Circulatory System Fetal Circulatory System Capillary Tissue Fluid Exchange Antigen and Antibodies Lymphatic System

Goals this Section... Identify and describe differences in structure and circulation between fetal and adult systems Describe capillary-tissue fluid exchange Explain the roles of antigens and antibodies Describe the functions of the lymphatic system Identify and give functions of lymph capillaries, veins, and nodes

Fetal Circulatory System

Fetal Circulatory System Fetus doesn’t use the pulmonary circuit Oxygenated blood is transported to the fetus through the umbilical cord

Fetal Circulatory System Major Differences Oval Opening Arterial Duct Venous Duct Umbilical Vein Once baby is delivered the baby’s lungs expand with the 1st breath This causes the foramen ovule to close to allow the regular flow of blood through the heart

Capillary Tissue- Fluid Exchange

Capillary Fluid Exchange Oxygen moves into the blood in the alveoli in the lungs Occurs by diffusion: from the inhaled air into the alveoli and into the capillary wall and then the blood Oxygen binds to hemoglobin (iron-containing protein) in RBC’s Hemoglobin has 4 binding sites for O2 Oxyhemoglobin (HbO2 )is hemoglobin that transports O2 Oxygenated blood re-enters the heart through the left atrium where blood is shipped throughout the body to tissues

Capillary Fluid Exchange Arterioles take blood to capillary beds Here blood pressure has dropped from 100mmHg to 35mmHg Conditions in the tissues cause Hb to release O2 Blood pressure forces O2 , water and nutrients from blood plasma through capillary walls and into tissues O2 moves into cells by diffusion and nutrients move into cells by facilitated transport

Capillary Fluid Exchange Larger components stay in blood making it hypertonic to tissue fluids Water from tissues fluids is drawn back into capillaries at the venule end CO2 concentration is higher in the tissues compared to the blood (from cellular respiration) Therefore CO2 diffuses back into blood with the water

Capillary Fluid Exchange Ammonia and other metabolic wastes enter plasma too This exchange doesn’t normally change blood volume (exception in edema)

Antigens and Antibodies

Antigens and Antibodies Produced by B cells Have receptor sites to bind to foreign antigens causing agglutination (clumping) Then other WBC’s destroy these clumped cells Agglutination causes incompatibility during blood transfusions

Lymphatic System

Lymphatic System System of thin walled vessels (with valves) Start in tissue spaces Have capillaries that drain excess fluids and whatever else they can transport Transport fluid via a cleansing process run by the lymph nodes through lymph ducts back into the circulatory system Fluid is named lymph Lymph nodes contain B-cells that make antibodies to destroy foreign invaders in the lymph

Recall this Section... Identify and describe differences in structure and circulation between fetal and adult systems Describe capillary-tissue fluid exchange Explain the roles of antigens and antibodies Describe the functions of the lymphatic system Identify and give functions of lymph capillaries, veins, and nodes