Physiology of Blood Pressure
40 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the main reason for the pressure wave becoming larger as it moves down the arterial tree?

  • Due to the increase in arterial stiffness (correct)
  • Due to the decrease in blood flow rate
  • Due to the increase in blood cell velocity
  • Due to the decrease in arterial stiffness

    • What is the approximate velocity of the blood cell in the aorta?

  • 32 cm/s (correct)
  • 25 cm/s
  • 33 cm/s
  • 5 m/s

    • What happens to the blood flow during systole?

  • 25% of the stroke volume is pushed forward into the smaller arteries (correct)
  • 75% of the stroke volume is pushed forward into the smaller arteries
  • It is completely pushed forward into the smaller arteries
  • It is completely stored in the aorta and large arteries

    • What is the main component of total peripheral resistance (TPR)?

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

    What happens to the pressure wave as it moves into the arterioles and microcirculation?

    <p>It becomes smaller and dies out</p> Signup and view all the answers

    What is the approximate length of the aorta?

    <p>33 cm</p> Signup and view all the answers

    What happens to the flow during systole?

    <p>It becomes pulsatile and irregular</p> Signup and view all the answers

    What is the characteristic of blood flow in the aorta and arteries?

    <p>It is pulsatile and irregular</p> Signup and view all the answers

    What is the primary reason for the development of the thrifty genotype in humans?

    <p>To crave and conserve nutritional resources during times of plenty</p> Signup and view all the answers

    What is the primary consequence of eating too much salt?

    <p>Increased blood volume and plasma osmolality</p> Signup and view all the answers

    What would happen to plasma [Na+] if an individual started eating very little salt?

    <p>It would decrease due to reduced salt intake</p> Signup and view all the answers

    What is the primary function of ADH in response to changes in salt intake?

    <p>To conserve water by increasing plasma osmolality</p> Signup and view all the answers

    What is the primary driver of the human desire to consume salt?

    <p>The genetic programming to conserve salt in response to its scarcity in the savannah environment</p> Signup and view all the answers

    What is the ultimate consequence of the thrifty genotype in modern humans?

    <p>Increased susceptibility to diseases of civilisation, such as hypertension and type 2 diabetes</p> Signup and view all the answers

    What is the main function of the Arterial Baroreflex?

    <p>To regulate blood flow to certain organs while maintaining a constant flow to other organs</p> Signup and view all the answers

    What is the primary mechanism by which the baroreflex responds to changes in blood pressure?

    <p>Changes in sympathetic and parasympathetic nervous system activity</p> Signup and view all the answers

    What is the main determinant of mean arterial blood pressure?

    <p>Cardiac output and total peripheral resistance</p> Signup and view all the answers

    What is the role of the Renin-Angiotensin-Aldosterone System (RAAS) in regulating blood pressure?

    <p>To increase blood pressure by promoting vasoconstriction</p> Signup and view all the answers

    What is the primary mechanism by which the baroreflex regulates blood pressure?

    <p>By increasing or decreasing total peripheral resistance</p> Signup and view all the answers

    What is the normal range of systolic blood pressure measured using a sphygmomanometer?

    <p>100-140 mmHg</p> Signup and view all the answers

    What is the effect of an increase in arterial blood pressure on the baroreflex?

    <p>It decreases the firing of baroreceptors</p> Signup and view all the answers

    What is the formula for calculating mean blood pressure?

    <p>2/3 x DBP + 1/3 x SBP</p> Signup and view all the answers

    What is the role of the kidneys in long-term regulation of blood pressure?

    <p>To regulate blood volume by controlling sodium excretion</p> Signup and view all the answers

    Where would you measure blood pressure to get the highest reading?

    <p>In an artery below the heart</p> Signup and view all the answers

    What is the effect of angiotensin II on blood pressure?

    <p>It increases blood pressure by promoting vasoconstriction</p> Signup and view all the answers

    What is the term for the oscillation of blood pressure with the cardiac cycle?

    <p>Pressure and flow waves</p> Signup and view all the answers

    What is the mechanism that helps regulate mean blood pressure in the short-term?

    <p>Baroreceptor reflex</p> Signup and view all the answers

    What is the role of pressure natriuresis in regulating blood pressure?

    <p>It decreases blood pressure by promoting sodium excretion</p> Signup and view all the answers

    What is the primary way the kidneys regulate mean blood pressure in the long-term?

    <p>Controlling Na+ excretion and extracellular fluid volume</p> Signup and view all the answers

    What is the primary determinant of extracellular fluid volume?

    <p>Sodium concentration</p> Signup and view all the answers

    What is the term for the increased excretion of Na+ and water by the kidneys in response to high blood pressure?

    <p>Pressure natriuresis</p> Signup and view all the answers

    What is the typical measurement location for blood pressure using a sphygmomanometer?

    <p>Arm at the level of the heart</p> Signup and view all the answers

    What is the effect of increased blood volume on atrial stretch receptors?

