Cardio-Respiratory Week One Flashcards
1
Q
What does the myocardium consist of?
A
Cardiac muscle. This is involuntary and striated.
2
Q
What does the endocardium consist of?
A
Loose connective tissue, endothelium (simple squamous)
3
Q
What is the passage of blood flow through the heart?
A
Superior or inferior vena cava - right atrium - tricuspid valve - right ventricle - pulmonary valve - pulmonary artery - lungs - pulmonary vein - left atrium - bicuspid (mitral) valve - left ventricle - aortic valve - aorta
4
Q
Where is the coronary sinus?
A
Right atrium
5
Q
Where is the chordinea tendinae located and what is their function?
A
These are connected to the atrioventricular valves and papillary muslces. When ventricles are relaxed, chordinea tendinae are loose and when contracted, the papillary muscles contract the chordinea tendinae, preventing the cusps from swinging into the atria.
6
Q
What is the function of the crista terminals?
A
Divides the muscular pectani from smooth muslce of atrium.
7
Q
What is the function of the pectinate muslces, located in the atria?
A
They improve voluminous nature as their folds act as volume reserves.
8
Q
Where is the trabeculae carnae located?
A
In the ventricles and their function is the contract and pull on the chordinea tendinae
9
Q
The crista terminalis splits the atrium into two parts, which two parts?
A
Sinus venarum: posterior side (pectinate muscles)
Atrium proper: anterior
10
Q
Where are the auricles and what is their function?
A
Located in the atria and serve to increase capacity of the atria.
11
Q
What is the function of the following:
- interatrial septum
- interventricular septum
- coronary sulcus
- anterior interventricular sulcus
- posterior interventricular sulcus
A
- interatrial septum: divides atria
- interventricular septum: divides ventricles
- coronary sulcus: divides atria and ventricles
- anterior interventricular sulcus: located on sternocostal surface and divides ventricles. Contains a branch of left coronary artery
- posterior interventricular sulcus: located on diaphragmatic surface and divides ventricles. It contains the posterior interventricular artery and middle cardiac vein.
12
Q
What is the function of the cardiac skeleton?
A
Anchor valves to myocardium.
13
Q
Where is the main nerve supply to the heart from?
A
Medullar Oblongata: cardiaccelatory centre and cardioinhibitory centre
14
Q
Which Vagus nerve supplies the SA and AV node?
A
The right supplies the SA node and the left supplies the AV node.
15
Q
What are the two types of intercalated discs in cardiomyocytes?
A
GAP junctions: molecules passage
Desmosomes: hold adjacent cell together
16
Q
How many nuclei do cardiomyocytes have?
A
One
17
Q
What is the pathway of cardiac impulses?
A
SA node (anatomical pacemaker which starts automaticity) - intermodal pathways - AV node - Bundle of HIS - Purkinje fibres
18
Q
Where is the SA node located?
A
Superiorly to superior vena cava. This node spontaneously depolarises creating an AP around 100 beats a minute.
19
Q
What is the function of the Bachmann’s bundle?
A
Transmit impulses from SA node to left atrium
20
Q
What is the function of the AV node?
A
This slows down the impulse to around 40-60 beats and this allows a delay between atrial and ventricular contraction
21
Q
Where is the bundle of HIS located?
A
Interventricular septum
22
Q
What is resting membrane potential, threshold and depolarisation peak of SA action potential?
A
Resting: -60mV
Threshold: -40mV
Peak: +10mV
23
Q
What causes a SA depolarization?
A
Calcium influx. Reversal is done by potassium.
24
Q
What is resting membrane potential, threshold and depolarisation peak of cardiomyocytes?
A
Resting: -90mV
Threshold: -40mV
Peak: +25mV
25
What does depolarization of adjacent autorhythmic cells stimulate in cardiomyocytes?
Sodium channels opening
26
What is the plateau phase during cardiomyocytes depolarization?
This is maintained depolarization. There are slow voltage gated calcium channels open which causes calcium influx (this also causes calcium release from sarcoplasmic reticulum) and a potassium efflux.
27
What is a refractory period?
Period of not responding to stimuli
28
What is the difference between absolute and relative refractory periods?
Absolute: membrane cant respond to stimuli due to sodium channels already being open or closed and inactivated. This include plateau and initial rapid repolarization.
Relative: voltage-gated sodium channels are closed, but can open. Membrane can respond to strong stimuli
29
Describe the cardiac cycle
* Atrial systole begins: atrial contraction forces small amount of blood into relaxed ventricles
* Isovolumetric contraction (ventricular systole part one): atrial systole ends and diastole begins. Ventricular contraction push AV valves closed but does not create enough pressure to open semi-lunar valves.
