in the volume of blood in the ventricles

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14
Q

Which side of the heart is located most anteriorly ?

A

Right (Pulmonary)

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15
Q

Which side of the heart is located most posteriorly ?

A

Left (Systemic)

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16
Q

What separates the Right and Left Ventricles?

A

Anterior Interventricular Groove

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17
Q

What separates the Right Atrium and Ventricle?

A

Anterior Atrioventricular Groove

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18
Q

Where is the right auricle located?

A

Superior surface of the right atrium

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19
Q

What vessels supplies the lungs with deoxygenated blood?

A

Pulmonary Arteries

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20
Q

Where do the pulmonary arteries arise from?

A

Pulmonary Trunk from Right ventricle

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21
Q

Where does the Inf. Vena Cava arise from?

A

Diaphragm, brings blood from lower half of body

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22
Q

Where does the Sup. Vena Cava arise from?

A

Joining of Brachiosophalic and Subclavian artery.

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23
Q

What are the 3 parts of the pericardium?

A

Fibrous Pericardium
Parietal Pericardium
Visceral Pericardium

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24
Q

What is the gap between the parietal and visceral pericardium called?

A

Pericardium Cavity (Full of pericardiac fluid)

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25
Q

What forms the majority of the view on the posterior aspect of the heart?

A

Left Ventricle

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26
Q

What are the roles of the valves in the heart?

A

To prevent flowback in the heart during constriction

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27
Q

What valve separates the Right Ventricle and Pulmonary Trunk?

A

Semi Lunar Valve

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28
Q

What valve separates the Right Atrium and Ventricle?

A

Tricuspid Valve

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29
Q

What do the Chorda Tendini do?

A

They prevent the tricuspid valves from ‘blowing back’ into the right atrium.

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30
Q

Where do the Chorda Tendini attach?

A

Papillary Muscles and Tricuspid Valves

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31
Q

What is the Fossa Ovalus?

A

A fossa in the right atrium and left ventricle. Open as foetus to allow blood to ‘skip’ pulmonary system.

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32
Q

What is the Coronary Sinus?

A

A collection of veins delivering deoxygenated blood to the right atrium

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33
Q

What is the coronary’s sinus relationship to the position of the AVN?

A

It is slightly inferior

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34
Q

What is the AVN?

A

Atrio Ventricular Nodes

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35
Q

What is the SAN?

A

Sino-Atrial Nodes

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36
Q

What is known as the pacemaker?

A

The SAN

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37
Q

What are the layers of the heart wall?

A

Pericardium,
Myocardium
Endocardium

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38
Q

Function of Pericardium?

A

Fixes the heart to the mediastinum,
Gives protection against infection
Provides the Lubrication for the heart

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39
Q

What is the function of the Myocardium?

A

Stimulates heart contractions and relaxation

Provides scaffolding for heart chambers

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40
Q

What is the function of endocardium?

A

Controls myocardial function

Controls blood-heart barrier

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41
Q

What are the main cells of the myocardium?

A

Cardiomyocytes

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42
Q

What are the main identifiable structures in a cardiomyocyte?

A 
T-Tubule
Sarcomere
Z Disk
Intercalated Disk (Joint with neighbouring cell)
Sarcoplasmic Reticulum
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43
Q

Characteristics of cardiomyocytes?

A

Single centrally located nucleus
Branching structure
Plenty of mitochondria
Abundant reserve of myoglobin

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44
Q

What two fibres make up the cardiac autorythmic system?

A

Pacemaker Cells

Conduction fibres

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45
Q

What is sarcoplasmic reticulum?

A

Periphery layer of endoplasmic reticulum, important in cardiomyocytes for absorption and storage of calcium

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46
Q

What is the main substrate for oxidative phosphorylation in cardiomyocytes?

A

Lipids

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47
Q

What do T-Tubules do?

A

Increase surface area of cardiomyocytes. Allows for maximum Ca2+ absorption Required for excitation of the cells.

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48
Q

Where are T-Tubules found?

A

In the outer membrane, present as indentations increasing surface area

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49
Q

Where could you find a gap junction in cardiac muscle?

A

Between the cardiomyocytes, more specifically the intercalated disks

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50
Q

What are gap junctions?

A

intercellular channels that allow for direct chemical communication between adjacent cells through diffusion of ions and small molecules without contact with the extracellular fluid.

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51
Q

What are desmosomes?

A

fasteners through the plasma membrane of adjacent cells by means of intermediate filaments composed of keratin or desmin to form a dense plaque.

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52
Q

What are Tight junctions?

A

act as barriers that regulate the movement of water and solutes between epithelial layers.

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53
Q

Are tight junctions present in cardiomyocytes?

A

NO!!!!!!

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54
Q

What proteins are present in the gap junctions?

A

Connexin
Innexin
Pannexin

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55
Q

What is Connexon?

