Animal Reproduction and Development Flashcards

Flashcards for vocabulary terms related to Animal Reproduction and Development.

Sexual Reproduction

Offspring form by the fusion of a male gamete (sperm) and female gamete (ovum) to form a zygote; results in offspring of varied genotypes.

Asexual Reproduction

Offspring are produced from a single parent; offspring are genetically identical (clones) to the parent.

Budding

Portion of the parent organism pinches off to from a complete, new individual

Regeneration

A completely new organism can be formed from a fragment of an animal's body.

Parthenogenesis

Development of a new individual from an unfertilized egg.

Gametogenesis

The production of gametes.

Acrosome

Specialized vesicle containing enzymes that help sperm penetrate an egg

Cumulus mass

Layer of cells that protect and nourish the oocyte

Theca

Outer layer of cells that produces hormones which control oocyte growth

Zona pellucida

Layer of glycoproteins which surrounds the secondary oocyte

Fertilization

Haploid egg and sperm unite to form diploid zygote

Acrosomal reaction

Proteolytic enzymes digest zona pellucida and sperm contacts the plasma membrane of egg

Cortical reaction

After sperm fuses with egg, other sperm are blocked

External Fertilization

Eggs are released by the female are fertilized by sperm in the external environment

Internal Fertilization

Sperm are deposited in or near the female reproductive tract, and fertilization occurs within the tract

Seminiferous tubules

Site of spermatogenesis

Leydig cells

Endocrine cells that secrete testosterone

Sertoli cells

Provide nutrients and protection to developing sperm

Semen

Sperm plus secretions from accessory glands

Vagina

Smooth muscle structure of the female reproductive system

Blastocyst

A ball of 32 to 150 cells that enters the uterus.

Follicle

A partially developed egg, called an oocyte, surrounded by support cells

Menopause

Oocytes become depleted and ovulation stops

Gonadotropin-releasing hormone (GnRH)

Directs the release of FSH (follicle stimulating hormone) and LH (luteinizing hormone) from the anterior pituitary

Positive feedback (HPG axis)

Increased GnRH production at puberty initiates release of LH and FSH

Negative feedback (HPG axis)

High concentrations of testosterone inhibits secretion of GnRH from the hypothalamus and LH secretion by the anterior pituitary

Follicular Phase

First half, with growth and differentiation of follicle, fairly low LH levels stimulate follicular cells to make estradiol, and estradiol levels slowly increase

Ovulation

Empty follicle becomes the corpus luteum, which secretes progesterone that stimulates uterus to sustain embryo

Luteal phase

Corpus luteum develops and secretes progesterone, inhibits FSH and LH secretion and prepares uterus to receive embryo

Proliferative phase

Endometrium becomes thicker and more vascularized

Secretory phase

Glands develop that secrete nutritive substances to sustain embryo for first 2 weeks