BIOL 129 Lecture Notes - Lecture 12: Pulmonary Artery, Umbilical Vein, Fetus
Document Summary
Heart arter(cid:455) capillar(cid:455) (cid:894)gas a(cid:374)d (cid:374)utrie(cid:374)t e(cid:454)cha(cid:374)ge(cid:895) vei(cid:374) heart. Systemic circulation: blood flow to capillaries everywhere else in the body. Two exceptions to this pattern: portal system and anastomosis. *remember: deoxygenated blood from the gi tract is first filtered through the liver before returning to the heart. Caval system: blood flows directly into the inferior vena cava. Drains abdominal walls, kidneys, pelvis and lower limbs. Portal system: blood drains into the hepatic vein. Heart arter(cid:455) capillaries of gi tract portal vei(cid:374) capillaries of the liver i(cid:374)ferior ve(cid:374)a cava heart. Venous anastomosis: two veins merge, allows alternative drainage routes. Arterial anastomosis: two arteries merge, allows alternate path for blood flow, common around joints (collateral circulation) Surgical anastomosis: coronary artery bypass graft (cabg): blood flows around a blocked vessel (bypasses blockage) and aorta supplies blood to coronary arteries. Tunica media: smooth muscle, collagen, elastic fibers*, allow vessels to dilate and contract, autonomic innervation. Tunica externa: thin outer layer, loose connective tissue.
