vessels ch 21 m flashcards.txt

  1. types of vessels and fxn
    • 1. arteries: carry blood away from the heart
    • 2. arterioles: very abundant, become metarterioles prior to cap
    • 3. capillaries: site of exchange
    • 4. venues: thinner walls than arterioles
    • 5. veins: carry blood TO the heart
  2. 3 layers or tunics
    • Tunica interna (intima)
    • Tunica media
    • Tunica externa
  3. Muscular Arteries
    • Tunica media has MORE smooth muscle & fewer elastic fibers
    • THICK walls
    • capable of large vasodilation & vasoconstriction
  4. Capillaries
    • Smallest blood vessels
    • fxn to exchange b/w blood & interstitial fluid
    • LACK tunica media & externa: substances pass thru 1 layer of epithelial cells & basement membrane
  5. Veins
    • Not as distinct structural changes as arteries
    • same 3 layers as in arteries BUT NOT designed to withstand HIGH pressure (thinner walls)
    • Valves: fold on tunica interna to form cusp & PREVENT backflow
  6. Capillary EXCHANGE
    • 3 methods of movement b/w blood & interstitial fluid & body cells
    • 1. Diffusion: O2 move down the conc. gradient to body cells, CO2 goes vice versa. Can cross capillary walls thru Intracellular clefts or thru epithelial cells
    • 2. Transcytosis: small quantities. Important for lipid insoluble molecules as its the only way for them to cross
    • 3. Bulk flow: passive process, salt & ions move together, involved in reabsorption from interstate to cap. Important for regulation of volumes of blood & interstit fluid
    Takes 1 min @ REST for 1 drop of blood to flow from RA back to the RA
  8. blood brain barrier
    tight junctions which LIMIT diffusion
  9. Circulation
    • Important diff b/w pulmonary & systemic circulation in autoreg response
    • Systemic blood vessels dilate in response to LOW O2 levels (ACTING to INCREASE O2 delivery)
    • Walls of PULMONARY blood vessels CONSTRICT when LOW O2 to ENSURE most blood flows to more ventilated areas of LUNGS
Card Set
vessels ch 21 m flashcards.txt