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Animal Reproduction.

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Presentation on theme: "Animal Reproduction."— Presentation transcript:

1 Animal Reproduction

2 Modes of Reproduction 2 modes: asexual reproduction fission budding
regeneration parthenogenesis



5 Modes of Reproduction sexual reproduction hermaphroditism
fertilization internal and external hermaphroditism sequential hermaphroditism

6 Reproductive Systems simplest animals do not have gonads (produce gametes) polychaetes’ gametes develop from undifferentiated cells lining the coelom more complex animals have gonads and a system of ducts and glands

7 Reproductive Systems non-mammalian vertebrates possess a cloaca
mammals have separate openings for each system

8 Spermatogenesis sperm structure: head acrosome midpiece tail


10 Oogenesis production of an ovum occurs in the ovaries


12 Regulation of Male Reproductive System

13 Regulation of Female Reproductive System
pattern of hormone secretion is cyclic menstrual cycle endometrium is shed if no implantation occurs (menstruation) estrous cycle endometrium is reabsorbed

14 Menstrual Cycle average length is 28 days refers to changes in uterus
1. Menstrual flow phase menstrual bleeding 2. Proliferative phase endometrium regenerates Secretory phase (about 2 weeks long) glands in endometrium secrete glycogen

15 Ovarian Cycle 1. Follicular phase 2. Luteal phase
several follicles begin to grow ends in ovulation 2. Luteal phase follicle cells remaining after ovulation develop into corpus luteum


17 Hormonal Control Follicular phase
FSH and LH secreted in response to GnRH follicle cells have only FSH receptors follicle cells secrete estrogens slow rise in estrogen levels, keeping FSH and LH levels steady

18 Hormonal Control positive feedback- sharp increase in estrogens cause sharp increase in FSH and LH (increases GnRH release) LH receptors develop on follicle cells high LH causes final follicle maturation ovulation occurs about 1 day after LH surge

19 Hormonal Control Luteal phase
LH stimulates follicle cells to form corpus luteum corpus luteum releases progesterone and estrogens negative feedback- production of progesterone and estrogen inhibits release of LH and FSH

20 Hormonal Control ovarian cycle and menstrual cycle are sychronized
corpus luteum disintegrates in 8-10 days, releasing negative feedback FSH production resumes and the cycle continues over again ovarian cycle and menstrual cycle are sychronized

21 Hormonal Control follicular phase and proliferative phase are linked
estrogens cause endometrium to thicken uterus is prepared for implantation before ovulation luteal phase and secretory phase are linked estrogens and progesterone maintain endometrial lining

22 Hormonal Control rapid drop in ovarian hormones after corpus luteum disintegrates causes arteries in endometrium to spasm, depriving endometrium of blood menstruation results




26 Menopause cessation of ovulation and menstruation
ovaries lose responsiveness to FSH and LH










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