Fetal Period - 15.2 Flashcards
When does the fetal period start?
The 9th week - lasts until birth
What is the difference between the embryonic and fetal period?
*Embryonic - organs are taking shape (time of morphogenesis)
- Fetal period - present organs continue to develop (time of refinement and growth of existing structures)
When are external reproductive organs distinguishable as male or female?
At the end of the 12th week
When can the heart beat of the fetus be heard under a stethoscope?
The fourth month
What happens during the fifth month?
- Fetus is covered in fine, soft hair
- Oily substance to protect still developing skin
What happens in the 6th month?
- Skin appears wrinkled - little fat underneath
- Skin becomes pink as blood filled capillaries extend to it
What trimester does fetal brain cells form rapidly - connecting to form more and more intricate networks?
Third and final trimester
When does the males testes descend into scrotum?
In the third trimester?
Which systems are the last to mature?
Respiratory and digestive system
Which trimester is nutrition very important?
The third trimester
What is a teratogen?
An agent that causes structural abnormalities due to exposure during pregnancy
How does cigarette smoking affect baby?
- Constricts fetal blood vessels - oxygen can’t get through
- Baby becomes overweight
- still births, premature births, and miscarriages (behavioural and intellect ability is also a factor)
What is the most damaging teratogen?
Alcohol
How can alcohol affect baby?
Can affect the fetus’: brain, CNS, and physical development
* Decreased weight, malformations in head and face
* Learning and memory difficulties - aggression and personality disorders
What is the term used to describe related alcohol consumption during pregnancy?
FASD - fetal alcohol spectrum disorder
What was thaladomide?
A medication prescribed to mothers in 1950s to reduce morning sickness
What was the effects of thalidomide?
The babies were born with missing and deformed limbs
What can thalidomide treat?
Leprosy and cancers of the bone marrow (myeloma)
What nutrient consumed in large amounts can lead to teratogen?
Vitamin C - after birth baby can develop scurvy (bruises easily, prone to infection)
Does radiation cause teratogenic affects?
Yes - X ray, pollutants, organic mercury compounds, PCBs
What is the birthing process?
Partuition
What are the contractions like through pregnancy?
20 - 30 seconds occuring every 15-20 mins
What are the uterine contractions on the onset of labour?
Occur every 15 to 20 minutes last 40 seconds or longer
What does oxytocin do?
It stimulates the uterine muscles to contract
What does prostaglandis do?
Stimulates the uterus to contract
What is prolactin?
Hormone that is needed for milk production
* High levels of estrogen and progesterone suppress its production in the anterior pituitary - once mother has given birth the anterior pituitary secretes prolactin
What is colostrum?
Contains anti bodies from mother - providing baby with protection from various infectious agents
What does the suckling of breasts do?
Stimulates the production of milk from the mother
- Stimulates a nerve impulse to the hypothlamaus - stimulates the posterior pituitary to release oxytocin
What does ocytocin do?
Causes contractions of the mammary lobules
* alveoli (sacs with cells that produce milk)
( Lobules - end in mammary ducts at the nipple
What are the three stages of partuition?
Dilation stage, expulsion stage, and placental stage
What happens in the dilation stage?
*Uterine contractions and oxytocin cause the cervix to open or dilate
* Amniotic sac breaks and amniotic fluid is released through the vagina
* Lasts from 2 to 20 hours
What happens in the expulsion stage?
*Forceful contractions push the baby through the cervix to the birth canal
* As the baby moves through canal, head rotates making it easier for the body to move through birth canal
* Lasts 0.5 to 2 hours
What happens in the placental stage?
- About 15 to 20 minutes after the baby is born
- umbilical cord are expelled from uterus
- expelled placenta is called afterbirth
