Biology 212 Anatomy & Physiology I Blood Vessels

Pulmonary Circuit

Systemic Circuit

Arteries: Always carry blood from heart toward capillaries Have higher blood pressure within them Have thicker walls relative to size of lumen Never have valves Veins: Always carry blood from capillaries toward heart Have lower blood pressure within them Have thinner walls relative to size of lumen May have valves

Elastic (Large) Arteries: Aorta, pulmonary trunk, & their close branches Large Veins: Return blood to heart Muscular (Medium) Arteries: Distribute blood to head, limbs, & organs Medium Veins: Gather blood from head, limbs, & organs Distributing (Small) Arteries: Distribute blood within organs and tissues Small Veins: Gather blood from tissues Arterioles: Distribute blood within organs & tissues Venules: Gather blood from capillaries. Also some exchange of same materials as capillaries Capillaries: Primary site for exchange of gases, nurients, ions, wastes, hormones, cells, etc.

Pathway Variations:

Entire circulatory system (heart, all vessels) lined by simple squamous epithelium called endothelium Capillaries consist only of epithelium and very thin layer of areolar connective tissue. Larger vessels, either veinous or arterial, also have layers of connective tissue and/or smooth muscle surrounding this endothelium.

Contraction of right ventricle provides force to drive blood through pulmonary circuit & contraction of left ventricle provides force to drive blood though systemic circuit, But: not entire story: During systole, large mass of blood pushed out of ventricle under pressure, into elastic artery. Elastic walls of artery expand to absorb this pressure & volume. During diastole (aortic and pulmonary valves closed), stretched walls of these arteries squeeze back against blood, forcing it to flow into more distal arteries. Arterioles restrict blood flow, so blood in arteries remains under pressure. This pressure = major force pushing blood through arterioles into capillaries.

Deep Veins

Superficial Veins

Deep Veins

Superficial Veins

You should be able to identify the following arteries, know from where each artery receives blood, and know to where each artery delivers blood. Aorta Pulmonary trunk Brachiocephalic artery Pulmonary arteries Subclavian arteries Common carotid arteries Axillary arteries Internal carotid arteries Brachial arteries External carotid arteries Radial arteries Vertebral arteries Ulnar arteries Basilar artery Common iliac arteries Renal arteries Internal iliac arteries Celiac trunk External iliac arteries Hepatic artery Femoral arteries Splenic artery Popliteal arteries Left gastric artery Anterior tibial arteries Superior mesenteric arteries Posterior tibial arteries Inferior mesenteric arteries Gonadal arteries Coronary arteries Example: Each external iliac artery receives blood from the common iliac artery on that side and delivers blood to the femoral artery on that side

You should be able to identify the following veins, know from where each vein receives blood, and know to where each vein delivers blood. Superior vena cava Hepatic portal vein Inferior vena cava Splenic vein Brachiocephalic veins Inferior mesenteric vein Subclavian veins Superior mesenteric vein Axillary veins Common iliac veins Brachial veins Internal iliac veins Radial veins External iliac veins Ulnar veins Femoral veins Cephalic veins Popliteal veins Basilic veins Anterior tibial veins Median cubital veins Posterior tibial veins Vertebral veins Greater saphenous veins Internal jugular veins Lesser saphenous veins External jugular veins Gonadal veins Example: Each external iliac vein receives blood from the femoral vein on that side and delivers blood to the common vein on that side