Circulation and TransportTRANSPORT IN SELECTED ORGANISMSCONCEPTUAL LIFE SCIENCECirculation and TransportTRANSPORT IN SELECTED ORGANISMSCytoplasmic streaming (cyclosis)Cytoplasmic streaming is a circulation of the cytoplasm inside a cell. It is noticeable under the microscope in plant cells. The cells of the leaf circulate their cytoplasm pushing the chloroplasts along. It is possible to see them move.Transport in vascular plantsXylem transports water and minerals upward from the roots. Phloem carries nutrients to all living cells in the plant. Phloem can transport materials both upward and downward.Circulation in the earthworm (closed system)The earthworm has five pairs of specialized blood vessels on each side of the digestive system near the mouth. The earthworm has a closed circulatory system becausethe blood is always contained within blood vessels. As the 10 pumping blood vessels contract, they push blood back toward the rear of the animal. The blood at the rear movesforward and is circulated by the pumping vessels.Circulation in the grasshopper (open system)In the grasshopper, blood is pumped forward through a main blood vessel known as the aorta. After it is pumped forward it passes through the end of the blood vessel and into a large space inside the body cavity known as a blood sinus. The blood flows freely through the blood sinus to the rear of the animal at which point it is taken back into the blood vessel and pumped forward again. This type of circulatory system is called an open circulatory system because sometimes the blood is not found within blood vessels. Most molluscs and all arthropods have an open circulatory system.CIRCULATION IN THE HUMANThe heartThe heart is a specialized pumping organ. Heart muscle can contract on its own. Specialized pacemaker cells regulate the contractions of the heart muscles. The pacemaker cells produce electrical signals that cause the heart muscles to contract. Systole is the contraction of the heart. Diastole is the relaxation period between heart contractions.11-111-2Blood enters the heart through atria. The atria contract and pump the blood into the ventricles. Then the ventricles contract and pump the blood out of the heart. The closing of the heart valves after the contractions produces the heart sounds.Arteriosclerosis and atherosclerosisArteriosclerosis is a disease of old age. It is characterized by a loss of elasticity ofthe arteries. In older times it was known as “hardening of the arteries.”Atherosclerosis can occur at any age. It is produced as a result of the closing of the lumens of the arteries by buildup of cholesterol deposits and calcification.ArteriesBlood is carried away from the heart by arteries. The pulmonary arteries carry blood from the right ventricle of the heart to the lungs. The aorta leaves the left ventricle and carries blood to the rest of the body. The aorta is the largest artery in the body. Otherarteries going to the body branch from it.- Blood to and from the lungs is called the PULMONARY CIRCULATION.- Blood to and from the body is called the SYSTEMIC CIRCULATION.- Blood to and from heart muscle tissue is the CORONARY CIRCULATION.Table XI-1. Major arteries.Artery Target OrganLeft and Right Carotid BrainLeft and Right Subclavian ArmsLeft and Right Renal KidneysLeft and Right Iliac LegsMesenteric IntestinesHepatic LiverCoronary HeartVeinsVeins carry blood back to the heart. Veins contain valves to prevent the blood from flowing backward in them. The pulmonary veins leave the lungs and go tot he left atrium. All other veins enter the right atrium through the superior and inferior venae cavae. There is one exception. The hepatic portal vein carries blood from the intestines to the liver. This enables the liver to remove all of the nutrients from digestion before theblood is sent to other parts of the body. The blood leaves the liver and returns to the heartvia the hepatic vein and the inferior vena cava.11-3Table XI-2. Major veins.Vein OriginTo superior vena cava Jugular From brain Subclavian From armsTo inferior vena cava Iliac From legs Renal From kidneys Hepatic From liverOther: Hepatic portal vein From intestines to the liverBloodBlood is a solution of plasma and cells. Plasma is 92% liquid and 8% solids. Plasma contains water, ions, proteins, nitrogenous wastes (such as creatinine, urea and uric acid), glucose, amino acids, cholesterol, gases and hormones. Blood is slightly alkaline with a pH of 7.4.Pathway of the bloodBlood leaves the heart and travels to one or more arteries that branch into smaller arteries and finally into capillaries. Blood from the capillaries is collected in venules that transfer it to veins that return it to the heart.Blood pressureBlood pressure is the pressure required to close off an artery. It depends on whether or not the heart is contracting. Systolic pressure is the pressure required to close off an artery during systole, the contraction of the heart. Diastolic pressure is the pressure required to close off an artery during diastole, the relaxation period between heart contractions.BLOOD CELLSRed blood cellsRed blood cells contain hemoglobin. Hemoglobin carries O2 for the circulatory system. The red blood cells, which are called erythrocytes, have many types of antigens on their surfaces. The ABO system is the most widely known, followed by the Rh system. These cells have no nuclei. They last about 90 days.Sickle-cell anemia is a hereditary (genetic) condition in which there is a slight alteration in the amino acid sequence of the hemoglobin protein. This alteration causes the erythrocytes to sickle, or become flattened, when they are not carrying oxygen.11-4White blood cellsThere are five types of white blood cells, which are also called leukocytes. The prefix “leuko-“ means lacking color or without color. Thus, these are the colorless blood cells. They are really not white in color. There are two major groups called the granular (polymorphonuclear) leukocytes and the agranular (mononuclear) leukocytes. The granular leukocytes have tiny spots or granules visible when they are stained. They are called polymorphonuclear (“poly” means many, “morpho” refers to shape or form) because the nuclei of these cells take on many shapes. The most numerous cells of this type are the neutrophils. These cells are phagocytic and move around in the body looking for foreign material to