Animal reproduction
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Animal Reproduction. Modes of Reproduction. 2 modes: asexual reproduction fission budding regeneration parthenogenesis. Modes of Reproduction. sexual reproduction fertilization internal and external hermaphroditism sequential hermaphroditism. Reproductive Systems.

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Animal Reproduction

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Animal reproduction

Animal Reproduction


Modes of reproduction

Modes of Reproduction

  • 2 modes:

    • asexual reproduction

      • fission

      • budding

      • regeneration

      • parthenogenesis


Modes of reproduction1

Modes of Reproduction

  • sexual reproduction

    • fertilization

      • internal and external

  • hermaphroditism

    • sequential hermaphroditism


Reproductive systems

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


Reproductive systems1

Reproductive Systems

  • non-mammalian vertebrates possess a cloaca

  • mammals have separate openings for each system


Spermatogenesis

Spermatogenesis

  • sperm structure:

    • head

      • acrosome

    • midpiece

    • tail


Oogenesis

Oogenesis

  • production of an ovum

  • occurs in the ovaries


Regulation of male reproductive system

Regulation of Male Reproductive System


Regulation of female reproductive system

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


Menstrual cycle

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


Ovarian cycle

Ovarian Cycle

  • 1. Follicular phase

    • several follicles begin to grow

    • ends in ovulation

  • 2. Luteal phase

    • follicle cells remaining after ovulation develop into corpus luteum


Hormonal control

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


Hormonal control1

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


Hormonal control2

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


Hormonal control3

Hormonal Control

  • 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


  • Hormonal control4

    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


    Hormonal control5

    Hormonal Control

    • rapid drop in ovarian hormones after corpus luteum disintegrates causes arteries in endometrium to spasm, depriving endometrium of blood

    • menstruation results


    Menopause

    Menopause

    • cessation of ovulation and menstruation

    • ovaries lose responsiveness to FSH and LH


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