Pregnancy Flashcards
(25 cards)
What happens to primary oocytes at puberty?
- They become responsive to gonadotrophins
- Resume meiosis to form secondary oocytes
- Ovulation
What are blastomeres?
Cells with the embryo during early cleavage stages
What is the structure of a blastocyst?
- An inner cell mass
- Trophoblast
- Enclosed in the zona pellucida
What is the inner cell mass in blastocyst?
The cells that give rise to all the tissues of the foetus
What is the trophoblast in blastocyst?
The cells that play a crucial role in placenta development
What is the outer membrane of a blastocyst called?
Zona pellucida
What are the five functions of the placenta?
- Production of hormones
- Supports foetal development
- Regulates foetal nutrition and waste
- Maintains osmotic balance
- Replaces functions of foetal lungs, kidneys, liver and gut
What are the four types of placental villi distribution?
- Diffuse
- Zonary
- Discoid
- Cotyledonary
What are the three types of placental layer intimacy from least to most?
- Epitheliochorial
- Endotheliochorial
- Hemochorial
What is the difference between cotyledon and caruncle?
- Cotyledon is the foetal side
- Caruncle is the maternal side
What are the three ways nutrients move across the placenta?
- Simple diffusion
- Facilitated transport
- Active transport
What are some harmful substances that can cross the placenta?
- Alcohol
- Lead
- Viruses
- Bacteria
What three substances are blocked by the placenta?
- Maternal proteins
- Lipids
- Most maternal hormones
What initiates the parturition cascade?
- Fetal stress triggers cortisol
- Increase in oestrogen
- Decrease in progesterone
- Uterine contractions
What occurs at the first stage of parturition?
- Uterine contractions
- Cervix dilations
- Vulval swelling
What occurs at the second stage of parturition?
Foetus expelled through birth canal
What occurs at the third stage of parturition?
The placenta is expelled
What happens after birth?
- Production of colostrum
- Involution of the uterus
What are mammary alveoli and what do they do?
Structures where milk is secreted by epithelial cells into the alveolar lumen
What controls milk secretion?
Hormones - primarily prolactin
What is the milk ejection reflex 5 step sequence?
- Teat stimulation
- Signal to hypothalamus
- Oxytocin released from posterior pituitary
- Myoepithelial cell contractions
Milk ejected into ducts
What is a diffuse placenta?
A placenta where villi are uniformly distributed across the entire surface of the chorion
What is a zonary placenta?
A placenta with three distinct zones
What is a discoid placenta?
A placenta with a single round disc shaped area of chorionic tissue
