+ Importance of Blood

+ Functions Transports oxygen and nutrients to cells. Carries away metabolic wastes and secretions (including hormones). Stabilizes internal pH. Serves as a highway for white blood cells. Helps stabilize body temperature in mammals.

+ What is blood made of? Plasma- a straw colored liquid that serves as a transport medium for blood cells and platelets. Red Blood Cells- aka Erythrocytes- concave disks that transport oxygen to cells and carry away carbon dioxide. White Blood Cells- aka Leukocytes-made in the bone marrow they engulf dead cells and anything foreign to the body (bacteria). Platelets-cell fragments that initiate blood clotting.

+ Plasma 92 % Water 8% proteins,ions,nutrients… Accounts for 50-60% of blood volume. Transports lipids and vitamins through the body. Gives blood the “liquid” texture. Acts as a solvent- sugars, lipids, amino acids, vitamins, oxygen, carbon dioxide and nitrogen are all dissolved into plasma.

+ Red Blood Cells Transport Oxygen to cells. Carries carbon dioxide away from cells Do not have a nucleus. Live for about 120 days. Phagocytes remove old blood cells.

Why are Red Blood Cells red? Red blood cells are made up of a protein pigment called hemoglobin. Hemoglobin contains iron which binds to oxygen. Hemoglobin helps RBCs to carry oxygen. Acts on the same principle of rust.

+ White Blood Cells Made in the bone marrow and usually clump together in lymph nodes and the spleen. They continue to divide until needed while in the lymph nodes. There are 5 types of WBC- neutrophils, eosinophils, basophils, monocytes, and lymphocytes Neutrophils and monocytes act as phagocytes to destroy foreign invaders. Lymphocytes are more specialized.

+ Platelets Cell fragments wrapped in plasma membrane. Lasts 5-9 days Hundreds of thousands are constantly in the blood stream. Release substances that cause clotting- a necessary part of the blood.

+ Review What gives blood its liquid texture? _______________________ What kind of cell transports oxygen? ______________________ What is the protein called that gives blood its red color? ____________________ Where are white blood cells made? ____________________________ When you cut yourself, what helps the blood clot?____________________________