Exam 2 Flashcards
(28 cards)
- List and describe the functions of the cardiovascular system
Gives oxygen to tissues
Gives nutrients to tissue
Gives hormones throughout the body
Removes c02 from tissue
Removes waste material from tissue
Is involved in thermoregulation
- List and describe the various parts of the cardiovascular system including the different types of blood vessels (arteries, arterioles, capillaries, venules and veins).
Heart: The central muscular pump with four chambers (left/right atria and left/right ventricles).
Arteries: Thick-walled vessels that carry oxygenated blood away from the heart.
Arterioles: Smaller branches of arteries that regulate blood flow.
Capillaries: The smallest vessels for oxygen and nutrient exchange with tissues.
Venules: Collect blood from capillaries and merge into veins.
Veins: Carry deoxygenated blood back to the heart; often have one-way valves.
- Describe the flow of blood through the heart and the various circulations (systemic, pulmonary, and coronary circulation).
Right Atrium: Receives deoxygenated blood from the body via the superior and inferior vena cava.
Right Ventricle: Contracts to send blood to the lungs via the pulmonary artery.
Lungs: Oxygenation occurs in the pulmonary capillaries.
Left Atrium: Oxygenated blood returns from the lungs via the pulmonary veins.
Left Ventricle: Contracts to send oxygen-rich blood to the body via the aorta.
Circulations:
Systemic Circulation: Carries oxygenated blood from the left ventricle to the body’s tissues and returns deoxygenated blood to the right atrium.
Pulmonary Circulation: Transports deoxygenated blood from the right ventricle to the lungs for oxygenation and returns oxygenated blood to the left atrium.
Coronary Circulation: Supplies the heart muscle itself with oxygen and nutrients through coronary arteries and veins.
- Illustrate and describe the anatomy of the heart with regard to the gross structures (chambers, vessels, valves, etc.), the electrical conduction system (sinoatrial node, etc.), and the coronary circulation.
Chambers:
Four chambers: Right atrium, right ventricle, left atrium, left ventricle.
Vessels:
Superior and inferior vena cava bring deoxygenated blood to the right atrium.
Pulmonary artery carries deoxygenated blood from the right ventricle to the lungs.
Pulmonary veins return oxygenated blood from the lungs to the left atrium.
Aorta carries oxygenated blood from the left ventricle to the body.
Valves:
Tricuspid valve (right atrioventricular valve) separates the right atrium and right ventricle.
Bicuspid valve (mitral valve or left atrioventricular valve) separates the left atrium and left ventricle.
Pulmonary valve and aortic valve regulate blood flow out of the ventricles.
Electrical Conduction System:
Sinoatrial (SA) Node:
Initiates electrical impulses.
Located in the right atrium.
Atrioventricular (AV) Node:
Delays the impulse for the atria to contract before it travels to the ventricles.
Located near the atrioventricular septum.
Bundle of His and Purkinje fibers:
Transmit electrical signals rapidly to the ventricles, causing them to contract.
Coronary Circulation:
Coronary Arteries:
Branch from the aorta.
Supply the heart muscle with oxygen and nutrients.
Include the left and right coronary arteries.
Coronary Veins:
Collect deoxygenated blood and return it to the right atrium.
- Describe atherosclerosis and coronary heart disease (CHD) and its primary risk factors.
Atherosclerosis is the narrowing of blood vessels
Most prevelant CHD risk factor is physical inactivity, followed by Cigarette smoking, Serum cholesterol and high blood pressure
- Describe how the electrocardiogram (ECG) is recorded and list the purposes for which it is recorded and used (determine HR, detect hypertrophy, detect CHD, etc.).
Recording an ECG:
Electrodes are placed on the skin at specific locations on the body, typically on the chest, arms, and legs.
The ECG machine records electrical signals generated by the heart.
The resulting waveform represents the electrical activity of the heart over time.
Purposes of ECG:
Determine Heart Rate (HR):
ECG helps calculate heart rate by measuring the intervals between heartbeats.
Detect Hypertrophy:
ECG can identify abnormal thickening of the heart muscle (hypertrophy).
