Reproduction Flashcards
What does life cycle begin with?
- Life cycle begins with a single cell
- Growth and differentiation
Whats established during embryonic development?
Reproductive traits
What is asexual reproduction ideal environment?
Constant, stable environment
What are clones?
Buds from somatic tissue
Whats parthenogenesis?
- No male gamete required
- Ova and female reproductive system only
What are 5 elements of sexual reproduction?
- Sex determination
- Gametogenesis
- Mating
- Fertilization
- Development
What is sex determination? In mammals? Birds? Honeybees?
-Determination of sex by genotype.
-Mammals
XX= female; XY= male
-Birds and butterflies
ZW= female; ZZ= male
-Honeybee
Asexual or sexual
Sexual always produces female (diploid= 2 sex chromosomes)
Asexual always produces male through parthenogenesis (haploid= 1 sex chromosome)
Whats hermaphroditism?
Capacity to produce both eggs and sperm
What are simultaneous hermaphrodites? Serial hermaphrodites?
- Simultaneous hermaphrodites
- Has both functional male and female sexual organs at the same time. Self-fertilization often occurs.
- Serial hermaphrodites
- Change sex in response to environmental cues
- Protygynous- Female organs develop
- Protandrous- Male organs develop
What is TSD?
- Temperature-dependent sex determination
- Environmental temperature during a critical period of embryonic development that determines whether an egg develops as male or female
Whats gametogenesis?
Process in which cells undergo meiosis to form gametes
What’s oogenesis? When does it start in a females life?
- Production of an ovum.
- Starts when fetus is 8-20 weeks old
What is an ovary composed of?
-Ova-producing oogonia and surrounding somatic cells
Whats follicluogenesis? When does it occur?
- Some follicles stimulated to mature
- Prior to ovulation
How do vertebrate ooctyes grow?
Grow by accepting material from somatic follicle cells
What are 3 modes distinguished by fate of ova prior to and after fertilization? Define each.
*Ovipary
Producing young by means of eggs that are hatched after they have been laid by the parent.
*Vivipary
Development of the embryo. Producing living young from within the body.
*Ovovivipary
Producing young by means of eggs that are hatched within the body of the parent,
How does the angler fish reproduce?
Parasitic mating
The male fuses himself onto the flesh of the much larger female anglerfish.
All that’s left of the male is his reproductive organs, which the female Angler will use to fertilize her eggs
Whats spermatogenesis? When? Where?
- Production of sperm
- Continuous
- In the seminiferous tubules of the male testes
3 Seminiferous tubule cell types?
- Leydig cells- adjacent to the seminiferous tubules in the testicle. They produce testosterone in the presence of luteinizing hormone (LH).
- Spermatogenic cells- Cells that give rise to sperm
- Sertoli cells- Absorbing extra cytoplasm from newly created spermatozoa- helps in spermatogenesis by keeping cells healthy and nourished/
Whats the male sex hormone for sexual maturation? Location? Function?
Androgens
Testes
Promote hair growth, voice deepening and libido
What are 5 male sex hormones for spermatogenesis? Location? Function?
- GnRH- Hypothalamus
- Stimulates LH release, FSH synthesis and release - LH- Anterier pituitary
- Androgen synthesis and release - FSH- Anterior pituitary
- stimulates spermatogenesis - Androgens- Testes (Leydig cells)
- stimulates spermatogensis - Prostaglandins- Seminal vesicles
- Induce changes within uterus that affect sperm motility
What happens in sperm release? Where is the sperm stored?
- Spermatids become sperm
- Nearly mature spermatozoa (cannot swim) released into the lumen of the tubule
- Sperm stored in the epididymis where they mature further – gain capacity to swim
What happens during ejaculation? What is the sperm propelled down? How?
-During ejaculation, sperm propelled by cilia or smooth muscle contractions along the vas deferens which connect to the urethra
What glands is seminal fluid added to the sperm by during ejaculation?
Seminal vesicles- 60% of fluids; made of fructose
Prostate- produce seminal fluid
Bulbourethral gland-
What is the full male reproductive tract?
Produced in seminiferous tubules in testes. Stored in the epidiymis. The sperm then move to the vas deferens, or sperm duct. The seminal vesicles and prostate gland produce a whitish fluid called seminal fluid, which mixes with sperm to form semen when a male is sexually stimulated.
Whats an intromittant (compulatory) organ? 2 types?
-Increases the efficiency of sperm transfer.
1. Hemipene
One of a pair of intromittent organs of male squamates (snakes, lizards and worm lizards). Hemipenes are usually held inverted within the body, and are everted for reproduction via erectile tissue, much like that in the human penis
2. True penis
-Changes in blood distribution change penis shape (erection)
-Many mammals also have a bone in the penis (os penis or baculum)
What is the echidna penis like?
- Males have a 4-headed penis
- 2 used per copulation event (female has 2 branches in reproductive tract)
Whats a duck penis like?
