Download Questions in Mammalian Reproduction I

Mammalian Reproduction II
Estrous cycles, Gestation, & Lactation
EEOB 625
6 February 2004
Questions in Mammalian
Reproduction II
•
Estrous cycle and menstrual cycle:
Is the difference in the name?
•
Are the physiological, morphological, or
behavioral changes different in the two types?
•
Induced vs. Spontaneous ovulation: What is
same and what is different about LH?
The Estrous Cycle and Gestation in
Mammals 1
Estrous cycle is a series of recurring physiological,
morphological, and behavioral changes in the
female, marked by estrus and ovulation.
• A matrix of glands, hormones, and time
1) Hypothalamus – GnRH, 2) Anterior pituitary - FSH
& LH, 3) Ovary – estrogen & progesterone, 4) uterus
Cascade of hormonal effects: GnRH
FSH & LH
estrogen & progesterone
uterine tissues
Hypothalamus
H-P-G Axis
Pituitary
Ovary
Uterus
Fig. 9.6, Feldhamer
The Estrous Cycle and Gestation in
Mammals: 2
•
•
Ovary: follicular phase, ovulation, luteal phase
Uterus: proliferative phase and secretory phase
•
Hormonal control of follicular development, estrus, ovulation,
and secretion of progesterone
•
Signals for estrous & ovulation: 1, 2, 3, 4, 5
Positive feedback of estradiol on LH release
LH surge
• LH surge stimulates ovulation. Meiosis I in the oocyte
is completed at this time
• The process of ovulation: rupture of the follicle wall
• Spontaneous & Induced (e.g. cats) ovulators compared
Questions in Mammalian
Reproduction II
•
Estrous cycle and menstrual cycle:
Is the difference in the name?
•
Are the physiological, morphological, or
behavioral changes different in the two types?
•
Induced vs. Spontaneous ovulation: What is
same and what is different about LH?
The Estrous Cycle and Gestation in
Mammals 3
Corpus luteum from granulosa cells of ruptured follicle
Conception: Union of pronuclei (gametes) in oviduct
Implantation of the blastocyst & development of placenta
• Four extraembryonic membranes of amniotes
- Function of each in oviparous species
- Vitelline (yolk sac) membrane and allantois in
metatherians and eutherians
The Placenta and Gestation - 4
• Ovulation, Fertilization, and Oviductal
transport of the embryo
• Hormonal (E, LH, & P) control of events
• Eutherian Implantation: Chorioallantoic
placenta and uterine epithelium (Figs 9.11, 9.12)
• Placenta
• Choriovitelline placenta of metatherians
•
Delayed fertilization & delayed implantation?
The Placenta and Gestation
• Ovulation, Fertilization, and Oviductal
transport of the embryo
• Hormonal (E, LH, & P) control of events
• Eutherian Implantation: Chorioallantoic
placenta and uterine epithelium (Figs 9.11, 9.12)
• Placenta
Austin & Short 1973
Austin & Short (1973)
Harder & Kirkpatrick (1996)
Harder et. Al 1993
Questions in Mammalian
Reproduction III
• Origin of the mammary gland: What’s a
brood patch (or sweat) got to do with it?
• Why is lactation dependent upon suckling?
• Milk is milk: How different can it be?
Mammary Gland & Lactation
• Origin & evolution: derived sweat glands?
• Nutritive secretions in other taxa: ___, ____
• Original (pre-mammary) function ?
• Origin of the mammary gland: What’s a
brood patch (or sweat) got to do with it?
• Epidermal secrections: first source of
1) moisture for the neonate?
2) source of nutrition?
3) or something else? __________________
Mammary Gland & Lactation
•
•
•
•
Origin & evolution: derived sweat glands?
Nutritive secretions in other taxa: ___, ____
Original (pre-mammary) function ?
Epidermal secrections: first source of
1) moisture for the neonate?
2) source of nutrition?
3) or something else? __________________
• Histology, internal anatomy, & hormones
Mammary Gland & Lactation
•
•
•
•
Origin & evolution: derived sweat glands?
Nutritive secretions in other taxa: ___, ____
Original function: water, nutrition, or _____
Location & Morphology: udder, teat, & nipple
• Histology & internal anatomy (handout)
• Hormones - Somatotropin, P, & E during
development
Physiology of Lactation and the
Nature of Milk
• Prolactin: a hormone of maternal care
• Synthesis of milk: Prolactin & lactiferous cells
Secondary effect on ovarian activity (anestrus)
• Delivery of milk: oxytocin & myoepithelial cell
Physiology of Lactation and the
Nature of Milk
• Prolactin: a hormone of maternal care
• Synthesis of milk: Prolactin & lactiferous cells
Secondary effect on ovarian activity (anestrus)
• Delivery of milk: oxytocin & myoepithelial cell
• Components of milk: Casein, lactose & lipids
• Taxonomic variation in fat content of milk
• Change of content during the period of lactation
Reproduction II
END