Detect Coronary Heart Disease (CHD):
ECG can reveal irregularities in the heart’s electrical activity, which may suggest CHD.
Diagnose Arrhythmias:
ECG is used to diagnose various heart rhythm disorders (arrhythmias).
Evaluate Heart Health:
It assesses overall cardiac health and identifies abnormalities, such as conduction disturbances or blockages.
- Graph how heart rate (HR) responds to rest, submaximal exercise, and recovery, and explain how it is regulated during each phase (rest, anticipatory rise, rapid rise, etc.) by a combination of intrinsic factors (filling pressure, temperature, etc.), extrinsic factors acting through the autonomic nervous system (chemical changes, etc.), and hormones.
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- Define stroke volume (SV) and explain what factors (in addition to those that control HR) lead to an increased venous return (muscle pump, etc.) by way of the Frank-Starling principle.
Stroke volume (SV) = The volume of blood ejected from the left ventricle per beat (ml/beat)
EDV = end-diastolic volume
ESV = end-systolic volume
SV = EDV - ESV
Muscle pump, breathing pump and Selective vasoconstriction lead to an increased venous return
Frank-Starling Principle: The Frank-Starling principle states that the more the heart is filled with blood during diastole (the relaxation phase), the greater the force of contraction during systole.
Factors for Increased Venous Return: Preload, Muscle pump, Respiratory pump and Venous tone
- Define cardiac output (Q) and explain how and why it increases during exercise based on changes in heart rate and stroke volume.
Cardiac output (Q) is the volume of blood the heart pumps per minute, typically measured in liters per minute (L/min).
Heart Rate (HR): During exercise, heart rate increases in response to signals from the autonomic nervous system. This results in more heartbeats per minute, contributing to an elevated cardiac output.
Stroke Volume (SV): Exercise leads to an increased venous return (blood returning to the heart) due to factors like greater muscle activity and breathing. This results in a higher preload, stretching the heart muscle, and allowing it to pump out more blood with each contraction, which increases stroke volume.
Why It Increases: The combined effect of higher heart rate and increased stroke volume during exercise leads to a significant increase in cardiac output. This is necessary to supply the muscles with more oxygen and nutrients to meet the body’s increased demand during physical activity.
- Describe and explain how blood flow is redistributed during exercise through the combination of autoregulation (local changes within the working muscle) and extrinsic factors. Describe especially how relative (% of cardiac output) and absolute (L∙min-1) muscle blood flow increase with exercise.
Autoregulation: Local changes within the working muscle:
As muscles contract during exercise, they release metabolic byproducts like adenosine, CO2, and lactic acid.
These byproducts signal nearby arterioles to dilate, increasing blood flow to meet the muscles’ oxygen and nutrient demands.
Autoregulation ensures that blood flow matches the metabolic needs of the active muscles.
Extrinsic Factors: Controlled by the nervous and endocrine systems:
The sympathetic nervous system releases norepinephrine, which constricts non-essential blood vessels, directing blood toward active muscles.
Hormones like epinephrine (adrenaline) also support vasoconstriction in non-essential areas and vasodilation in active muscles.
Relative Muscle Blood Flow:
Definition: Relative muscle blood flow refers to the proportion of cardiac output directed to the active muscles compared to other tissues.
Increase During Exercise: Relative muscle blood flow increases significantly during exercise, sometimes accounting for up to 85% of cardiac output.
Absolute Muscle Blood Flow:
Definition: Absolute muscle blood flow measures the actual volume of blood (in liters per minute) delivered to the working muscles.
Increase During Exercise: Absolute muscle blood flow increases with exercise, potentially reaching levels of 20-25 liters per minute in highly trained athletes, compared to about 5 liters per minute at rest.
- Define total peripheral resistance (TPR) and explain its relationship to blood vessel radius and blood pressure.
Definition: TPR is the overall resistance to blood flow in the systemic circulation, primarily determined by the resistance of arterioles throughout the body.
Relationship to Blood Vessel Radius: TPR is inversely proportional to blood vessel radius. Constricted arterioles (smaller radius) increase TPR, restricting blood flow, while dilated arterioles (larger radius) decrease TPR, allowing for increased blood flow.