A

6 Connexin subunits

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56
Q

What is Innexon?

A

6 Innexin subunits

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57
Q

What is Pannexon?

A

6 Pannexin subunits

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58
Q

What are the main pacemakers in the heart?

A 
SAN
AVN
Bundle of His (Their)
Purkinje Fibres
Bachmann's Bundle
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59
Q

What does the SAN do?

A
  • establishes rhythm at the highest rate of pulse generation (70-100 bpm)
  • impulse spreads from the SA node throughout specialized internodal pathways:
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60
Q

What is the AVN?

A
  • intrinsic rate of AV node is 40-60 bpm
  • delays the impulse from SA node by ~100-120 ms to let ejected blood fully migrate from atria before ventricles contract
  • it electrically connects the right atrium and right ventricle
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61
Q

What is the Bundle of His

A
  • intrinsic rate of the bundle of His is 20-40 bpm
  • transmits impulses from the atrioventricular node to the ventricles of the heart
  • branches into the left and the right bundle branches
  • speed of impulse is 1 m/s
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62
Q

What are the purkinje fibres?

A
  • intrinsic rate of Purkinje fibers is 15-30 bpm
  • distribute the impulse to the myocardial contractile cells in the ventricles
  • speed of impulse is 5 m/s
  • excitation and contraction begin at the apex and travels toward the base of the heart
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63
Q

What is Bachmann’s bundle?

A

a specialized pathway band that conducts the impulse directly from the right atrium to the left atrium

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64
Q

What is the importance of Calcium?

A

regulation of Ca2+ homeostasis is central to the control of the heart

  • It is responsible for depolarisation and execution
  • Responsible for activation of contraction of cardiac muscle
  • Important signal molecule and second messenger
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65
Q

What is the basic mechanism of contraction?

A

1 – Na+ channels
2 –L-type Ca2+ channels
3 – Ca2+ induced Ca2+ release from Ryanodine receptors (RYR)
4 – Ca2+ stimulates the contractile apparatus

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66
Q

What is the basic mechanism of Relaxation?

A

1 – Ca2+ reuptake into SR
2 – withdrawal of Ca2+ to the extracellular media
3 – Exchange of Ca2+ for 3Na+ then 3Na+ exchanged for 2K+
4 – Activation of K+ channels

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67
Q

Where are Ryanodine Receptors found?

A

On the sarcoplasmic reticulum

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68
Q

What helps exchange Ca2+ for 3Na+ in relaxation?

A

A Na+/Ca2+ exchanger

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69
Q

What helps swap 3Na+ for 2K+ in relaxation?

A

Na+/K+ ATPase

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70
Q

What is SERCA?

A

Sarco Endoplasmic Reticulum Calcium ATPase

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71
Q

What is SERCA’s function?

A

It helps ‘pump’ Ca2+ ions into the sarcoplasmic reticulum

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72
Q

How is SERCA activated?

A

It is constantly inhibited by PLB, when PLB is phosphorylated the SERCA is activated

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73
Q

Average diastolic (relaxed) sarcoma length is?

A

2-2.2 um

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74
Q

Maximal length of sarcomere is?

A

2.6 um

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75
Q

What is average man’s resting cardiac output?

A

5L/min

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76
Q

What is the average man’s exercise cardiac output?

A

Fit young person: 20L/min

World Class Athlete: 35L/min

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77
Q

What is Diastole?

A

Heart muscles at rest

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78
Q

What is systole?

A

Heart muscles contracting

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79
Q

Roughly, how long is spent in diastole?

A

2/3 of the time

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80
Q

What does MAP stand for?

A

Mean Arteriole Pressure

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81
Q

How do you calculate MAP?

A

Diastolic Pressure + 1/3 Pulse Pressure

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82
Q

What unit is pressure measure in?

A

mmHg

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83
Q

What is Pulse Pressure?

A

Systolic - Diastolic pressure

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84
Q

How do you work out Diastolic pressure?

A

Lower end of Aortic Pressure

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85
Q

How do you work out Systolic Pressure?

A

Upper end of Aortic Pressure

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86
Q

What causes the characteristic ‘Lubb’ ‘Dubb’ sounds?

A

Closing of AV and Aortic valves respectively

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87
Q

What are the phases of the cardiac cycle?

A
  • Atrial Contaction
  • Isovolumetric Contraction
  • Ventricular Ejection
  • Isovolumetric Relaxation
  • Atrial Filling
  • Ventricular Filling
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88
Q

What is Cardiac output (CO)?

A

Amount of blood pumped by the heart per minute

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89
Q

What is heart rate (HR) ?

A

Number of beats per minute

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90
Q

What is stroke volume (SV)?

A

Amount of blood pumped per beat

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91
Q

What is the calculation for CO?

A

CO = HR * SV

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92
Q

What is significant about venous return?

A

It is the SAME as cardiac output

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93
Q

What is End-Diastolic Volume (EDV) ?

