Pulmonary Circulation
18 Questions
0 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 role of the cardiovascular center?

Helps regulate heart rate, stroke volume, neural, hormonal, and local negative feedback systems that regulate blood pressure and blood flow to specific tissues.

Where is blood pressure highest?

  • In the capillaries
  • In the arteries
  • In the aorta (correct)
  • In the veins

    • Chemoreceptors monitor the concentration of various chemicals in the blood.

    True

    Resistance to blood flow depends directly on the total blood vessel ________.

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

    Match the following hormones with their actions:

    <p>Renin-angiotensin-aldosterone system = Regulates blood pressure by vasoconstriction and enhancing water reabsorption Epinephrine and norepinephrine = Increase cardiac output by raising heart rate and force of contractions Antidiuretic hormone (ADH) = Increases water reabsorption in the kidneys to raise blood volume and pressure Atrial natriuretic peptide (ANP) = Lowers blood pressure by causing vasodilation and promoting loss of salt and water in urine</p> Signup and view all the answers

    What is the main function of pulmonary circulation?

    <p>Carries blood from the right side of the heart to the lungs to get O2 and eliminate CO2.</p> Signup and view all the answers

    Explain the route of pulmonary circulation starting from the right ventricle.

    <p>Right ventricle (RV) -&gt; pulmonary trunk -&gt; pulmonary arteries (both lungs) -&gt; pulmonary capillaries -&gt; pulmonary veins (both left and right) -&gt; left atrium.</p> Signup and view all the answers

    What is the main purpose of hepatic portal circulation?

    <p>To transport blood from the digestive organs to the liver, storing excess sugars and maintaining glucose levels.</p> Signup and view all the answers

    Where does the exchange of materials with maternal blood occur during fetal circulation?

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

    At birth, the foramen ovale closes.

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

    List two changes related to aging that commonly impact cardiovascular health.

    <p>Stiffening of the aorta and loss of cardiac muscle strength.</p> Signup and view all the answers

    Tachycardia is defined as a rapid resting HR (>100 bpm), whereas bradycardia is characterized by a slow resting HR (__ bpm).

    <p>less than 60</p> Signup and view all the answers

    What are the three methods involved in capillary exchange?

    <p>Diffusion, Transcytosis, Bulk flow</p> Signup and view all the answers

    Which type of capillary has extensive intercellular gaps and allows the passage of the largest molecules?

    <p>Sinusoid capillary</p> Signup and view all the answers

    Bulk flow is more important for regulating the relative volumes of blood and interstitial fluid than for solute exchange.

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

    What is the formula for Net Filtration Pressure (NFP)?

    <p>NFP = (BHP + IFOP) - (BCOP + IFHP)</p> Signup and view all the answers

    What aids in the return of venous blood to the heart through systemic veins?

    <p>Skeletal muscle pump and respiratory pump</p> Signup and view all the answers

    What is the main method by which substances move between blood and interstitial fluid in capillary exchange?

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

    Study Notes

    Cardiovascular System

    • The cardiovascular system consists of blood vessels, heart, and circulation.

    Blood Vessel Structure and Function

    • Arteries:
      • Thicker walls, narrower lumen
      • Carry oxygenated blood away from heart
      • Divide into smaller arterioles
    • Veins:
      • Larger lumen, thinner walls
      • Carry deoxygenated blood back to heart
      • Have valves to prevent backflow
    • Capillaries:
      • Composed of endothelium (very thin cells)
      • Allow for easy diffusion of substances
      • Connected to arterioles and venules in networks
      • Three types: continuous, fenestrated, and sinusoids

    Capillary Exchange

    • Movement of substances between blood and interstitial fluid
    • Three methods:
      1. Diffusion:
        • Most important method
        • Substances move down their concentration gradient
        • Oxygen and nutrients move from blood to interstitial fluid to body cells
        • Carbon dioxide and wastes move from body cells to interstitial fluid to blood
      2. Transcytosis:
        • Small quantity of material
        • Substances in blood plasma become enclosed in pinocytotic vesicles
        • Important for large, lipid-insoluble molecules
      3. Bulk flow:
        • Passive process
        • Move together in the same direction
        • Based on pressure gradient
        • Filtration and reabsorption occur in capillaries