Relationship to Blood Pressure: TPR significantly influences blood pressure. Increased TPR elevates blood pressure, while decreased TPR lowers blood pressure. Blood Pressure = Cardiac Output x Total Peripheral Resistance.
- Define arterial blood pressure including blood flow (cardiac output) and total peripheral resistance.
Arterial blood pressure is the force exerted by circulating blood on the walls of arteries. It’s typically expressed as systolic pressure over diastolic pressure (e.g., 120/80 mm Hg).
Cardiac output contributes to arterial blood pressure by determining the volume of blood entering the arteries with each heartbeat.
TPR affects arterial blood pressure by regulating the ease with which blood flows through arterioles. Increased TPR raises blood pressure, while decreased TPR lowers it.
- Graph how systolic (SBP) and diastolic (DBP) blood pressures respond to graded exercise and explain the control of each based on changes in blood flow (Q) and total peripheral resistance (TPR).
- Describe the anatomy of the conductive and respiratory portions of the respiratory system.
Conductive Portion:
Nose and Mouth: Air enters through these openings and is filtered, humidified, and warmed.
Pharynx: A passageway for air and food, located at the back of the mouth and throat.
Larynx: Contains the vocal cords and aids in sound production.
Trachea: A cartilaginous tube that carries air to the lungs.
Bronchi: The trachea splits into two primary bronchi, one for each lung.
Respiratory Portion:
Bronchioles: Smaller airways branching from bronchi, leading to the alveoli.
Alveoli: Tiny air sacs where gas exchange occurs, allowing oxygen to enter the bloodstream and carbon dioxide to exit.
- Explain the mechanics of pulmonary ventilation (VE) including the respiratory muscles involved in inhalation and exhalation at rest and during exercise.
Pulmonary ventilation is the process of moving air in and out of the lungs to facilitate gas exchange.
Respiratory Muscles at Rest:
Inhalation:
The primary muscle is the diaphragm, which contracts and moves downward.
Intercostal muscles assist by elevating the ribcage slightly.
Air enters the lungs due to the increase in thoracic volume.
Exhalation:
At rest, exhalation is primarily a passive process.
The diaphragm and intercostal muscles relax, causing the chest cavity to decrease in size.
Air is expelled as a result of the elastic recoil of the lungs and chest wall.
Respiratory Muscles During Exercise:
Inhalation:
During exercise, additional muscles like the external intercostals and scalene muscles may assist in elevating the ribcage.
Accessory muscles, such as the sternocleidomastoid and pectoralis minor, can also help in expanding the chest.
Exhalation:
Exhalation remains primarily a passive process, even during exercise.
Exhalation muscles are typically not as actively engaged as inhalation muscles.
- Describe the respiratory control center (in the medulla oblongata) and the factors that affect the control of pulmonary ventilation at rest and during exercise.
Respiratory Control Center:
Location: Located in the medulla oblongata of the brainstem.
Function: Regulates the rate and depth of breathing to maintain appropriate levels of oxygen and carbon dioxide in the blood.
Factors Affecting Pulmonary Ventilation:
At Rest:
Chemoreceptors: Sensitive to blood carbon dioxide (CO2) and pH levels. A rise in CO2 or drop in pH stimulates increased ventilation.
Stretch Receptors: In the lungs, they limit excessive lung inflation, preventing overinflation.
Cerebral Cortex: Can voluntarily influence breathing patterns.
During Exercise:
Chemoreceptors: More responsive to elevated CO2 levels and lower pH during exercise, leading to increased ventilation.
Muscle Receptors: Muscle proprioceptors signal increased ventilation due to higher muscle activity, demanding more oxygen.
Thermoreceptors: Increased body temperature during exercise can stimulate increased ventilation to facilitate heat dissipation.
- Define pulmonary ventilation (VE) and explain how and why it increases during exercise based on changes in breathing rate (BR) and tidal volume (TV) including how activation of pulmonary stretch receptors are involved by initiating the Hering-Breuer reflex.
Pulmonary ventilation is the volume of air moved in and out of the lungs per minute (expressed in liters per minute, L/min).
