Cardiopulmonary Physiology Flashcards
(93 cards)
1
Q
What are some classic features of fetal circulation?
A
Presence of
1. Foramen Ovale
2. Ductus Arteriosus
3. Ductus Venosus
2
Q
What is the role of the Foramen Ovale?
A
Foramen Ovale shunts blood from the right atrium to the left atrium
3
Q
What is the role of the Ductus Arteriosus?
A
Ductus Arteriosus bypasses the lungs by connecting the Pulmonary artery to the Aorta
4
Q
Talk briefly on the embryological development of the cardiovascular system
A
The heart is formed between week 3-8, from Mesodermal cells.
The cardiac tube fuses and loops to create the 4 chambered heart.
Heart beat behind followed by formation of Atria and ventricles.
5
Q
What are some Neonatal Transitions that take place at birth?
A
- Fetal shunts(foramen Ovale, ductus Arteriosus,ductus Venosus) all close
- Establishment of independent pulmonary and systemic circulation.
- Left Ventricular dominance replaced fetal right dominance.
6
Q
What are some characteristic features in post natal and childhood development?
A
In neonates, heart rate is high (120-160bpm) and lower blood pressure.
However, in Adolescents, heart rate drops to 70-100bpm, and BP rises due to increased vascular resistance.
Through these phases, arterial walls thicken and development of vascular tone happens
7
Q
Talk about the embryonic development of the respiratory system.
A
Lung development begins at week 3-7 and development occurs through 5 essential stages.
1. Embryonic (week 3-7)
2. Pseudoglandular (week 7-17)
3. Canalicular stage (week 16-25)
4. Saccular (week 24-38)
5. Alveolar (birth - 8 years)
8
Q
What happens in the embryonic stage?
A
Formation of Lung buds occur
9
Q
What happens in the pseudoglandular stage?
A
Branching of the airway tree
10
Q
What happens in the Canalicular stage?
A
Formation of respiratory bronchioles and vascularization.
11
Q
What happens in the Saccular stage?
A
There is expansion of airspaces and formation of alveolar sacs.
12
Q
What happens in the alveolar stage?
A
There is maturation and multiplication.
13
Q
What are some Neonatal Transitions in pulmonary Physiology at birth
A
Changes that take place after first breath
1. Expansion of the lungs, clearance of amniotic fluid that fills the Fetal lungs
2. There is increase in oxygen levels leading to pulmonary vasodilation and decreased pulmonary vascular resistance.
3. There is establishment of functional residual capacity.
14
Q
What are some post natal and childhood developments observed?
A
- At birth there are about 20, million alveoli, at age 8, there’s about 300 million alveoli.
- Compliance increases as chest wall stiffens
- There is increased lung efficiency with increased lung volume and surface area.
15
Q
Mention some common disorders linked to development in the Cardiovascular System
A
- Congenital Heart defects e.g; Atrial Septum Defect (ASD), Ventricular Septum Defect (VSD), Tetralogy of Fallot.
- Patent Ductus Arteriosus (PDA)
16
Q
A
17
Q
What is ASD?
A
ASD is Atrial septum defect, it is the failure of the foramen Ovale to close, leading to mixing of oxygenated and deoxygenated blood.
18
Q
What is VSD?
A
VSD is a defectof interventricular septum that causes left to right shunting
19
Q
Explain Tetralogy of Fallot?
A
It is a combination of 4 defects
VSD,
Pulmonary stenosis
Right ventricular Hypertrophy
Overriding aorta
20
Q
What is patent Ductus Arteriosus?
A
PDA is when the Ductus Arteriosus remains open after birth, leading to increased pulmonary blood flow
21
Q
Mention some common Respiratory disorders.
A
- *Respiratory distress syndrome (RDS)** : caused by insufficient surfactant production, causing alveolar collapse.
-
Bronchopulmonary Dysplasia :
Is a chronic lung disease that happens when am infant is born premature and hence requiring oxygen via mechanical ventilation. This can damage the lungs and lead to prolonged required dependence on oxygen therapy
Other disorders include; Congenital diaphragmatic Hernia, Pulmonary Hypoplasia.
22
Q
Mention some Cardiovascular adaptations in fetus
A
- In fetus, gas exchange occurs via Placenta and not lungs
- The Ductus Venosus directs oxygenated blood from umbilical vein to the inferior vena cava, bypassing the liver.
- The Foramen Ovale enables bypass of pulmonary circulation.
- The Ductus Arteriosus also diverts blood from pulmonary artery to the Aorta to minimise blood flow to the lungs.
