348 THE VERTEBRATE BODY 



bloods are properly matched for type. This contact with the Rh factor, 

 however, may cause the production of antibodies against it and a 

 second transfusion from the same person could prove fatal. 



Also, the Rh factor has significance in childbirth in some instances. 

 When a negative woman marries a positive man, she may bear a posi- 

 tive child. Her first positive child will be born normally, but she may 

 develop some Rh antibodies as a result of this contact with the Rh fac- 

 tor within her body. If sufficient antibodies are formed, her second posi- 

 tive child may be born with a serious blood defect known as erythro- 

 blastosis, which is frequently fatal to the child unless vigorous steps are 

 taken to save it. This condition in the child is brought about by the 

 reaction of the antibodies of the mother's plasma with the Rh antigen in 

 the blood of the child. Such a condition can arise only in marriages 

 between negative women and positive men. Couples with such a com- 

 bination should realize the possible danger and receive sound medical 

 advice as their children are born. 



REVIEW QUESTIONS 



1. Trace food through the alimentary tract of the frog. 



2. Give three important functions of the liver. 



3. Tell how the frog gets air into its lungs. Compare this method with that 

 found in man. 



4. Why will a frog die if its skin dries out? 



5. Tell how sound is produced in the larynx. 



6. Name the types of blood corpuscles and give the function of each. 



7. Why is the three-chambered heart of the frog less efficient than the four- 

 chambered heart of man? 



8. How do the erythrocytes of man differ from those of the frog? 



9. What is lymph and what is its function? 



10. What is the importance of physical exercise in relation to lymph? 



11. Why do we call the vermiform appendix a vestigial organ? 



12. What type of food is digested in the intestine and by what enzyme ? 



13. What enzymes are secreted by the pancreas? 



14. What vessels pick up the digested fats, the sugars, the amino acids? 



15. What systems open into the cloaca in the frog? 



16. How does puncturing the chest wall help treat tuberculosis ? 



17. What is the function of the cartilage rings of the trachea? 



18. How is lymph returned to the blood vessels in the frog and in man? 



19. How do the lymph nodes purify the lymph ? 



20. Why is it important that blood be typed before transfusions are given? 



21. If some blood from a person with type AB blood is mixed with some plasma 

 from type O blood, what would happen and why? 



22. Explain how the Rh factor may cause erythroblastosis in a child. 



23. List all of the Rh combinations of couples who would never need to worry 

 about possible Rh induced erythroblastosis in their children. 



