15.2 Fetal Development and Birth Flashcards
When does the fetal period of development start?
The ninth week and lasts until birth
What is the main difference between the embryonic and fetal period?
In the embryonic period organs are usually forming and in the fetal period it is usually just growth of existing structures
What are the weeks of the first trimester?
1-12 weeks
What happens during the last four weeks of the first trimester?
Growth in the length of the body accelerates and the growth of the head slows. The cartilage based skeleton begins to harden. Reproductive organs are visible
What are the weeks of the second trimesters?
13 to 24 weeks
What happens during the fourth month of fetal development?
The heartbeat of the fetus is strong Bones of the skeleton begin to form The brain grows rapidly Nervous system begins to function Legs grow and develop
What happens during the fifth month?
The fetus becomes covered with a fine soft hair and oily substance to protect the skin
What happens during the sixth month of fetal development?
The skin appears wrinkled because there is very little fat beneath it.
The skin becomes pink as blood filled capillaries extend into it
What are the weeks of the 3rd trimester?
25 to 38 weeks
What happens during the third trimester?
Fetal brain cells develop rapidly
Testes descend into the scrotum
A layer of fat develops beneath the skin
Digestive and Respiratory systems mature
Why is proper nutrition important during the third trimester?
Because proper nutrition damages the placenta which can lead to low birth weight, short stature, delayed sexual development, and learning disabilities
What is the day that a baby is ready to be born?
266 days
When is are a baby’s developing organs most highly susceptible to damage?
The first 9 weeks
What is a Teratogen?
Any agent that causes structural abnormality due to exposure during pregnancy
What can cigarette smoke do to a fetus?
Constrict fetus’s blood vessels preventing the fetus from getting enough oxygen
