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71 Cards in this Set
- Front
- Back
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What is the process of formation of gametes? (ie how eggs/sperm formed)
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GEMETOGENESIS
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Why does meiosis lead to genetic diversity?
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crossing over
homologous x-somes independent assortment |
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Crucial steps of sexual reproduction (3)
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GAMETOGENESIS-making gametes
MATING-getting gametes together FERTILIZATION-fusing gametes |
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Where does gametogenesis occur?
What are male/female organs/gametes called? |
GONADS
TESTES: male, make sperm OVARIES: female make ova |
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What kinds of cells make gametes?
What are all other cells called? |
GERM CELLS: occur early in development, migrate to gonads
other embryonic cells are SOMATIC cells |
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What happens to germ cells? (3 main steps)
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They undergo MITOSIS and produce SPERMATOGONIA in males and OOGONIA in females.
MITOSIS continues again to make PRIMARY SPERMATOCYTES and PRIMARY OOCYTES (2N) MEIOSIS makes N cells that mature into sperm and ova |
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What is the name for sperm formation?
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SPERMATOGENESIS
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How does spermatogenesis happen?
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2n GERM CELL divides via mitosis
to 2n SPERMATOGONIUM, divides via mitosis to 4n PRIMARY SPERMATOCYTE, divides via meiosis into TWO 2n SECONDARY SPERMATOCYTES, then FOUR n SPERMATIDS, divide into SPERM cells. (INSERT PIC) |
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What connects the secondary spermatocytes and spermatids?
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CYTOPLASMIC BRIDGES
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What is the name for female egg development?
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OOGENESIS
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How does oogenesis happen?
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2n FEMALE GERM CELL divides via mitosis to
2n OOGONIUM divides via mitosis to 4n PRIMARY OOCYTE, grows larger. stops until puberty, when meiosis resumes, nucleus divides into two cells of unequal sizes: 2n SECONDARY OOCYTE (larger one) and FIRST POLAR BODY (smaller, desintegrates). divides via meiosis to make n OOTID (large, becomes mature ovum), SECOND POLAR BODY (disintegrates) |
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What is FERTILIZATION? What does it create?
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union of haploid sperm and egg
creates a ZYGOTE (2n) |
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Fertilization steps (6)
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RECOGNITION of sperm and egg, binding to receptors
ACTIVATION of sperm FUSION of plasma membranes BLOCKING of additional sperm ACTIVATION of egg FUSION of nuclei. |
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Protective layers around the egg (2)
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JELLY COAT
VITELLINE ENVELOPE |
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What is a key structure on the sperm head?
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ACROSOME-membrane enclosed structure
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What is the reaction that happens when a sperm first touches the egg?
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ACROSOMAL REACTION: triggered by jelly coat.
membranes of sperm head and acrosome break down, releasing enzymes to digest jelly coat. |
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What happens after the acrosomal reaction (binding)
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ACROSOMAL PROCESS extends from head, coated with BINDIN (recognition molecules), which acts on receptors on vitelline envelope. plasma membranes fuse to form a FERTILIZATION CONE
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What surrounds the egg? (2)
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CUMULUS-a gelatinous matrix
ZONA PELLUCIDA-glycoprotein envelope under cumulus. is species specific. When sperm attaches to it, acrosomal reaction is triggered |
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Why can only one sperm fertilize an egg?
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BLOCKS TO POLYSPERMY (fast vs slow)
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What kind of fertilization happens in aquatic environments? How is fertilization ensured?
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EXTERNAL FERTILIZATION-gametes released into water. synchronized via day length, temp, weather.
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What kind of fertilization do mammals practice?
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INTERNAL FERTILIZATION-sperm released directly into reproductive tract.
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kinds of mothers (3)
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OVIPAROUS-lay eggs outside body
VIVIPAROUS-fetus develops in mother's body OVOVIVIPAROUS-embryo develops in body but in eggs |
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Where do mammalian embryos develop
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in UTERUS, surrounded by PLACENTA
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Levels of sex organs (2)
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PRIMARY-testes/ovaries
ACCESSORY-genitalia, ducts, glands |
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Where are sperm made?
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GONADS (aka TESTES), in SCROTUM
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Where does spermatogenesis occur?
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in epithelial lining of SEMINIFEROUS TUBULES-in testes
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What makes testosterone in testes?
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LEYDIG/INTERSTITIAL cells
between tubules |
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cells that provide nutrients for sperm?
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SERTOLI CELLS-in seminiferous tubules.
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Where are differentiated sperm cells shed?
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LUMEN of seminiferous tubules
(INSERT fig 42.10 |
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Where are sperm stored? How does it connect to urethra?
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stored in EPIDIDYMIS where they mature.
connected to urethra via VAS DEFERENS |
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What secretes semen?
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SEMINAL VESICLES
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What does the prostate gland do?
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surrounds urethra and contributes to semen.
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Another gland in the male organ
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BULBOURETHRAL GLANDS-secrete an alkaline solution that neutrelizes acidity in urethra, provides lubrication during climax.
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What is the tip of the penis called?
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GLANS PENIS
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How does an erection happen?
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NO stimulates production of cGMP in vessels, causes dilation.
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How does an erection go away?
