Blood vessels and Hemodynamics part 3

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  1. venous return
    the volume of blood flowing back to the heart through the systemic veins, occurs due to pressure generated by contractions of the left ventricles.
  2. the skeletal muscle pump
    at rest, the venous valves in the lower limbs are open and blood flows towards the heart.  Contraction of the leg muscles pushes the blood through the proximal valve while closing the distal. As the leg relaxes the proximal valve closes and the distal valve opens
  3. the respiratory pump
    during inhalation the diaphragm moves downwards which causes a decrease in pressure in the thoracic cavity and an increase in pressure in the abdominal cavity. As a result abdominal veins are compressed and a greater volume of blood moves into the thoracic veins and into the right atrium
  4. circulation time
    is the time required for a drop of blood to pass from the right atrium, through the pulmonary circulation, back to the left atrium through the systemic circulation down to the foot and back to the right atrium
  5. cardiac accelerator nerve
    how sympathetic impulses reach the heart from the CV centre in the medulla oblongata. Increase heart rate and contractility
  6. vagus X nerve
    parasympathetic nerve that carries impulses from the CV centre decrease the heart rate and contractility.
  7. vasomotor nerve
    the CV centre also continually sends impulses to smooth muscle in blood vessels via this nerve.
  8. vasomotor tone
    the vasomotor region of the cardiovascular centre continually sends impulses over these routes to arterioles throughout the body.  The result is a moderate state of tonic contraction or vasoconstriction
  9. baroreceptor
    pressure sensitive sensory recepters are located in the aorta, internal carotid arteries. They send impulses to the CV centre to help regulate blood pressure.
  10. Baroreceptor reflexes: carotid sinus reflex
    this helps regulate blood pressure in the brain
  11. Baroreceptor reflexes: aortic reflex
    which regulates systemic blood pressure.  nerve impulses from aortic baroreceptors reach the cv centre via sensory axons of the Vagus X nerves
  12. chemoreceptor reflexes
    sensory receptors that monitor the chemical composition of blood.  They detect changes in blood level of O2 CO2 and H+
  13. Renin- angiotensin-aldosterone (RAA) system
    when blood volume drops or flow to kidneys decreases, renin is secreted into the blood stream.  In sequence the renin and angiotensin converting enzymes act on their substrates to produce the active hormone angiotensin 2, which raises blood pressure
  14. Epinephrine and norepinephrine
    in response to sympathetic stimulation the adrenal medulla secretes these. These hormones increase cardiac output by increasing the rate and force of heart contractions.  They also cause vasoconstriction of arterioles and veins and vasodilation of arterioles in cardiac and skeletal muscle
  15. Antidiuretic hormone
    is produced by the hypothalamus and is released by the posterior pituitary gland in response to dehydration or decreased blood volume.  It causes vasoconstriction.
  16. atrial natriuretic peptide (ANP)
    released from cells in the atria of the heart, ANP lowers blood pressure by causing vasodilation and by promoting loss of salt and water in urin which reduces blood volume
  17. autoregulation
    the ability of tissue to automatically adjust its blood flow to match its metabolic demandes
  18. pulse
    the alternating expansion and recoiling of elastic arteries after each systole of the left ventricle creates a traveling pressure wave
  19. sphygmomanometer
    the device used to measure blood pressure
  20. systolic blood pressure
    the force of blood pressure on arterial walls just after ventricular contraction
  21. diastolic blood pressure
    represents the force exerted by the blood remaining in the arteries during ventricular relaxation
  22. kortokoff sounds
    the sounds heard while taking blood pressure
  23. pulse pressure
    the difference between systolic and diastolic pressure, usually 40 mmHg
  24. shock
    is a failure of the cardiovascular system to deliver enough oxygen and nutrients to meet cellular metabolic needs
  25. hypovolemic shock
    due to decreased blood volume. A common cause is acute (sudden) hemorrhage.  It may be external or internal.  Loss of other body fluids may also cause this
  26. cardiogenic shock
    due to poor heart function. The heart fails to pump adequately.  Most often because of a myocardial infarction (heart attack)
  27. vascular shock
    due to inappropriate vasodilation
  28. obstructive shock
    due to obstruction of blood flow
  29. circulatory routes
    blood vessels are organized into these and carry blood to specific organs in the body.
  30. pulmonary circulation routes
    need not be pumped as far as in the systemic routes. They carry blood to and from the lungs. These arteries are larger, with thinner walls and less elastic tissue.  The resistance is very low meaning it requires very low pressure
  31. hepatic portal circulation
    carries venous blood from the gastrointestinal organs and the spleen to the liver.
  32. hypertension
    persistently high blood pressure.  it is the most common disorder affecting the heart and blood vessels and is the major cause of heart failure, kidney disease and stroke
  33. aneurysm
    a thin, weakened section of the wall of an artery or a vein that bulges outward, forming a balloon like sac .  Common causes are syphilis, artherosclerosis, congenital blood defects and trauma
  34. deep venous thrombosis
    the presence of a thrombus (blood clot)in a deep vein of the lower limbs
  35. hypotension
    low blood pressure, most commonly used to describe an acute drop in blood pressure, as occurs during excessive blood loss
  36. occlusion
    the closure or obstruction of the lumen of a structure such as a blood vessel
  37. phlebitis
    inflammation of a vein involving clot formation
  38. thrombophlebities
    inflammation of a vein involving clot formation
Card Set:
Blood vessels and Hemodynamics part 3
2013-04-15 17:25:10
Blood vessels Hemodynamics part

Blood vessels and Hemodynamics part 3
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