THE MAJOR BLOOD VESSELS

B. The Major Blood Vessels of the Body Cranial vein VENA CAVA

Cranial artery Brachial artery AORTA

Aorta Biggest Artery Carries O2 rich blood from left ventricle to body systems Loops over top of heart, creating the AORTIC ARCH Goes down inside of backbone = DORSAL AORTA Smaller arteries branch off to ‘feed’ the body cells

Coronary Arteries/Veins Very first branch off the aortic arch Blood vessels that “FEED” the heart muscle Why can’t the heart just get its oxygen and nutrients from the blood that passes through it? Why can’t the heart just get its oxygen and nutrients from the blood that passes through it? The muscle tissue is too dense and thick, and the blood travels though it too quickly for diffusion to occur

Carotid Arteries Branch off the aortic arch to take the blood to the head Supply blood to brain = highly specialized: CHEMORECEPTORS detect oxygen content PRESSURE RECEPTORS detect changes in blood pressure Reasonably close to the surface, pulse can be found in neck

Blood Brain Barrier Disruption The blood brain barrier is a filter mechanism that allows only selected substances into the brain. This works to our advantage when harmful substances, such as certain chemicals or bacteria, are prohibited from entering. However, it works to our disadvantage when substances we want to enter the brain, such as chemotherapy, are kept out.

Try standing on your head for a while! Jugular Veins Take blood out of head region to the anterior vena cava These veins DO NOT contain any valves! Blood flows down them because of gravity only These veins correspond to the carotid arteries and. Therefore, the Try standing on your head for a while!

5. Subclavian Arteries/Veins Arteries branch off of aorta and travel under the clavicle Branch to feed chest wall/arms (via brachial arteries) Note For Later: Lymphatic Ducts join circulatory system right before the subclavian veins meet up with the anterior vena cava These arteries branch off of the aorta and travel under the clavicle (collar bone). They branch to feed the arms (via the BRACHIAL ARTERIES) and the chest wall region.   It is interesting to note that the lymphatic ducts join the circulatory system right before the subclavian veins meet up with the anterior vena cava

6. Mesenteric Arteries Branch off from the dorsal aorta Go to the intestines Branch into capillaries of the intestinal villi Pick up the newly digested nutrients (glucose, amino acids and nucleotides) Mesentary These arteries branch off from the dorsal aorta. They go to the intestines, where they branch into the capillaries that can be seen in the villi. They pick up the newly digested nutrients and carry them to the liver.

Mesenteric Arteries

Remember the liver functions?? 7. Hepatic Portal Vein Hepatic = Liver; Portal = capillary bed on either end This vein transports blood rich in nutrients directly from the intestines to the liver Remember the liver functions?? Significant functions for the circulatory system: Hepatic = Liver; Portal = capillary bed on either end. This vein transports blood rich in nutrients directly from the intestines to the liver. You have already studied all of the functions of the liver. Significant functions for the circulatory system are: regulation of blood glucose concentration, destruction of aged RBC’s, and detoxification of blood regulation of blood [glucose] Destroys old RBC’s detoxification of blood

HEPATIC PORTAL VEIN

8. Hepatic Veins 9. Renal Arteries/Veins Carries the blood from liver to posterior vena cava 9. Renal Arteries/Veins Renal arteries branch off dorsal aorta and bring blood to kidneys Renal veins take blood from kidneys to posterior vena cava Hepatic Vein Carries the blood from the hepatic portal vein to the posterior vena cava Renal Arteries and Veins The renal arteries branch off the dorsal aorta and bring blood to the kidneys. The renal veins take blood from the kidneys to the posterior vena cava. We will discuss this in depth in Unit O (Urinary System).

