Parturition and Lactation

Question 1

What are the 3 stages of parturition

Answer 1

Cervical dilation and onset uterine contraction
Expulsion of foetus
Expulsion of placenta

Question 2

What hormonal changes initiate the first stage of parturition

Answer 2

Foetal cortisol - stimulates enzymes to convert progesterone to oestrogen

Oestrogen increase oxytocin and prostaglandin production

Progesterone levels drop, removing its inhibitory effect on contraction

Question 3

What are the effects of oestrogen on the uterus before parturition

Answer 3

Increases muscles mass
Increases calcium channels and oxytocin receptors
Increases gap junctions between smooth muscle cells for coordinated contraction

Question 4

How do prostaglandin assist with cervical ripening

Answer 4

Loosen ground substance by altering collagen and glycosaminoglycan composition in the cervix

Question 5

What’s the Ferguson reflex

Answer 5

Positive feedback loop where pressure on cervix stimulates oxytocin release - increasing uterine contraction

Question 6

What’s the role of foetal cortisol

Answer 6

Triggers conversion of progesterone to oestrogen in placenta - initiate contraction and cervical ripening

Question 7

What’s the general location of mammary glands across species

Answer 7

Pig, dog cats - along mammary ridges
Primates, elephants - thoracic
Cows, goats, mares - inguinal

Question 8

What regulates milk production post-birth

Answer 8

Progesterone allows prolactin secretion from anterior pituitary

Prolactin stimulates milk production and suppress GnRH - inhibit FSH/LH

Question 9

How does suckling influence milk let-down

Answer 9

Suckling triggers neuroendocrine reflex
Stimulates oxytocin release -> contraction of myoepithelial cells -> milk ejection

Question 10

What structure of mammary gland produces milk and stores it

Answer 10

Alveoli

Question 11

What’s the lobule of mammary gland

Answer 11

150-200 alveoli with duct

Question 12

What are groups of lobules called

Answer 12

Lobes