Cardiovascular System Overview

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Questions and Answers

What is the primary factor that determines blood flow in the cardiovascular system?

Viscosity of the blood

Oxygen levels in the blood

Hydrostatic pressure (correct)

Temperature of the blood

Which of the following statements about flow rate and flow velocity is correct?

Flow rate and flow velocity refer to the same measurement.

Flow rate is constant along all vessels in the circulatory system.

Flow rate is dependent on the cross-sectional area of the vessel. (correct)

Flow velocity increases as cross-sectional area increases.

What role do venous valves play in the circulatory system?

They control the speed of blood flow in arteries.

They allow backflow of blood during muscular contraction.

They increase blood pressure in the veins.

They prevent backflow of blood in the veins. (correct)

Which structure is NOT a part of the left heart in the cardiovascular system?

Tricuspid valve Signup and view all the answers

What is hydrostatic pressure in the context of blood flow?

The pressure exerted by fluid on the walls of blood vessels Signup and view all the answers

What physiological mechanism maintains blood flow without the use of energy after ventricular contraction?

Elastic recoil of arteries Signup and view all the answers

Which formula correctly represents Mean Arterial Pressure (MAP)?

MAP = Diastolic Pressure + 1/3 Pulse Pressure Signup and view all the answers

How does blood pressure change as blood moves through the circulatory system?

Blood pressure decreases Signup and view all the answers

What role do valves play in the circulatory system?

They prevent the backflow of blood Signup and view all the answers

What is the significance of the elasticity of arteries?

It maintains blood flow through energy storage Signup and view all the answers

What is the relationship between resistance and flow in the given context?

Larger radius corresponds to smaller resistance. Signup and view all the answers

Calculate the velocity at Point Y given a flow rate of 34 cm³/sec and a cross-sectional area of 17 cm².

2 cm/sec Signup and view all the answers

If the flow rate in capillaries is 5000 cm³/min with a cross-sectional area of 5000 cm², what is the velocity of blood in the capillaries?

1 cm/min Signup and view all the answers

Why is low velocity preferred in the capillary bed?

To facilitate exchange of nutrients. Signup and view all the answers

How does the flow rate relate to velocity and cross-sectional area based on the provided equations?

Flow rate decreases as cross-sectional area increases. Signup and view all the answers

What happens to flow through a vessel given an increase in the vessel's radius?

Flow rate increases due to decreased resistance. Signup and view all the answers

Given a fixed flow rate of 5000 cm³/min, how would a larger cross-sectional area affect the velocity in the aorta?

Velocity would decrease. Signup and view all the answers

What is the velocity of blood flow through the aorta if the flow rate is 5000 cm³/min and the area is 200 cm²?

25 cm/min Signup and view all the answers

What does a pressure gradient indicate about flow?

Flow increases with a greater difference in pressure. Signup and view all the answers

How is flow rate defined?

Volume of fluid per unit time. Signup and view all the answers

What is the relationship between resistance and radius in a flow system?

Resistance increases as the radius decreases. Signup and view all the answers

Which scenario would result in the same pressure gradient and flow?

100 mm Hg to 75 mm Hg and 40 mm Hg to 15 mm Hg. Signup and view all the answers

Which of the following correctly describes flow velocity?

It refers to the distance a particle moves per unit of time. Signup and view all the answers

How does changing the radius of a tube affect flow velocity?

Decreasing the radius may increase flow velocity due to increased resistance. Signup and view all the answers

What is the function of elastic arteries in the cardiovascular system?

They store and release blood volume. Signup and view all the answers

What is the significance of the equation Flow µ DP?

It indicates flow is directly proportional to the pressure gradient. Signup and view all the answers

What effect does friction have on pressure in a flow system?

Friction causes the pressure to drop with increased distance. Signup and view all the answers

What is the average flow rate of blood at rest through the cardiovascular system?

5 L/min Signup and view all the answers

What does the term 'sphygmogram' refer to in blood pressure measurement?

