1. Arteries: Transport blood away from the heart. They have thick elastic walls so that the walls can expand when it needs too. The expansion of the arteries is the pulse we feel. Arteries are usually found deep and along bones in the body. This protects them from injury and temperature loss. Arteries have a very high blood pressure.
2. Arterioles: Control the blood flow to capillaries. They are smaller in diameter than arteries, they have thinner walls. They also have a pre-capillary sphincter, they contract and dilate to increases or decrease blood flow to a particular capillary bed. Arterioles are located leading towards all capillaries. Blood pressure > osmotic pressure.
3. Capillaries: Connect arteries to veins and are the site of the capillary fluid exchange. They have very thin walls and are found everywhere within a few cells of each other.
4. Venules: They drain blood from the capillaries and join to form veins. They have thinner walls then veins. The are located often near the surface. Osmotic pressure > Blood pressure.
5. Veins : Transport blood towards the heart. Veins have inelastic walls that contains valves that prevent blood from flowing backwards.They are often near the surface and are surrounded by skeletal muscle. 'squeeze' the blood along. Blood pressure and velocity is much lower than in arteries.
Some major arteries and veins are:
1. Subclavian arteries bring blood to the chest wall and arms. Subclavian veins bring blood away from the chest wall and arms to the superior vena cava of the heart.
2.Carotid arteries bring blood to the brain. Jugular veins carry blood away from the brain to the superior vena cava of the heart.
3. Mesenteric arteries bring blood to the digestive system. Then the hepatic portal vein carries the blood from the digestive system to the liver. The Hepatic vein takes the blood from the liver to the inferior vena cava of the heart. The Hepatic arteries tale blood from the heart to the liver.
4. Renal arteries take O2 blood to the kidneys and the renal veins takes the deO2 blood from the kidneys to the inferior vena cava of the heart.
5. Iliac arteries take O2 blood from the heart to the trunk and legs and the iliac veins takes the deO2 blood from the trunk and legs to the inferior vena cava of the heart.
6. The coronary Arteries brings O2 blood to the heart and the coronary vein takes deO2 blood from the heart to the inferior vena cava.
7. The Pulmonary arteries take deO2 blood away from the heart to the lungs to get replenished with O2. The Pulmonary veins take O2 rich blood from the lungs into the heart where that blood will be sent out to the rest of the body systems.
The aorta take O2 blood to the arteries for the top part of the body the dorsal aorta takes O2 blood to the arteries involving the lower part of the body.
Systemic circulation is the system of blood vessels that delivers O2 blood to the body systems. Pulmonary circulation is the system of blood vessels that delivers deO2 blood to the lungs to be replenished with oxygen.
How to do a blood trace: To do a blood trace you follow the way the blood goes through the body and name all the parts it goes though. For example:
Something that can help you do this if you don't have the circulatory system memorized is this: 
However, it is better that one memorizes the system.
However, it is better that one memorizes the system.
Fetal Circulation
A fetus does not use its lungs, it receives O2 blood from the placenta. There are four features that fetus' have that adults do not and they are:
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 by pass the lungs and reroutes most of the blood from the right atrium into the left atrium.
Ductus Arteriosus (Arterial Duct): This is a small arterial connection, like a shunt, between the pulmonary artery and the aorta. It further allows blood to bypass the lungs.
Umbilical Cord: Has three blood vessels traveling through it. The largest one is the umbilical vein, which transports blood with oxygen and nutrients to the fetus. The other two are the umbilical arteries, which branch off of the iliac arteries in the fetus and take used (CO2 and wastes) blood back into the mother via the placenta.
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 duct venosus bypasses the liver and this blood is sent directly to the heart, blood will eventually go to the liver but not until it reached the hepatic portal vein. This is why the fetus is so susceptible to toxins in the blood.
Lymphatic System
The lymphatic system has four main jobs and they are to take up excessive tissue fluids, transport fatty acids and glycerol, fight infections and to trap and remove cellular debris. This system consists of Lymph ducts and capillaries that drain and collect excess fluids from tissue and takes the fluid to nodes to be cleaned. The cleansed lymph then travels through lymph duct to the Subclavian vein where they are dumped into the inferior vena cava. Lymph nodes remove debris from lymph. It contains phagocytic lymphocytes. WBC make antibodies and attack invaders. Lactaels absorb and transport fatty acids and glycerol in the villi of the small intestine. Other organs in the lymphatic system are tonsils, appendix, spleen and thymus gland.
Blood
Blood is made up of three things: 55% of Plasma, less than 1% of White blood cells(Leukocytes) and platelets(Thrombocyte), and 45% or red blood cells (Erythrocytes). The Plasma potion of the blood is 91% water which maintains blood volume and transports molecules. 7% is proteins which are clotting proteins, albumin and immunoglobulin (antibodies). 2% is miscellaneous things that must be carried around the body, for example, salts, gases, nutrients, wastes, hormones , vitamins and hormones.
Red Blood cells (Erythrocytes): They have not nuclei and transports CO2, O2 and H+ ( acts as a buffer). They look like doughnuts without the hole all the way through it and are dark purple to bright red. Typically, they live for about four months. Erythrocytes contain hemoglobin molecules, carbonic anhydrase and antigens. They are made in the red bone marrow.
White Blood Cells (Leukocytes): They make histamines, antibodies and hunter killer cells. Their purpose is to fight infections. They can squeeze out of blood vessels to attack invaders. To distinguish a leukocyte it has a strangely shaped nuclei. They are also made in the red bone marrow.
Platelets (Thrombocytes): These are just fragments of cells with no nuclei. They are mad in bone marrow and we make about 200 billion a day. Thrombocytes are used to aid in blood clotting and can recognize micro tears in blood vessels and bind together to form a blood clot.
Antigens, Antibodies and Blood Type
An antigen is and identification protein on a RBC. It is a glycoprotein on the RBC membrane. There are two types of antigens on human RBC: A and/or B. A person can have one of the four different types of blood: Antigen A--> type A blood, Antigen B---> type Blood, Antigen A and B ----> type AB blood or No Antigen ---> type O blood.
An antibody is a protein designed to combat any foreign protein. They are made by WBC and will bind to foreign protein with foreign antigens, this will cause agglutination (clumping). WBC's will then destroy the agglutinated cells. Our blood has antibodies that are opposite the antigens we have on our RBC's, so we do not attack our own blood.
Capillary Fluid Exchange
Net blood pressure forces water out of the blood into the interstitial fluid. The water carries O2 and nutrients with is out. Because there is more O2 and nutrients in interstitial fluid, it diffuses into body cells. The large things for example RBC, WBC, platelets and blood proteins stay in the capillary because they are too big to leave. Since most of the water has left, the blood becomes very concentrated. The venule side of the capillary is therefore under great osmotic pressure to draw back water into the blood. The water carries CO2 and metabolic wastes(urea), these are carried to the kidneys and other excretory organs to be removed.
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