Biology 12-3.2B Circulation--Circuits and Pathways

Overview

This lesson introduces the pulmonary and systemic circuits of the circulatory system and the main blood vessels of the body. These large blood vessels are the arteries and veins that transport blood between the heart and the major organs or areas of the body. In most cases, the artery and vein are named after their location in the body or the system or area to which they transport blood. For example, the renal artery carries blood to the renal system or kidneys and the renal vein carries blood away from the kidneys and back to the heart. The subclavian artery and vein are named for their location under the clavicle or collar bone. You will see many other similar examples.

renal arteries

blood vessel that brings blood into the kidney.

Coronary Arteries

Branch off the aorta and take oxygenated blood to the heart muscle

Hepatic portal vein

Carries blood rich in nutrients from the intestines to the liver for processing before returning to the heart

Pulmonary Vein

Carries oxygenated blood from the lungs to the left atrium of the heart

subclavian veins

Each subclavian vein is a continuation of the axillary vein and runs from the outer border of the first rib to the medial border of anterior scalene muscle. From here it joins with the internal jugular vein to form the brachiocephalic vein

iliac veins

In human anatomy, the common iliac veins are formed by the external iliac veins and internal iliac veins. The left and right common iliac veins come together in the abdomen at the level of the fifth lumbar vertebra, forming the inferior vena cava. They drain blood from the pelvis and lower limbs.

hepatic vein

In human anatomy, the hepatic veins are the veins that drain de-oxygenated blood from the liver into the inferior vena cava. There are usually three upper hepatic veins draining from the left, middle, and right parts of the liver.

Superior Vena Cava

Large vein that collects deoxygenated blood from head and arms and returns it to the right atrium of the heart

Subclavian Veins

Lie beneath the clavicles; take deoxygenated blood from the arms back to the anterior vena cava.

Subclavian Arteries

Lie beneath the clavicles; take oxygenated blood to the arms

List the structures through which a red blood cell would travel on a trip from the left ventricle of the heart to the brain and back to the left ventricle.

Pathway to the Brain and Back aorta carotid artery brain capillaries (RBC releases oxygen gas carried by hemoglobin) jugular vein anterior/superior vena cava right atrium right ventricle pulmonary artery lung capillaries (RBC picks up oxygen on hemoglobin molecules) pulmonary vein left atrium left ventricle

Coronary Vein

Return deoxygenated blood from the heart muscle to the right atrium

Renal veins

Return deoxygenated blood from the kidneys to the posterior vena cava

Iliac veins

Return deoxygenated blood from the legs to the posterior vena cava.

Hepatic vein

Returns deoxygenated blood from the liver to the posterior vena cava

systemic circuit

Systemic circulation is the part of the cardiovascular system which carries oxygenated blood away from the heart to the body, and returns deoxygenated blood back to the heart.

Jugular Veins

Take deoxygenated blood from the head back to the anterior vena cava.

hepatic artery

The common hepatic artery is a short blood vessel that supplies oxygenated blood to the liver, pylorus of the stomach, duodenum and pancreas.

renal veins

The renal veins are veins that drain the kidney. They connect the kidney to the inferior vena cava. They carry the blood filtered by the kidney.

hepatic portal vein

a vein conveying blood to the liver from the spleen, stomach, pancreas, and intestines.

coronary arteries

an artery supplying blood to the heart.

jugular veins

any of several large veins in the neck, carrying blood from the head and face.

coronary veins

any of several veins that drain blood from the heart wall and empty into the coronary sinus.

iliac arteries

either of the large arteries supplying blood to the lower trunk and hind limbs and arising by bifurcation of the aorta which in humans occurs at the level of the fourth lumbar vertebra to form one vessel for each side of the body—called also common iliac artery.

circulation

movement in a regular or circuitous course, as the movement of the blood through the heart and blood vessels.

pulmonary arteries

the artery carrying blood from the right ventricle of the heart to the lungs for oxygenation.

Inferior Vena Cava

Large vein that collects deoxygenated blood from the abdomen and lower body and returns it to the right atrium of the heart.

Aorta

Largest artery in the body; receives oxygenated blood, at pressure, directly from the left ventricle and transports it to the body

Indicate the function of the blood vessels in the following table. Include the region of body that blood is transport to or from by the vessel, and whether the blood carried in the vessel is oxygenated or deoxygenated.

