Biology 1306- Chapter 46
Third Trimester
- Growth - Local regulators and hormones induce and regulate labor
Changes that occur in the mother during the 1st trimester
- Mucus plug to protect against infection - Growth of the placenta and uterus - Cessation of ovulation and the menstrual cycle - Breast enlargement - Nausea is also very common
Spermatogensis differes from oogenesis in 3 ways
- all 4 products of meiosis develop into sperm while only one of the four becomes an egg - spermatogensis occurs throughout adolescence - sperm are produce continuously without the prolonged interruptions in ooogenesis (periods)
______________ and _____________ are invasive techniques in which amniotic fluid or fetal cells are obtained for genetic analysis
Amniocentesis ; chorionic villus sampling
FSH promotes the activity of ________, which nourish developing sperm
Sertoli Cells
Spontaneous abortion/miscarriage occurs in __________ of all pregnancies
¹/₃
To ensure the survival of offspring, animals
- have eggs with calcium and protein containing shells (eggs) - retain embryo, which develops inside the female - enforce parental care to ensure survival
First trimester
- main period of organogenesis - major structures are present by 8 weeks (fetus) - Changes occur in the Mother
Plan B One Step (post sexual relation)
- may prevent or delay ovulation - interfere with fertilization of an egg - also possible to prevent implantation of a fertilized egg in the uterus by altering is lining - does not cause miscarriage or abortion because it cannot stop fetus development one the fertilized egg implants in the uterus - does not work if you are already pregnant
Second Trimester
-fetus grows and is very active - mother may feel fetal movements - uterus grows enough for the pregnancy to become obvious
3 methods of contraceptive
1. Preventing release of eggs and sperm 2. keeping sperm and egg apart 3. Preventing implantation of an embryo
Permanent Sterilization
1. Tubal Ligation: ties off the oviducts 2. Bipolar Coagulation: most popular method of laparoscopic female sterilization, method uses electrical current to cauterize sections of the fallopian tube 3. Vasectomy: ties off the vas deferens
Choose the pair of contraceptive methods that are the most similar in function. 1.oral contraceptives and condoms 2. tubal ligation and vasectomy 3. abortion and diaphragm 4. coitus interruptus and the rhythm method
2. Tubal Ligation and Vasectomy ; both disrupt the network of ducts needed to unite gametes
The combination of estrogen and progesterone in most oral contraceptive for women 1. stimulates LH and FSH secretion by the anterior pituitary, thus inhibiting follicle development. 2. enhances secretion of GnRH by the hypothalamus, thus overstimulating secretion of LH and FSH. 3. inhibits secretion of LH and FSH by the anterior pituitary, thus inhibiting follicle development. 4. tricks the body into responding as if a pregnancy were already underway
3.inhibits secretion of LH and FSH by the anterior pituitary, thus inhibiting follicle development.
An advantage of internal fertilization over external fertilization is that: 1. internal fertilization allows animals to reproduce sexually. 2. internal fertilization requires much less expenditure of resources. 3. internal fertilization produces more offspring, ensuring rapid population growth. 4. internal fertilization prevents the drying out of gametes in a dry environment
4. internal fertilization prevents the drying out of gametes in a dry environment
Each year, _________ women in the US have an abortion preformed by a physician
850K
Luteal Phase
After ovulation, follicular tissue left behind transforms into the coprus luteum
_____________ of the fetus poses ethical questions and can present parents with difficult decisions
Genetic Testing
Sequential Release of _________ then _______ and _____ stimulates follicle growth
GnRh; FSH; LH
An infant suckling on the breast of a woman who has recently given birth sends a nerve impulse to the pituitary gland. The pituitary gland then secretes oxytocin, which stimulates the mammary glands in the breasts to release milk. What type of hormonal feedback is this?
