Composition and Function of the Blood Chapter 6 Composition and Function of the Blood

Outline Composition and Function of Blood Plasma Red Blood Cells White Blood Cells Types of White Blood Cells Blood Clotting Capillary Exchange Blood Typing

The Composition and Functions of Blood Blood is divided into two layers. Formed Elements. Red Blood Cells. White Blood Cells. Platelets. Plasma.

Functions of Blood Transport of oxygen, hormones, and waste. Defense against pathogens. Regulation of body temperature.

Plasma Water makes up about 92% of plasma, while the remaining 8% consists of various salts and organic molecules. Three major plasma proteins help to maintain homeostasis. Albumins. Globulins. Fibrinogen.

Red Blood Cells Red blood cells (erythrocytes) contain hemoglobin that allows oxygen transport. All blood cells are formed from stem cells. Engulfed by macrophages in the liver and spleen after about 120 days. Releases hemoglobin. Insufficient number of red blood cells or hemoglobin leads to anemia. Hemolysis is rupturing of blood cells.

White Blood Cells White Blood Cells (leukocytes) have a nucleus and lack hemoglobin. Fight infection and help maintain homeostasis. Derived from stem cells. Found in blood, tissue fluid, and lymph.

Types of White Blood Cells Granular Leukocytes. Neutrophils. Eosinophils. Basophils. Angular Leukocytes. Monocytes. Lymphocytes.

Blood Clotting Platelets (thrombocytes) result from fragmentation of megakaryocytes. Platelets clump at the site of a puncture in the skin and usually seal the break. Coagulation. At least twelve factors participate in the formulation of a blood clot.

Blood Clotting

Capillary Exchange Pumping of heart sends blood out via arteries to the capillaries where exchange takes place through capillary walls. Blood returns via veins. Arterial blood contains more oxygen and nutrients than venous blood. Venous blood contains more wastes, including carbon dioxide, than arterial blood.

Capillary Exchange

Blood Capillaries Processes at work during capillary exchange. Blood pressure. Diffusion. Osmotic pressure.

Arterial End of Capillary When arterial blood enters tissue capillaries: Bright red due to high oxygen levels. Rich in dissolved nutrients. Blood pressure is higher than osmotic pressure. Water and nutrients exit capillary.

Venous End of Capillary Blood pressure is reduced because capillaries have a greater cross-section compared to blood vessels that enter and leave capillaries. No reduction of osmotic pressure. Water tends to enter capillary.

Lymphatic Capillaries Lymphatic vessels are one-way system that carry lymph. Valves prevent backflow. Lymphatic capillaries absorb excess fluid at blood capillaries.

Lymphatic Capillaries

Blood Typing In the ABO system, the presence or absence of type A and type B antigens on red blood cells determines a person’s blood type. Within the plasma are antibodies to the antigens that are not present on the person’s red blood cells.

Blood Typing

Blood Typing Another important antigen is the Rh factor. Eighty-five percent of US population have Rh antigen on red blood cells and are Rh+. Rh- individuals normally do not have antibodies to the Rh factor, but may make them when exposed. Hemolytic disease may exist in newborns when mother is Rh- and father is Rh+.

Hemolytic Disease

Review Composition and Function of Blood Plasma Red Blood Cells White Blood Cells Types of White Blood Cells Blood Clotting Capillary Exchange Blood Typing