* Ventricular systole (phase two): as ventricular pressure rises and exceeds pressure in arteries, semilunar valves open and blood is ejected
* Ventricular diastole early (isovolumetric relaxation): as ventricles relax, pressure in ventricles drop. Blood flows back against cusps of semi-lunar valves and forces them closed. Blood flows into relaxed atria.
* Ventricular diastole late: all chambers are relaxed and ventricles fill passively.
30
What is the difference between EDV and ESV?
EDV: blood in ventricle after diastole (filling)
ESV: volume of blood remaining in each ventricle at end of systole
31
What is stroke volume and how is it expressed?
This is amount of blood pumped out of ventricle during each beat.
SV = EDV - ESV
32
Why is the second heart beat split?
The split S2 can be commonly heard during deep inspiration. When there is a deep breath taken in, the decrease in the intrathoracic pressure will cause an increase in the venous return. This will mean that, because of the more blood in the right ventricle, it will take longer to pump the blood out during systole. This causes the pulmonary valve to close after the aortic valve. This is best heart in the pulmonic area.
33
What is S3?
Can be heard during early diastole and is caused by rapid ventricular filling.
34
What is S4?
This is caused by forceful atrial contraction against as stiff ventricle
35
When are systolic and diastolic murmurs heard?
Systolic: between S1 and S2. Occurs when heart contracts
Diastolic: occur between S2 and next S1. Occurs when heart relaxes and fills
36
Explain the grading system of murmurs
I - barely audible on listening carefully
II - faint but easily audible
III - loud and easily audible, no thrill
IV - loud murmur with no thrill
V - heard with scope barely touching chest
VI - audible with scope not touching chest
37
What are some common examples if people with innocent murmurs?
Young children, young and think patients.
38
Describe Aortic Stenosis
This is the narrowing of the aortic valve which causes restriction of blood through to the aorta. This is a systolic crescendo-decrescendo murmur. As it gets worse, it can blend into S2 and cause S2 to get quieter.
This often radiates to carotids and there will be a weal and delayed sluggish upstroke of the carotids.
Causes include age-related calcification, congenital bicuspid aortic valve (2 out of 3 cusps fused) and high calcium content causing calcification.
This is best heard of 2nd right intercostal space.
39
is Aortic Stenosis systolic or diastolic?
Systolic
40
What is the sound of Aortic Stenosis?
Crescendo-decrescendo
41
What murmur radiates to carotid?
Aortic Stenosis
42
Describe Aortic regurgitation
This is a leaky valve where it doesn't close properly. This is a decrescendo blowing diastolic murmur. The left ventricle will go through hypertrophy and dilation due to receiving more blood than usual. There is a larger stoke volume and hence systolic blood pressure increase but diastolic decreases. This causes head bobbing.
There is a water hammer pulse ( strong during systole and weak during diastole).
Common causes are connective tissue disorders of Marfans.
43
What is a water hammer pulse?
Strong during systole and weak during diastole
44
What murmur causes head bobbing?
Aortic regurgitation
45
What is the sound of Aortic regurgitation?
Decrescendo blowing diastolic murmur
46
Is Aortic regurgitation diastolic of systolic?
Diastolic
47
Describe Mitral valve regurgitation
This is a holosystolic murmur head best at apex. There is backflow of blood from left ventricle to left atrium during systole.
There is an increase in left atria pressure which causes an increased pulmonary pressure.
Left ventricle will pump more blood to compensate and hence undergo hypertrophy.
This is common with Rheumatic fever. This radiates to the axilla.
48
Where does Mitral valve regurgitation radiate to?
Axilla
49
Is Mitral valve regurgitation Diastolic or systolic?
Systolic
50
Describe Mitral stenosis?
This is narrowing of mitral valve and blood is restricted in atrium. There is less blood to the left ventricle and as a result, less blood goes to lung and this creates shortness of breath. The left atrium will enlarge due to higher volume and this may cause fluid in lungs.
Rheumatic fever is common.
This is a diastolic murmur and there is an opening snap after S1. After the opening snap, there will be a diastolic rumble.
51
What is the sound in Mitral stenosis?
Opening snap
52
Is Mitral stenosis diastolic or systolic?
Diastolic
53
Describe Tricuspid regurgitation
This is a systolic murmur. This is where the tricuspid valve is leaky and blood flows back into right atrium. The right atrium may enlarge. There is a holostyolic sound between S1 and S2.The valve is damaged with intravenous drug use.
54
What is the diaphragm and bell used for with the stethoscope?
Diaphragm: high pitched
Bell: low pitched
55
What are the different areas to place the stethoscope?
Aortic: right second intercostal space
Pulmonary: left second intercostal space
Erbs: third left intercostal space
Tricuspid: lower left sternal edge on 4th intercostal space
Mitral: left 5th intercostal space mid-clavicular
56
What ribs joins at sternal angle?