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after ejaculation, NO release decreases
enzymes break down cGMP, blood vessels TO penis contstrict vessels AWAY from penis open |
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How do erectile dysfuction drugs work?
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inhibit breakdown of cGMP, enhancing effect of NO on blood vessels
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Describe male sexual hormone action at puberty
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GnRH (gonadotropin releasing hormone) released by hypothalmus.
causes anterior pituitary to increase LH (leutenizing hormone) and FSH (folicile stimulating hormone) |
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Functions of LH and FSH
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LH: increases testosterone in testes via leydig cells, increases growth rate
FSH (with testosterone) controls spermatogenesis in sertoli cells (also produces INHIBIN-negative feedback on hypothalmus and anterior pituitary) |
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Where does the female release the eggs (two names)
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OVIDUCT
aka FALLOPIAN TUBE |
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What happens in the oviduct/fallopian tube?
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can be FERTILIZED
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Where does the oviduct lead to?
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UTERUS
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What happens in the uterus?
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fetus development
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What is at the bottom of the uterus?
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CERVIX, opens to VAGINA
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Folds around the vagina (2)
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LABIA MINORA-inner folds
LABIA MAJORA-outer folds w/ CLITORIS |
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What happens to the zygote first?
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undergoes CELL DIVISION and becomes a BLASTOCYST
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What happens to the blastocyst?
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moves down oviduct, attaches to ENDOMETRIUM-lining of uterus,
then burrows into endometrium (IMPLANTATION) |
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Female reproductive cycles (2)
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OVARIAN CYCLE-produces eggs and hormones
UTERINE CYCLE-prepares endometrium for a blastocyst |
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What happens if no blastocyst is formed?
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endometrium sloughs off
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How long is the ovarian cycle?
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28 days
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What happens in the ovarian cycle? (2 parts)
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1st half-OVULATION-primary oocyte matures into egg and expelled from ovary
2nd half-ovarian cells develop endocrine functions. stop if no fertilization |
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What happens to oocytes throughout a woman's life?
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start w/ million, most degenerate.
only a few left at MENOPAUSE |
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What is the functional unit of the ovary? What happens to it?
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FOLLICLE-primary oocyte and surrounding ovarian cells.
Grows for two weeks then OVULATION-follicle ruptures and egg released |
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What happens to the remaining follicular cells after ovulation?
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form CORPUS LUTETUM-endocrine gland to produce estrogen and progesterone for two weeks.
degenerates unless blastocyst implants in endometrium |
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How long is the uterine cycle?
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28 days.
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What happens in the uterine cycle?
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buildup and breakdown of endometrium. remains prepared for 9 days after ovulation.
MENSTRUATION-sloughing off of endometrium through vagina |
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How do hormones act in female cycles?
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ESTROGEN-inhibits LH and FSH release during most days except OVULATION (day 13). peaks @ ovulation, plateaus, then drops off.
PROGESTERONE-starts low, starts to get bigger @ ovulation, peaks @ day 19, plateaus, then drops off by day 28 (INSERT FIG 42.14) |
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What happens to the female around the time of ovulation?
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ESTRUS-state of female sexual receptivity
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What happens to female hormones at puberty?
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GnRH stimulates production of FSH and LH,
they stimulate ovarian tissue to grow, produce ESTROGEN, causes sex organs to mature. |
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What happens a few days before menstruation?
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PITUITARY increases FSH and LH
FOLLICLES in ovary grow, make more estrogen ONE FOLLICLE matures completely |
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How does estrogen's function change?
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most of the time, it inhibits ipituitary.
days 12-14 it becomes a positive feedback signal for surge of LH and FSH, which causes follicle to release egg, develop corpus luteum |
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How is there negative feedback in the female cycle?
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Corpus leuteum secretes estrogen+progesterone, exert negative feedback on pituitary, inhibiting GnRh and thus new follicle maturation
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What happens to the blastocyst after fertilization and implantation?
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HUMAN CHORIONIC GONADATROPIN-released by cells covering blastocyst.
makes corpus luteum continue to produce estrogen/progesterone Endometrium remains-no menstruation |
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What kinds of contractions occur in the uterus?
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BRAXTON-HICKS CONTRACTIONS-weak, rhythmic, occur throughout pregnancy
FALSE LABOR CONTRACTIONS-stronger ones, happen in 3rd trimester |
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What happens to hormones during labor?
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less PROGESTERONE made (inhibits uterine contractions)
more ESTROGEN (stimulates contractions) more OXYTOCIN (stimulates strong uterine contractions) |
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How does the fetus help stimulate contractions?
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when it is fully grown, stretches uterus, pressure on cervix.
leads to release of more OXYTOCIN |
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Stages of delivery (3)
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EARLY-contractions 15 min appart, cervix dilates.
MID-contractions become more intense DELIVERY- |
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How does the pill work?
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estrogen+progesterone lead to negative feedback to suspend ovarian cycle
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how does IUD work?
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inflames uterus, fertilized egg does not implant
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How does the morning after pill work?
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blocks progesterone receptors
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What is in vitro fertilization?
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Female gets hormones to stimulate many follicles to mature
eggs collected, combined with sperm in culture medium Embryos implanted into mother's uterus |