Increase in VE During Exercise:
Breathing Rate (BR):
BR increases during exercise in response to signals from the central and peripheral chemoreceptors, primarily detecting rising carbon dioxide (CO2) and lowering pH levels.
Increased BR helps expel excess CO2 and maintain blood gas homeostasis.
Tidal Volume (TV):
TV, the volume of air moved in and out with each breath, also increases during exercise.
This rise is due to enhanced neural drive and signals from muscle proprioceptors, which demand more oxygen during physical activity.
Hering-Breuer Reflex:
Pulmonary stretch receptors, activated by lung inflation, initiate the Hering-Breuer reflex.
This reflex helps prevent lung overinflation and facilitates appropriate breathing rhythm during exercise.
Why It Increases: The combined effects of higher BR and increased TV during exercise lead to greater pulmonary ventilation, ensuring more oxygen is delivered to working muscles while removing excess CO2.
- Graph how ventilation responds to rest, submaximal exercise, and recovery, and explain how it is regulated during each phase (rest, anticipatory rise, rapid rise, etc.) by a combination of extrinsic factors acting through the autonomic nervous system (chemical changes, etc.), and hormones (leading to bronchodilation).
- Graph how ventilation responds to graded exercise and identify and explain the ventilatory threshold.
- Describe how the partial pressures of gasses (O2 and CO2) in inspired air are determined from barometric pressure and how they are influenced by exposure to altitude.
The partial pressures of O2 and CO2 in inspired air are determined by their respective percentages in the atmosphere and the barometric pressure. The partial pressure of a gas is its fractional concentration multiplied by the total barometric pressure.
Influence of Altitude:
At Low Altitude: At sea level or low altitudes, barometric pressure is higher, resulting in higher partial pressures of O2 and CO2 in inspired air.
At High Altitude: At higher altitudes, barometric pressure decreases, causing a reduction in the partial pressures of O2 and CO2 in inspired air. This can lead to lower oxygen availability and altered respiratory responses due to reduced partial pressure of oxygen.
- Illustrate the diffusion and exchange of O2 and CO2 between the atmosphere, the lungs, the blood vessels, and the skeletal muscles. Identify the PO2 and PCO2 in each step and explain how appropriate pressure gradients are maintained during exercise by increases in cardiac output and pulmonary ventilation.
- Describe the composition of the blood (plasma, red blood cells, etc.).
Plasma: A pale yellow fluid component of blood, primarily composed of water, electrolytes, proteins, and waste products.
Red Blood Cells (RBCs): Disc-shaped cells responsible for carrying oxygen (bound to hemoglobin) and removing carbon dioxide from tissues.
White Blood Cells (WBCs): Immune cells that help the body fight infections and foreign invaders.
Platelets: Tiny cell fragments that play a crucial role in blood clotting and wound healing
- Describe the oxygen carrying capacity of the blood based primarily on hemoglobin content.
Hemoglobin: Hemoglobin, a protein in red blood cells, binds with oxygen to form oxyhemoglobin.
Capacity: The oxygen-carrying capacity of blood is determined by the amount of hemoglobin in red blood cells. Each gram of hemoglobin can carry approximately 1.34 milliliters of oxygen.
Factors: An individual’s blood oxygen-carrying capacity is influenced by the number of red blood cells and their hemoglobin content.
- Explain how the O2-carrying capacity of the blood can be decreased (anemia, etc.) or increased (altitude exposure, RBC reinfusion, EPO, etc.).
Decreased O2-Carrying Capacity:
Anemia: Insufficient red blood cells or hemoglobin, leading to reduced O2-carrying capacity.
Acute exposure to altitude (hypoxia)
Lung disease (COPD)
Increased O2-Carrying Capacity:
Altitude Exposure: Exposure to higher altitudes stimulates an increase in red blood cell production to compensate for reduced oxygen levels.
RBC Reinfusion: Infusion of additional red blood cells to increase O2-carrying capacity.
EPO (Erythropoietin): Administration of erythropoietin, a hormone that stimulates red blood cell production, can boost O2-carrying capacity.
