- Slides: 20
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. Capillary – Characteristics: • Connective Tissue • Smooth Muscle • 3 Types: 1. Arteries 2. Capillaries 3. Veins 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. • 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. Capillary
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? Arteries • Is this person’s blood pressure normal? Yes – What’s the systolic reading? 120 – What’s the diastolic reading? 80 • Where is the blood pressure the weakest? 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: 1. 2. 3. 4. 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.