Corkscrew-shapes penis
How do females store sperm?
Can be retained in the female reproductive tract until ovum is released.
Whats the estrous reproductive cycles of mammals?
- Estrus- a recurring period of sexual receptivity and fertility in many female mammals; heat
- Metestrus- occurring after ovulation and characterized by development of the corpus luteum, increased progesterone secretion, and decreased estrogen secretion
- Diestrus- period of sexual inactivity between recurrent periods of estrus
- Proestrus- preparatory period immediately preceding estrus and characterized by growth of graafian follicles, increased estrogenic activity, and alteration of uterine and vaginal mucosa.
Whats the ovarian cycle of mammals?
- Follicular- Estradiol hormone secreted from follicle causing LH and FSH stimulate follicle growth. Estradiol peak causes LH surge which triggers ovulation. Days 0-14
- Ovulation- From the LH peak the follicle releases the ovum into the fallopian tube. Estradiol hormone decreases. Day 15
- Luteal- Forms corpus luteum which secretes progesterone and estradiol which promotes thickening of endometrium. Days 15-28
Whats the menstrual cycle of mammals?
- Menstrual flow phase- Shedding of endometrium
- Proliferation phase- follicles in ovaries mature for ovulation
- Secretory phase- Endometrium thickens from increased progesterone and estradiol
What are 2 female sex hormones?
- Estrogen; Ovary; promote fat deposition of ovaries
2. Androgens; ovary; hair growth and libido
What are 4 female follicular hormones?
- GnRH; Hypothalamus; Control LH release and FSH synthesis
- LH- Anterior pituitary; triggers ovulation
- FSH- Anterior pituitary; stimulates estrogen synthesis and follicle maturation
- Estrogens- Ovarian follicle; proliferation of cells
What are 3 female luteal hormones?
- Estrogens- Corpus luteum; inhibit GnRH release, reduce FSH and LH release
- Progesterone- Corpus luteum; Promote maturation of endometrium, reduce uterine smooth muscle contractility
- Inhibin- Corpus luteum; impairs FSH synthesis and release
Whats gestation in Altricial vs precocial species?
Altricial species- shorter gestation; give birth to relatively helpless, undeveloped offspring that need extended rearing
Precocial species- longer gestation; give birth to more developed offspring that are mobile and independent and require minimal rearing
Whats parturition (birth) induced by in mammals?
- Induced by contraction of smooth muscle (myometrium) of uterus
- Begins in response to series of hormonal changes
Whats prolactin?
a hormone released from the anterior pituitary gland that stimulates milk production after childbirth
2 cells in mammary gland?
Exocrine- produce and secrete substances onto an epithelial surface by way of a duct
Myoepithelial- These may be positive for alpha smooth muscle actin and can contract and expel the secretions of exocrine glands
What are components of milk?
Source of water, salts, nutrients for infant
Whats colostrum?
First milk produced
What are 3 pregnancy hormones?
- Chorionic gonadotopin- Placenta; release of estrogen from corpus luteum
- Estrogens- Placenta; stimulte proliferation of secretory cells but prevent milk secretion
- Progesterone- Placenta; Blocks estrogens stimulation of smooth muscle and prevents ovulation
3 parturition hormones?
- Oxytocin- Posterior pituitary; promotes smooth muscle contraction
- Prostaglandins- Placenta; promote smooth muscle contraction
- Prolactin- Anterior pituitary; promotes growth and colostrum synthesis.
2 post partum hormones?
- Oxytocin- Posterior pituitary; promote smooth muscle contraction
- Prolactin- Anterior pituitary; stimulates growth and milk synthesis
What do each of these hormones do in the female body? Estrogens Androgens GnRH LH FSH Progesterone Chorionic gonadotropin oxytocin prostalandins prolactin
Estrogens
-Sexual Maturation
“secondary sex characteristics
Fat, ovary, mammary glands”
-Follicular phase
Follicle maturation, edometrium thickening
-Luteal phase
Inhibit GnRH
-Pregnancy
“-milk secretion
- Stimulate uterine smooth muscle”
Androgens
Sexual Maturation- Secondary sex characteristics– hair growth, libido
GnRH
Follicular phase-Control LH, FSH synthesis and release
LH
Follicular phase- Ovarian follicle – triggers ovulation
- *FSH**
- Follicular phase- Stimulates estrogen synthesis and follicle maturation
- *Progesterone**
- Luteal phase- Maturation of endometrium
- Pregnancy- Blocks estrogen stimulation of smooth muscle
- *Chorionic gonadotropin**
- Pregnancy- Release of estrogen from corpus luteum
- *oxytocin**
- Parturition-Smooth muscle contraction- uterus
- Post-partum- Smooth muscle contraction - mammary
- *prostalandins**
- Parturition- Smooth muscle contraction
- *prolactin**
- Parturition- Milk synthesis
- Post-partum- Milk synthesis
