Vessels and Circulation

Arteries

Blood vessels that carry blood away from the heart.

Veins

Blood vessels that carry blood toward the heart.

Capillaries

Small vessels where gas exchange occurs.

Companion vessels

Arteries and veins that travel together and serve the same region.

Blood pressure

Force of blood pushing against vessel walls.

Anastomosis

Connection between blood vessels that provides an alternate route for blood flow.

Lumen

Interior space through which blood flows.

Tunics

Layers that surround the lumen of a blood vessel.

Tunica intima

Innermost layer of a blood vessel.

Tunica media

Middle layer composed mainly of smooth muscle.

Tunica externa

Outermost connective tissue layer.

Endothelium

Simple squamous epithelium lining blood vessels.

Subendothelial layer

Areolar connective tissue beneath the endothelium.

Elastic arteries

Largest arteries with many elastic fibers.

Muscular arteries

Medium-sized arteries with a thick tunica media.

Arterioles

Smallest arteries that lead to capillaries.

Veins

Vessels that return blood to the heart.

Valves

Structures that prevent backflow of blood in veins.

Skeletal muscle pump

Muscle contractions that help move blood through veins.

Venules

Smallest veins that drain capillaries.

Capillary bed

Network of capillaries between arterioles and venules.

Postcapillary venule

Small venule that directly receives blood from capillaries.

Thoroughfare channel

Direct pathway through a capillary bed.

Precapillary sphincter

Smooth muscle controlling blood flow into capillaries.

Metarteriole

Vessel connecting an arteriole to a capillary bed.

Heart → Elastic artery → Muscular artery → Arteriole → Metarteriole → Capillary bed → Postcapillary venule → Venule → Vein

General pathway of blood flow.

Ascending aorta

First section of the aorta leaving the heart.

Aortic arch

Curved portion of the aorta.

Brachiocephalic trunk

First branch of the aortic arch.

Right common carotid artery

Supplies the right side of the head and neck.

Right subclavian artery

Supplies the right upper limb.

Left common carotid artery

Supplies the left side of the head and neck.

Left subclavian artery

Supplies the left upper limb.

Common carotid artery

Main artery supplying the head and neck.

Internal carotid artery

Supplies the brain.

External carotid artery

Supplies the face and scalp.

Cerebral arterial circle (Circle of Willis)

Arterial ring at the base of the brain.

Subclavian artery

Major artery supplying the upper limb.

Axillary artery

Artery within the armpit region.

Brachial artery

Major artery of the arm.

Radial artery

Lateral forearm artery on the thumb side.

Ulnar artery

Medial forearm artery on the pinky side.

Descending aorta

Portion of the aorta traveling downward through the body.

Intercostal arteries

Arteries supplying the spaces between the ribs.

Intercostal veins

Veins draining the spaces between the ribs.

Azygos system

Venous network that drains the thoracic wall.

Azygos vein

Vein on the right side of the thorax.

Hemiazygos vein

Vein on the left side of the thorax.

Accessory hemiazygos vein

Vein draining the upper left thorax.

Superior vena cava

Returns blood from the upper body to the heart.

Inferior vena cava

Returns blood from the lower body to the heart.

Cephalic vein

Superficial vein on the lateral side of the arm.

Basilic vein

Superficial vein on the medial side of the arm.

Median cubital vein

Vein connecting the cephalic and basilic veins.

Radial veins

Deep veins accompanying the radial artery.

Ulnar veins

Deep veins accompanying the ulnar artery.

Brachial veins

Deep veins of the upper arm.

Axillary vein

Vein that drains the axilla and upper limb.

Subclavian vein

Vein beneath the clavicle.

Internal jugular vein

Drains blood from the brain and deep head structures.

External jugular vein

Drains superficial regions of the head and neck.

Brachiocephalic vein

Formed by the union of the jugular and subclavian veins.

Thoracic aorta

Portion of the aorta within the thorax.

Abdominal aorta

Portion of the aorta within the abdomen.

Common iliac artery

Terminal branch of the abdominal aorta.

Internal iliac artery

Supplies pelvic organs.

External iliac artery

Supplies the lower limb.

Renal arteries

Supply the kidneys.

Lumbar arteries

Supply the posterior abdominal wall.

Testicular (ovarian) arteries

Supply the gonads.

Celiac trunk

Supplies the stomach

Superior mesenteric artery

Supplies most of the small intestine and part of the large intestine.

Inferior mesenteric artery

Supplies the distal large intestine.

Femoral artery

Major artery of the thigh.

Deep femoral artery

Supplies deep thigh muscles.

Popliteal artery

Artery behind the knee.

Adductor canal

Passageway for vessels through the thigh.

Adductor hiatus

Opening where the femoral artery becomes the popliteal artery.

Anterior tibial artery

Supplies the anterior lower leg.

Posterior tibial artery

Supplies the posterior lower leg.

Fibular artery

Supplies the lateral lower leg.

Caval system

Venous system that drains into the inferior vena cava.

Portal system

Venous system that carries blood to the liver.

Hepatic veins

Drain blood from the liver.

Renal veins

Drain blood from the kidneys.

Testicular (ovarian) veins

Drain blood from the gonads.

Common iliac veins

Formed by the union of pelvic veins.

Hepatic portal vein

Carries nutrient-rich blood to the liver.

Superior mesenteric vein

Drains much of the small intestine.

Splenic vein

Drains the spleen.

Inferior mesenteric vein

Drains part of the large intestine.

Femoral vein

Major vein of the thigh.

Popliteal vein

Vein behind the knee.

Anterior tibial veins

Drain the anterior lower leg.

Posterior tibial veins

Drain the posterior lower leg.

Fibular veins

Drain the lateral lower leg.

Internal iliac vein

Drains pelvic organs.

External iliac vein

Continuation of the femoral vein above the inguinal ligament.

Great saphenous vein

Longest superficial vein in the body.

Tunics of a blood vessel (outer to inner)

Tunica externa → Tunica media → Tunica intima.