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

2. 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

3. Fetal Circulatory System

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

5. 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

6. Capillary Tissue- Fluid Exchange

7. 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

8. 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

9. 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

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

12. Antigens and Antibodies

13. 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

15. Lymphatic System

16. 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

18. 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