Practice Exam on Action Potential and Alveolar Pressure

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Questions and Answers

The systemic circuit carries than the pulmonary circuit & thus the strongest (most muscular) chamber of the heart is .

Cooler blood; right ventricle

Blood further; left ventricle (correct)

Thicker blood; left atrium

Warmer blood; right atrium

Which of the comparisons regarding the level of blood oxygenation is correct?

Higher in right ventricle than in left ventricle

Higher in pulmonary artery than in pulmonary vein

Higher in left atrium than in right atrium

Higher in aorta than in pulmonary vein (correct)

Which of the following choices correctly describes what happens during an inspiration (inhalation)?

Diaphragm contracts -> increase volume -> pressure decreases inside the lungs (correct)

Diaphragm relaxes -> decrease volume -> pressure decreases inside the lungs

Diaphragm contracts -> decrease volume -> pressure increases inside the lungs

Diaphragm relaxes -> increase volume -> pressure increases inside the lungs

Gas exchange with surrounding tissues occurs across because these vessels are so .

Capillaries; thin walled Signup and view all the answers

When arterial PCO2 is above normal, blood pH becomes more _. A negative feedback loop causes a(n) __ in the rate & depth of breathing to correct the problem.

Acidic; increase Signup and view all the answers

Depolarization of the cardiac myocytes causes _ which creates a pressure gradient to allow blood throughout the body.

Muscle contraction, bulk flow of Signup and view all the answers

If Pavleolus = 499 and Patmosphere = 500, this is most likely the start of an _ and the diaphragm is __.

Inhalation, relaxed Signup and view all the answers

Blood in the _ circuit travels the furthest; this is possible because the ventricle produces the highest pressures.

Systemic, left Signup and view all the answers

The relaxation of the smooth muscle in bronchioles can _____.

Decrease resistance to airflow Signup and view all the answers

If the atmospheric pressure = 750 mmHg, which alveolar pressure will cause the greatest exhalation volume?

745 mmHg Signup and view all the answers

The movement of gases between blood & alveoli is referred to as _____.

Diffusion Signup and view all the answers

Which blood vessel carries deoxygenated blood to the lungs?

Pulmonary artery Signup and view all the answers

The pressure gradient is lower for the pulmonary circuit because pulmonary blood travels a distance.

Diffusion; shorter Signup and view all the answers

Which condition would lead to an increased rate and depth of breathing?

High PCO2 Signup and view all the answers

What is the alveolar pressure that would allow for the deepest exhalation at an atmospheric pressure of 700 mmHg?

695 mmHg Signup and view all the answers

What will occur if the SA node is damaged?

The AV node will continue to depolarize Signup and view all the answers

During which phase do the semilunar valves of the heart open?

Ventricular systole Signup and view all the answers

Which alveolar pressure will create the largest volume of inhaled air if the atmospheric pressure is 750 mmHg?

752 mmHg Signup and view all the answers

What happens during ventricular diastole if the aortic semi-lunar valve is leaky?

Blood would flow from the aorta into the left ventricle Signup and view all the answers

Pulmonary ventilation and internal respiration depend on which principle?

Flux, a concentration gradient Signup and view all the answers

What substance is likely produced by muscles doing a lot of work that lowers the pH of the blood?

CO2 Signup and view all the answers

Which type of channels facilitate the repolarization process in the pacemaker cells at the SA node?

Potassium (K+) Signup and view all the answers

What causes blood to move in a consistent direction through the body?

Pressure gradients Signup and view all the answers

What anatomical structures primarily regulate airflow into the exchange zones?

Bronchioles and arterioles Signup and view all the answers

During inhalation, what happens to the diaphragm and what pressure change occurs in the lung tissue?

Contract, Low Signup and view all the answers

Blood returning to the left atrium has which characteristics of PO2 and where does it travel next?

High, left ventricle Signup and view all the answers

If atmospheric pressure is 500 mmHg, what can be said about the alveolar pressure for inhalation?

In the mountains; less than Signup and view all the answers

In the action potential diagram, what is caused by the outflow of K+ ions which also relates to the neurons and the SA node?

Both use this ion Signup and view all the answers

To slow down heart rate, the parasympathetic system mainly does what?

Decreases the slope of region P Signup and view all the answers

Which chamber of the heart is considered the strongest, most muscular?

