Blood Vessels

Types:

• Arteries - Takes blood away from heart

  • Maintain proper shape

• Arterioles

• Capillaries

  • Capillary beds drop of O2 and pick up CO2

  • Merge down to form…

• Venules

  • Merge to create…

  • Also have valves

• Veins - Bring blood back to heart

  • Have valves to prevent blood from flowing backwards

  • Collapse

Layers: Tunic = coat

• Tunica interna (intima)

  • Full contact with blood

  • Endothelium - Consistent simple squamous

• Tunica media

  • Vasomotor skills

    • Vasoconstriction

    • Vasodialation

  • Muscle which changes the diameter of the veins

    • SMOOTH muscle

  • MUCH thicker in artery, little in vein, none in capillaries

    • Arteries heighten pressure, veins lower

• Tunica externa (adventitia)

  • Connective tissue to hold blood vessels in place

    • Not in capillaries, inly arteries and veins —> Capillaries need to move o2 and co2 efficiency

      • Capillaries are incredibly delicate

• Precapillary sphincters

  • Circular muscle which closes an opening

    • Restricts (does not STOP) blood flow to an area

• Capillaries ONLY have epithelial inner layer

  • Fenestrations - very porous, allows more stuff to leave

    • In kidneys —> RBCs still cannot function

  • Impervious - TIgt junctions, ponly verys mal stuff can leave - O2

    • In blood-brain barrier

• why does pressure drop so much in the arterioles

  • pressure decreases bc otherwise capillaries would burt - cannot handle

    • As more branchesare made, the

• what is pressure as blood enters right atrium

  • 0 (as it exits, it is 10)

• if pressure is so low in veins, how does blood get back to the heart?

  • muscular pump —> as leg muscles contract, it squeezes veins, and sends the blood higher

  • respiratory pump —>

• varicose veins - distended veins, blood pooling in valves —> stretches veins out, and they bulge from skin - will not go back

  • decrease blood that goes back to heart

  • more swelling in legs

• blood goes through ivf

  • if it is closed, you can use side “roads”, which are smaller

    • side ones are around spine

    • if too much use, it will get varicose

increase volume of chest, not abdomen, abdomen has more pressure, sends blood to the

BLOOD PRESSURE: the rate at which blood is pushing against the walls of the vessel

• measured due to resistance

  • blood viscosity - thickened with sugar

  • blood vessel length - when more mass, blood pressure increases to reach all the cells

  • blood vessel diameter (vasomotor activity) - small changes in diameter SIGNIFICANTLY change the pressure —> less diameter = higher pressure

    • how you regulate blood pressure every day

• vasocontrictors

  • antihistamines - constrictor

  • caffeine -

  • tetrahydrozoline hydrochloride (eye drops) -

• vasodialators

  • prostoglandin

  • histamines

  • alcohol

  • nitric oxide - NO

• epinephrine increases heart rate and force of contraction

  • more pronounced effect on force

• acetylcholine decreases heart rate and force of contraction

  • more pronounced effect on rate