Major Blood vessels Label the following blood vessels on the diagram below: subclavian arteries and veins, jugular veins, carotid arteries, mesenteric arteries, anterior and posterior vena cava, pulmonary veins and arteries, hepatic vein, hepatic portal vein, renal arteries and veins, iliac arteries and veins, coronary arteries and veins, aorta
Route of Blood Through the Heart and Lungs -deoxygenated blood returning to the heart from the body enters the right atrium (auricle) of the heart through
2 large veins. The Posterior (inferior) vena cava (brings blood back from the body) and the Anterior (superior) vena cava (brings blood back from the head). -this blood first travels to the right ventricle through an atrioventricular valve (A-V valve) and is then sent to the lungs to be reoxygenated.
It first travels through a semilunar valve which separates the right ventricle and the pulmonary artery. The circulation of blood between the lungs and heart is called the pulmonary circuit. -oxygenated blood returning from the lungs enters the left atrium of the heart through the pulmonary vein, travels through another A-V valve into the left ventricle and leaves the heart to enter the body through another semilunar valve which separates the left ventricle and the aorta. The Chordae Tendinae prevent the valves from inverting (turning inside out) when they shut. The blood will now circulate through the body and back into the heart again through the vena cavas. This circulation of blood through the body to meet the needs of the tissues is called the systemic circuit.
Be able to label the chambers, blood vessels, septa, chordae tendinae, and valves in the 2 diagrams of the heart below W = posterior vena cava X = anterior vena cava
Y = Aorta Z = Pulmonary Artery v. Nervous System –
Sympathetic system (adrenalin) will increase heart rate, which increases amount of blood pumped and increases pressure. It also constricts the lumen (size of the diameter) of the arteries increasing blood pressure.
Parasympathetic system (acetylcholine) will decrease the heart rate and amount of blood pumped reducing the pressure. It also dilates the lumen
Sympathetic system - increases the rate and strength of the heart beat and constricts the lumen of the arteries increasing blood pressure. ii. Parasympathetic system - decreases the rate and weakens the strength of the heart beat and dilates the lumen of the arteries decreasing blood pressure 6. Structure of the Blood vessels
Arteries - are blood vessels that carry blood away from the heart. They are composed of three layers.
an outer layer of connective tissue, containing elastic fibers which give the arteries their characteristic elasticity;
a middle layer of smooth muscle which can regulate the size of the arterial lumen (opening); and
an inner layer of connective tissue lined with endothelial cells. Arterioles are smaller versions of arteries ii. Veins - are blood vessels that carry blood towards the heart. The walls of veins are thinner and the lumens larger than those of arteries. The same three layers are present but the outer layer has fewer elastic fibers and the middle layer of smooth muscle is much thinner. The walls of the veins are therefore much less rigid and easily change shape when the muscles press against them. Veins also have valves which prevent backflow and maintain the direction of blood flow to the heart. Venules are smaller versions of veins. Look a the diagram of a vein shown below. Notice the valve.
Blood flows in the direction the valve is pointing iii. Capillaries - are blood vessels that connect the arteries and veins.
1.They are thin walled, (one endothelial cell layer thick) which permits rapid diffusion of substances through the capillary membrane.
2.They are extensively branched, which increases the cross sectional area of the capillary system, which causes the blood to slow down allowing more time for the exchange process to occur.
3.They have a very small diameter which provides friction which increases the resistance of flow. This causes the blood pressure to drop in the capillaries which allows easier passage of materials between the tissues and the blood.
Blood and Lymph system 1. Major components of blood -made up of the following things: a. Plasma - Blood cells are suspended in the plasma. Plasma makes up 55% of the blood. Made up mostly of water (90%) it carries a number of important things like:
Fibrinogen - plasma proteins made in the liver involved in blood clotting ii. Gamma globulins - plasma proteins made in the liver involved in fighting infections (immunoglobulins = antibodies)
Albumin -plasma proteins that maintain the high osmotic potential of the plasma preventing loss of fluid from the bloodstream to the tissues
Angiotensinogen - Involved in re absorption of sodium and control of blood volume and blood pressure
Nutrients -(glucose, fats and amino acids)
Gases - oxygen and carbon dioxide
Miscellaneous substances - various ions, hormones, and waste materials (e.g. urea and ammonia.)