    <p>Increases atrial natriuretic peptide (ANP) release</p> Signup and view all the answers

    What is the effect of increased blood pressure on renal sodium excretion?

    <p>Increases renal sodium excretion</p> Signup and view all the answers

    Which of the following is NOT a mechanism that contributes to long-term blood pressure control?

    <p>Parasympathetic nervous system activity</p> Signup and view all the answers

    What is the effect of increased sympathetic nervous system (SNS) outflow to the kidney?

    <p>Decreases renal sodium excretion</p> Signup and view all the answers

    What is the role of the baroreceptor reflex in blood pressure control?

    <p>It is a negative feedback mechanism</p> Signup and view all the answers

    Why are vasodilators effective anti-hypertensive drugs?

    <p>Because they decrease vascular tone</p> Signup and view all the answers

    What is the effect of increased central venous pressure (CVP) on atrial stretch receptors?

    <p>Increases atrial natriuretic peptide (ANP) release</p> Signup and view all the answers

    Which of the following is an alternative model of blood pressure control?

    <p>Regulation of vascular tone</p> Signup and view all the answers

    Study Notes

    Physiology and Anatomy of Systems

    Blood Pressure - A Brief Review

    • Blood pressure (BP) refers to the pressure in the large arteries, oscillating with the cardiac cycle
    • BP is typically measured at the level of the heart in one arm using a sphygmomanometer
    • Normal systolic and diastolic pressures are approximately 120/80 mmHg
    • Mean BP is calculated as the time-weighted average of the systolic and diastolic blood pressures or 2/3 x DBP + 1/3 x SBP

    Mechanisms Governing Pressure and Flow Waves in the Arteries

    • Blood from the heart hits the aorta, causing pressure and flow waves propagated down the vascular system
    • The pressure wave becomes larger as it moves down the arterial tree due to greater arterial stiffness
    • Flow is progressively smoothed out as blood moves into the arterioles and the microcirculation
    • Blood flow is pulsatile in the aorta and arteries, with pulse and pressure waves moving at approximately 5 m/s
    • Blood cells move at approximately 32 cm/s, with an average aortic length of approximately 33 cm

    Acute Regulation of Blood Pressure: Baroreceptor Reflex

    • Baroreceptors contain fine nerve endings sensitive to stretch (mechanoreceptors)
    • Decreased pressure causes decreased firing, most sensitive when mean BP is between 80-150 mmHg
    • Sensitivity also increased by a large pulse pressure, with receptors showing adaptation
    • Baroreceptors respond rapidly to changes in MAP and pulse pressure in the short-term
    • The baroreflex responds rapidly to changes in MAP and pulse pressure, communicating via sympathetic/parasympathetic NS

    Determinants of Mean Arterial Blood Pressure

    • Baroreceptor reflex
    • Arterial tone
    • Total peripheral resistance
    • Cardiac output (CO x TPR = BP)
    • Heart rate and contractility (i.e., heart)
    • Venous return (i.e., veins)
    • Blood volume (i.e., kidneys)

    Renin-Angiotensin-Aldosterone System (RAAS)

    • RAAS activates vasoconstriction, increasing total peripheral resistance
    • RAAS increases blood volume through sodium retention and potassium excretion
    • RAAS also stimulates the release of aldosterone, promoting sodium reabsorption and potassium excretion in the kidneys

    Regulation of Mean Arterial Blood Pressure by RAAS

    • Various stimuli activate the RAAS, leading to increased renin release from juxtaglomerular cells
    • Renin converts angiotensinogen to angiotensin I, which is then converted to angiotensin II by angiotensin-converting enzyme (ACE)
    • Angiotensin II stimulates vasoconstriction, aldosterone release, and sodium reabsorption in the kidneys

    Long-term Determinants of Mean Arterial Blood Pressure

    • Stable body sodium content
    • Stable extracellular fluid volume
    • Stable plasma/blood volume
    • Pressure natriuresis

    Pressure Natriuresis

    • Increased renal perfusion and medullary blood flow decrease angiotensin II production
    • Increased nitric oxide, prostaglandins, and renal kinins stimulate natriuresis and diuresis
    • Pressure natriuresis increases renal interstitial hydrostatic pressure, decreasing tubular sodium reabsorption and increasing sodium excretion

    Long-term Regulation of Arterial Blood Pressure

    • Stabilization of BP in the long term is mainly due to maintenance of a constant ECF volume
    • ECF volume is controlled by the sodium concentration of the ECF
    • Diseases of civilization, such as hypertension and type 2 diabetes, may be explained by the thrifty genotype hypothesis
    • Human evolution has programmed us to crave and conserve nutritional resources, contributing to the development of hypertension and type 2 diabetes.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    A brief review of blood pressure, its measurement, and calculation. Learn about normal systolic and diastolic pressures, and the mechanisms governing blood pressure.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser