Arteries. Away from the heartThick, muscular wallsVery elasticArteriolesDiameter varies in response to neural stimuli and local chemical influences.. CapillariesConsist of a single tunica internaGas, nutrient, and waste exchangeBrain capillariesBlood-brain barrierCapillary bedsPrecapillary sphincterShunting of bloodDigestion.
1. Blood Vessels Closed circulatory system
Lumen Tunica interna
3. Arteries Away from the heart
Thick, muscular walls
Diameter varies in response to neural stimuli and local chemical influences. Capillaries
Consist of a single tunica interna
Gas, nutrient, and waste exchange
Shunting of blood
4. Venous System Toward the heart
Venules—porous—free movement of fluids and white blood cells.
3 tunics—but thin
hemorrhoids Maintenance of Blood Pressure
Shunting and vasoconstriction.
Carotid and aorta
Higher brain centers
Atrial natrietic peptide
5. Hypertension 30% of people over 50
Causes heart failure, vascular disease, renal failure, stroke, and blindness.
Enlargement falled by hypertrophy of the myocardium Contributing factors:
Diet (sodium, saturated fat, cholesterol.)
Smoking—nicotine is a vasoconstrictor.
6. Atherosclerosis Damage to the tunica interna
Fatty streak stage Arteriosclerosis
tPA—tissue plasminogen activator
HDL—removes cholesterol from vessel walls.
7. Arteries Aorta—largest artery
Right and left coronary arteries
Common carotid arteries—branch to form internal and external carotids
External—supply tissues of the head except the brain and orbits.
Internal—supply the orbits and most of the cerebrum.
Vertebral arteries—branch to the cervical spinal cord, neck, cerebellum, pons, and inner ear.
10. Arteries to Know Know the arteries on the proceeding chart plus:
Arteries of the arm—brachial, radial, ulnar
Arteries of the leg—femoral, popliteal, anterior tibial, posterior tibial
Be able to identify these arteries on a diagram like that on page 631. Also know the locations served by these arteries.
11. Veins Dural sinuses—veins of the brain drain into these enlarged chambers and drain to the internal jugular veins.
External jugular veins—superficial head structures.
Vertebral veins—cervical vertebrae & neck muscles.
Brachiocephalic—mammary glands and first 2 or 3 intercostal spaces.
14. Veins to Know Know the veins on the preceding chart plus:
The veins of the arms—cephalic, axillary, brachial, radial, ulnar.
The veins of the legs—external iliac, femoral, popliteal, anterior tibial, posterior tibial, great saphenous vein, hepatic portal vein.
The great saphenous vein is a superficial vein. Connect with many of the deep veins of the legs and thighs.
Be able to identify these veins on a diagram like that on page 638. Also know the locations served by these arteries.