10. Iliac Arteries/Veins Dorsal aorta branches into two iliac arteries in the pelvic area One iliac artery goes down each leg Femoral artery branches off iliac artery to large quadricep muscle Iliac veins return blood to posterior vena cava When the dorsal aorta gets to the pelvic area, it branches into two iliac arteries. One goes down each leg. The femoral artery is a major branch of the iliac artery that serves the large quadricep muscle of the leg. The iliac veins bring the blood back to the posterior vena cava

11. Pulmonary Arteries/Veins deO2 blood collected from the body is pumped into the pulmonary artery from the right ventricle Pulmonary artery brings deO2 blood to lungs Blood picks up O2 in the alveoli of lungs Pulmonary vein takes high O2 blood back to left atrium of heart Pulmonary Vein Pulmonary Artery The deoxygenated blood has been collected from the rest of the body moves into the right atrium and then ventricle, and is pumped into the pulmonary artery and taken to the lungs to be replenished. The pulmonary vein takes the newly oxygenated blood back to the heart and into the left atrium and then ventricle (where it is pumped into the aorta and to the rest of the body).

Fetal Circulation

A fetus does not use its lungs. The fetus receives its O2 blood from the placenta, not its lungs. To do this, there are four features in the fetus not present in the adult.

1. Foramen Ovale This is an opening between the Left and Right atria It is covered by a flap that acts as a valve It allows the blood to bypass the lungs It reroutes most of the blood from the right atrium into the left atrium.

2. Ductus Arteriosis This is a small arterial connection, like a shunt. Between the pulmonary artery and the aorta. It further allows blood to bypass the lungs.

3. Umbilical Cord The Umbilical Cord has three blood vessels traveling through it. The largest one is the umbilical vein, which transports blood with oxygen and nutrients into the fetus. The other two are the umbilical arteries, which branch off of the iliac arteries in the fetus, and take “spent” (wastes and CO2) blood back into the mother via the placenta.

4. Ductus Venosus This blood vessel connects the umbilical vein to the vena cava. The O2 blood from the umbilical vein mixes with deO2 blood in the vena cava. The ductus venosus bypasses the liver and this blood is sent directly to the heart. Blood will go to the liver eventually, but not until it has reached the hepatic portal vein. This is why the fetus is so susceptible to toxins in blood.

Changes At Birth The First Breath: the lungs are filled with air instead of fluid and higher oxygen levels in the blood and alveoli results in an increase in pulmonary blood flow. Anatomical Changes: The placenta is removed from circulation. The foramen ovale, ductus venosus, and ductus arteriosus close.

Part D. The Lymphatic System “A system of thin-walled vessels with valves that drain fluids from bodies tissue spaces”  The lymphatic system is a system of thin-walled vessels with valves (like veins) that start in the tissue spaces throughout the body.  

Functions of the Lymphatic System Take up excessive tissue fluids Transport fatty acids and glycerol (from intestines to subclavian vein) Fight infection (lymphocytes) FUNCTIONS? 1.     Take up excessive tissue fluids 2.     Transport fatty acids and glycerol (from intestines) 3.     Fight infection (lymphocytes) Trap and remove cellular debris Trap and remove cellular debris

Structures of the Lymphatic System Lymph Ducts and Capillaries Drain and collect excess fluids from tissues Take fluids to nodes to be cleaned Cleansed lymph travels through lymph ducts to the subclavian vein where they are dumped into the anterior vena cava Lymph Nodes Remove debris from lymph = ‘cleanse’ lymph Structure? 1. Lymph Vessels: The lymph capillaries drain excess fluids and plasma proteins, and transport this fluid through a CLEANSING PROCESS controlled by the Lymph Nodes. The smooth muscle around the vessels and the skeletal muscle surrounding the vessels both contract to move the lymph towards the nodes and elsewhere. The cleansed ‘lymph’ travels through lymph ducts back to the circulatory system where they meet up with the subclavian veins just as they are dumping their contents into the anterior vena cava. 2. Lacteals: blind ends found in the villi of the small intestines which absorb and transport fats. 3. Lymph Nodes: small ovoid/round structures packed with phagocytic macrophages. These macrophages produce lymphocytes which produce T and B cells. These cells produce antibodies that combine with and deactivate foreign proteins found on bacteria, cancerous cells, and incompatible blood types, etc….   4. Other lymphoid organs: Tonsils, Appendix, Spleen, and Thymus gland. All fight infection and make WBC’s. Contain Phagocytic Lymphocytes White Blood Cells make antibodies and attack invaders

Lacteals Other Lymphoid Organs absorb/transport fatty acids & glycerol in the villi of the small intestine. Other Lymphoid Organs Tonsils, Appendix, Spleen, and Thymus gland