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The Cardiovascular System (13-3 (Neural control of blood pressure and…

- - - - Includes: the endothelial lining of the vessel and an underlying layer of connective tissue dominated by elastic fibers
    - - Includes: smooth muscle tissue in a framework of collagen and elastic fibers.
  - - - the entrance to each capillary is guarded by a precapillary sphincter( a band of smooth muscle)
  - - - Muscular
        
        arterioles
      - Pulmonary trunk, aorta
  - - - Consist of a single layer of endothelial cells inside a basement membrane
      - Dont function as individual units but as part of an interconnected network called capillary bed.
  - - - have relatively thin walls
- - - - blood can not be compressed
      - If a pressure difference exists a liquid will flow from an area of higher pressure toward an area of lower pressure
      - the largest pressure difference is pressure gradient
      - Circulatory pressure is divided into 3 components: arterial pressure, capillary pressure, venous pressure
    - - any force that opposes movement
      - total peripheral resistance- the resistance of the entire cardiovascular system.
      - peripheral resistance- resistance of the arterial system
    - - the resistance of the blood vessels to blood flow
      - the most important factor in vascular resistance is friction between the blood and the vessel walls.
    - - the resistance to flow resulting from interactions among molecules and suspended materials in a liquid
      - anemia- the hematocrit is reduced due to inadequate production of hemoglobin, rbcs, or both
    - - neural and hormonal control mechanisms regulate blood pressure, keeping it relatively stable
  - - - systolic pressure- the peak blood pressure measured during ventricular systole
    - - capillary pressure- the pressure of blood within a capillary bed
      - lymphatic vessels- empty into the bloodstream
    - - muscular compression- the contractions of skeletal muscles near a vein compress it, helping push blood toward the heart.
      - respiratory pump- as you inhale, decreased pressure in the thoracic cavity draws air into the lungs
- - - - monitor the degree of stretch in the walls of expandable organs
      - the baroreceptors involved in cardiovascular regulation are located
        
        in the aortic sinuses, pockets in the walls of the aorta adjacent to the heart
        
        in the walls of the carotid sinuses, expanded chambers near the bases of the internal carodid arteries of the neck
        
        in the wall of the right atrium. these receptors initiate baroreceptor reflexes, autonomic reflexes that adjust cardiac output and peripheral resistance to maintain normal arterial pressures
    - - responds to changes in carbon dioxide oxygen or ph in blood and cerebrospinal fluid
      - carotid bodies- located in the neck near the carotid sinuses
      - aortic bodies- near the arch of the aorta
  - - - is relased at the posterior pituitary glan in response to decrease in blood volume and increase in the osmotic concentration of the plasma or the presence of angiotensin ii
    - - is formed in the lood floowing the release of the enzyme renin by specialized kidney cells in response to the fall in blood pressure
    - - is released by the kidneys when blood pressure falls or the oxygen content of the blood becomes abnormally low
    - - release is stimulated by increased blood pressure
- - - - short term responses appear almost as soon as blood pressure starts to decline, when the carotid and aortic reflexes increase cardiac output and cause peripheral vasoconstricion.
      - venous reserve- large reservoirs of slowly moving venous blood in the liver, bone marrow, and skin
    - - it can take days before blood volume returns to normal
- - - - the first systemic vessel and largest artery is the aorta
      - the ascending aorta begins at the aortic semilunar valve of the left ventricle
    - - 3 elastic arteries 1. barchiocephaliac truck, 2. left common carotid, 3. left subclavian
      - brachiocephaliac
        
        right common carotid arter and right subclavian artery
    - - supply blood to the arms chest wall shoulders back and central nervous system.
      - before leaving thoracic acvity gives rises to internal thoracic artery which supplies the pericardium and anterior wall of the chest . vertervral artery which supplies muscles and tissues of neck shoulder and upper back
      - after passing first rib subclavian gers a new names the axillary artery then to the brachial then radial arter then ulnar artery
      - the carotid artery and the blood supply to the brain
        
        external carotid
        
        located by pressing on side of windpipe
        
        supply blood to the pharynx esophagus larynx and face
        
        internal carotid
        
        delivers blood to brain and eye
    - - thoracic aorta
        
        gives rise to small arteries that end in capillary beds in the esophagus pericardium and other mediastinal structures
        
        travels within the mediastinum providing blood to the intercostal arteries, carry blood to teh vertebral column area and body wall
        
        phernic arteries deliver blood to the muscular diaphragm
      - inferior abdominal aorta
        
        delivers blood to abdominoplevic organs and structures the celiac trunk, superior mesenteric arter and inferior mesenteric artery
        
        these provide blood to all of the digestive organs in the abdominopelvic cavity
        
        celiac trunk divides into 3 branches that deliver blood to the liver gallbladder stomach and spleen
        
        superior mesenteric artery supplies the pancrease small intestine and most of large intestine
        
        inferior mesenteric delivers blood to the last portion of the large intestine and rectum
  - - - receives blood from 2 regions the head and neck and the upper limbs shoulders and chest
      - venous return from the head and neck
        
        dural sinuses- small veins in the neural tissue of the brain empty into a network of thin walled channels
        
        the largest the superior sagittal sinus is located within the fold of dura mater lying between the cerebral hemisheres
        
        internal jugular veins- descending parallel to the common carotid artery in the neck
        
        external jugular veins collect blood from the superficial structures of the head and neck
        
        verterbral veins drain the cervical spinal cord and the posterior surface of the skull descending within the transverse foramina of the cervical vertebrae alongside the vertebral arteries
- - - - ductus arteriosus consists of short muscular vessels
- - - - reduction in maximum cardiac output 2. changes in activities of nofal and conduction cells 3. reduction in the elasticity of the fibrous skeleton 4. progressive atherosclerosis which can restrict coronary circulation 5. the placement of damaged cardiac muscle cells by scar tissue
    - - inelastic walls of arteries become less tolerant of sudden pressure increases 2. calcium salts can be deposited on weakened vascular walls increasing the risk of a stroke 3. throbi can form at atherosclerotic plaques