A

Volume of blood in ventricles just before systole.

Relares to the length of sarcomeres in cardiac muscle prior to systole

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94
Q

What is End-systolic volume (ESV)?

A

Volume of blood in a ventricle and end of contraction.

It is used clinically as a measurement of systolic function

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95
Q

How can you calculate Stroke Volume (SV)?

A

SV = EDV - ESV

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96
Q

What is Ejection Fraction (EF)?

A

This is the % of blood ejected from a ventricle with each heartbeat

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97
Q

How do you calculate Ejection Fraction (EF)?

A

EF = SV/EDV

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98
Q

What is the Frank-Starling Law?

A

Stroke volume (SV) of the heart increases in response to an increase in the volume of blood filling the heart when all other factors remain constant.

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99
Q

What helps regulate the heart rate?

A

Sympathetic stimulation can raise the heart rate to close to 200bpm
Vagal Stimulation can suppress the heart rate to 20bpm and also decrease strength of contraction

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100
Q

What can regulate the SAN?

A

Acetylcholine and Noradrenalin

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101
Q

How does Acetylcholine regulate the SAN?

A

It increases K+ permeability thus decreasing rate of spontaneous depolarisation

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102
Q

How does noradrenaline regulate the SAN?

A

Increases Na+/Ca2+ permeability thus increasing rate of spontaneous depolarisation

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103
Q

What is Resting membrane potential?

A

It is a voltage difference across the plasma membrane

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104
Q

What’s the typical resting membrane potential in cardiomyocytes?

A

-90 to -80 mV

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105
Q

What is an action potential?

A

Change of voltage polarity across the plasma membrane

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106
Q

What molecules help form the typical cardiac membrane potential?

A
  • Potassium Channels (K+) (Main)
  • Sodium Channels (Na+)
  • Calcium Channels (Ca2+)
  • Chloride Channels (Cl-)
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107
Q

What is the major ion for membrane potential maintenance?

A

Potassium (K+)

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108
Q

What is Phase 4?

A

Resting membrane potential

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109
Q

What is Phase 0?

A

Depolarisation as Na+ starts to enter in abundance.

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110
Q

What is Phase 1?

A

Early Repolarisation,
K+ ‘leak’ through the membrane increases.
Inactivation of sodium channels

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111
Q

What is Phase 2?

A

The Plateau,
Ca2+ Channels activated increasing concentration inside the cell
K+ ‘leak’ still occurring

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112
Q

What is Phase 3?

A

Rapid Repolarisation,
Calcium Channels inactivated.
K+ leaving and Ca2+ absorption by organelles cause return to resting membrane potential

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113
Q

What is different about the action potential in pacemaking and contractile cardiac cells?

A
  • In pacemaking cells they don’t have a Phase 2 (Plateau).
  • In Pacemaking cells the depolarisation is mainly caused by influx of Ca2+.
  • The resting potential in pacemaking cells are - 60mV
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114
Q

What is the basic sequence of electrical events in the heart?

A
  • SAN depolarises
  • Waves of depolarisation spread across both atria
  • AVN slows the signal from the atria to ventricles
  • Wave of depolarisation spreads to the bundle of His
  • Depolarisation spreads throughout the myocardium of the heart via the Purkinje fibres
  • Once depolarisation has occurred depolarisation of the ventricles begin
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115
Q

What does the P wave represent?

A

Atrial depolarisation

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116
Q

What does the QRS complex represent?

A

Ventricular depolarisation

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117
Q

What does the T wave represent

A

Ventricular repolarisation

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118
Q

What does the U wave represent?

A

Papillary muscle repolarisation and repolarisation of the Purkinje fibres

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119
Q

What is the PR interval?

A

Start of the P wave to the start of the QRS complex

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120
Q

What is the QT interval?

A

Start of the QRS complex to the end of the T wave

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121
Q

What is the ST segment?

A

End of S wave to start of T wave

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122
Q

What two ways can you measure heart rate?

A
  • Atrial Rate; frequency of P waves

- Ventricular Rate; Measuring the RR interval

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123
Q

How do you calculate heart rate using RR interval?

A
  • Measure the RR interval.
  • Divide length by 5.
  • Then divide 60 by this number
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124
Q

What artefacts could you have on the ECG?

A

Muscle Tremor
Sloping Baseline
Patient movement artefact
Alternating current interference

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125
Q

What is sinus bradycardia?

A

Slow heart rate

- defined as under 60 BPM in adults

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126
Q

What is sinus tachycardia?

A

Heart rate exceeding normal resting rate

- Above 100 BPM is accepted as tachycardia

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127
Q

What is Sinus arrhythmia?

A

Normal increase in heart rate during inspiration.

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128
Q

What is Atrial Fibrillation?

A

abnormal heart rhythm characterised by rapid and irregular beating.
No clear P waves

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129
Q

What is Atrial premature beat/ectopic?