Positive
RU-486
abortion pill
Menopause may have evolved to
allow a mother to provide better care for her children and grandchildren
Syphilis
bacteria; multiple system damage and fatal; 4 out of 1000 infants infected
Gonorrhea
bacteria; scar tissue, blindness in infants, antiobiotic resistant
Chlamydia
bacteria; very common and often undetected; may cause sterility
Barrier Methods
block fertilization with a pregnancy rate of less than 10% 1- condom 2- diaphragm is inserted into vagina before intercourse
Menopause
cessation of ovulation and menstruation that occurs after about 500 cycles; unusual among animals
Hormones closely link to cycles of female reproduction
changes in the uterus define menstrual cycle (aka uterine cycle) & changes in the ovaries define the ovarian cycle
Most animals exhibit cycles related to
changing seasons
Estrous cycles
characteristics of most mammals; endometrium is reabsorbed by the uterus; sexual receptivity is limited to a "heat" period; length and frequency of estrus cycles vary from species to species
Corpus Luteum disintegrates, and the ovarian steroid hormones __________
decrease
Contraception
deliberative prevention of the pregnancy
Organogenesis
development of the body organs
Hermaphroditism
each individual has a male and female reproductive system; two hermaphrodites can mate and some can self fertilize
External Fertilization
eggs shed by the female are fertilized by sperm in the external environment
Fetus
embryo (at or around 8 weeks)
Menstrual Cycle
endometrium is shed from the uterus in a bleeding called menstruation
All fertilization requires
environmental cues; pheromones and/or courtship behavior
Follicle growth and an increase in the hormone estradiol characterize the ______________ of the ovarian cycle
follicular phase
To produce sexually, animals must produce
gametophytes
FSH and LH regulate processes in the________ and the production of _________________
gonads; sex hormones
Simple systems do not have _______ but form gametes from ______________
gonads; undifferentiated tissue
Birth Control Pills
hormonal contraceptives with a pregnancy rate of less than 1%
Human reproduction is coordinated by
hormones
Reproductive cycles are controlled by
hormones and environmental cues
Intrauterin Devices (IUDs)
inserted into uterus and interfere with fertilization and implantation; pregnancy rate is less than 1%
Eggs
larger and carry out their funcition within the female
LH regulates ____________, which secrete testosterone and other androgens, which in turn promote spermatogensis
leydig cells
In Vitro Fertilization (IVF)
mixes egg with sperm in culture dishes and returns the embryo to the uterus at the 8 cell stage
Sperm
motile and must pass from male to female
Ultrasound Imaging
noninvasive procedure to detect fetal condition
Mammary Galds
not a part of the reproductive system but are important to mammalian reproduction; within the glands, small sacs of epithelial tissue secrete milk
Menstrual cycles are characteristic of
only humans and some other primates;
Gonads
organs that produce gametes;
Follicular phase ends at _______, and the secondary ______ is released
ovulation; oocyte
Gametogenesis
production of gametes: sperm & eggs
Estrogens and androgens have multiple effects including
promotion of specific behaviors
Trichomoniasis
protozoan; parasite inhabits urogenital tract and spreads through intercourse or toilet facilities; can result in sterility
Monogamy is
rare among animals
Fraternal Twins
release and fertilization of two eggs
Gonadotropin - releasing hormone (GnRH)
secreted by the hypothalamus and directs the release of FSH and LH from the anterior pituitary
Secretory Phase
secretion of nutrients during the this phase coordinates with the luteal phase
A blood sample taken from a woman in her 40s showing high levels of estrogen, progesterone, hCG, and prolactin suggests that 1. she will ovulate within one week. 2. she has not been sexually active for several months. 3. she is pregnant. 4. she is undergoing early menopause.
she is pregnant; woman is probably pregnant and an embryo or fetus is producing HCG
Menstrual Flow Phase
shedding of the endometrium during this phase coordinates with the growth of the new ovarian follicles
Intracytoplasmic Sperm Injection (ICSI)
sperm are injected directly into an egg
Internal Fertilization
sperm is deposited in or near the female reproductive tract, and fertilization occurs within the tract; requires behavioral interactions and compatibility copulatory organs
Identical Twins
splitting of the embryo during the first month
Assisted Reproductive Technologies
technology that can treat infertility
Abortion
termination of pregnancy; RU-486 can result in abortion within the first 7 weeks of a pregnancy
Proliferative Phase
thickening of the endometrium during this phase coordinates with the follicular phase
Sexual receptivity is not limited to a __________.
time frame
Rhythm method/ Natural Family Planning
to refrain from intercourse when conception is most likely; it has a pregnancy of about 10-20%
Fertilization
union of egg and sperm
Hormones coordinate the _________ with the _________
uterine cycle; ovarian cycle
Genital Herpes
virus; may be implicated in cervical cancer
Coitus Interruptus
withdrawal of the penis before ejaculation (unreliable)