- The right ventricle pumps more blood than the left to support placements circulation
- Fetal heart rate ranges from 120-160 BPM
23
Q
Mention respiratory changes in fetus
A
- Lungs are fluid filled, not air
- Pulmonary vascular resistance(PVR) is high, minimizing blood flow to the lungs.
- Gas exchange occurs entirely in the placenta
- Fetal hemoglobin has a higher affinity for oxygen than adults hemoglobin.
24
Q
A
25
Why does fetal hemoglobin have higher affinity for oxygen than adults hemoglobin.
This is to ensure oxygen transfer from maternal blood.
26
Mention some Cardiovascular adaptations in old age.
1. There is increased wall thickness (Ventricular Hypertrophy), due to chronic pressure load.
2. There is decreased elasticity of the myocardium, leading to diastolic dysfunction.
3. Artery walls thicken and lose elasticity (Arteriosclerosis), causing systemic vascular resistance and blood pressure.
27
Mention some other Cardiovascular adaptations in old age
1. There is decreased sensitivity to catecholamines reducing heart rate variability.
2. There is decreased maximum cardiac output
3. Calcification and thickening of valves e.g Aortic stenosis.
All these additions lead to higher risk of heart failure, arrhythmias and hypertension.
28
Mention some respiratory system changes in old age
1. There is loss of compliance due to calcification of coastal cartilages
2. Reduced elastic recoil leading to air leading to air trapping and increased residual volume.
3. There is reduced surface area for gas exchange as alveolar walls become thinner.
29
Mention some other respiratory changes different from previously mentioned
1. Decreased vital capacity and forced expiratory volume(FEV1).
2. There is increased work of breathing due to stiffer lungs and chest walls
All the respiratory changes in old age cause increased susceptibility to respiratory infections e.g Pneumonia.
There is also higher risk of chronic obstructive pulmonary disease (COPD) and sleep apnea.
30
Mention some Cardiopulmonary adaptations at rest
1. Heart rate typically ranges between 60-100 BPM.
2. Stroke volume is 70ml per beat
3. Blood volume at rest is 120/80 mmHg
4. The normal respiratory rate is 12-20 breaths per minute in adults.
5. At rest breathing is predominantly regulated by medulla and Pons.
31
Mention some Cardiopulmonary adaptations to moderate stress(e.g exercise or emotional stress).
1. Increased heart rate and stroke volume.
2. Increased cardiac output
3. Vasodilation in active muscles, vasoconstriction of non-essentials(e.g G.I tract)
4. Systolic Bp goes up according to exercise intensity, Diastolic BP remains the same
5. Increased ventilation, i.e, respiratory rate increases
6. Increased oxygen consumption by working muscle.
32
Mention
33
Mention some Cardiopulmonary adaptations to severe stress(e.g Strenuous exercise or critical illness).
1. Significant increase in heart rate(180-200) BPM.
2. Redistribution of blood flow with priority to muscles, brain and heart.
3. Cardiac output peaks up to 20-25L per minute in trained individuals
4. Systolic Bp can ride to ~200 mmHg while diastolic remains stable
5. Respiratory rate may rise to ~40 - 50 breaths
6. Lactic acid accumulation from anaerobic metabolism leads to drop in blood pH
34
35
Explain Hypertension?
Hypertension in simple terms
Is a state of persistent elevated blood pressure over a given period of time. (140/90 mmHg).
It can be physiological or pathological.
36
Mention some pathological causes of Hypertension?
1. Increased peripheral resistance
2. Elevated blood volume
3. Left Ventricular Hypertrophy
37
Chronic hypertension can lead to??
1. Arterial remodeling and atherosclerosis
2. Damage to the heart, kidneys, brain and retina.
38
What is Cardiac failure ?
Cardiac failure is the inability of the heart to pump enough blood to meet metabolic demands.
39
What is COPD?
COPD is a chronic, progressive lung disease characterised by airflow obstruction.
40
What are the causes(pathophysiology) of COPD?
1. Airway inflammation due to continuous exposure to irritants(e.g cigarette smoke).
2. Emphysema reduces surface area for gas exchange
3. Increased airway resistance prevents complete expiration, leading to trapped air and hyper inflated lungs.
41
Symptoms of COPD?
1. Chronic cough
2. Sputum production
3. Dyspnea
4. Exercise intolerance
It could also lead to respiratory failure, right heart failure and recurrent infections.
42
Talk about Pulmonary embolism?
Pulmonary embolism is the obstruction of pulmonary arteries by a blood clot, far or air embolus.
