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111 Cards in this Set
- Front
- Back
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formation of new individuals whose genes all come from one parent
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asexual reproduction
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methods of asexual reproduction
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fusion
budding fragmentation |
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asexual reproduction in which a parent separates into two or more approximately equal-sized individual.
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fusion
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asexual reproduction in which new individuals split off from existing ones
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budding
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the breaking of the body into several pieces, some or all of which develop into complete adults.
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fragmentation
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b) Advantages of sexual reproduction
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• Can reproduce without needing to find a mate
• Can of numerous offspring in a short period of time • In a stable environments, allows for the perpetuation of successful genotypes |
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formation of offspring by the fusion of haploid gametes
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sexual reproduction
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female gamete-usually large and nonmotile
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egg/ ovum
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male gamete-usually small and motile
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sperm
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Sexual Reproduction
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Sexual reproduction increases genetic variation
among offspring |
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the process by which an unfertilized egg develops into an (often) haploid adult
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parthogensis
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ex of parthogenesis
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honeybees, wasp, ant, rotifers
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one individual is functional as both a male and a female
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hermaphrodite
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External fertilization requires
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requires a moist habitat that will protect a developing egg from desiccation and heat stress
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chemical signals released by one organism that
influence the behavior of other individuals of the same species |
pheromones
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sperm are deposited in or near female reproductive tract
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internal fertilization
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internal fertilization requires
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(1)
a higher investment from organisms for internal fertilization |
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are the female gonads
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ovaries
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Each ovary is enclosed in
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a tough productive capsule
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Each ovary contains
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follicle
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each follicle consist of
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of one egg cell surrounded by one or more layers of follicle cells
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follicles produce
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estrogen
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nourish and protect the developing egg cell
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Follicle cells
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Usually one follicle matures and releases its egg during each
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menstrual
cycle |
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After ovulation the remaining folliclar
tissue develops into the |
corpus luteum
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secretes estrogen and progesterone
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corpus luteum
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Maintains the uterine lining during pregnancy
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corpus luteum
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pregnancy does not occur
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corpus luteum disintegrates
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At ovulation the egg is released into the abdominal cavity near the opening of the
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oviduct
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cilia lined funnel like opening of the oviduct draws in the egg and conveys the egg through the oviduct to the
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uterus
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highly vascularized inner lining of the uterus
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endometrium
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The neck of the uterus, the ______, opens into the vagina
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cervix
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is a thin-walled chamber that forms the birth canal and is the repository for sperm during copulation
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vagina
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a)
During sexual arousal- women |
(1)
The clitoris, vagina, and labia engorge with blood and enlarge (2) Bartolin's glands- secret mucus into the vestibule |
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Mammary Glands
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Are present in both males and females
Are not a component of the reproductive system Contain epithelial tissue that secrete milk (a) Milk drains into a series of ducts opening at the nipple |
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external components of the male reproductive system |
penis and scrotum
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• Sperm pathway
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seminiferous tubules (in testes)-- epididymis--
vas deferens-- (joins duct from seminal vesicle)-- ejaculatory duct-- urethra |
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male gonads
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testes
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(1)
consist of many highly coiled surrounded by layers of connective tissue |
testes
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coiled tubules that are area of sperm production
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seminiferous tubules
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Sperm form in
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seminiferous tubles
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scattered between seminiferous tubules produce androgens
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leydig cells
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Testes are located in the _______ outside the body capity
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scrotum
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keeps testicular temperature cooler than the rest of the body cavity
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testes
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form the seminiferous tubules sperm pass to the cooled tubes of
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epididymis
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It takes about ______ scattered between seminiferous tubules produce androgens for sperm to pass through the sperm to pass through the
tubules of the epididymus |
scattered between seminiferous tubules produce androgens
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sperm become motile and gain the ability to fertilize in
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epididymis
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composed of three layers of spongy erectile tissue
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penis
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In men during sexual arousal
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erectile tissue fills with blood from arteries
pressure seals off the veins that drain the penis The engorgement of the penis with blood causes an erection |
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propels sperm from the epididymis to the vas deferens
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epididymis
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run from the scrotum and behind the urinary bladder
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vas deferens
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the vas deferens and seminal vesicle join to
form an |
ejaculatory duct
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ejaculatory ducts open into the
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urethra
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drains both the excretory and reproductive system
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The urethra
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in semen thin the mucus at the opening of the
uterus and stimulate uterine contractions |
prostaglandins
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semen is ___ compared to the vagina
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basic
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is thick, yellowish and
alkaline-(basic) |
Seminal fluid
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seminal fluid contains
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it contains mucus, fructose, and coagulation enzyme ascorbic acid and prostaglandins
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prostate gland is secreted
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directly into the urethra
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prostate gland is composed of
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thin and milky and contains anticoagulant enzyme and citrate