    Venous Return

    • Volume of blood flowing back to heart through systemic veins
    • Occurs due to pressure generated by constriction of left ventricle
    • Aided by:
      1. Skeletal muscle pump
      2. Respiratory pump

    Skeletal Muscle Pump

    • Proximal and distal valves
    • Contraction of muscle:
      • Pushes blood through valves
      • Closes distal valve
      • Opens proximal valve
    • Relaxation of muscle:
      • Opens distal valve
      • Closes proximal valve
      • Fills with blood from foot

    Respiratory Pump

    • Diaphragm movement:
      • Inhalation: diaphragm moves downward, decreases thoracic pressure, and increases abdominal pressure
      • Exhalation: diaphragm moves upward, increases thoracic pressure, and decreases abdominal pressure
    • Suction of the heart:
      • Contraction of the heart during systole
      • Increases atrial cavity
      • Atrioventricular valve pulled downward
      • Facilitates suction of blood from superior and inferior vena cava

    Blood Flow through Blood Vessels

    • Cardiac output (CO) = stroke volume (SV) x heart rate (HR)
    • Blood pressure (BP) = pressure exerted by blood on walls of blood vessels
    • Resistance: opposition to blood flow due to friction between blood and walls of blood vessels

    Regulation of Blood Pressure

    • Interconnected negative feedback systems
    • Control blood pressure by adjusting heart rate, stroke volume, systemic vascular resistance, and blood volume
    • Factors that increase blood pressure:
      • Increased heart rate
      • Increased stroke volume
      • Increased systemic vascular resistance
      • Increased blood volume

    Role of Cardiovascular Center

    • Location: medulla oblongata
    • Function: helps regulate heart rate and stroke volume, controls neural, hormonal, and local negative feedback systems that regulate blood pressure and blood flow to specific tissues

    Neural Regulation of Blood Pressure

    • Reflexes:
      • Baroreceptors: monitor pressure changes and stretch in blood vessel walls
      • Proprioceptors: monitor movements of joints and muscles
      • Chemoreceptors: monitor concentration of various chemicals in the blood
    • Output from cardiovascular centre flows along neurons of autonomic nervous system (ANS)
    • Sympathetic (stimulatory) opposes parasympathetic (inhibitory)

    Hormonal Regulation of Blood Pressure

    • Hormones:
      • Renin-angiotensin-aldosterone (RAA) system
      • Epinephrine and norepinephrine
      • Antidiuretic hormone (ADH)
      • Atrial natriuretic peptide (ANP)
    • Actions:
      • Help regulate blood pressure and blood flow
      • Alter cardiac output
      • Change systemic vascular resistance
      • Adjust total blood volume

    Renin-Angiotensin-Aldosterone (RAA) System

    • Renin: released by kidney when blood volume falls or blood flow decreases
    • Angiotensin converting enzyme (ACE): acts on substrates to produce active hormone angiotensin II
    • Angiotensin II: raises blood pressure by vasoconstriction and secretion of aldosterone
    • Aldosterone: increases water reabsorption in kidneys to raise blood volume and pressure

    Epinephrine and Norepinephrine

    • Released by adrenal medulla in response to sympathetic stimulation
    • Increase cardiac output by increasing rate and force of heart contractions
    • Raise blood pressure

    Antidiuretic Hormone (ADH) or Vasopressin

    • Released by cells of atria
    • Lowers blood pressure by causing vasodilation and promoting loss of salt and water in urine
    • Reduces blood volume

    Atrial Natriuretic Peptide (ANP)

    • Released by cells of atria
    • Lowers blood pressure by causing vasodilation and promoting loss of salt and water in urine
    • Reduces blood volume

    Circulatory Routes

    • Circulation of blood through the body

    • Includes the heart, arteries, capillaries, and veins### Hemodynamics: Factors Affecting Blood Flow

    • Blood flow is the volume of blood that flows through a tissue in a given period of time (in mL/min).

    • Total blood flow equals cardiac output (CO), which is the volume of blood that circulates through systemic or pulmonary blood vessels each minute.

    • CO = heart rate (HR) x stroke volume (SV).

