Arteries, Veins, and Special Circulation Anatomy Ch. 11 Part 3 Arteries, Veins, and Special Circulation

Major Arteries Aorta: largest artery in the body, arises from the left ventricle of the heart Parts of the aorta Ascending aorta: leaves the heart Aortic arch: arches toward the left side of the body Thoracic aorta: part that continues downward through the thorax Abdominal aorta: part that continues into the abdomen

Arterial branch of the ascending aorta Right and left coronary arteries heart

Arterial branches of the aortic arch Brachiocephalic trunk Right common carotid artery (brain) Right subclavian artery (right arm) Left common carotid artery Left internal carotid (brain) Left external carotid (skin and muscles of the head and neck) Left subclavian artery Vertebral artery (brain) Axillary artery (major artery of the arm) Brachial artery (arm) Radial and ulnar arteries (forearm)

Arterial branches of the thoracic aorta Intercostal arteries (muscles of thorax walls) Bronchial arteries (lungs) Esophageal arteries (esophagus) Phrenic arteries (diaphragm)

Arterial branches of the abdominal aorta Celiac trunk Left gastric artery (stomach) Splenic artery (spleen) Common hepatic artery (liver) Superior mesenteric (most of the small intestine and first half of the large intestine) Renal arteries (kidneys) Right and left gonadal arteries (gonads)

Lumbar arteries (muscles of the abdomen and trunk walls) Inferior mesenteric artery (second half of the large intestine) Right and left common iliac arteries Internal iliac artery (pelvic organs like the bladder and rectum)

External iliac artery Femoral artery (thigh) Popliteal artery (knee) Anterior and posterior tibial arteries (leg and foot) Dorsalis pedis artery (foot) Arcuate artery (bottom of the foot)

Veins Arteries are general located in deep well protected body areas. Veins are more superficial Veins are more easily seen Most veins follow the course of major arteries The naming of most veins is identical to that of their companion arteries

Major Veins All veins converge on the vena cava which enters the right atrium of the heart Veins draining the head and arms empty into the superior vena cava Veins draining the lower body empty into the inferior vena cava

Veins and the areas they drain (superior) Radial and ulnar veins: forearm Brachial vein: arm Cephalic vein: lateral aspect of the arm Basilic vein: medial aspect of the arm Medial cubital vein: arm, site for blood removal for blood testing Subclavian vein: arm

External jugular vein: skin and muscles of the head Vertebral vein: posterior part of the head Internal jugular vein: dural sinuses of the brain Brachiocephalic veins: receive blood from the subclavian, vertebral, and internal jugular veins Azygos vein: thorax

Veins and the areas they drain (inferior) Anterior and posterior tibial veins and fibular veins: calf and foot Popliteal vein: knee Femoral vein: thigh Great saphenous veins: longest in the body, superficial leg Iliac veins: pelvis Right and left gonadal veins: gonads

Renal veins: kidneys Hepatic portal vein: digestive tract organs, carries the blood through the liver before it enters circulation Hepatic veins: liver

Special Circulations Arterial supply of the brain and the circle of Willis Internal carotid arteries run through the neck and enter the skull through the temporal bone Once inside the cranium, each divides into cerebral arteries which supply most of the cerebrum

Cerebral arterial circle (circle of Willis) Basilar artery Forms from combined vertebral arteries Serves the brain stem and cerebellum Cerebral arterial circle (circle of Willis) The anterior and posterior blood supplies of the brain are united to form a complete circle of connecting blood vessels which surrounds the base of the brain Protects the brain by providing more than one route for blood to reach the brain in case of blockage anywhere in the brain The carotid, cerebral, and basilar arteries make up the circle of Willis

Fetal Circulation Because the lungs and digestive system are not functioning in the fetus all nutrient, excretory, and gas exchange occur through the placenta The umbilical cord contains 3 blood vessels: Umbilical vein: carries blood rich in nutrients and oxygen to the fetus Umbilical arteries: carry CO2 and debris from the fetus to the placenta

As blood flows toward the heart of the fetus most of it bypasses the immature liver through the ductus venosus Because the fetal lungs are nonfunctional and collapsed, 2 shunts ensure that they are almost entirely bypassed. Foramen ovale: allows blood to pass from the right atrium directly into the left atrium. Fossa ovalis: remnant after birth Ductus arteriosus: allows blood that enters the right ventricle and pulmonary trunk to pass directly into the aorta. Ligamentum arteriosum: remnant after birth

Hepatic portal circulation The veins of this circulation drain the digestive organs, spleen, and pancreas and delivers this blood to the liver through the hepatic portal vein The liver is a key body organ involved in maintaining proper glucose, fat, and protein concentrations in blood. This circulation ensures that the liver processes these substances before they enter circulation

As blood flows through the liver some of the nutrients are stored and processed for later release to blood. The liver is drained by hepatic veins This system is unique because it is veins rather than arteries that feed circulation

Major vessels of hepatic portal circulation Inferior mesenteric: terminal large intestine Splenic: spleen, pancreas, left side of the stomach Superior mesenteric: small intestine and first part of the colon Left gastric: right side of the stomach