Pregnancy, Development, & Lactation

Question 1

Capacitation: Definition and function

Answer 1

Definition:
- A series of changes spermatozoa go through in the female repro tract to increase chances of fertilization.
Function:
- Subtle changes in ion movement through the cell membranes; increases in cells metabolic rates.
- Causes digestive enzymes on the Acrosome to be exposed & will help with penetrating through the layers around the ovum.

Question 2

Describe fertilization

Answer 2

Physical penetration through the cell memb of the ovum, delivering its genetic info into the ovum’s cytoplasm. After spermatozoa penetrates, changes in cell memb block others from entering.

Question 3

Placenta structure and function

Answer 3

Function:
- Site of blood nutrients and wastes exchange.
Structure:
1. Allantois: Surrounds allantoic sac (accum.s waste).
- Outermost layer is covered with chorion.
- Chorion attaches to uterus lining and is linked to fetus via umbilical cord.
2. Amnion: Membranous layer immediately surrounding fetus.
- Forms amniotic sac.
- Fetus floats in the sac.

Question 4

Placental attachments (4)

Answer 4

1. Diffuse: Spread over whole surface of the placenta & utrine lining.
2. Cotyledonary: Many small, separate attachment sites.
3. Zonary: Belt-shaped attachment that encircles the placenta.
4. Discoid: Placenta & uterus attached at a single disk-shaped area.

Question 5

Mammary glands structure & function

Answer 5

Structure:
- Specialized skin glands
Function:
- Produce milk and colostrum
- Present in male and female animals. Males don’t secrete proper hormone cocktail to utilize.

Question 6

Mammary gland development (3)

Answer 6

• Develop in response to hormones produced at puberty.
• Prolactin & GH directly encourage development.
• Estrogen & progesterone encourage mammary alveoli & duct systems to develop.

Question 7

Colostrum’s function

Answer 7

• Contains antibodies that offspring will get through milk (passive immunity).
• Contains large amounts of proteins, lipids, amino acids, & vitamins.
• Laxative effect helps clear newborns GI tract.

Question 8

Lactation process

Answer 8

• Physical stimulation of nipple/teat & regular removal of milk from gland stimulates anterior pit. to cont production of hormones that keep lactation going.
• Without hormonal stimulation and increased pressure on the mammary gland will gradually cause lactation to cease.

Question 9

Stages of labor

Answer 9

1. First stage: uterine contractions
2. Seconds stage: delivery of newborn
3. Third stage: delivery of placenta

Question 10

First stage of labor

Answer 10

Uterine contractions
- Myometrium contracts and presses fetus down against the cervix
- Sustained contractions cause the cervix to gradually dilate.

Question 11

Second stage of labor

Answer 11

Delivery of newborn
- Results from combo of strong uterine & abdominal muscles contractions.
- Rupture pf amitotic and allantoic sacs of the placenta usually precedes the actual delivery of the newborn.

Question 12

Third stage of labor

Answer 12

Delivery of the placenta
- Placenta separates from wall of the uterus and is expelled by weaker uterine contractions.

Question 13

What is a zygote?

Answer 13

Official name for fertilized ovum.
- Will have nucleus of the sperm and ovum to give us the diploid chromosome

Question 14

Pregnancy stages (3)

Answer 14

1. First trimester: embryonic period.
   - Placenta develops
2. Second trimester: fetal period.
   - Body tissues, organs, & systems develop
3. Third trimester: fetal growth period.