Cardiovascular System Flashcards
What is the primary function of veins?
Veins carry blood to the heart under low pressure and contain valves to prevent the backflow of blood.
Why do arteries have thick, muscular walls?
Arteries have thick, muscular walls to withstand high pressure as they carry blood away from the heart.
What structural feature of capillaries allows for efficient gaseous exchange?
Capillaries have very thin walls (one cell thick), which allow for efficient diffusion of gases.
What is the role of vasoconstriction and vasodilation in blood vessels?
Vasoconstriction narrows blood vessels to reduce blood flow, while vasodilation widens blood vessels to increase blood flow.
How do the walls of veins differ from those of arteries?
Veins have thin walls compared to the thick, muscular walls of arteries.
Why do veins have valves, and what is their function?
Veins have valves to prevent the backflow of blood and ensure it flows toward the heart.
What type of pressure is blood under in arteries, and how does their structure support this?
Blood in arteries is under high pressure, supported by their thick, muscular walls and narrow lumen.
What feature of capillaries makes them suitable for diffusion?
Their very thin walls, which are one cell thick, make capillaries suitable for diffusion.
How do arteries regulate blood flow to different areas of the body?
Arteries regulate blood flow through vasoconstriction (narrowing) and vasodilation (widening).
What role do capillaries play in the exchange of gases?
Capillaries allow for the diffusion of oxygen and carbon dioxide between the blood and tissues.
What is the function of the smooth muscle in arterial walls?
The smooth muscle in arterial walls enables vasoconstriction and vasodilation to adjust blood flow.
Compare the lumen size in arteries and veins.
Arteries have a narrow lumen to maintain high pressure, while veins have a wide lumen to accommodate low-pressure blood flow.
What is the purpose of vascular shunt during exercise?
Vascular shunt redistributes blood to muscles with higher demand and diverts it away from areas with lower demand.
How do blood vessels adapt to increased muscle activity during exercise?
Blood vessels widen (vasodilation) to increase blood flow to active muscles and narrow (vasoconstriction) to reduce blood flow to less active areas.
What is the vascular shunt mechanism?
The vascular shunt mechanism is the process of redistributing blood to areas of greater demand, such as working muscles, during exercise, while diverting blood away from less active areas.
What happens to blood vessels in areas of high oxygen demand during the vascular shunt?
Blood vessels in areas of high oxygen demand undergo vasodilation, widening to allow more blood flow.
What role does vasoconstriction play in the vascular shunt?
Vasoconstriction narrows blood vessels in areas of lower demand, reducing blood flow to those areas.
How does the vascular shunt mechanism benefit muscles during exercise?
The vascular shunt mechanism ensures that more oxygen and nutrients are delivered to active muscles, supporting their increased energy requirements.
During intense physical activity, how does the vascular shunt affect blood flow to the digestive system?
Blood flow to the digestive system is reduced through vasoconstriction, as it is a low-demand area during exercise.
What is the main function of the pulmonary vein?
The pulmonary vein carries oxygenated blood from the lungs to the left atrium of the heart.
Name the valve that separates the right atrium and the right ventricle.
The tricuspid valve separates the right atrium and the right ventricle.
Name the four chambers of the heart.
The four chambers are the left atrium, right atrium, left ventricle, and right ventricle.
What is the function of the pulmonary artery?
The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs for oxygenation.
What is the function of the aorta?
The aorta carries oxygenated blood from the left ventricle to the body.
What is the role of the vena cava in the circulatory system?
The vena cava carries deoxygenated blood from the body back to the right atrium.
Describe the pathway of deoxygenated blood through the heart.
Deoxygenated blood travels from the body → vena cava → right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary artery → to the lungs.
How does oxygenated blood return to the heart from the lungs?
Oxygenated blood returns via the pulmonary vein → left atrium → bicuspid valve → left ventricle → aortic valve → aorta → to the body.
How is maximum heart rate (MHR) calculated?
Maximum heart rate is calculated using the formula: MHR=220−age.
Write the formula for cardiac output (CO).
Cardiac output is calculated as: CO=SV×HR, where SV is stroke volume and HR is heart rate.
How is heart rate (HR) measured?
Heart rate is measured in beats per minute (BPM).
Define stroke volume (SV).
Stroke volume is the amount of blood ejected by the heart in one contraction.
What is cardiac output (CO)?
Cardiac output is the total volume of blood pumped by the heart per minute.
How does cardiac output change during exercise?
Cardiac output increases during exercise due to an increase in both heart rate and stroke volume to meet the body’s increased oxygen demands.
What happens to stroke volume as fitness levels improve?
Stroke volume typically increases as fitness levels improve, allowing the heart to pump more blood per contraction.
What is the ideal range for blood pressure?
The ideal range for blood pressure is between 90/60 mmHg and 120/80 mmHg.
Name two factors that can affect blood pressure.
Any of the following: activity levels, stress, diet and age.
What is the difference between systolic and diastolic blood pressure?
Systolic blood pressure measures the pressure when the heart contracts, while diastolic pressure measures the pressure when the heart relaxes.
What does systolic pressure measure?
Systolic pressure measures the force of blood against the artery walls when the heart contracts.
What does diastolic pressure measure?
Diastolic pressure measures the force of blood against the artery walls when the heart relaxes.
At what reading is blood pressure considered high?
Blood pressure is considered high when it is 140/90 mmHg or more.
At what reading is blood pressure considered low?
Blood pressure is considered low when it is less than 90/60 mmHg.
How does physical activity affect blood pressure?
Physical activity temporarily increases blood pressure but can lower resting blood pressure over time with regular exercise.
How does age affect blood pressure?
Blood pressure tends to increase with age due to decreased elasticity of the blood vessels.
Why does stress raise blood pressure?
Stress triggers the release of hormones like adrenaline, which increase heart rate and constrict blood vessels, raising blood pressure.