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are a pair of small glands along the urethra below the prostate
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bulbouresthral gland
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clear mucus that neutralizes and acidic urine remaining in the urethra is secreted by
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bulbourethral gland
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production of mature sperm cells from spermatogonia
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spermatogensis
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spermatogenesis is a ___ cycle
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continuous and prolific process in the adult male
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spermatogenesis occurs in
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semiferous tubules
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Development goes from
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the inside to the cortex
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Sperm development order
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Spermatogonium- primary spermocyte- secondary spermocyte- early spermatid- spermatozoa
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sperm structure
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haploid nucleus
tip with an acrosome a large number of mitochondria flagellum |
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acrosome contains
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Contains enzymes that help in the sperm penetrate to the egg
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Oogenesis
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egg development
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oogenesis differs from spermatogenesis in three major ways
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1.) At birth ovary contains all of the primary oocytes it will haver have
2.) Unequal cytokinesis during meiosis results in the formation of a single large secondary oocyte and three small polar bodies 3.) Oogenesis has long resting periods |
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Oogocyte Development
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1.) primary germ cell in embryo differentiation
2.) Oogonium 3.) Mitotic division 4.) Primary oocyte, 5.) completion of meiosis 1 and onset of meiosis II 6.) Creates the first polar body 7.) Secondary oocyte arrested at metaphase of meiosis II 8.) second polar body is formed |
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Humans and many other primates have
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menstrual cycles
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If pregnancy does not occur the endometrium is
shed through the cervix and vagina |
menstration
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Most animals have ____ cyles
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estrous
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If pregnancy does not occur the endomentrium is reabsorbed by the
uterus |
estrous cycle
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Ovarian cycle is composed of two major phases
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follicular phase and luteal phase
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follicular phase
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1. several ovarian follicles begin to grow
2. the developing egg enlarges coat of follicle cells thicken 3. Usually only one follicle continuous to develop the others disintegrate 4. The follicular phase ends with ovulation |
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luteal phase
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(a)
follicular tissue develops into corpus luteum Corpus luteum secretes estrogen and progesterone |
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GnRH gonatropin-releasing hormone (GnRH) is secreted by
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Hypothalamus
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Follicle-stimulating hormone (FSH) is secreted by
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anterior pituitary
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Luteinizing hormone (LH) is secreted by
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anterior pituitary
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Estrogens are secreted by
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ovaries
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Progesterone and estrogen is secreted by
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corpus luteum
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follicular phase hormone regulation
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(1) LH and FSH produced by anterior by anterior pitutary in response to GnRH
(2) FSH stimulates follicle cells: Follicle cells make estrogen (3) Slow rise in estrogen keeps LH and FSH low (4) Sharp rise in estrogen has opposite effect: LH and FSH levels peak (5) Final maturation of follicle ovulation |
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Luteal Phase hormonal regulation
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(1) LH stimulates the corpus luteum secrete estrogens and progesterone
(2) High levels of estrogen and progesterone inhibit FSH and LH secretion (3) Near the end of the luteal phase the corpus luteum disintegrates (4) Concentration of estrogen and progesterone decline abruptly (5) FSH secretion increases and initiates a new follicular phase |
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Menstruation cycle consist of the
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Flow phase
Proliferative phase Secretory Ohse |
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Menstrual flow phase
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menstrual bleeding
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Proliferative phase
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regeneration thickening of the endometrium
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Secretory Phase
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Continued endometrial thickening the vascularization & endometrium develops glands; secretes fluid rich in glycogen
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(1) The _____ phase of the ovarian cycle is coordinated with the ____ phase of the menstrual cycle
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luteal & secretory
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estrogens and progesterone
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of the luteal phase stimulate development and maintenance of the endometrium
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With the disintegration of the corpus luteum _______ and _____________
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estrogens and progesterone
levels decline Menstruation occurs and a new menstrual cycle begins |
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Other functions of estrogen
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(1)Deposition of fat in the breast and hips
(2)Increased water retention (3)Affects calcium metabolism (4) Stimulates breast development (5)Mediates female sexual behavior |
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are responsible for primary and
secondary sex characteristics |
androgens secreted by leydigs cells
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Primary sex characteristics
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(a) Development of the vasa deferentia and other ducts
(b)Development of the external reproductive structures. (c)Sperm production. |
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Secondary sex characteristics
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deepening of the voice
distribution pattern of facial and pubic hair muscle growth |
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are also
responsible for sexual behavior and general aggressiveness |
Androgens
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is proceeded by conception and continues until birth
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pregnacy
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human pregnancy averages _____ days
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266
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pregnancy is divided into
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trimesters
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The embryo secrete
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Humann chrorionic gonadotrophin (HGC)
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Humann chrorionic gonadotrophin (HGC) maintains
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the endometrium
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High levels of progesterone cause
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(a) Increased mucus in the cervix
(b) Growth of the maternal part of the placenta (c) enlargement of the uterus (d) Cessation of ovarian and menstrual cycling (e) Rapid Enlargement of the breast |
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occurs as a result of labor
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parturition
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Parturation stages
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(1) First stage opening up and thinning of the cerix
(2) Ending in complete dilation (3) Second stage: expulsion of the baby as a result of strong uterine contractions (4)Third stage: Expultion of the placenta 2. Contraception can work in several ways |
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Contraception occurs as
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chemical
surgical barrier methods prevents embryo from implantation |
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Birth control in women
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Both estrogen and progesterone
Pregesterone |
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Estrogen and progesterone in birth control
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Inhibits GnRH
Which causes no FSH or LH thus no ovulation |
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Progesterone only in birth control
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Decrease ovulation frequency alter endometrium
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birth control in men
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Try to supress GnRH release yet still have testosterone present
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