    • Distribution of CO depends on:

      • Pressure differences that drive blood through tissue (flows from higher to lower pressure).
      • Resistance to blood flow in specific blood vessels (higher resistance means smaller blood flow).

    Circulatory Routes

    • There are two main routes: systemic and pulmonary circulation.
    • Systemic circulation:
      • Oxygenated blood travels from the heart throughout the body, deoxygenating as it goes.
      • All systemic arteries branch from the aorta.
      • All systemic veins empty into the superior vena cava, inferior vena cava, or the coronary sinus.
      • Deoxygenated blood returns to the heart.
    • Subdivisions of systemic circulation:
      • Coronary circulation
      • Hepatic portal circulation
    • Other circulatory routes:
      • Pulmonary circulation (blood flow to the lungs for gas exchange)
      • Cerebral circulation (route to the brain)
      • Fetal circulation (between the developing fetus and mother)

    The Anatomy of Blood Vessels

    • Arteries and veins have three layers:
      • Tunica intima (innermost layer)
      • Tunica media (middle layer)
      • Tunica adventitia (outer layer)
    • Lumen is the blood vessel cavity.
    • Arteries are thicker and stronger than veins.
    • Arterioles are small arteries that attach to capillaries.
    • Capillaries allow for gas, nutrient, and waste exchange.
    • Venules connect capillaries to veins.
    • Veins are less elastic than arteries and contain valves.

    Major Arteries and Veins

    • Aorta and its branches:
      • Ascending aorta
      • Aortic arch
      • Thoracic aorta
      • Abdominal aorta
    • Circulatory routes:
      • Aorta + branches
      • Arch of aorta
      • Pelvis and lower limbs
      • Principle veins

    Pulmonary Circulation

    • Carries blood from the right side of the heart to the lungs for gas exchange.
    • Route:
      • Right ventricle ! Pulmonary trunk ! R+L pulmonary arteries ! Both lungs ! Carry “blue blood” low in O2 and high in CO2
      • Pulmonary capillaries: gas exchange ! R and L pulmonary veins ! L atrium
      • Carry “red blood” (high in O2 and low in CO2)

    Hepatic Portal Circulation

    • Route travels back from the intestine of the digestive tract to the liver.
    • To store excess sugars from digestion into liver after a meal and to release stored sugar as glycogen between meals to maintain glucose levels.
    • Portal vein: transports blood from one organ’s capillary bed to another.
    • GI organs ! Splenic and superior mesenteric veins ! Hepatic portal vein (“blue blood”) ! Sinusoids (“leaky capillaries” in liver) ! Mixes “blue blood” with “red blood”
    • Hepatic vein ! Inferior vena cava (IVC) ! Heart

    Fetal Circulation

    • Exists only between the developing fetus and mother.
    • Specialized for exchange of materials with maternal blood and bypass of lungs.
    • Exchange in placenta ! Umbilical vein
    • ! Ductus venosus (bypasses liver)
    • ! Inferior vena cava ! R atrium (mixes with deoxygenated blood from lower body)
    • ! Foramen ovale ! L atrium

    Changes at Birth

    • Umbilical arteries ! Medial umbilical ligaments
    • Umbilical vein ! Ligamentum teres
    • Ductus venosus ! Ligamentum venosum
    • Placenta expelled after birth
    • Foramen ovalis closes ! Fossa ovalis
    • Ductus arteriosus ! Ligamentum arteriosum

    Aging

    • Stiffening of aorta
    • Loss of cardiac muscle strength
    • Reduced cardiac output (CO) and increased systolic pressure
    • Higher risk for:
      • Coronary artery disease (CAD)
      • Congestive heart failure (CHF)
      • Atherosclerosis

    Checking Circulation: Pulse

    • Pulse in arteries = heart rate (HR)
    • Sites used:
      • Radial artery (thumb side of wrist)
      • Carotid artery (neck)
      • Brachial artery (arm)
    • Tachycardia: rapid resting HR (>100 bpm)
    • Bradycardia: slow resting HR (<60 bpm)

    Studying That Suits You

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

    Quiz Team

    Description

    This quiz covers the flow of blood from the right side of the heart to the lungs for oxygenation and removal of carbon dioxide, including the route of pulmonary arteries and veins.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser