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
What can alcohol do to a developing fetus?
Affect the brain, central nervous system, and physical development
What do babies who have FAS look like physically?
Low weight, height, head size, as well as malformations on the face and head
What are the mental disabilities the children with fetal alcohol syndrome have?
Learning and memory disabilities and unusual aggression or personality disorders
What is Fetal Alcohol Spectrum Disorder?
The term used to describe all the disorders related to alcohol consumption during pregnancy
What are some medications that have Teratogenic effects?
Some antibiotics
Acne medications
Antithyroid drugs
Thalidomide
What is Thalidomide used for?
Skin conditions associated with leprosy and bone marrow cancer
How can vitamin C affect a fetus?
Before birth a fetus becomes accustomed to large amounts of vitamin C. After birth the supply drops and the baby develops symptoms of a vitamin C deficiency
What is parturition?
The birthing process
What is the onset of labor marked by?
Contractions for 15 to 20 minutes that last for 40 seconds or longer
What are uterine contractions induced by?
A stretching of the cervix which brings about the release of oxytocin from the posterior pituitary gland
How does oxytocin affect the body?
It stimulates the uterine muscles directly and through prostaglandins
What do uterine contractions do?
Push the fetus downward and stretches the cervix
What is lactation?
The secretion and formation of breastmilk from the mother
What hormone is needed for milk production?
Prolactin
What suppresses the production of Prolactin during pregnancy?
High levels of estrogen and progesterone
What is colostrum?
A thin yellowish fluid that is similar to milk but contain more protein and less fat
What does colostrum and milk contain?
Anti-bodies from the mother that provide the baby with with protection from various infections
How does suckling stimulate the release of milk from the breast?
Nerve endings of the areola are stimulated. Which sen nerve impulses to the hypothalamus which in turn stimulate the posterior pituitary to release oxytocin. The oxytocin causes contractions within the mammary lobules
