Flashcards in Human Reproduction Deck (77):
Creation of an offspring by fusion of a male
gamete (sperm) and female gamete (egg) to form a zygote
is creation of an offspring without the fusion of egg and sperm
How many parents needed in Asexual?
How many parents needed in Sexual?
Two; Mom and Dad
Asexual; How many gametes required?
Sexual; Are gametes required?
Asexual; Are they genetically identical?
Sexual; Are they genetically identical?
Simple form of asexual reproduction found only among invertebrates.
Asexual; Where do they rise from?
From outgrowths of existing ones
Asexual; Binary Fission
Many invertebrates reproduce asexually by fission,
separation of a parent into two or more individuals of about the same size.
It is where each individual has male and female reproductive systems. They can mate, and some can self-fertilize
Example of Hermaphroditism?
Snails and Worms
Variation in Patterns of Sexual Reproduction 2
Individuals in some species undergo sex reversals changing sex ratios
Examples of Male to Female reversal
Examples of Females to Male reversal
Coral Reef Fish
What is Fertilization?
Union of egg and sperm, plays important role in sexual reproduction
What is External Fertilization?
Effs shed by the female are fertilized by sperm in the external environment
Why is a most habitat important?
Always required for external fertilization to allow sperm to swim to the egg and to prevent the gametes from drying out
Internal Fertilization; where are sperm deposited?
In or near the female reproductive tract
What is internal fertilization associated with?
Production of fewer gametes but the survival of a higher fraction of zygotes
Where are the testes in the male mammals held?
In the scrotum, where the temperature is lower than in the abdominal cavity
What are Testes?
Consist of highly coiled tubes surrounded by connective tissue
Where do sperm form in the testes?
Form in the seminiferous tubules
What are Leydig cells?
Produce hormones and are scattered between the tubules
From the seminiferous tubulues of the testis, sperm passes where?
Passes into the coiled duct of the epidiymis?
During ejaculation, where does sperm go?
Propelled through the muscular vas deferens and the ejaculatory duct, and then exit the penis through the urethra
What is semen composed of?
Composed of sperm plus secretions from three sets of accessory glands
What contributes to 60% of the total volume of semen?
Two seminal Vesicles
What does the Prostate Gland do?
Secretes it products directly into the uretra through several small ducts
What do Bulbourethral Glands do?
Secrete a clear mucus before ejaculation that neutralizes acidic acid urine remaining in the uretha
Penis is composed of how many cylinders of spongy erectile tissue?
The glans is surrounded by a fold of skin called?
Female external reproductive structure includes ?
Clitoris and two sets of labia
What internal organs are in a female reproductive system?
Are a pair of gonads and a system of ducts and chambers that carry gametes and house the embryo and fetus
Where do Ovaries lie in the female?
In the abdominal Cavity
What does each female ovary contain?
Many follicles, which consist of a partially developed eff called an oocyte surrounded by support cells
Where from the egg cell travel from the ovary to the uterus?
Travels via an oviduct, or fallopian tube
Cilia in the oviduct convey the egg to the ___
uterus, also called the womb
What is the uterus lining called?
The vagina opens to the outside at the ____
What does the Vulva consist of?
Labia Majora, Labia Minora, Hymen, and Clitoris
What is the head of the clitoris called?
Glands, covered by the prepuce (a small hood of skin)
What are mammary glands?
Are not part of the reproducitve system but ar important to mammalian reproduction
What is Gametogenesis?
Production of gametes (sperm and eggs)
What is Spermatogenesis?
Formation of sperm, is continuous and prolific.
How many sperm produced per day?
Hundreds of millions
How long does it take for sperm to develop?
What is Oogenesis?
Development of a mature egg, a prolonged process
What hormones coordinate human reproduction?
Hypothalamus, Anterior Pituitary and Gonad
GnRH is secreted and directs the release of what?
Secreted by the hypothalamus and directs release of FSH and LH from anterior pituitary
What do FSH and LH do?
Regulate processes in the gonads and the production of sex hormones
What is the main sex hormone?
What is the main androgen?
What does Estrogen consist of?
Mainly estradiol and Progesterone
What does FSH do in Males?
Promotes activity of Sertoli cells which nourish development sperm
What does LH do in males?
Regulates Leydig cells, secrete testosterone and other androgens which in turn promote spermatogensis
Testosterone regulates production of__
GnRH, FSH, LH through negative feedback
Sertoli cells secrete the hormone ___
Inhibin, which reduces FSH secretion from the anterior pituitary
In females, secretion of hormones and reproductive events they regulate are ___
Prior to ovulation, what happens?
Endometrium thickens with blood vessels in preparation for embryo implantation
What happens if the embryo does not implant in the endometrium?
ENdometrium is shed in a process called menstruation
Hormones link what two cycles of female reproduction?
Urerine and Ovarian
Uterine Cycle does what?
Changes in teh uterus define the menstrual cycle
What happens in the Ovarian cycle?
Changes in the Ovaries
In the Ovarian Cycle, what is released?
GnRH and then FSH and LH stimulate follicle growth
Ovarian Cycle Step 1
Follicle growth and an increase in the hormone estradiol characterize the follicular phase
Ovarian Cycle Step 2
The follicular phase ends at olulation and the secondary oocyte is released
What happens in the Luteal Phase?
Following Ovulation, the follicular tissue left behind is stimulated to transform into a corpus luteum
What does the Corpus Luteum secrete?
Progesterone and Estradiol, which exert negative feedack on the hypothalamus and pituitary
What coordinates the uterine cycle with the ovarian cycle?
What happens during the proliferative phase?
Thickening of the endometrium during the proliferative phase coordinates with the follicular phase
What happens during the secretory phase?
Secretion of nutrients during the secretory phase coordinates with the luteal phase
What happens during the menstrual flow phase?
Shedding of the endometrium during the mentrual flow phase coordinates with the growth of new ovarian follicles
When does a new cycle begin?
If no embryo implants in the endometrium
What is Endometriosis?
When swelling of these cells in response to hormone stimulation