Principles of Biology

By

Frank H. Osborne, Ph. D.

Circulation and Transport

Transport in Selected OrganismsCytoplasmic streaming (cyclosis)

•Cytoplasmic streaming is a circulation of the cytoplasm inside the 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.

Cytoplasmic streaming (cyclosis)

Transport in Selected OrganismsTransport in Vascular Plants

•Xylem 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.

Transport in Vascular Plants

Transport in Selected OrganismsCirculation 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 because the blood is always contained within blood vessels.

Transport in Selected OrganismsCirculation in the earthworm (closed system)

•As the 10 pumping blood vessels contract, they push blood back toward the rear of the animal.

•The blood at the rear moves forward and is circulated by the pumping vessels.

Earthworm (closed system)

Transport in Selected OrganismsCirculation 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.

Transport in Selected Organisms

Circulation in the grasshopper (open system)

•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.

Transport in Selected Organisms

Circulation in the grasshopper (open system)

•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.

Grasshopper (open system)

Human Circulatory SystemThe Heart•The 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.

The Heart

The Heart

Human Circulatory SystemThe Heart

•Blood 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.

Human Circulatory SystemArteriosclerosis and atherosclerosis

•Arteriosclerosis is a disease of old age. It is characterized by a loss of elasticity of the 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.

Human Circulatory SystemBlood vessels

•Blood is carried away from the heart by arteries. They branch to form arterioles.

•Blood is carried toward the heart by venules. These come together to form veins.

•Between arterioles and venules are the capillaries. The capillaries are so small in diameter that blood cells pass through in single file.

Blood vessels

Human Circulatory SystemArteries•Blood 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 of the heart and carries blood to the rest of the body. The aorta is the largest blood vessel in the body. Other arteries going to the body branch from it.

Human Circulatory System

Human Circulatory System

Human Circulatory System•Blood to and from the lungs is called the PULMONARY CIRCULATION.

•Blood to and from the body is called the SYSTEMIC CIRCULATION. This includes all organs except the heart.•Blood to and from heart muscle tissue is the CORONARY CIRCULATION.

Pulmonary circulation

Systemic circulation

Coronary circulation

Major arteries

Artery Target OrganL/R Carotid BrainL/R Subclavian ArmsL/R Renal KidneysL/R Iliac LegsMesenteric IntestinesHepatic LiverCoronary Heart

Major arteries

Human Circulatory SystemVeins

•Veins 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 to the left atrium. All other veins enter the right atrium through the inferior and superior venae cavae with one exception, the hepatic portal vein.

Human Circulatory SystemVeins

•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 the blood is sent to other parts of the body.

•The blood leaves the liver and returns to the heart via the hepatic vein and the inferior vena cava.

Major veins

Major veins

To superior vena cava Origin Jugular from brain Subclavian from armsTo inferior vena cava Renal from kidneys Iliac from legs hepatic from liverOther: hepatic portal from intestines to liver

Hepatic portal circulation

Human Circulatory SystemBlood

•Blood 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.

Human Circulatory SystemPathway of the blood

•Blood 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.

Human Circulatory SystemBlood Pressure•Blood pressure is the pressure required to close off an artery. It depends upon 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 cells•Red 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.

Blood Cells

Red blood cells

Blood CellsRed blood cells•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.

Sickle-cell

Blood CellsWhite blood cells•There are five types of white blood cells, which are also called leukocytes. The prefix "leuko-" means lacking color or without color.•These are the colorless blood cells. They are not really white in color.

White blood cells

Blood Cells

White blood cells•There are two major groups of leukocytes called the granular (polymorphonuclear) leukocytes and the agranular (mononuclear) leukocytes.

White blood cells

Blood Cells

White blood cells: granular leukocytes•The granular leukocytes have tiny spots or granules visible when they are stained. They are called polymorphonuclear ("poly" means many, "morpho" refers to the shape or form) because the nuclei of these cells take on many shapes.

Blood Cells

White blood cells: granular leukocytes•The most numerous cells of this type are the neutrophils. These cells are phagocytic and move around the body looking for foreign material to phagocytize.

Blood Cells

White blood cells: agranular leukocytes•The agranular leukocytes do not have visible granules in their cytoplasm when they are stained. They are also called mononuclear because these cells each have a large, prominent nucleus.

Blood Cells

White blood cells: agranular leukocytes•The lymphocytes are the cells that produce the antibody molecules for the immune system. The monocyte is a type of leukocyte that is motile and phagocytic.

White blood cells

Granular (Polymorphonuclear) Leukocytes

Neutrophils (60-70%)

Eosinophils (1-3%)

Basophils (0.3%)

Agranular (Mononuclear) Leukocytes

Lymphocytes (20-35%)

Monocytes (3%)

How Blood Clots•Formation of blood clots is important to prevent blood from leaking out of the body due to wounds or breaks in the capillaries.

•When blood clots form, it is the result of a series of five steps. These steps involve platelets, which are formed elements in the blood. Platelets are not really blood cells per se, but they are not blood proteins either.

How Blood Clots•The other materials involved are fibrinogen, a protein that leads to formation of fibrin, the clotting protein; and a series of blood proteins called factors.

•Hemophilia is a disease characterized by a lack of Factor VIII. In people with hemophilia, the absence of Factor VIII prevents their blood from clotting normally.

The Immune System•The blood cells in the immune system are primarily the monocytes and the lymphocytes. Both types are white blood cells of the agranular category.

•Monocytes can behave like amoebas and move out of the blood stream into the connective tissue space. When they are in the connective tissue space their name changes to macrophages.

The Immune System

•The macrophages engulf and devour foreign matter such as bacteria.

•Then they process the molecules of the bacteria, thus initiating an immune response.

The Immune System

Types of lymphocytes: T-cells

•There are two types of lymphocytes involved in the immune response. The T-lymphocytes (T-cells) recognize the molecules that the macrophages are carrying and make antibodies against them.

The Immune System

Types of lymphocytes: B-cells

•The second type of lymphocyte is the B-lymphocyte (B-cell), which assists the T-cells by making high concentrations of antibodies against foreign molecules.

The Immune System•These antibodies are blood proteins that bind and react with the foreign molecules (such as bacterial surface proteins) and combat disease by the bacteria.

•Sometimes the immune system develops antibodies against your own body tissues. This results in autoimmune disease. Examples are lupus, antithyroid, and ulcerative colitis, non-Hodgkins lymphoma.

The Immune System•Human Immunodeficiency Virus (HIV) is a virus that attacks the T-cells. Viruses are different from bacteria in that they cannot reproduce independently. They must invade a host cell. In the case of HIV, the host cell is the T-cell.

The Immune System•Acquired Immunodeficiency Syndrome (AIDS) is a series of infections and other medical problems that result in people with HIV virus because their immune system does not function properly due to HIV viral activity.

The Lymphatic System•The lymphatic system is a series of ducts in the body. These ducts serve as collection conduits for tissue fluid, which is otherwise known as lymph. •Tissue fluid is a liquid found in all body spaces between the cells and surrounding body structures and organs. These locations are known as the connective tissue space.

Lymphatic System

The Lymphatic System•The lymph ducts contain lymph nodes where macrophages, T-cells and B-cells are ready to respond to any bacteria or viruses they encounter.•The tissue fluid is eventually returned to the bloodstream.

The End

Principles of Biology

Circulation and Transport