Main Blood Vessel Functions aorta carries oxygenated blood from the left side of the heart to the body; part of the systemic circulation system vena cava has two parts; anterior vena cava returns blood from the upper body to the right side of the heart; posterior vena cava returns blood from the lower body to the right side of the heart carotid arteries carry oxygenated blood to both sides of the head jugular veins return deoxygenated blood from the head subclavian arteries carry oxygenated blood to the arms subclavian veins carry deoxygenated blood from the arms back to the anterior vena cava coronary arteries carry deoxygenated blood from the heart muscle back to the heart coronary veins carry deoxygenated blood from the heart muscle back to the heart pulmonary arteries carry deoxygenated blood from the right side of the heart to the lungs pulmonary veins carry oxygenated blood from the lungs to the left side of the heart hepatic artery carries oxygenated blood from the dorsal aorta to the liver hepatic vein carries deoxygenated blood from the liver to the posterior vena cava renal arteries carry oxygenated blood from the dorsal aorta to the kidneys renal veins carry deoxygenated blood from the kidneys to the posterior vena cava mesenteric arteries carry oxygenated blood from the dorsal aorta to the intestines hepatic portal vein carries nutrient-rich deoxygenated blood from the capillary beds of the intestines to the capillary beds of the liver without returning to the heart iliac arteries carry oxygenated blood to the lower body and legs iliac veins carry deoxygenated blood from the lower body to the posterior vena cava.

List the structures through which a red blood cell would travel on a trip from the left ventricle of the heart to the intestines and back to the left ventricle.

Pathway to the Intestines and Back aorta dorsal aorta mesenteric artery intestine capillaries in villi (RBC releases oxygen gas carried by hemoglobin) hepatic portal vein (blood from the intestines goes directly to the liver without returning to the heart - this allows processing of absorbed molecules) liver hepatic vein posterior/inferior vena cava right atrium right ventricle pulmonary artery lung capillaries (RBC picks up oxygen on hemoglobin molecules) pulmonary vein left atrium left ventricle

Pulmonary Artery

Receives deoxygenated blood, at pressure, from the right ventricle and takes it to the lungs.

Carotid Arteries

Take oxygenated blood to head.

Renal arteries

Take oxygenated blood to kidneys

Mesenteric Arteries

Take oxygenated blood to the intestines

Iliac arteries

Take oxygenated blood to the legs

Pulmonary and Systemic Circuits

The circulatory system is responsible for the transport of blood throughout the body. The heart acts as the pump for this system. The circulatory system takes oxygen to all of the tissues in the body and carries away wastes, such as carbon dioxide. The circulatory system has two circuits—the pulmonary circuit and systemic circuit. The pulmonary circuit involves the transport of blood to and from the lungs. Deoxygenated blood returns to the right side of the heart, where it is pumped by the right ventricle into the pulmonary artery and through the capillaries of the lungs. In the capillaries of the alveoli, oxygen enters the blood and binds to hemoglobin in red blood cells as carbon dioxide diffuses out of the blood into the lungs for removal. The oxygenated blood then travels through the pulmonary vein to the left atrium of the heart and joins the systemic circuit. The systemic circuit involves the transport of blood to and from all the tissues of the body. This circuit is much larger than the pulmonary circuit, so the walls of the left ventricle of the heart are much larger than on the right side. This thicker muscle generates the force required to pump blood throughout the systemic circuit. Here's the path it takes: oxygenated blood is pumped by the left ventricle into the aorta the aorta branches into many smaller arteries that carry blood to all areas of the body via the capillaries, oxygen is delivered to cells and carbon dioxide is removed deoxygenated blood returns from the upper body through the anterior vena cava and from the lower body through the posterior vena cava the superior vena cava and inferior vena cava enter the right atrium of the heart from there, blood enters the pulmonary circuit to become re-oxygenated.

pulmonary circuit

The pulmonary circuit is the path deoxygenated blood takes through the heart to the lungs. This lesson explains the reason for the journey and outlines the path through the pulmonary circuit.

subclavian arteries

The subclavian arteries are paired major arteries of the upper thorax (chest), below the clavicle (collar bone) in human anatomy. They receive blood from the aortic arch.

vena cava

a large vein carrying deoxygenated blood into the heart. There are two in humans, the inferior vena cava (carrying blood from the lower body) and the superior vena cava (carrying blood from the head, arms, and upper body).

List the structures that transport blood through the systemic circuit.

left ventricle, aorta, major artery, capillary bed in tissues, major vein, vena cava, right atrium

mesenteric arteries

one of two branches of the aorta that pass between the two layers of the mesentery to the intestines

List the structures that transport blood through the pulmonary circuit.

right atrium, right ventricle, pulmonary trunk, pulmonary artery, capillaries of the lungs, pulmonary vein, left atrium.

carotid arteries

the carotid arteries are major blood vessels in the neck that supply blood to the brain, neck, and face. There are two carotid arteries, one on the right and one on the left. In the neck, each carotid artery branches into two divisions: The internal carotid artery supplies blood to the brain.

aorta

the main artery of the body, supplying oxygenated blood to the circulatory system. In humans it passes over the heart from the left ventricle and runs down in front of the backbone.