CVR Physiology

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Questions and Answers

What is the effect of low pH on hemoglobin's affinity for oxygen?

Decreases affinity for oxygen (correct)

Fluctuates based on temperature

No effect on affinity

Increases affinity for oxygen

How does a high concentration of carbon dioxide (PCO2) affect hemoglobin's affinity for oxygen?

Enhances oxygen binding under high pH

Has no impact on affinity

Reduces affinity for oxygen (correct)

Increases affinity for oxygen

What role does 2,3 BPG play in oxygen delivery in red blood cells?

It helps hemoglobin release oxygen more easily (correct)

It inhibits hemoglobin from releasing oxygen

It binds to hemoglobin only at high oxygen levels

It solely regulates carbon dioxide levels

In individuals with chronic anemia, how does the level of 2,3 BPG change?

Increases significantly to aid oxygen delivery Signup and view all the answers

What unique characteristic does fetal hemoglobin have in comparison to adult hemoglobin?

Higher affinity for oxygen Signup and view all the answers

What initiates the pacemaker potential in the SA node?

Opening of gated calcium channels Signup and view all the answers

Which process follows after calcium enters the cardiomyocyte through L-type calcium channels?

Calcium triggers the release of ryanodine receptors Signup and view all the answers

During which phase does rapid depolarization occur?

When the threshold is reached and calcium influxes rapidly Signup and view all the answers

What does the P wave of an ECG represent?

Depolarization of the atrial muscle wall Signup and view all the answers

What role does the SERCA calcium channel play at the end of contraction?

It transports calcium back to the sarcoplasmic reticulum Signup and view all the answers

What is the isoelectric line in an ECG indicative of?

The resting membrane potential Signup and view all the answers

What causes the change in the electrical vector during an action potential?

Movement of sodium and calcium ions into the cell Signup and view all the answers

What role does the Renin-angiotensin-aldosterone mechanism play in blood pressure control?

It helps to control long-term blood pressure by managing resistance. Signup and view all the answers

What happens to arterial pressure when peripheral resistance increases?

Arterial pressure increases. Signup and view all the answers

Which of the following is a common consequence of hypertension?

Stroke and damage to the eyes. Signup and view all the answers

How does age affect arterial health?

Increases stiffness and decreases sensitivity of baroreceptors. Signup and view all the answers

What initiates the process of atherosclerosis?

Injury to the endothelium leading to inflammation. Signup and view all the answers

What occurs during external respiration?

Gas exchange occurs between alveoli and capillaries. Signup and view all the answers

What is 'dead space' in the respiratory system?

The part of the airway that does not participate in gas exchange. Signup and view all the answers

What happens to alveolar dead space during diseases affecting blood flow in the lungs?

It increases as blood flow decreases. Signup and view all the answers

Secondary hypertension can be caused by which of the following?

Kidney disease and vascular changes. Signup and view all the answers

What does VO2max indicate regarding a person's fitness level?

The maximum rate of oxygen utilization during intense exercise Signup and view all the answers

How is a MET defined in the context of physical activity?

It compares the energy used during activities to resting energy expenditure Signup and view all the answers

Which of these factors does NOT control heart rate and ventilation during physical activity?

Involuntary reflexes Signup and view all the answers

During exercise, what change occurs in the body's sympathetic and parasympathetic activities?

Parasympathetic activity decreases while sympathetic increases Signup and view all the answers

What is the role of tidal volume in respiratory response during physical activity?

It indicates the amount of air breathed in or out per normal breath Signup and view all the answers

What is characterized as sedentary behavior?

Activities performed while sitting or lying down Signup and view all the answers

Which of the following describes heavy exercise intensity?

Activity performed at a vigorous level with significantly increased heart rate Signup and view all the answers

What physiological signal is primarily sent out to increase oxygen supply during exercise?

Increased adrenaline production Signup and view all the answers

Which exercise intensity domain includes the highest level of physical exertion?

Extreme Signup and view all the answers

What is the typical breathing frequency during moderate exercise?

Between 12 to 20 breaths per minute Signup and view all the answers

What is the formula for calculating minute ventilation?

Tidal volume x breathing frequency Signup and view all the answers

What happens to stroke volume during exercise as intensity increases up to 60% of VO2max?

It increases and then levels off Signup and view all the answers

Which parameter is NOT typically monitored during cardiopulmonary exercise testing (CPX)?

Oxygen saturation levels Signup and view all the answers

Why is hemoglobin considered an allosteric protein?

It changes conformation based on oxygen levels Signup and view all the answers

What is the oxygen saturation level of hemoglobin in the veins after oxygen delivery?

77% Signup and view all the answers

What type of chains does hemoglobin consist of?

2 alpha and 2 beta chains Signup and view all the answers

What occurs in the lungs regarding hemoglobin and oxygen levels?

Hemoglobin binds almost all available oxygen due to high pressure Signup and view all the answers

What is the primary function of the cardiopulmonary unit tested in CPX?

To analyze cardiovascular efficiency Signup and view all the answers

During exercise, which blood pressure component remains relatively unchanged?

Diastolic pressure Signup and view all the answers

What characterizes fetal hemoglobin compared to adult hemoglobin?

It has a higher affinity for oxygen Signup and view all the answers

Study Notes

Cardiac Physiology

Heart pumps blood from low-pressure veins to high-pressure arteries
Pulmonary circuit pressure is approximately 28/8 mmHg
Systemic circuit pressure is approximately 120/80 mmHg
Heart failure in adults is commonly caused by the left ventricle's inability to function properly (e.g., filling or ejecting blood efficiently).
Cardiac cycle is one heartbeat to the next

Cardiac Conduction System

Intercalated discs link muscle cells, including desmosomes and gap junctions
Gap junctions allow rapid action potential transmission
Myocardial cells can depolarize spontaneously
Random depolarization potential creates pacemaker potential
Fibrous tissue separates atria and ventricles to allow electrical isolation

Cardiac Pacemakers

Sinoatrial (SA) node depolarizes over time, causing gradual reduction in resting membrane potential (pacemaker potential).
Action potential triggered when membrane potential exceeds threshold (every 0.8 seconds).
Atrioventricular (AV) node cells depolarize slower, triggering action potential before spontaneous depolarization.

Cardiac Action Potential

Pacemaker potential involves sodium inflow, calcium inflow, followed by calcium channel opening for rapid depolarization.
Plateau maintained by calcium influx and potassium efflux
Repolarization involves calcium channel closure and potassium outflow.

Excitation-Contraction Coupling

Action potential leads to contraction of cardiac muscle cells
Chemical signal converts to mechanical energy with aid of contractile proteins (crucial role of calcium)
Calcium enters cytosol during action potential to trigger muscle contraction and sarcoplasmic reticulum release.

Cardiovascular Regulation

Baroreceptors in carotid arteries and aorta sense pressure
Increased BP leads to decreased heart rate and lower BP (baroreceptor reflex)
Hormones (e.g., Renin-angiotensin-aldosterone) regulate BP over longer periods
Arterioles constrict to increase resistance and reduce blood flow, while dilation decreases resistance and increases flow.

Risk Factors

Hypertension (essential and secondary)
Age
Other modifiable and unmodifiable factors

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Description

This quiz explores the intricate relationships between hemoglobin's affinity for oxygen and factors like pH, carbon dioxide concentration, and 2,3 BPG levels. Additionally, it delves into cardiac physiology including the SA node's pacemaker potential and the electrical aspects of an ECG. Test your understanding of these vital physiological processes!