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Chapter 13 (13.7 Systemic Circuit (Venous system: Veins, that return blood…

- - - - ascending aorta
      - aortic arch
      - thoracic aorta
      - abdominal aorta
  - - - right common carotid a. (right side of head)
        
        external carotid a. (scalp)
        
        internal carotid a. (brain)
        
        vertebral (cervical vertebrae/skull)
        
        Basilar a. (brain)
        
        circle of willis (brain)
        
        right subclavian a (right arm)
        
        axillary (armpit)
        
        brachial (upper arm)
        
        radial (lateral forearm)
        
        ulnar (medial forearm)
        
        palmar arches (palm)
        
        digital (fingers)
    - - external carotid a.
      - internal carotid a.
    - - Branches follow same pattern as right subclavian artery
  - - - common hepatic a. (liver)
      - left gastric a. (left stomach)
      - splenic artery (spleen)
  - - - femoral a. (thigh)
        
        popliteal a. (knee region)
        
        posterior tibial a. (lower leg)
        
        plantar arteries (heel, foot, and toes)
        
        anterior tibial a.
        
        dorsalis pedis a. (foot and toes)
  - - - external jugular vein (face and scalp)
      - internal jugular vein (brain)
    - - Cardiac veins (caps of myocardium)
    - - hepatic portal vein (drains gastric, mesentric and splenic veins)
        
        gastric vein (stomach)
        
        mesentric veins (intestines)
        
        splenic vein (spleen)
        
        These veins do not drain directly into the inferior vena cava. Instead, the blood drained from these abdominal organs travels to the liver via the portal vein. Recall the hepatic portal system discussed during digestion
    - - drain intercostal veins and lumbar veins
- - - - a layer of endothelium (simple squamous epithelium)
      - a basement membrane
      - an internal elastic lamina
    - - smooth muscle cells
      - elastic fibers
    - - elastic fibers
      - collagen fibers
  - - - very small arteries
      - deliver blood to capillaries in tissues
      - play a major role in regulating blood flow to capillaries and therefore rugulate blood pressure
  - - - higher cellular needs (brain, muscle) = more elaborate network
      - lower cellular needs = less branching
    - - smooth muscles control blood entry into capillary beds
      - metabolic need controls precapillary sphincter
    - - gases, nutrients, and wastes are exchanged between blood in capillaries and tissues in three ways
        
        Diffusion
        
        most common
        
        substances include oxygen, CO2, glucose & hormones
        
        Lipid- soluable substances pass directly through endothelial cell membrane
        
        water soluble subtances must pass through gaps between endothelial cells
        
        Vesicular transport (endo/ exocytosis
        
        bulk flow
        
        filtration
        
        hydrostatic (blood) pressure pushes small solutes and fluid out of capillary
        
        colloid osmotic pressure (osmosis) draws fluid back into capillary
        
        net affect is fluid loss at the beginning of capillary bed but most is regained by the end of the capillary bed
        
        fluid not regained enters lymphatic vessels (next chapter)
  - - - tunica intima = endothelium and basement membrane
      - tunica media = thin layer of smooth muscle; much thinner than artery
      - tunica externa = elastic and collagen fibers
- - - - vasodilators
      - vasoconstrictors
  - - - (or pressoreceptors) that detect changes in BP in aorta and corotid arteries
    - - detect changes in key blood chemical concentrations (H+, CO2, and O2)
  - - - Epinephrine and norepinephrine
        
        increases CO (rate & force of contraction) and causes vasoconstriction of arterioles
      - Antidiuretic hormone (ADH) Posterior pituitary gland
        
        increases reabsorption of water by the kidneys (DCT), and causes vasoconstriction of arterioles during diuresis and during hemorrhage
      - Angiotensin II Liver (Renin released from kidneys)
        
        has four different targets that cause vasoconstriction of arterioles and causes secretion of aldosterone, (ADH) stimulates cardiac output
      - Aldosterone
        
        increases Na+ and water reabsorption in the kidneys
      - EPO
        
        stimulates red blood cell production
    - - Atrial Natriuretic Peptide (ANP)
        
        causes vasodilation of arterioles and promotes the loss of salt and water in urine
      - Histamine
        
        causes vasodilation of arterioles (plays a key role in inflammation)
- - - - extensive vasodilation
        
        peripheral resistance drops
        
        capillary flow increases
      - venous return increases
        
        skeletal muscle contractions
        
        increased respiration rate (repiratory pump)
      - Cardiac output increases
        
        Frank Starling principle (ventricle reflex)
        
        Bainbridge reflex (atrial reflex)
  - - - blood donation 500 ml 10%
        
        vasomotor enough to restore pressure & flow
      - venous reserve (venoconstriction)
        
        slow moving blood (liver, bone marrow, and skin)
        
        restore 15-20% loss
      - sympathetic stimulation (major loss of blood)
        
        E, NE, ADH, Renin
    - - ADH, aldosterone & increase thirst
      - EPO
  - - - hypotension
      - pale, cool, and moist
      - confusion & disorientaton (no blood to brain)
      - rapid and weak pulse
      - no urine
      - drop in blood pH
- - - - rise from internal iliac arteries
    - - exchange of nurtrients
    - - liver
      - ductus venosus
        
        inferior vena cava
- - - - aneurysm, stroke, myocardial infarction, or massive blood loss
- - - - liquids cannot be compressed (hydrostatic pressure)
        
        liquid will flow from high to low
      - circulatory pressure 100 mm Hg base of aorta (pressure gradient)
        
        needed to force blood through arterioles & into capillaries
        
        arterial pressure (blood pressure) measured on arm
        
        capillary pressure
        
        venous pressure
      - peripheral resistance (R = opposition to blood flow usually due to friction)
    - - vascular resistance, viscosity, and turbulence
      - for blood to flow circulatory pressure has to be (up arrow) TPR
        
        resistance is the oppostion to blood flow primarily due to friction. This friction depends on three things
      - blood viscosity
        
        normally constant
        
        direct relationship
      - blood vessel radius
        
        most significant factor in determining blood pressure
        
        indirect relationship
  - - - in clinical use, we most commonly refer to aterial blood pressure because the blood pressure in the veins is essentially insignificant
      - the arterial blood pressure rises to its maximum during systole (contraction) and falls to its lowest during diastole (relaxation)
      - in a normal adult at rest, the BP = 120 mm Hg/ 80 mm Hg
    - - capillary pressure pushes on capillary walls
        
        permeably to ions, nutrients, organic wastes, dissolved gasses & water