Cardiovascular System Overview Quiz
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Questions and Answers

What is primarily responsible for regulating blood flow at the local level?

  • Valves in veins
  • Vascular smooth muscle (correct)
  • Cardiac output
  • Elastic tissues

Veins cannot collapse while arteries remain open.

False (B)

What is the primary effect of the Frank-Starling mechanism on cardiac output?

It increases cardiac output by allowing the heart to pump more effectively based on the volume of blood filling the heart.

The _______ is responsible for maintaining basal vascular tone.

<p>vascular smooth muscle</p> Signup and view all the answers

Which of the following is a key factor in determining preload?

<p>Venous return (A)</p> Signup and view all the answers

Match the following terms with their descriptions:

<p>Preload = Volume of blood in the ventricles at the end of diastole Afterload = Pressure the heart must work against to eject blood Cardiac output = Volume of blood pumped by the heart per minute Venous return = Amount of blood returning to the heart</p> Signup and view all the answers

Parasympathetic nerves are involved in vasoconstriction.

<p>False (B)</p> Signup and view all the answers

What role do valves in veins play concerning venous return?

<p>Valves prevent backflow and support the return of blood to the heart against gravity.</p> Signup and view all the answers

Which of the following factors can influence venous return?

<p>All of the above (D)</p> Signup and view all the answers

The Frank-Starling mechanism state that an increased preload leads to an increased stroke volume.

<p>True (A)</p> Signup and view all the answers

What is the main effect of afterload on cardiac output?

<p>It decreases cardiac output.</p> Signup and view all the answers

The_____________ nervous system plays a crucial role in regulating heart rate and contractility.

<p>autonomic</p> Signup and view all the answers

Match the following terms with their definitions:

<p>Preload = The degree of stretch of the heart muscle before contraction Afterload = The resistance the heart has to overcome to eject blood Cardiac Output = The volume of blood the heart pumps per minute Venous Return = The amount of blood returning to the heart</p> Signup and view all the answers

Which of the following conditions can cause oedema?

<p>Heart failure (B)</p> Signup and view all the answers

Fenestrated capillaries are found only in the liver and spleen.

<p>False (B)</p> Signup and view all the answers

What is one consequence of lymphatic dysfunction?

<p>Oedema.</p> Signup and view all the answers

What does CO stand for in the context of the cardiovascular system?

<p>Cardiac Output (B)</p> Signup and view all the answers

In heart failure, the amount of blood entering the ventricle during diastole decreases involuntarily.

<p>False (B)</p> Signup and view all the answers

What mechanism helps the heart cope with variations in venous return?

<p>Frank-Starling Mechanism</p> Signup and view all the answers

Increased TPR leads to increased ______ for the same cardiac output.

<p>Afterload</p> Signup and view all the answers

Match the following terms with their descriptions:

<p>Preload = Load on the heart before contraction Afterload = Resistance to blood ejection from the heart Cardiac Output = Volume of blood pumped by the heart per minute Venous Return = Amount of blood returning to the heart</p> Signup and view all the answers

Which factors can augment the preload on the heart?

<p>Increased plasma volume (D)</p> Signup and view all the answers

The sympathetic nervous system decreases heart rate and contractility.

<p>False (B)</p> Signup and view all the answers

What hormone is important in preventing blood pressure from becoming too low during heart failure?

<p>Renin-Angiotensin II</p> Signup and view all the answers

Blood flow to the arteries during ventricular systole is referred to as ______.

<p>ejection</p> Signup and view all the answers

Match the following responses with their triggers:

<p>Skeletal muscle contraction = Increases venous return Decreased PCO2 = Dilates systemic arterioles Increased heart rate = Enhances cardiac output Fluid retention = Raises preload</p> Signup and view all the answers

Which of the following describes the condition when venous return is effectively less than normal?

<p>Heart failure (A)</p> Signup and view all the answers

The baroreceptor reflex plays a role in regulating heart rate and blood pressure.

<p>True (A)</p> Signup and view all the answers

What is the primary determinant of afterload?