Left ventricle Signup and view all the answers

What occurs in the body during a stressful event regarding the nervous system?

Sympathetic, increase the strength of cardiac muscle contractions Signup and view all the answers

What is the likely immediate effect at the SA node if voltage-gated Ca2+ channels are blocked?

The SA node would lack the fast depolarization event Signup and view all the answers

What primary factor is the ventilation rate most sensitive to?

Blood PCO2 Signup and view all the answers

In the ventilation rate control system, which organ is the target and what is the control center?

Diaphragm, brain Signup and view all the answers

What is the state of blood leaving the lungs concerning PO2 and blood pressure?

High, high Signup and view all the answers

Which option describes the relationship between metabolic acids and viscosity in the context of muscle activity?

Increases viscosity directly Signup and view all the answers

Which of the following mechanisms primarily influences the return of blood to the heart against gravity?

Venous valves Signup and view all the answers

Study Notes

Practice Exam Questions & Resource

Practice exam questions are from previous 118 professors. Exam writing style may vary.
Exams will be multiple choice, focusing on similar concepts.
If stuck on a question, review notes, utilize Piazza, or attend study sessions.
Avoid immediately checking answer keys; investigate independently.
Learning is maximized by seeking answers from memory and collaborating.
These questions are not an exhaustive list of exam topics. Additional study is crucial.

Figure D: Action Potential

Figure D illustrates an action potential.
The graph shows membrane potential (mV) over time (seconds).
A characteristic upward peak (labeled 'Threshold') is a key indicator of an action potential.
Region R (on the graph) is a specific feature of the action potential caused by ion outflow.

Questions from Practice Exam

Alveolar Pressure: 750 mmHg alveolar pressure creates the largest inhaled air volume, compared to other pressures.
Muscle Work and Blood Composition : Increased muscle work yields metabolic acids and lowered blood pH, that subsequently increases ventilation.
Blood Flow Direction: Blood flows consistently due to pressure gradients. This consistent flow is termed "bulk flow."
Figure D Region R: Outflow of K+ ions is the cause of region R.
Heart Rate Control: Parasympathetic system slows heart rate by influencing the sloped features of the action potential.
Voltage-Gated Calcium Channel Blocker on SA Node: A drug blocking voltage-gated Ca2+ channels would most likely prevent reaching threshold in the SA node.
SA Node Damage: Damage to the SA node affects the heart's ability to function as a pacemaker.
Heart Valve Leak: A leaky aortic semilunar valve would allow blood flowing back into the left ventricle during ventricular diastole because the valve isn't closing fully.
Pulmonary Ventilation and Internal Respiration: Pulmonary ventilation and internal respiration both exemplify flux with a concentration gradient.
Diaphragm during Inhalation: During inhalation, the diaphragm contracts, lowering pressure in the lungs to facilitate air entering.
Blood returning to Left Atrium: Blood returning to the left atrium is low in oxygen—it comes from the pulmonary veins.
Blood flow after lungs: Blood exits the lungs carrying oxygen (high PO2) and travels next to the left ventricle.
Stress Response and Cardiac Output: Sympathetic activation during stress increases cardiac muscle contraction strength.
Ventilation Rate Control: Lung alveoli and the brain (diaphragm) are involved in controlling ventilation rate.
Blood leaving the Lungs: Blood leaves the lungs with a high PO2 and low PCO2.
Cardiac Chambers: The left ventricle is the strongest chamber during the heart cycle.
Primary Pacemaker of the Heart: The SA node is the heart's primary pacemaker.
Ventilation Rate Sensitivity: Ventilation is most sensitive to changes in blood PCO2 levels.
Systemic vs Pulmonary Circuits: The systemic circuit has a higher pressure gradient than the pulmonary circuit leading to the left ventricle's greater strength.
Semilunar Valves: The semilunar valves prevent blood from moving from the ventricles back into the arteries.
Inspiration and Expiration Details: Inhalation involves diaphragm contraction-reducing lung volume which lowers pressure to allow air entry and expiration involves relaxation which forces air out.
Gas Exchange: Gas exchange occurs across capillaries, which are characterized by their thin walls.

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Description

This quiz focuses on the key concepts of action potential and alveolar pressure derived from previous exams by various professors. It is designed to test understanding through multiple-choice questions. Review your notes and collaborate with peers for maximum learning effectiveness.