A graphical representation of pressure over time Signup and view all the answers

What is the normal diastolic pressure range indicated in blood pressure measurements?

Below 80 mm Hg Signup and view all the answers

In the blood pressure measurement process, what does the inflatable cuff do?

It restricts blood flow to determine systolic pressure. Signup and view all the answers

Which measurement indicates the systolic blood pressure during sphygmomanometry?

140 mm Hg when the first Korotkoff sound is heard Signup and view all the answers

How does the time spent in diastole compare to the time spent in systole during the cardiac cycle?

Most time is spent in diastole compared to systole. Signup and view all the answers

What pressure gauge reading is considered a hypertension indicator during blood pressure readings?

Above 120 mm Hg Signup and view all the answers

What is the purpose of listening for the Korotkoff sound while measuring blood pressure?

To identify diastolic pressure accurately. Signup and view all the answers

What is the typical cuff pressure that signifies an inflated cuff during measurement?

Just above 120 mm Hg Signup and view all the answers

Study Notes

Functional Model of the Cardiovascular System

The cardiovascular system is composed of the heart, blood vessels, and blood.
Blood flow is driven by pressure gradients, moving from areas of higher pressure to areas of lower pressure.
The heart is a pump that generates pressure, propelling blood through the circulatory system.
The aorta is the largest artery, carrying oxygen-rich blood from the heart to the rest of the body.
Arteries branch into smaller arterioles, which regulate blood flow to capillaries.
Capillaries are the smallest blood vessels, facilitating the exchange of gases, nutrients, and waste products between blood and tissues.
Venules collect blood from capillaries and merge into larger veins, returning blood to the heart.
Veins contain valves that prevent backflow of blood.

Flow is Determined by Pressure Gradients

Flow is directly proportional to the pressure gradient.
Pressure gradient is the difference in pressure between two points.
Larger pressure gradients result in greater flow.

Flow Rate vs Flow Velocity

Flow rate is the volume of fluid flowing per unit of time.
Flow velocity is the speed of fluid movement.
Flow rate is measured in mL/sec or L/min.
Flow velocity is measured in cm/sec.
Flow rate remains constant throughout the circulatory system.
Flow velocity is inversely proportional to cross-sectional area.
Velocity is low in capillaries, allowing for adequate exchange of materials.

Resistance & Tube Radius Affect Flow

Resistance is the opposition to flow.
Resistance is inversely proportional to the fourth power of the radius.
A larger radius means lower resistance and greater flow.
Arterioles are the main site of resistance regulation due to their ability to constrict and dilate.

Blood Pressure Decreases Moving Through System

Blood pressure is highest in the aorta and decreases as blood moves through the circulatory system.
Blood pressure is influenced by factors including cardiac output, vascular resistance, and blood volume.
Mean Arterial Pressure (MAP) is a reflection of average arterial pressure over time.
MAP is calculated as: MAP = (1/3) * PP + Diastolic Pressure.
Pulse Pressure (PP) is the difference between systolic and diastolic pressures.
Systolic pressure represents peak pressure during ventricular ejection.
Diastolic pressure represents the minimum pressure in the arteries during ventricular relaxation.

Measuring blood pressure: Sphygmomanometry

Sphygmomanometry is the most common method for measuring blood pressure.
A sphygmomanometer consists of an inflatable cuff, a pressure gauge, and a stethoscope.
The cuff is inflated until it occludes the brachial artery, stopping blood flow.
The cuff is then gradually deflated, allowing blood flow to resume.
Korotkoff sounds, heard through the stethoscope, indicate blood flow.
Systolic pressure is recorded when the first Korotkoff sound is heard.
Diastolic pressure is recorded when the sounds disappear.

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Description

Explore the functional model of the cardiovascular system, focusing on the roles of the heart, blood vessels, and blood flow dynamics. Learn how pressure gradients drive blood circulation and the significance of arteries, capillaries, and veins in maintaining bodily functions.