The Internal Anatomy of the heart

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  1. On which side of the heart is the coronary groove continuous?
    The right
  2. What vessels carry venous blood to the right atrium?
    Cranial and caudal vena cava, and right azygous vein
  3. What separates the flow from the cranial and caudal vena cavae?
    An intervenous tubercle
  4. Which species also have a left azygous vein?
    Pigs and ruminants
  5. Where does venous return from the coronary circulation enter the right atrium?
    At the coronary sinus
  6. What type of muscles are present in the auricles and what is their function?
    Pectinate muscles - they dampen down turbulent blood flow through the atrium
  7. What is the fossa ovalis?  Where is it located?
    A remnant of the foramen ovale (an opening between the right and left atria during foetal circulation).  It is located on the inter-atrial septum.
  8. What are the two nodes within the right atrium and where are they located?
    • SA node is located on the terminal crest
    • AV node is located on the inter-ventricular septum, just cranial to the coronary sinus
  9. What valve is present in the right atrium?  How many cusps does it have?
    Right AV or tricuspid valve.  It has 3 cusps.
  10. How are the valve flaps of the tricuspid valve adherent to the wall of the heart?
    By a fibrous annular ring
  11. What structures do the chordae tendinae attach to?
    Papillary muscles and multiple valve flaps
  12. What is the function of the tricuspid valve?
    To prevent back flow of blood from the RV into the RA during systole
  13. Describe how the tricuspid valve functions
    When the atria are filling with blood the valve flaps are flat against the wall of the ventricles.  When the ventricles contract blood flows behind the valve flaps which causes them to close passively and stops blood flow back into the atria.  When the ventricle relaxes blood stops pushing against the valves and the flaps passively fall down again.
  14. The closing of the right and left atrioventricular valves causes which heart sound?
    1st heart sound = 'lub'
  15. What is the function of the papillary muscles?
    They contract and take up the tension from the chordae tendinae to stop the valve reflecting back into the atria
  16. What structure is present in the right ventricle that causes contraction of the papillary muscles just ahead of ventricle contraction?
    Moderator band
  17. The right ventricle extends around the cranial/caudal margin of the heart?
  18. Which ventricle wall is thicker: right or left?
  19. What valve is present between the right ventricle and pulmonary trunk?
    The pulmonary semilunar valve
  20. True or false: there are no chordae tendinae or papillary muscles associated with the aortic/pulmonary semilunar valves?
  21. What heart sound does closure of the pulmonary and aortic semi-lunar valves account for?
    The 2nd heart sound = 'dub'
  22. What condition of the pulmonary semilunar valve can cause right heart enlargement?
    Stenosis (narrowing of the valve) - the heart has to work harder to force blood out of the right ventricle
  23. The ... links the pulmonary trunk to the aorta?
    Ligamentum arteriosum
  24. What foetal structure is the ligamentum arteriosum a remnant of?
    The ductus arteriosus
  25. The pulmonary veins bring oxygenated/deoygenated blood to the left atrium?
  26. What valve is present between the left atria and ventricle?
    Mitral/bicupsid/left atrioventricular valve
  27. How many valve flaps does the mitral valve have?
  28. Which chamber forms the apex of the heart?
    The left ventricle
  29. What valve is present at the entrance to the aorta?
    The aortic semilunar valve
  30. Where does the aorta exit the heart?
    In the middle of the base of the heart
  31. Where are the origins of the coronary circulation located?
    Behind the valve flaps of the aortic semilunar valve
  32. Which valves can be heard on auscultation of the thorax on the a) left b) right side of an animal?
    • a) pulmonary semilunar, aortic semilunar and mitral valve (PAM 3,4,5)
    • b) Tricuspid (4)
  33. Describe species differences in the blood supply of the heart via the left vs right coronary arteries (ruminants and carnivores, horses and pigs)
    • Ruminants and carnivores - the left coronary artery supplies a larger area of the heart than the right coronary artery
    • Horses and pigs - the left and right coronary arteries each supply half the area of the heart
  34. Where is the impulse for contraction of the heart generated?
    In the SA node, in the right atrium
  35. Describe the conduction system of the heart
    SA node --> right atrial muscle --> left atrial muscle --> AV node --> interventricular septum --> bundle of his --> bundle branches --> endocardium --> purkinjie fibres --> epicardium
  36. What is the function of moderator bands?
    They allow impulses to bypass the normal circuit and cause the papillary muscles to contract ahead of ventricular contraction
  37. What structures supply sympathetic/parasympathetic innervation to the heart?
    • Sympathetic - sympathetic chain via the cervicothoracic ganglion and middle cervical ganglion
    • Parasympathetic - vagus nerve
  38. What effect does sympathetic/parasympathetic innervation have on the heart?
    • Sympathetic - increases heart rate and force of contraction
    • Parasympathetic - decreases heart rate
  39. Describe the course of the vagus nerve over the heart
    The vagus nerve splits into two branches at the base of the heart (a dorsal and ventral branch). These travel across the heart and meet before going through the oesophageal hiatus in the diaphragm.
  40. As the vagus nerve goes over the base of the heart it sends a loop back up towards the neck - what is the name of this nerve?
    The recurrent laryngeal nerve
Card Set:
The Internal Anatomy of the heart
2015-03-04 18:52:40
Heart Anatomy

Vet Med - Module 10
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