Cardiovascular

Topic 8 - cardiovascular/circulatory system

cardiovascular/circulatory system

  • Made up of parts responsible for blood circulation and nutrient distribution throughout the body

  • Main coverage of the main study of angiology

Components of the circulatory system

Heart

  • Primary organ of the circulatory system

  • Hollow muscular organ that circulates around the body

  • It has 3 layers:

  1. Epicardium 

    • outer layer

  2. Myocardium 

    • middle and thickest layer

    • Made up of cardiac muscles

  3. endocardium 

    • Inner layer

    • Continuous with the cardiac valves inside


It has 4 chambers:

  1. Right atrium

    • smallest cardiac chamber

  2. Right ventricle

    • second largest cardiac chamber

  3. Left atrium

    • third largest cardiac chamber

  4. Left ventricle

    • largest cardiac chamber

Four valves:

  1. Atrioventricular valves

    • valves situated between the atria (above) and ventricle (below) 

    1. Tricuspid valve - right atrioventricular valve

    2. bicuspid/mitral valve - left atrioventricular valve


  2. semilunar valves 

    1. Pulmonic valve - situated between the right ventricle and pulmonary artery

    2. Aortic valve - situated between left ventricle and aorta


  • An apex - pointed portion and directed caudally

  • A base - wide portion and situated opposite the apex (directed cranially)

  • Left and right auricles - ear-like appendages attached to the sides of the left and right atria

  • Coronary blood vessels:

    1. Coronary arteries

      • Red vessels

      • Transport oxygenated blood and nutrients to myocardia layer of the heart

      • Myocardial infection - coronary arteries are obstructed due to obstruction of cholesterol plaques, which can cause obstruction of blood flow in myocardial layer of the heart. Will result in heart attack

  • Coronary arteries

    • Supporting structures of cardiac valves = supports the atrioventricular valves to prevent backflow of blood from ventricles to atria

  • Chordae tandinea

    • cord/string-like structure

  • Papillary muscles

    • connected to the ventricular walls

  • Major blood vessels attached: 

    • Vena cava

      • connected inside the right atrium

    • Pulmonary artery

      • connected to the right ventricle inside

    • Pulmonary vein

      • connected to the left atrium inside

    • Aorta

      • connected to the left ventricle inside

      • Has 2 segments

        1. Thoracic aorta 

          • Is cranial to the diaphragm

        2. Abdominal aorta

          • Is caudal to the diaphragm

  • Has 6 segments:

    1. Phrenic - is the first branch of abdominal aorta

    2. Coeliac - is the first major branch of abdominal aorta; supplies blood to the stomach, liver, and spleen

    3. Cranial mesentery (SI)

    4. Renal (K/L????)(idk lol)

    5. testis/ovary

    6. Caudal mesentery (LI)


Blood vessels

  • Conducting tubes that transport blood throughout the body

  • Types of blood vessels:

    1. Arteries and arterioles - transport oxygenated blood away from the heart

      • Arteries - bigger, thicker walls than other kinds of blood vessels

      • Arterioles - smaller

      • Both generally transports oxygenated blood except:

        1. Pulmonary artery

        2. Umbilical artery

        3. Omphalomesenteric artery

        4. Vitelline artery


    1. Veins and venules - transports deoxygenated blood towards/back to the heart. It has valves inside that prevent the backflow of blood. It is generally bluish in color due to deoxygenated blood

      • Veins - bigger than venules

      • Venules - smaller

      • Both generally transports deoxygenated blood except:

        1. Pulmonary vein

        2. Umbilical vein

        3. Omphalomesenteric vein

        4. Vitelline vein


    1. Capillaries

      • Located between the arterioles and venules

      • small/microscopic vessels

      • Site of exchange of oxygen, nutrients, and waste products between tissues and circulation

  • Layers of blood vessels:

    1. Tunica intima

      • Inner layer

      • Made up of endothelium or endothelial cells


    2. Tunica media

      • Middle layer

      • Made up of smooth muscles

      • Thickest in arterie

        Tunica adventitia

    3. External layer

      • Made up of connective tissue

Blood

  • Specialized connective tissue in solid and liquid components

  • Solid components = blood cells/blood corpuscles


    1. Red blood cells/erythrocytes 

      • transports oxygen molecule due to hemoglobin (iron containing molecule) (oxygen carrying molecule)

    2. White blood cells/leukocytes 

      • Soldiers of the body

      • Fights infections

      • Has 2 types:

        1. Granulocytes

          • cytoplasmic granules(spotted with nucleus at the middle) are present

          1. Neutrophils

            • increases when there’s bacterial infection 

            • Decreases when there’s viral infection

            • no change in color

            • Marked by presence of hypersegmented/multilobed nucleus (polymorphonucleus)

            • Capable of phagocytosis (phagocyte)

            • Can leave the blood vessel to go to site of inflammation, name remains

          2. Eosinophils 

            • increases when there’s parasitic infection 

            • red dots

            • Marked by presence of bilobed nucleus (2)

            • Capable of phagocytosis (phagocyte)

            • Can leave the blood vessel to go to site of inflammation, name remains

          3. Basophils 

            • increases when there’s allergic reaction 

            • blue dots

            • Marked by presence of unilobed or bilobed nucleus (bilobed is rare)

            • Can leave the blood vessel to go to site of inflammation, will be called mast cell

            • Contains vasoactive substances (histamines, serotonin, prostaglandin)

            • Once basophil/mast cell ruptures, histamines will come out. This promotes dilation of blood vessels


        2. Agranulocytes

          • cytoplasmic granules is absent while nucleus is present at the center

          1. Lymphocytes 

            • have round nuclei which almost occupy the cytoplasm of the cell

            • Undifferentiated lymphocytes 

            • present During embryonic and fetal development

            • Types: 

              1. T cell 

                • undifferentiated lymphocytes that were transported into the thymus

              2. B cell 

                • undifferentiated lymphocytes that were transported into the bursa of fabricius (avians) or bone marrow (mammals)

                • Will transform into memory cell or plasma cell (produces antibodies/immunoglobulin)

  • 5 types of immunoglobulin

    1. Ig-M - will increase upon body’s first encounter of disease;primary response of body (first shot)

    2. Ig-G - secondary response (second shot)

    3. Ig-A

    4. Ig-E

    5. Ig-D



        1. Monocytes 

          • can be differentiated from lymphocytes by the presence of indented nucleus (heart shaped/v shaped)

          • Type of blood cell inside circulation

          • Capable of migrating from the blood vessel to the site of inflammation

          • Macrophage

          • “Big eater”

          • Capable of phagocytosis (phagocyte)

          • Resident macrophage - stays where they are even if there’s inflammation

          • Mobile macrophage - from blood vessels;are capable of going to site of inflammation


    1. platelets/thrombocytes

      • remnants/fragments of bone marrow megakaryocytes

      • Plays certain role in clotting mechanism by forming platelet plug

      • Does not meet the requirements to be considered as a cell

  • Liquid component:

  • Plasma - contains clotting factor

  • Serum - doesn’t contain any clotting factor

  • Clotting factors 

  • Hemophilia = Lack of either clotting factor 8, 9, or 11

  • Disorder in Clotting factor 8 - hemophilia A

  • Disorder in Clotting factor 9 - hemophilia B

  • Disorder in Clotting factor 11 - hemophilia C

  • Antihemophilic factors = factors 8, 9, and 11 

  • 13 clotting factors

  • Clotting factor 1 - fibrinogen

  • Clotting factor 8 - antihemophilic globulin

  • Clotting factor 9 - plasma thromboplastin component/Christmas factor (Stephen Christmas - first patient with hemophilia B)

  • Clotting factor 11 - plasma thromboplastin antecedent

  • Clotting factor 13 - fibrin stabilizing factor