43
What are the causes(pathophysiology) of Pulmonary embolism?
1. Vascular obstruction
2. Increased pulmonary artery pressure
3. Inflammatory response
44
Talk about Asthma?
Asthma is a chronic respiratory disorder characterised by hyper sensitivity of the airway
45
Pathophysiology of asthma?
1. Inflammation of airway due to exposure to allergens/irritants,etc
2. Mucus hypersecretion
46
Can you mention any other Cardiopulmonary conditions?
1. Acute Respiratory Distress Syndrome
2. Ischemic heart disease
47
What is R-A-A-S?
R-A-A-S means Renin-Angiotensin-Aldosterone-System.
It is a hormonal system that regulates blood pressure, fluid balance, and electrolyte homeostasis.
48
R-A-A-S is activated by?
1. Low BP
2. Low sodium levels
3. Decreased renal blood flow (Hypoperfusion)
4. Sympathetic nervous system stimulation
49
The primary site of R-A-A-S activation is?
The Juxta-Glomerular Apparatus in the kidneys.
50
Can you explain the action of R-A-A-S?
Renin acts as an enzyme, to convert angiotensin produced by the liver to angiotensin 1.
Angiotensin 1 is converted to angiotensin 2 in the lungs by Angiotensin converting enzyme(ACE).
Angiotensin 2 now has it's varying effects as a potent vasoconstrictor.
It also influences Aldosterone release from Adrenal gland which increases sodium and water retention in the kidneys
51
Explain Servo-Merchanism
Servo mechanism is a system that maintains control over a physiological process through feedback regulation. It ensures homeostasis.
52
A servo mechanism is a self regulating control system that consists of?
1. Sensors(detect physiological changes)
2. Controllers (process information and generate responses)
3. Effectors (implements corrective actions)
53
Mention some Cardiopulmonary adaptations in aviation(high altitudes)?
1. Hypoxia happens,
2. Hyperventilation (respiratory rate increases)
3. Increased heart rate and cardiac output
4. Pulmonary vasoconstriction
54
What happens in Acclimatization to high altitude?
1. Increased red blood cell production
2. Oxygen diffusion is enhanced
3. Rightward shift in oxygen-hemoglobin dissociation curve.
55
What are some medical conditions/concerns in aviation
1. Acute Mountain Sickness
2. High Altitude Pulmonary Edema
3. High Altitude Cerebral Edema
56
What do you know about space Physiology?
In space, Microgravity eliminates gravitational forces, leading to fluid redistribution, Cardiovascular deconditioning and respiratory adaptations.
In simple terms, the body has to learn to work differently to regulate itself and stay in homeostasis
57
What are some Cardiovascular adaptations in space?
1. Fluid shift: blood and other fluids move from lower to upper body(puffy face, thinner legs)
2. There is reduced blood volume and decreased plasma volume
3. Cardiac atrophy: the heart muscle weakens as it works against gravity
4. Orthostatic intolerance : refers to dizziness and fainting, astronauts experience when then return to gravity; due to reduced blood tone
58
What are some respiratory changes in space?
1. There is increased carbon dioxide retention
2. Uniform lung perfusion (irrespective of zone)
59
Why is Cardiopulmonary changes in deep sea (Hyperbaric Physiology) important?
In deep sea diving, high ambient pressure and increased gas density affect respiration and circulation.
60
What are some Cardiopulmonary adaptations in deep sea diving?
1. Increased hydrostatic pressure compresses gas volumes in the lungs
2. Increased oxygen partial pressure(Hyperoxia)
3. Nitrogen Narcosis
4. Decompression sickness
61
What is diving reflex?
Diving reflex refer to things that happen at diving such as
1. Bradycardia
2. Peripheral Vasoconstriction
3. Increased lung compression to curb expansion
4. Increased myoglobin stores to improve oxygen storage in muscles
5. Elevated hematocrit
6. Greater lung elasticity
62
Explain ECG?
ECG means Electrocardiography.
It is a non invasive diagnostic tool used to measure the electrical activity of the heart over time
63
There are 3 types of ECG, name them?
1. Resting ECG
2. Exercise or stress ECG
3. Ambulatory or Holter ECG
64
What do this mean?
1. SA node
2. AV node
1. SA node: means **Sinoatrial Node** are natural pacemakers (~60-100bpm)
2. AV node: means **Atrioventricular node** delays impulse to allow Ventricular filling
65
What are the role of the following?