A

Heart beat of atrial origin that occurs earlier than expected
early and abnormal p wave

130
Q

What is ventricular premature beat/ ectopic?

A

Abnormal impulse originating from with the ventricle.
p waves not seen before ecotopic
no PR interval
QRS wide and bizarre

131
Q

What is Ventricular tachycardia?

A

Usually defined as three or more ventricular beats with a heart rate greater than 120bpm
independent p wave activity
‘fusion’ of beats

132
Q

What is ventricular fibrillation?

A

Impulse originates in one or more places in the ventricles at a very fast rate, resulting in uncoordinated activity in the ventricular muscle
p wave unrecognisable
PR interval absent
QRS absent

133
Q

What is Asystole?

A

Also known as flatline, state of no electrical activity.

134
Q

Atrial depolarisation is represented by?

A

P wave

135
Q

Ventricular depolarisation is represented by?

A

QRS complex

136
Q

Ventricular repolarisation is represented by?

A

T wave

137
Q

What is Heart Failure?

A

A condition in which the heart can’t pump enough blood to meet the body’s needs.

138
Q

What is congestive heart failure?

A

The heart cannot pump blood to the rest of the body with enough force

139
Q

What are common risk factors for development of heart failure?

A
  • Previous heart attacks
  • Hypertension
  • Heart Valve disease
  • Heart muscle disease
  • Congenital heart defects
  • Alcohol/tobacco/drug use
140
Q

What factors of cardiac output become abnormal in heart failure?

A

Contractility, Heart Rate, Afterload and Preload

141
Q

What is the sequence of heart failure?

A
  • Incapability to pump enough blood the maintain blood pressure
  • Systemic vasoconstriction
  • Reduced flow to Brain, Heart, Kidneys etc.
  • Ischemic tissue damage
  • Pain
  • Death (if no adequate treatment)
142
Q

What are direct causes of heart failure?

A

Heart Muscle and heart valves

143
Q

What are indirect causes of heart failure?

A

Circulation - peripheral blood vessels

144
Q

What is Hypertrophic cardiomyopathy?

A

Disease in which a portion of the myocardium in enlarged without any obvious cause

145
Q

What are problems with hypertrophic cardiomyopathy ?

A

The hear can’t fill with enough blood

146
Q

What is dilated cardiomyopathy?

A

A condition in which the heart becomes enlarged

147
Q

What are the problems with dilated cardiomyopathy?

A

The heart can’t pump enough blood to the rest of the body with enough force

148
Q

What two types of heart valve disease are there?

A 
Valve stenosis (Narrowing)
Valve incompetence (leaky)
149
Q

What are the problems with Valve stenosis?

A

If the valve does open fully it will obstruct the blood flow, this will put extra strain on the hear

150
Q

What are the problems with valve incompetence?

A

It will allow blood to leak backwards

151
Q

What is coronary circulation?

A

The circulation of the blood in the blood vessels of the heart muscle

152
Q

What is hyperaemia?

A

Increase of blood flow to the tissue

153
Q

What is active hyperaemia?

A

The increase in organ blood flow that is associated with increased metabolic activity of an organ or tissue

154
Q

What is reactive hyperaemia

A

the transient increase in organ blood flow that occurs following a brief period of ischemia

155
Q

What is ischemia?

A

Inadequate supply of blood to an organ or part of the body, especially the heart muscles

156
Q

What is Atherosclerosis?

A

Hardening of the arteries due to plaque formation

157
Q

What is Atheroma?

A

Degeneration of the walls of the arteries caused by accumulated fatty deposits and scar tissue

158
Q

What are factors that may induce atherosclerosis?

A

Increased cholesterol in diet, cigarette smoking, obesity

159
Q

What can atherosclerosis result in?

A

Ischemia and local necrosis

160
Q

What is Coronary artery disease (CAD) sometimes known as?

A

Ischemic Heart Disease (IHD)

161
Q

What diseases come under CAD and IHD?

A

Stable Angina, Unstable Angina, Myocardial infarction and sudden cardiac death

162
Q

What fraction of ‘natural’ deaths involve IHD

A

1/3

163
Q

What is Q-T syndrome?

A

Short and long Q-T syndromes are a condition associated with the dysfunction of depolarisation mechanisms of ventricular cardiomyocytes

164
Q

What is defibrillation?

A

A treatment for life-threatening dysrhythmias.

165
Q

What 3 methods are used to defibrillate the heart?

A

Physical: A blow depolarises the heart and allows sinus rhythm to be re-established
Electrical: Stimulus to depolarise and allow AVN to gain control
Chemical: Infusion of KCl to abolish fibrillation, wash out and AVN regains control

166
Q

What does inotropy mean?

A

Change of the force of cardiomyocytes contraction

167
Q

What does chronotropy mean?

A

Change of the heart rate

168
Q

What does dromotropy mean?