<p>Total Peripheral Resistance</p> Signup and view all the answers

During isovolumetric contraction, the ventricles ______ without changing their volume.

<p>contract</p> Signup and view all the answers

Flashcards

Cardiac Cycle Phases

The four phases of the heart's pumping action: atrial filling, rapid ventricular filling, diastasis (slower ventricular filling), and atrial systole, followed by ventricular systole.

Cardiac Output (CO)

The amount of blood pumped by the heart per minute, calculated as Stroke Volume (SV) multiplied by Heart Rate (HR).

Venous Return (VR)

The amount of blood flowing back into the heart's ventricles during diastole.

Preload

The amount of stretch on the heart muscle before contraction, determined by left ventricular end-diastolic pressure (LVEDP).

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Frank-Starling Mechanism

The heart's ability to adjust its strength of contraction in response to changes in venous return.

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Afterload

The force the heart must overcome to eject blood during ventricular systole.

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Total Peripheral Resistance (TPR)

The resistance to blood flow in the systemic circulation, mainly due to vascular tone.

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Heart Failure

A condition where the heart's ability to pump blood effectively is compromised.

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Baroreceptors

Sensory receptors that monitor blood pressure.

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Sympathetic Nervous System

Part of the autonomic nervous system that speeds up heart rate and increases contractility.

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Parasympathetic Nervous System

Part of the autonomic nervous system that slows down heart rate.

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Stroke Volume (SV)

The amount of blood ejected by the heart with each beat.

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Atrial Systole

The contraction of the atria, which forces additional blood into the ventricles.

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Venous Capacitance

The ability of veins to accommodate changes in blood volume.

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Left Ventricular End-Diastolic Pressure (LVEDP)

The pressure in the left ventricle at the end of diastole

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Vicious Cycle of Heart Failure

A self-perpetuating process where heart failure leads to further deterioration of cardiac function.

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Elastic Arteries

The largest arteries, containing abundant elastic fibers that allow continuous blood flow and prevent damage.

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Vascular Smooth Muscle Tone

A constant state of contraction in vascular smooth muscle that regulates blood circulation and regional blood flow.

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Resistance Vessels

Small arteries and arterioles that control systemic blood pressure.

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Vasoconstriction

Narrowing of blood vessels resulting from signals such as adrenaline, angiotensin II, endothelin, or other circulating mediators.

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Blood Redistribution

Veins adjust their size (constrict or expand) to redistribute blood as needed.

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Vasodilation

Widening of blood vessels due to signals including beta-2 adrenergic receptors, parasympathetic nerves, and chemicals like histamine, nitric oxide, and prostaglandins.

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Myogenic Response

A process where the smooth muscle in blood vessels can constrict or dilate in response to changes in blood pressure.

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Artery/Vein Response

Arteries and veins respond differently to changes in blood volume.

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Capillaries

Small blood vessels connecting arteries and veins, allowing for exchange of oxygen, nutrients, and waste products.

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Vein Collapse

The ability of veins to collapse, allowing them to accommodate varying blood volumes without significantly altering blood pressure.

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Oedema Causes

Swelling caused by high hydrostatic pressure, low oncotic pressure, increased capillary permeability, or lymphatic dysfunction.

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Venous Valves

Valves in veins that prevent blood from flowing backward and help maintain blood flow from lower extremities against gravity.

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Hydrostatic Pressure

The pressure exerted by fluid against the walls of blood vessels that can lead to fluid leakage into tissues.

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Oncotic Pressure

The pressure from proteins in blood that pulls fluid back into blood vessels. Low oncotic pressure less effectively pulls fluid back.

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Lymphatic System

A low-pressure system with valves to return interstitial fluid to blood circulation.