Second. (T4/5)
57
What is costal cartilage?
Hyaline
58
What are the three openings of the diaphragm?
Caval opening: T8: inferior vena cava
Oesophageal opening: T10: oesophagus, Vagus nerve
Aortic opening: T12: aorta, thoracic duct, azygous vein
59
Where do the internal intercostal arteries arise from?
Subclavian
60
What are the three parts of the sternum?
manubrium, body and xiphoid process
61
What is the costotransverse and costovertebral joints?
Costotransverse: between tubercle of rib and transverse costal facet
Costovertebral: head of ribs with superior costal facet of corresponding rib and inferior costal facet of vertebrae above
62
What is the superior to inferior order of the neurovascular bundle in he intercostal space?
VAN
63
What is the difference between pectus excavatum and pectus carinatum?
Excavatum is inwards and carinatum in outwards.
64
Where do the posterior and anterior intercostal arteries originate?
Posterior: descending thoracic aorta
Anterior: internal thoracic artery
65
What is stroke volume?
The volume of blood pumped out of the left ventricle per beat
66
What does cardiac out equal?
Heart rate x Stroke volume
67
What does the Frank-Starling mechanism state?
Contractile strength depends on how much the heart was stretched.
68
What organ is supplied by diastolic?
The heart as the coronary arteries at unable to fill during systolic.
69
What is preload?
The EDV pressure which is stretching the walls of the ventricles.
70
What is afterload?
The resistance the ventricles must overcome to pump blood around the body. An increase in resistance will increase afterload but decrease stroke volume.
71
What are some examples positive ionotropic an negative ionotropic factors that affect contractility?
Positive: sympathetic stimulation, caffeine, hypercalcaemia
Negative: parasympathetic stimulation, hypocalcaemia, potassium increase, myocardial hypoxia
72
What rib only articulate with the corresponding vertebra?
1, 10, 11, 12
73
What is the sensory supply to the diaphragm?
Phrenic nerve, lower intercostal (T6-T11) and subcoastal nerve
74
Where do the anterior intercostal originate?
1-6: internal thoracic
| 7-9: musculophrenic
75
What is the difference between the azygous and the hemi-azygous vein?
The azygous vein drains the posterior right surface and ends in the superior vena cava.
The hemi-azygous vain drains the left posterior surface and drains into the azygous vein.
76
What are all valves closed?
- early ventricular systole
| - late ventricular diastole
77
What two layers make up the pericardium?
Outer Fibrous
| Inner Serous
78
What is the outer fibrous pericardium composed of?
Connective tissue: this prevents over-filling of the heart
79
What is the inner serous pericardium composed of?
The outer parietal layer and the inner visceral layer (epicardium). These layers are made up of a single layer of epithelium, known as mesothelium. There is the pericardial cavity between these two layers.
80
What are the cusps of the tricuspid valve?
- septal
- anterior
- posterior
81
What are the cusps of the mitral valve?
- anterior
| - posterior
82
What are the cusps of the pulmonary valve?
- left
- right
- anterior
83
What are the cusps of the aortic valve?
- left
- right
- posterior
84
What layer contains the purkinje fibres?
Subendocardial layer
85
When is S2 heard?
Diastole (end of systole)
86
How is an echocardiogram taken?
A liquid gel is applied on the chest area and a probe is placed to view the 3D images of the heart. High frequency sound waves (ultrasound) provide graphic pictures of the heart's size, valves and chambers. This allows the sonographer to see any abnormalities.
The device releases high-frequency sound waves. The transducer picks up the echoes of the sound waves and transmits them into electrical impulses. The echocardiogram machine converts these impulses into moving pictures of the heart.
87
What does the internal thoracic artery bifurcate into?
Superior epigastric and musculophrenic. This is at the level of ribs 6/7.
88
At what level does the internal thoracic arteries bifurcate?
Ribs 6/7
89
What is preload?
This is the amount of stretching in the ventricles. An increase in EDV will increase preload.
90
What is afterload?
This is the amount of pressure the ventricle must generate in order to push the blood out of the ventricle. This is related to the resistance that is generated, therefore if the afterload increases, the SV will decrease.
91
What is meant by the Frank-Starling mechanism?
This states the a greater EDV would increase the contractile strength of the ventricles and will increase the SV. The myocardium will be more stretched due to the grater volume, therefore, their increase sarcomere length results in increased calcium sensitivity and therefore a much stronger contraction.
92
What is the sensory supply to the diaphragm?
The intercostal nerves 6-11 and the subcostal nerve.
93
What is the lingula?
Extension of the superior lobe of the left lung