A

Change in the conduction speed in AVN

169
Q

What are sympathomimetics?

A

Increase of Inotropic, Chronotropic and Dromotropic effects

170
Q

What are Parasympathomimetics?

A

Decrease of Inotropic, Chronotropic and Dromotropic effects?

171
Q

What are examples of sympathomimetics?

A

Noradrenaline/Adrenaline

Phenilephrine

172
Q

What are examples of Parasympathomimetics?

A

Acetylcholine

Oxotremorine

173
Q

What are catecholamines?

A

The main neurotransmitters of the sympathetic nervous system

174
Q

What are some examples go catecholamines?

A

Noradrenaline, Adrenaline, Dopamine

175
Q

What is the main neurotransmitter of the parasympathetic nervous system?

A

Acetylcholine

176
Q

What are the Parasympathetic (Vagal) regulations of the heart

A
  • Acetylcholine
  • Focal innervation of pacemakers, i.e SAN, AVN and Purkinje fibres
  • Negative chrono/drono.
    /inotropy
177
Q

What are the sympathetic innervation of the heart?

A
  • Noradrenaline
  • Diffusive in the myocardium
  • Positive chrono/dromo/inotropy
178
Q

What are cardiac glycosides?

A

Compounds that increase the output force of the heart (+’ve inotropy) and decrease HR (-‘ve chronotropy)

179
Q

How do cardiac glycosides work?

A

They suppress the cellular Na+/K+ ATPase pump. THis increases Na+ concentration in the cell. In turn the cell exchanges this Na+ for Ca2+.

180
Q

What are common cardiac glycosides?

A

Digitalis, digoxin and ouabain.

181
Q

What is hyponatremia?

A

Low extracellular Na+

182
Q

What can hyponatremia in the heart cause?

A

Increased cardiac contractility (inotropic effect)
Increases heart rate (chronotropic and dromotropic effect)
Increased coronary blood flow

183
Q

What is hypernatremia?

A

High extracellular Na+

184
Q

What can hypernatremia in the heart cause?

A

Decreased cardiac contractility (negative inotropic effect)
Decreases heart rate (negative chronotropic and dromotropic effect)
Decreased coronary and systemic blood flow

185
Q

What is hyperkalaemia?

A

High extracellular K+

186
Q

What can hyperkalaemia cause?

A

Decreased cardiac contractility (Negative inotropic effect)
Decreased heart beat (Negative corn and dronotropic effects)
Deceased coronary and systemic blood flow

187
Q

What are clinically approved approaches to defibrillate the heart?

A

Electrical stimulus and physical blow

188
Q

What is the action of cardiac glycosides?

A

Increase SV and decrease HR

189
Q

What ionic conditions cause negative ino/dromo/chronotropic effects?

A

Hypernatremia, hyperkalaemia and hypocalcaemia

190
Q

What ionic conditions cause positive ino/dromo/chronotropic effects?

A

Hyponatremia, hypokalaemia and hypercalcaemia

191
Q

What is Blood Pressure?

A

The pressure of circulating blood on the walls of the blood vessels. It usually refers to the atrial pressure in the systemic circulation

192
Q

How is blood pressure usually expressed?

A

In terms of systolic pressure over diastolic pressure (mmHg)

193
Q

What is systolic pressure?

A

Maximum pressure during one heart beat

194
Q

What is diastolic pressure?

A

Minimum pressure between two heart beats

195
Q

What is the normal resting blood pressure?

A

120/80 mmHg

196
Q

What are Korotkov sounds?

A

Created by pulsatile blood flow through the compressed artery

197
Q

When can you hear Korotkov sounds?

A

When the cuff pressure is between 120/80 mmHg

198
Q

What is turbulent flow?

A

Occurs with narrowing of arterial lumen

199
Q

What are baroreceptors?

A

They are stretch receptors found in the carotid body, aortic body and the walls of large arteries in the neck and thorax

200
Q

How do baroreceptors regulate blood pressure?

A
  • Action potentials from the baroreceptors travel to the medullary cardiovascular control centre via sensory (afferent) neurons
  • The CV control centre integrates the input and initiates an appropriate response
  • Sympathetic or Parasympathetic autonomic neurons from the CV control centre target the Arterial Smooth muscle, Ventricular Myocardium or SAN.
201
Q

Where is the CV control centre located?

A

In the medulla oblongata

202
Q

Where does the parasympathetic output from the CV control centre target?

A

The SAN

203
Q

Where does the sympathetic output from the CV control centre target?

A

The Arterial smooth muscle, ventricular myocardium and the SAN

204
Q

How does the arterial smooth muscle control blood pressure?

A

Vasodilation can decrease peripheral resistance thus decreasing blood pressure

205
Q

How does the ventricular myocardium control blood pressure?

A

The force of contraction can decrease, this lowers cardiac output and thus blood pressure

206
Q

How does the SAN control blood pressure?

A

The SAN can lower heart rate, this reduces cardiac output and thus blood pressure

207
Q

Blood pressure regulation is an example of…?

A

Negative Feedback

208
Q

What is an example of long-term mechanism of blood pressure control?

A

The renin-angiotensin-aldosterone system

209
Q

Where does the renin-angiotensin-aldosterone system begin?

A

In juxtaglomerular cells in the kidneys?

210
Q

What do juxtaglomerular cells do?

A

Convert prorenin (in blood) to renin when renal blood flow is reduced.

211
Q

What does renin do in the blood?

A

Converts angiotensinogen (released by liver) to angiotensin 1

212
Q

What happens to angiotensin I in the lungs?

A

It is converted to angiotensin II by the ACE enzyme

213
Q

What does angiotensin II do?

A

causes blood vessels to narrow and stimulates release of aldosterone from adrenal cortex and ADH in the post. pituitary

214
Q

What does ADH and Aldosterone do?

A

Increases fluid retention and Na+ retention on the kidneys respectively

215
Q

What is peripheral circulation?

A

It is a system of blood vessels that delivers and collects blood flow from the distal boundaries and contact surfaces of the body.

216
Q

What are the contact surfaces of the body?

A

Skin, Alveolar Intestinal epithelium etc.

217
Q

What are the functions of the peripheral circulation?

A
  • Carries the blood
  • Exchanges nutrients, waste products and gases
  • Regulates blood pressure
  • Directs blood flow from large arteries towards the tissues.
218
Q

Peripheral circulation =?

A

All vessels of the body - Large Conduit vessels

219
Q

What are the blood vessels of peripheral circulation?

A

Arterioles, Muscular Artery, Capillaries and Venules

220
Q

What happens to peripheral circulation when oxygen levels are low?

A

It reduces pulmonary circulation but increases systemic.

221
Q

Why does pulmonary circulation slow down in Hypoxic conditions?

A
  • Slows down and redirects pulmonary circulation within the lungs
  • Improves ventilation/perfusion ratio and arterial oxygenation
222
Q

Why does systemic circulation speed up in hypoxic conditions?

A
  • Increases systemic circulation

- Facilitates diffusion and oxygen delivery to the tissues

223
Q

What is the triple response of lewis?

A

A reaction to scratching of the skin

224
Q

What are the steps of the triple response of lewis?

A

1) Red Reaction
2) Flare
3) Wheal

225
Q

What is the red reaction?

A

A red line formed from local vasodilation and histamine and cytokine effect

226
Q

What is the flare?

A

spreading redness beyond the redline (due to axon reflex)

227
Q

What is the wheal?

A

Swelling/localised oedema in the region of the red line (appears white)

228
Q

Where does the axon reflex in flare stage synapse?

A

In the dorsal root ganglion

229
Q

What are histamines?

A

They are released by mast cells and basophils and are involved in local immune responses acting as a neurotransmitter

230
Q

What is endothelium?

A

It is the largest endocrine organ formed of a thin layer of cells that line the interior surface of blood vessels and lymphatic vessels

231
Q

What are vascular endothelial cells?

A

They are in direct contact with blood

232
Q

What are common vasodilators for endothelia?

A 
Nitric Oxide (NO)
Prostacyclin
233
Q

What are common vasoconstrictors for endothelia?

A

Thromboxane, Angiotensisn II

234
Q

What pathway do vasoconstrictors act on endothelium?

A

They increase the concentration of Ca2+

235
Q

What are the main effects of NO in the body?

A

Reacts with DNA
Reduces blood cell aggregation
Reduces superoxide radicals
DILATES BLOOD VESSELS

236
Q

How is NO generated in the vasculature?

A

Receptor-stimulated NO formation

Flow-dependent NO formation

237
Q

Outline how NO dilate blood vessels?

A
  • Hyperpolarisation occurs through stimulation of K+ channels
  • The concentration of Ca2+ is reduced in the cell
  • As there is less Ca2+ it cannot stimulate contractile apparatus
238
Q

What is the role of the cardiovascular centre (CV centre)?

A

It regulates HR and SV

It also regulates vasodilation/constriction

239
Q

Where does the CV centre receive signals from?

A
  • Cerebral cortex, limbic system and hypothalamus
  • Chemoreceptors
  • Baroreceptors
240
Q

What is somatic sensation?

A

Touch, pain, pressure, temperature etc.

241
Q

What is visceral sensation?

A

Stretch, pain, chemical sensitivity, hunger, nausea

242
Q

What are the main neurotransmitters of the sympathetic nervous system?

A

Catecholamines (adrenaline, noradrenaline, dopamine)

243
Q

How do catecholamines increase contractility in cardiomyocytes?

A
  • They stimulate β adrenoreceptors
  • This activates a Gs coupled receptor which in turn stimulates SERCA.
  • This has a positive ino/chronotropic effect increasing contractility
244
Q

What is the main neurotransmitter of the parasympathetic nervous system?

A

Acetylcholine

245
Q

How does acetylcholine reduce contractility in cardiomyocytes?

A
  • They stimulate a M2 cholinoreceptor
  • This activates a Gi couple receptor which in turn will inhibit SERCA
  • This has a negative chrono/inotropic effect reducing contractility
246
Q

How do catecholamines stimulate vasoconstriction?

A

They stimulate α adrenoreceptors

  • This activates Gq coupled receptors which in turn will stimulate Ca2+ release from the sarcoplasmic reticulum
  • This stimulates vasoconstriction
247
Q

What is the effect of Angiotensin II on vasculature?

A

It triggers vasoconstriction

248
Q

How does acetylcholine effect on smooth muscle cells?

A

It triggers vasodilation

249
Q

How do postural changes affect circulation?

A

When standing blood pools in leg veins
When lying down blood is more evenly distributed, this increases central venous pressure, diastolic volume and stroke volume.
This in turn will increase pulse pressure

250
Q

What is venous return (VR)?

A

It is the volume o blood that returns to the right atrium

251
Q

What mechanisms are responsible for regulation of venous return?

A 
Skeletal muscle pump
Respiratory pump
Cardiac suction effect
Venous valves
Sympathetic constriction of venous smooth muscles
252
Q

What is the respiratory pump?

A

The diaphragm contacts so the thoracic cavity volume increases.
Lungs pressure drops and abdominal pressure increases.
Blood moves from higher pressure to lower pressure

253
Q

How do skeletal muscles work as a peristaltic pump?

A

When the calf muscles contract they pump blood up towards thorax, the venous valves prevent backflow.

254
Q

What class of enzymes generate endogenous Nitric Oxide?

A

NO-synthases

255
Q

What is the effect of phospholamban phosphorylation in cardiomyocytes?

A

Contractility Increases

256
Q

How does lying down influence stroke volume?

A

Increases

257
Q

What is the nature of transient orthostatic hypotension?

A

Delayed vasoconstriction of peripheral systemic arteries

258
Q

What are the branches of the ascending aorta ?

A

intercostal arteries

259
Q

What are the branches of the aortic arch?

A

on the right side - braciocephalic trunk - right common carotid and right subclavian
on the left side - left common carotid and left subclavian

260
Q

What is the braciocephalic vein formed from ?

A

the subclavian and internal jugular veins

261
Q

What are the branches of the descending aorta ?

A

intercostal arteries
bronchial arteries
oesophageal arteries

262
Q

What mechanisms exist to ensure blood flows in the correct direction through the heart ?

A

the right and left atrioventricualr bundles
pulmonary and aortic valves
aided by the chordae tendinae and the papillary muscles

263
Q

What are the features of the right atrium ?

A

fossa ovalis
crista terminalis
muscuale pectini

264
Q

What are the 3 surfaces of the heart ?

A

sternocostal
diaphragmatic
posterior

265
Q

What forms most of the anterior surface of the heart ?

A

right atrium
right ventricle
some left ventricle

266
Q

What forms the posterior surface of the heart ?

A

left atrium
left ventricle
right atrium
right ventricle

267
Q

What are the atrial and ventricular septa of the heart ?

A

septa maintain muscular continuity - syncytium

gap junctions allow impulses between the corresponding chamber

268
Q

What is the atrioventricular septum ?

A

fibrous skeleton between the atria and the ventricles
no muscular continuity or syncytium
electrically isolates the ventricles from the atrium

269
Q

What are the 2 grooves on the heart ?

A

anterior atrioventricular groove - between the atria and the ventricles
anterior interventricular groove - between the ventricles

270
Q

What is the crista terminalis ?

A

between the sup and inf vena cava

separates the right atrium into a smooth posterior walls and a rough anterior wall

271
Q

What are the musculi pectini ?

A

radiate from right angles from the crista terminalis

help to channel blood flow

272
Q

What is the fossa ovalis ?

A

oval depression in the right atrium - embryonic development shunt

273
Q

Where is the SAN ?

A

just below the superior vena cava

274
Q

Where is the AVN ?

A

Just above the coronary sinus

275
Q

What are the trabeculae carnae ?

A

ridges in the right ventricle

276
Q

What are the chordae tendinae ?

A

join the tricuspid valve to the papillary muscle

277
Q

What is the mediastinum ?

A

central component of the thoracic cavity - divides into the right and left pulmonary cavities

278
Q

How is the mediastinum divided ?

A

by the sternal angle into the superior and inferior mediastinum

279
Q

What are the divisions of the inferior mediastinum ?

A

anterior , middle and posterior relative to the pericardium

280
Q

What is the contents of the anterior superior mediastinum ?

A 
sternothyroid 
sternohyoid 
thymus gland 
superior vena cava 
braciocephalic vein
281
Q

How is the braciocephalic vein formed ?

