Cardiovascular system

• What is the function of the pericardial fluid?

  reduces friction between layers as the heart moves
• What are the functions of the lymphatic system?

  T drain the excess of interstitial tissue fluid and return to blood stream

  
  

  Immune system: detect toxins , enrich lymph and blood in cells and molecules involved in defense

  
  

  Transport of molecules: lacteals at the vili of the small intestine:lipid transport
• What is the structure of the ducts?

  Valve avoiding backflow of lymph
• What is the structure of the collecting vessels?

  thinner walls , more abundant valves , lymphatic pulse: peristaltic wave
• What is the structure of lymphatic capillaries?

  endothelium: very permeable

  Connective tissue:anchoring filaments
• What is the lymphatic vessels system composed of?

  lymphatic ducts , collecting vessels and capillaries
• What are differences between purkinje fibers and cardiomyocytes?

  Specialized muscle fibers , larger , rounded nuclei , less myofibrils , more glycogen and gap junctions
• What are the purkinje fibers?

  Nodal cells at the apex of the heart
• What is the Bundle of His?

  a node found next to the right ventricle
• What is the AVN?

  nodal cells of the subendocardial tissue in the septal wall of the right atrium that conducts the impulse from the atria to the ventricles
• What is the function of the internodal tracts?

  to transmit the impulse to the AV node and to the left atrium
• What type of fibers innervate the SAN?

  sympathetic and parasympathetic
• What is the sinoartrial node (SAN) , what is its composition and location?

  Cardiac pacemaker , formed by node cells; specialized atrial cardiomyocytes that contract in a rhythmic manner and generate impulses.

  
  

  Located in the subepicardial tissue of the right atrium and is between the superior vena cava and the right atrium
• What is the location and function of Chordae tendineae?

  Bind the valve leaflets to papillary muscle , dense CT core , covered by endocardium and stabilizes the atrioventricular valve (prevent regurgitation)
• What are the fibrous trigones?

  Dense CT , support structure for the fibrous rings , separates the cardiac chambers; the myocardium of the atria and Ventricles. Electrical insulator
• What is the fibrous ring?

  Annular dense CT structures surrounding the internal apertures of the heart where the valves are inserted
• What are leaflets/cusps?

  Endocardial folds with a central core of dense CT
• When do the valves open?

  Atrioventricular valves open in ventricular diastole

  
  

  Semilunar valves open in systole
• What is the structure of valves?

  Leaflets , fibrous ring , fibrous trigones and chorde tendinae
• what are the layers in the epicardium?

  Submesothelial layer: Loose CT , adipocytes , blood vessels , lymphatic vessels, nerves and ganglia

  
  

  Mesothelium: Single layer of squamous cells
• What are papillary muscles?

  Conical projection of muscle that attach to the cusps of the atrioventricular valves via the chordae tendineae
• What are cardiomyocytes?

  Endocrine granules , atrial natriuretic peptides , to regulate circulation blood volume and in response to injury
• What does the myocardium contain?

  intercalated disks , striated muscle , 1/2 centrally placed nuclei , branched fibers, numerous mitochondria , sarcoplasmic reticulum and T tubules
• What is the composition of the endocardium?

  1) Endothelium + loose CT

  2) Medium layer: dense CT , fibroblasts , elastic fibers and SMC

  
  

  3) Subendocardial layer: Blood vessels , lymphatic vessels , nerves , purkinje fibers
• Which chamber is thickest?

  left ventricle
• What is the cardiac wall composed of?

  Endocardium , myocardium , epicardium
• What is the process of circulation?

  deoxygenated blood enters heart through inferior vena cava into the right atrium then into right ventricle then to the left pulmonary artery to the lungs. Blood enters left side through the left pulmonary veins then to left atrium then to left ventricle then exits through aorta
• Where does blood enter?

  Inferior vena cava into the right atrium
• What is the heart formed from?

  2 atria , 2 ventricles , tricuspid valve, mitral valve , pulmonary valve , aortic valve
• What is the heart?

  Muscle pump which contracts rhythmically propelling the blood through the circulatory system (diastole and systole)
• What are examples of chemoreceptors?

  Carotid body and aortic bodies (abundant vascular irrigation and innervation)
• What is carotid sinus and what is it involved in?

  Baroreceptor for blood pressure and located in the first 2cm of the internal carotid artery and dilation of the tunica adventitia
• What are the type of fibers?

  Adrenergic ( most common)(vasoconstriction)(noradrenaline) and cholinergic fibers (vasodilation , acetyl choline)
• Why is motor innervation important?

  It regulated muscle tone , vasoconstriction, and vasodilation
• Where does innervation occur?

  In vessels with SMC , especially in arterioles and small muscular arteries
• In which veins can we find more venous valves?

  Infracardiac and supracardiac
• What mechanisms help blood return to heart?

  venous valves (flaps of tunica intima) that prevent blood back flow
• Why is the circulation of the venous blood returning to the heart is more difficult?

  Lower proportion of muscle in the venous system , lower blood pressure , against gravity in infracardiac veins
• what is the difference of larger veins from arterioles?

  tunica adventitia contains bundles of smooth muscle cells
• what is the difference of small + medium veins from arterioles?

  thinner tunica media and thicker tunica adventitia