Blood cells - make up 45% of the blood and consists of the following:
Red blood cells - Red blood cells, also called erythrocytes, transport oxygen. They are biconcave, (See diagram in text), live for 120 days and are produced in the red bone marrow of adults at the rate of about 1.5 million per second. As the blood cells mature they extrude their entire cell contents. (all the cell organelles) and use the increased area to carry hemoglobin. (hemoglobin carries oxygen in red blood cells). A diagram and an electron micrograph of red blood cells
White blood cells - white blood cells defend the body against viruses, bacteria, and other foreign invaders. They do this by engulfing invaders or by producing antibodies. There are 6000 to 9000 white blood cells per cc. of blood. Notice that the white blood cells in the diagram have nuclei There are two different kinds of white cells: Neutrophils - make up 60-70% of the white cells, produced in the red bone marrow, arrive at the site of an injury, first, are very active in phagocytosis and play a role in wound healing. Lymphocytes - two kinds of lymphocytes. B cells are produced in the lymph nodes and are involve in antibody synthesis. T cells originate in the thymus and are involved in rejection of foreign tissue (organ transplants) and other immune responses.
Platelets - look like plates, are colorless, round or biconcave, are smaller than red blood cells, play important roles in blood clotting and are produced in the bone marrow. 2. Lymph system - Fluid is forced out of the capillaries by blood pressure. Some of the fluid is returned to the capillaries by osmosis the rest is collected and returned by the lymph system. This system is similar to the venous system (the vessels are thin walled and have valves) except the vessels end blindly in the tissues. Right lymphatic duct empties into the right subclavian vein and the thoracic duct empties into the left subclavian vein. Lacteals are blind ends of lymph vessels. As the lymph system circulates it passes through lymph nodes. These nodes are found in clusters in the groin, armpits, and neck.
They have 2 functions; they manufacture B cells, and remove foreign particles from the lymph. The lymph nodes also contain leukocytes to attack bacteria and foreign invaders. b. Organs of the lymph system –
Spleen - manufactures lymphocytes, takes out defective or damaged red blood cells, removes iron from the hemoglobin and recycles it to the bone marrow
Thymus - produces T cell type lymphocytes.
Capillary Fluid Exchange- Exchange of materials at the tissue capillaries a. Arteriole side of capillary bed - blood pressure higher than osmotic pressure -blood from arterioles enters capillary beds of various tissues. The blood is carrying oxygen (on the hemoglobin of Red Blood Cells) and nutrients like amino acids and glucose in the plasma. -on the arteriole side of the capillary bed the blood pressure is higher than the osmotic pressure. -the higher blood pressure pushes fluid containing oxygen, water and nutrients (amino acids and glucose) into the tissues. -as the blood flows into the capillary bed it slows down.
This provides time for the fluid containing oxygen and nutrients to be pushed out of the capillaries by blood pressure and for the nutrients and oxygen to diffuse into the tissue cells. -Large molecules like red blood cells and plasma proteins, cannot cross into the tissues. This fluid in the tissues or tissue fluid has all the components of plasma except for proteins. b. Midsection of capillary bed - diffusion of material into the cells -Materials move into the cell by diffusion eg: high concentrations in tissue fluid move to low concentrations in the cell and vice versa. For example: - Oxygen diffuses into the cell from the tissue fluid, cell respiration uses the oxygen and produces carbon dioxide and water which diffuse out of the tissues, into the tissue fluid and eventually into the capillary bed.
Amino acids diffuse into the cell and are broken down producing amino groups. These amino groups are converted into ammonia which also diffuses out of the cell, into the tissue fluid and then into a capillary bed. c. Venule side of capillary bed - blood pressure lower than osmotic pressure -blood pressure is much reduce and is lower than osmotic pressure. As a result osmotic pressure (The force that causes the flow from a high concentration to a low concentration) fluid is forced back into the capillary. -this bring additional amounts of waste materials (carbon dioxide and ammonia)
