A&P Cardiovascular System: Blood Vessels

  1. Blood Vessels
    Tubels that convey blood between the heart and every functioning cell in the body
  2. Types of Blood Vessels
    Arteries, veins, and capillaries
  3. Vessel Wall Layers
    • Tunica interna (intima)
    • Tunica media
    • Tunica externa (tunica adventitia)
  4. Vessel Wall Layers: Tunica Interna (Intima)
    Lines lumen, single thin layer of endothelium
  5. Vessel Wall Layers: Tunica Media
    Bulky middle coat, smooth muscle and elastic tissue
  6. Vessel Wall Layers: Tunic Externa (Tunica Adventitia)
    Outermost tunic, areolar or fibrous CT
  7. Arteries - Structure & Function
    Large high-pressure vessels

    Structure: three wall layers, walls are thicker than those of veins and capillaries

    Function: carry blood from heart to lungs and tissues
  8. Types of Arteries
    Elastic, muscular, and arterioles
  9. Types of Arteries: Elastic Arteries
    Conducting, aorta and its major branches
  10. Types of Arteries: Muscular Arteries
    Distributing, smallest arteries which determine minute to minute blood flow
  11. Capillaries - Structure & Function
    Microscopic vessels that connect arterioles with venules

    Structure: thin vessels, consists of tunica intima only

    Function: exchange site for various substances between blood and tissue cells
  12. Types of Capillaries
    Continuous, fenestrated, discontinuous sinusoidal
  13. Capillary Bed
    Interwoven network
  14. Veins - Structure & Function
    Low pressure vessels

    Structure: largest vessels, three wall layers, tunica media thinner than artery

    Function: transport blood from lungs and tissues to heart
  15. Valves
    Composed of tunica intima, prevent backflow of blood away from heart
  16. Types of Veins
    Venules and Veins
  17. Types of Veins: Venules & Veins
    Venules: carry blood from capillaries to veins

    Veins: venous return
  18. Venous Sinuses
    Specialized flattened veins such as coronary sinus and dural sinuses
  19. Vascular Anastomoses
    Union of vascular channels

    a. arterial anastomoses/collateral channels

    b. arteriovenous anastomoses

    c. venous anastomoses
  20. Blood Flow
    Volume of blood flowing through a vessel, organ, or the entire circulation in a given period (ml/mm)

    Entire circulation blood flow = CO (cardiac output)
  21. Blood Pressue (BP)
    The force per unit area exerted on a vessel wall by contained blood (mm Hg)

    a. systemic arterial blood pressure in the largest arteries near heart

    b. driving force that keeps blood moving
  22. Resistance
    Opposition to flow, peripheral resistance

    a. measure of the amount of friction blood encounters as it passes through vessels

    b. sources of resistance
  23. Factors for Resistance
    Blood viscosity (thickness or stickiness)

    Total blood vessel length

    Blood vessel diameter
  24. Factors for Resistance: Blood Viscosity
    Thickness or stickiness

    The greater the viscosity the greater the resistance
  25. Factors for Resistance: Total Blood Vessel Length
    The longer the vessels are the greater the resistance
  26. Factors for Resistance: Blood Vessel Diamter
    Greatest Factor

    The smaller the tube the greater the resistance, resistance varies inversely with the fourth power of the vessel radius
  27. Systemic Blood Pressure: Types
    Arterial pressure, capillary pressure, and venous blood pressure
  28. Relationship between Flow: Pressure & Resistance
    • Blood Flow = Difference in blood pressure
    • Peripheral Resistance

    BF = CO
  29. Arterial Blood Pressure - Factors
    Compliance or distensibility (ability of elastic arteries close to heart to be stretched)

    Volume of blood forced into arteries at any time
  30. Arterial Blood Pressure - Terms
    • Stolic Pressure
    • Diastolic Pressure
    • Pulse Pressure
    • Mean Arterial Pressure
  31. Arterial Blood Pressure: Systolic Pressure
    Pressure exerted by blood on the blood vessel walls during ventricular contractions

    120 mm Hg
  32. Arterial Blood Pressure: Diastolic Pressure
    Arterial blood pressure reached during or as a result of diastole, lowest level of any given cardiac cycle

    70 - 80 mm Hg
  33. Arterial Blood Pressure: Pulse Pressure
    Difference between the systolic and diastolic pressure
  34. Arterial Blood Pressure: Mean Arterial Pressure (MAP)
    The pressure that propels the blood to the tissues

    • MAP = diastolic pressure + pulse pressure
    • 3

    • ex. MAP = 80 mm Hg + 40 mm Hg = 93 mm Hg
    • 3
  35. Venous Blood Pressure & Factors
    Steady and changes little during cardiac cycle

    Factors aiding venous return: respiratory pump & muscular pump
  36. Maintaining Blood Pressure
    BP varies directly CO, peripheral resistance and blood volume

    Major factors enhancing cardiac output are venous return, neural controls and hormonal controls
  37. Maintaining Blood Pressure: Short-Term Mechanisms - Neural Controls
    Maintaining adequate MAP by altering blood vessel diameter and altering blood distribution to respond to demand

    a. vasomotor center in medulla oblongata

    b. baroreceptor-initiated reflexes

    c. chemoreceptor-initiated reflexes

    d. influence of higher brain centers
  38. Maintaining Blood Pressure: Short-Term Mechanisms - Hormone Controls
    a. adrenal medulla

    b. atrial natriuretic peptide (ANP)

    c. antidiuretic hormone (ADH, vasopressin) - reabsorb water

    d. angiotensin II
  39. Maintaining Blood Pressure: Long-Term Mechanisms
    Renal regulation
  40. Monitoring Circulatory Efficiency
    Taking a pulse

    Measuring blood pressure
  41. Alterations of Blood Pressure
    Hypotension: low blood pressure

    Hypertension: high blood pressure
  42. Blood Flow Through Body Tissues: Tissue Perfusion
    Velocity of blood flow

    Autoregulation: local regulation of blood flow

    a. automatic adjustment

    b. metabolic controls

    c. myogenic control

    d. long-term autoregulation
  43. Circulatory Pathways
    • Pulmonary
    • Systemic
    • Hepatic Portal System
    • Major Pathways
  44. Circulatory Pathways: Hepatic Portal System
    1. hepatic circulation circulates blood through liver

    2. veins from digestive organs empty blood into hepatic portal vein

    3. venous blood from hepatic vein passes through the liver before entering the systemic circulation via hepatic veins
  45. Circulatory Pathways: Major Pathways
    1. head and neck

    2. upper limb and thorax

    3. abdomen

    4. pelvis and lower limbs
Card Set
A&P Cardiovascular System: Blood Vessels
A&P Cardiovascular System: Blood Vessels