A

union of the internal jugular and the subclavian

282
Q

What is the contents of the middle superior mediastinum ?

A 
aortic arch 
braciocephalic trunk 
left common carotid and left subclavian arteries 
vagus nerve 
phrenic nerve
283
Q

Where does the right recurrent laryngeal nerve form ?

A

at the level of the subclavian artery

284
Q

Where does the left recurrent laryngeal nerve form ?

A

at the aortic arch

285
Q

What are the contents of the posterior superior mediastinum ?

A

oesophagus

thoracic duct

286
Q

What is the pathway of electrical impulses from the SAN ?

A

Heartbeat initiated
passes to the AVN from the atrial walls
passes to the bundle of His
branches into the right and left aAV bundles
purkinje fibres take to the venricualr walls

287
Q

What are the 1st branches of the ascending aorta ?

A

the right and left coronary arteries

288
Q

Where does the right coronary artery run ?

A

in the anterior atrioventricular groove

289
Q

What are the branches of the right coronary artery ?

A

marginal artery

posterior interventricular artery

290
Q

What are the branches of the left coronary artery ?

A

anterior interventricular

circumflex artery

291
Q

What drains into the coronary sinus ?

A

70% of cardiac venous blood
great cardiac vein
middle cardiac vein
anterior cardiac vein drains into the right atrium directly

292
Q

How is contraction initiated in cardiomyocytes ?

A

Na channels open
L-type Ca channels open
calcium release from RyR
stimulation of concractile apparatus

293
Q

How is relaxation initiated in cardiomyocytes ?

A

Calcium uptake by the SR
exchange - calcium out and 3 Na in
Na/K ATPase - 2K in and 3Na out

294
Q

What does phospholamban do ?

A

inhibits SERCA in the unphosphorylated state

295
Q

How is SERCA activated through phospholamban ?

A

phosphorylate phospholamban using cAMP depdnent protein kinase A

296
Q

What is pulse pressure ?

A

systolic pressure - diastolic pressure

297
Q

How do you work out mean arterial pressure?

A

diastolic pressure + 1/3 pulse pressure

298
Q

What is isovolumetric contraction ?

A

contraction of the left ventricle means the pressure in the LV is greater than the pressure in the LA - bicuspid valve shuts
Pressure is the less than aortic pressure so the aortic valve is shut
volume is constant but the pressure is increasing

299
Q

What is isovolumetric relaxation ?

A

relaxation of the LV means that pressure in the LV is falling so the aortic valve shuts
the pressure in the LV is still higher than the LA so the bicuspid valve is shut
pressure is falling but volume is increasing

300
Q

What is cardiac ouTput ?

A

amount of blood pumped by the heart in a minute

301
Q

What is the heart rate ?

A

beats per minute

302
Q

What is stroke volume ?

A

amount of blood pumped per beat

303
Q

What is the EDV ?

A

end diastolic volume

amount of blood in the left/right ventricle before systole

304
Q

What is ESV ?

A

end systolic volume

amount of blood at the end of contraction

305
Q

How do you work out Stroke volume ?

A

EDV-ESV

306
Q

What is ejection fraction ?

A

fraction if blood ejected from the ventricle per beat

SV/EDV

307
Q

Which valves are open in ventricular systole ?

A

pulmonary and aortic valves

308
Q

What shows ventricukar diastole in the ECG ?

A

flatline following the T wave

309
Q

Are there more veins or arteries in the body ?

A

veins

310
Q

In which phase of the cardiac cycle does most of the blood enter the ventricles ?

A

atrial diastole

311
Q

What is bradycardia ?

A

decreased HR

312
Q

which parameter in Pioseuilles law varies physiologically to influence flow rate ?

A

radius

313
Q

Which connecting structures are present in cardiac intercalated discs ?

A

desmosomes and gap junctions

314
Q

What does the ECG l;ook like for atrial fibrilation ?

A

unclear or absent T wave

315
Q

What is the maximal efficinecy of the heart ?

A

20-25%

316
Q

What type of failure is hypertrophic cardiomyopathy ?

A

systolic failure

317
Q

What are the components of the peripheral circulation ?

A 
resistance arteries
arterioles 
capillaries 
venules 
veins
318
Q

Which division of the mediastinum is the heart within ?

A

middle division of the inferior mediastinum

319
Q

How is the pulsatile flow of the blood from the heart converted into continuous flow ?

A

Energy of the heart beat is stored in the elasticity of the arterial walls and this is released during dyastole and converts the pulsatile flow into continuous flow by reducing pulse pressure

320
Q

What are the contents of the superior mediastinum ?

A 
thymus gland 
sternohyoid and sternothyroid 
phrenic 
vagus 
aortic arch 
thoracic duct 
trachea 
oesophagus 
braciocephalic vein

BDS Stage 1 (39 decks)

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