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Oedema Types

Different types of swelling, such as ankle, sacral, or pulmonary oedema, caused by different underlying circulatory factors, influenced by position

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Study Notes

Cardiovascular System Overview

  • Circulation is cyclical movement, orderly movement in a circuit
  • Blood circulates oxygen and removes carbon dioxide
  • Transports nutrients to cells and removes waste
  • Protects against disease and infection
  • Stops bleeding with clotting
  • Regulates body temperature

Fluid Distribution in the Body

  • Body is approximately 60% water
  • Two-thirds of body water is intracellular
  • One-third is extracellular, consisting mostly of interstitial fluid
  • Blood plasma is part of the extracellular fluid (25%)
  • Plasma makes up 55% of whole blood
  • Blood cells make up 45% of whole blood

Blood Vessel Structure & Function

  • Vessel diameters vary greatly, from 30 mm (vena cava) to 7-8 µm (capillaries).
  • Flow rate is proportional to the fourth power of the radius
  • Flow is inversely proportionate to viscosity

Blood Pressure & Flow

  • Blood pressure drops most significantly across arterioles.
  • Average blood pressure = 120/70 mmHg
  • Pressure in pulmonary arteries = 25/10 mmHg
  • Elastic tissues in elastic arteries allow continuous flow & prevent damage.

Vascular Tone & Regulation

  • Vascular smooth muscle maintains basal tone, affecting blood pressure and flow
  • Systemic factors include vasoconstriction (adrenergic, angiotensin, endothelin) and vasodilation (B2 receptors, parasympathetic nerves, histamine, NO, prostglandins, etc.)
  • Local chemical factors affect vessels (interstitial pO2, pCO2, pH, K+, lactate, ATP/ADP/adenosine)

Venous System

  • Veins have valves to support against gravity
  • Collapsing and expanding veins accommodate changes in blood volume.

Capillary Types

  • Continuous capillaries: Tight junctions, low permeability (most tissues)
  • Fenestrated capillaries: Pores for increased permeability (kidneys, intestines)
  • Sinusoidal capillaries: Large openings, very permeable (liver, spleen)

Fluid Movement in Capillaries

  • Fluid moves due to hydrostatic and oncotic pressures.
  • A higher hydrostatic pressure and lower oncotic pressure can cause edema.

Specialized Circulatory Functions

  • Kidney functions in excretion and autoregulation
  • Gut includes liver (two blood supplies)
  • CNS has autoregulation and blood-brain barrier, CSF and fetal circulation
  • Changes occur at birth.

Heart Function I

  • CO = stroke volume x heart rate
  • Venous return dictates preload, affecting LV filling.
  • Preload = Left Ventricle Pre-contraction load = LVEDP
  • Affected by venous capacitance and filling.
  • Heart failure results in diminished venous return efficiency, leading to increased preload and potentially elevated CO.

Heart Function II

  • Frank-Starling mechanism balances venous return and two sides of the heart.
  • Extrinsic controls include autonomic nervous system (sympathetic and parasympathetic)
  • Extrinsic influences also impact heart rate and contractility (PNS→ slows, SNS→ speeds)

Reflexes & Circulatory Factors

  • Baroreceptors, chemical receptors, etc. affect volume load and respiration
  • Circulating factors affect vessels, including hormones like adrenal medulla and atrial natriuretic peptide

Heart Failure

  • Heart failure is a maladaptive state where homeostatic mechanisms to restore CO + ABP can exacerbate the condition.
  • Preload & afterload increase due to neuroendocrine activation, vasoconstriction, & water retention.

Risk Factors for Cardiovascular Disease

  • Poor fitness, obesity, insulin resistance, kidney disease, dyslipidaemia
  • Atherosclerosis, hypertension, hyperglycemia, lifestyle risks (smoking, diet, sleep), genetic factors.
  • Pulmonary hypertension, pulmonary embolism, venous thrombosis, varicose veins, and venous insufficiency (Veins)
  • Atherosclerosis, coronary heart disease, hypertensive disease, aneurysms, microvascular disease, and endothelial dysfunction (Arteries)
  • Vasculitis, a range of small vessel disorders (Immune complex, Medium-vessel, large-vessel)

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Introduction to the Cardiovascular System PDF

Description

Test your knowledge on the cardiovascular system, including circulation, fluid distribution, and the structure and function of blood vessels. This quiz covers essential concepts such as blood pressure, nutrient transport, and the body's regulation mechanisms.

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