Blood Vessels & Blood

Blood Vessels As the blood leaves the heart it travels through a network of vessels that all serve a very specific purpose. Characteristics: Connective Tissue Smooth Muscle 3 Types: Arteries Capillaries Veins Capillary Artery Vein

Arteries Carry blood away from the heart. Main transporters of oxygenated blood. Have very thick walls of stiff connective tissue and smooth muscle. Because of the pressure from each pump of the ventricles arteries are elastic allowing them to expand. Artery

Capillaries The smallest blood vessels Connect arteries and veins. Capillary The smallest blood vessels Connect arteries and veins. Only one cell thick – “Swiss Cheese” Site of exchange between blood and cells. Diffusion of oxygen and nutrients into the cells. Diffusion of carbon dioxide and wastes away from the cells.

Veins Carry deoxygenated blood back to the heart. High in carbon dioxide and waste products. Thin walls of connective tissue and smooth muscle. Contain one-way valves to keep blood from flowing backward. Contractions of skeletal muscles move the blood inside the veins.

Through the Loops Heart-Lung-Heart From the right atrium (11) to the right ventricle (1) blood is pumped out the pulmonary artery (2)to the lungs (3). Capillaries surrounding the lungs drop of waste products, carbon dioxide and water, and pick up oxygen. Blood returns to the heart through Pulmonary Veins to the left atrium (4) and down into the left ventricle (5).

Through the Loops Heart-Body-Heart From the left ventricle (5) blood is pumped out of the heart through the aorta, the largest and thickest artery of the body. The aorta splits moving blood to the head (7)and to the lower body (8). Oxygen is dropped off through capillaries and waste products are picked up. Blood return to the heart through veins, superior vena cava (9) and inferior vena cava (10) that contain valves that prevent the blood from flowing backward. Blood reenters the heart at the right atrium (11).

Blood Pressure Blood pressure is the force of your blood pushing against the walls of your arteries. The force is strongest when your ventricles contract and weakest when your ventricles relax. Two locations you can feel your pulse at: Your neck Your wrist

Blood Pressure Blood pressure is read as two numbers: Systolic pressure – the pressure on the artery when the ventricles contract. Diastolic pressure – Pressure on the artery when the ventricles relax. Normal blood pressure would be 120 over 80.

Systemic Blood Pressure Readings

Chart Questions: Where is the blood pressure reading the strongest? Is this person’s blood pressure normal? What’s the systolic reading? What’s the diastolic reading? Where is the blood pressure the weakest? Arteries Yes 120 80 Veins

Blood – The River of Life Connective tissue - connects all the body systems. The average person has between 4-6 L of blood. Blood is composed of 4 main components: Plasma Red Blood Cells (RBC) White Blood Cells (WBC) Platelets

1. Plasma 55% of the blood’s volume. The liquid portion of blood. 92% water. dissolved proteins and nutrients. Yellow in color.

2. Red Blood Cells – (Erythrocytes) 45% of the blood’s volume. The most numerous cells in whole blood. No nucleus - No cell division. Produced in the red bone marrow. Lifespan of 120 days. Looks like a pinched in ball that forms a disc. Thin and flexible

Hemoglobin Iron containing protein inside each red blood cell. This is what makes blood red. Binds to 4 oxygen molecules. Uses diffusion to pick up and drop off oxygen and carbon dioxide through the capillaries. Hemoglobin – Oxygen Transport

3. White Blood Cells – (Leucocytes) <1% of the whole blood. Approximately twice the size of red blood cells but fewer in number. 700:1 Produced in the red bone marrow. Fights disease and infection Lifespan of a month to years.

4. Platelets – (Thrombocytes) <1% of whole blood. Tiny cell fragments that stick to damaged tissue. “Life savers” of the blood. At the site of a cut they form a mesh that becomes a clot or scab. Number is too low = excessive bleeding Number is too high = clotting Lifespan of 10 days.

In A Drop of Blood In 1 drop of blood: 50 million RBC 100,000 WBC 2.5 million Platelets

The Lymphatic System As blood moves through the capillaries some plasma leaks out and bathes the body cells and keeps them moist - lymph. Too much fluid in the tissue = swelling. Excess fluid normally reenters the blood stream through small vessels in the lymphatic system. Prior to entering veins the lymph is filtered by lymph nodes to remove any harmful materials.