1. Bundle of HIS
2. Right &left bundle branches
3. Purkinje fibres
1. Bundle of HIS: conducts impulse to ventricles
2. Right &left bundle branches: transmit signals to each ventricle.
3. Purkinje fibres: spread impulses for synchronised contraction
66
Name the Types of ECG leads?
1. Limb leads
2. Augmented limb leads(aVr, aVL, aVF)
3. Precordial (chest) leads(V1-V6)
67
Explain ECG waveforms.
What do each mean?
1. P wave: Atrial depolarisation (SA node activation)
2. PR interval: Time from SA node activation to ventricular depolarisation
3. QRS complex: Ventricular depolarisation
4. ST segment: Early ventricular repolarization
5. T wave: Ventricular repolarization
6. QT interval: Duration of Ventricular depolarisation and repolarisation
68
Clinical importance of ECG?
ECG is helpful in diagnosis of Arrhythmias, myocardial infarction, electrolyte imbalance and conduction disorders
69
What are some common abnormalities noticed in ECG
1. Sinus bradycardia (Heart rate<60)
2. Sinus tachycardia (heart rate>100)
3. Atrial fibrillation : irregular irregular rhythm and absent P waves.
4. Myocardial infarction : ST elevation, T wave inversion, deep Q waves.
5. Ventricular tachycardia: wide QRS complex, rapid Heart rate
6. Hyperkalemia : tall peaked T waves
70
What are the causes of abnormal ECG?
1. Cardiac causes
2. Pulmonary caused
3. Metabolism and systemic causes
71
Mention some cardiac causes of abnormal ECG?
1. Arrhythmias (e.g Atrial fibrillation, Ventricular tachycardia)
2. Myocardial ischemia/infarction
3. Hypertrophy
4. Heart failure
5. Conduction blocks
72
What are some pulmonary causes of abnormal ECG?
1. COPD
2. Pulmonary embolism
3. Cor pulmonale(means right heart failure due to lung disease)
73
What are metabolic causes of abnormal ECG?
1. Electrolyte imbalances (hyperkalemia, hypokalemia, hypercalcaemia)
2. Drug effect (e.g digitalis toxicity, beta blockers, antiarrhythmics).
74
Calculation of arterial pressure is done by?
Arterial pressure (BP)= Cardiac output × Total peripheral resistance
Total peripheral resistance depends on vessel diameter and tone
75
Cardiac output is calculated by?
C.O= heart rate × stroke volume
76
Regulation of arterial pressure is done via?
1. Neural control (short term)
2. Hormonal/Renal control (long term)
77
Where are Baroreceptors found?
Carotid sinus and aortic arch
78
Explain neutral control of arterial pressure?
1. Baroreceptor reflex
2. Chemoreceptor reflex
3. CNS ischemic response
79
Explain the hormonal/renal control of arterial blood pressure
1. R-A-A-S
2. ANP (Atrial Natriuretic peptide)
3. Vasopressin (ADH)
80
Define haemorrhage?
Hemorrhage refers to excessive blood loss from the circulatory system due to trauma, surgery, rupture of blood vessels or underlying medical conditions.
81
Mention the types of hemorrhage?
1. Internal, and
2. External hemorrhage
82
What are physiological responses to hemorrhage?
1. Baroreceptor receptor
2. Hormonal response
3. Capillary fluid shift
4. Erythropoiesis
83
What is Shock?
Shock is a life threatening condition where blood circulation is inadequate to meet tissue oxygen demands, leading to organ failure.
84
Mention types of shock?
1. Hypovolemic shock
2. Cardiogenic shock
3. Distributive shock
4. Obstructive shock
85
What are the stages of shock?
1. Compensated shock
2. Decompensated (progressive) shock
3. Irreversible (refractory) shock
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88
Where do signals from Baroreceptors go to in the brain?
Medullary Cardiovascular center in the brainstem
89
What does baroreceptor reflex act to do?
1. Adjust heart rate
2. Stroke volume
3. Vessel diameter
90
What are the clinical relevance of servo mechanisms
1. Hypertension
2. Heart failure (reduced Cardiac output)
3. Sleep apnea
91
Mention Cardiopulmonary adaptations in aviation(high altitudes) ?
1. Hypoxia happens(that is, reduced oxygen delivery to tissues).
2. Hyperventilation (respiratory rate increases)
3. Increased heart rate and cardiac output
4. Pulmonary Vaconstriction
92
Explain acclimatization to high altitude?
1. Increased red blood cell production
2. Oxygen diffusion is enhanced
3. Rightward shift in oxygen-hemoglobin dissociation curve
93
