Reproduction Quiz Flashcards
1
Q
Annotate diagrams of male and female reproductive anatomy to show the names of structures and their functions.
A
Male:
- Testes - produce sperm (spermatogenesis inside structures called seminiferous tubules) and testosterone
- Epididymis - Maturation (motility) and storage of sperm cells
- Vas deferens/ Sperm duct - Carries mature sperm cells to seminal vesicle and prostate gland (arousal)
- Seminal vesicle - adds nutrient-filled fluids (fructose – for energy/ motility) and mucous (protection) to mature sperm cells (seminal vesicle secretions = 70% of fluid volume of semen)
- Prostate gland adds alkaline fluids (helps neutralize acidic environment of vagina so sperm can survive - prostate gland secretions = 30% of fluid volume of semen)
- Semen travels out of the body through the urethra inside the penis
Female:
- Ovaries - produce oocytes (they mature in the ovary during oogenesis prior to ovulation) and produces estrogen and progesterone
- Fimbriae - tissue adjacent to ovary that sweeps an “egg” into the fallopian tube
- Oviducts/ Fallopian tubes - tube that transports oocyte to uterus (where fertilization occurs as well)
- Uterus - location where fertilized egg will implant and develop
- Endometrium - Blood rich, mucous membrane lining the uterus to provide nutrients to implanting embryo
-
Vagina - passageway for penis to deliver sperm to
uterus (note that a muscular opening called the cervix protects the uterus); passageway for birth from uterus
2
Q
Annotate diagrams of the seminiferous tubule and explain the process of spermatogenesis (and be able to identify/ state which cells are diploid and which are haploid).
A
LOOK AT NOTES - Reproduction Part 1 slide 5: https://docs.google.com/presentation/d/1H5COb6j3ZBREd87cYH0rPdVy_ZUaIbUZxkG8GOz98Rw/edit#slide=id.p5
LOOK AT CAT DISSECTION LAB - Question 6
Seminiferous Tubule:
- Spermatogenesis (creation of male gametes) occurs in the testes in structures called seminiferous tubules
- Each tubule is surrounded by a membrane (basement membrane) which is lined with cells called germline epithelium cells (diploid)
- Germline epithelium cells divide by MITOSIS to make spermatogonia (which grow into primary spermatocytes (diploid cells) that divide by MEIOSIS to make spermatozoa)
- Sertoli cells in the tubules nourish developing spermatozoa
- Leydig cells (produce testosterone) and blood capillaries are found OUTSIDE/ surrounding the tubules
Spermatogenesis:
- Germline cells (in seminiferous tubules) divide by mitosis to produce spermatogonia (2n)
* - some return to basement membrane and some continue growth into primary spermatocytes (2n) - FSH (follicle-stimulating hormone) stimulates meiosis I in primary spermatocytes (producing haploid (n = 23) secondary spermatocytes)
* - Note: FSH is released by the anterior pituitary gland - LH (luteinizing hormone) stimulates Leydig cells in the testes to produce testosterone
* - Note: LH is released by the anterior pituitary gland - Testosterone stimulates meiosis II in secondary spermatocytes (producing 4, haploid (n= 23) spermatids) and stimulates Sertoli cells
* - Note: Testosterone also causes development of male genitalia during embryonic development, causes development of secondary sex characteristics during puberty, and maintains male sex drive throughout lifetime - Spermatids differentiate into sperm with nourishment from Sertoli cells (tails, midsections – mitochondria) and move into the interior portion of the seminiferous tubules (the lumen) to be transported to the epididymus (for storage and maturation – motility/ swimming)
3
Q
Annotate diagrams of the ovary and explain the process of oogenesis (and be able to identify/ state which cells are diploid and which are haploid).
A
LOOK AT NOTES - Reproduction Part 1 slide 10: https://docs.google.com/presentation/d/1H5COb6j3ZBREd87cYH0rPdVy_ZUaIbUZxkG8GOz98Rw/edit#slide=id.p9
LOOK AT CAT DISSECTION LAB - Question 7
Ovaries:
- Picture on slideshow! (no functions listed separately of oogenesis process)
Oogenesis:
- Germline cells in the ovaries divide by mitosis to produce oogonia (fetus)
- Oogonia undergo growth to become primary oocytes (fetus)
- Primary oocytes begin meiosis I, but are arrested at Prophase I until puberty
* - Note: Primary oocytes are each surrounded by a layer of supporting cells called follicle cells. Primary oocytes + follicle cells = “primary follicles”
PHASE 1: FOLLICULAR PHASE (Days 5-~14)
- FSH (follicle-stimulating hormone, from the anterior pituitary) stimulates ONE primary oocyte (“follicle”) to mature and complete meiosis I (producing two haploid (n = 23) cells – one secondary oocyte and one polar body)
* - Note: the division of the cytoplasm in meiosis in oocytes is UNEQUAL, resulting in one LARGE (largest cell in the human body by volume) secondary oocyte, and one small cell called a polar body (basically just a reservoir for the extra set of chromosomes – will later degenerate) - The secondary oocyte (“follicle”) secretes estrogen (to inhibit FSH - negative feedback - so only one follicle matures at a time, and to stimulate the lining of the uterus (endometrium) to “repair”/ grow and develop new tissues rich in blood vessels – to nourish an embryo if fertilization occurs)
- Secondary oocytes begin meiosis II, but arrest at Prophase II/ Metaphase II. (Note: meiosis II will ONLY be completed IF the oocyte is fertilized by a sperm cell (this will produce another polar body and an ovum))
PHASE 2: OVULATION (midway through the cycle, ~Day 14)
- Rising levels of estrogen stimulate LH (luteinizing hormone) and some FSH (in lesser amounts) to be released in a “surge” from the anterior pituitary (positive feedback). This “surge” of LH stimulates ovulation of an “egg” (a secondary oocyte surrounded by an inner layer of follicle cells and a glycoprotein coat called the zona pellucida) from the ovary into the fallopian tube
PHASE 3: LUTEAL PHASE (Days 14 - 28)
- LH stimulates the ruptured follicle inside the ovary to develop into a structure called the corpus luteum
- The corpus luteum secretes high levels of progesterone (and lower levels of estrogen). Progesterone thickens and maintains the highly vascular endometrium of uterus for 10-12 more days after ovulation in preparation for pregnancy.
- High levels of both estrogen and progesterone in the bloodstream act as a negative feedback mechanism on the pituitary (no FSH and no LH = no more mature follicles produced during this time)
PHASE 4: MENSTRUATION (Days 1-5)
- If fertilization occurs, an embryo implants in the endometrium and secretes hormones to maintain the corpus luteum (and endometrial lining of the uterus)
- If NO pregnancy, the corpus luteum degrades and levels of estrogen and progesterone drop
4
Q
Know the roles of FSH and LH in the processes of spermatogenesis and oogenesis.
A
FSH (follicle-stimulating hormone):
- Spermatogenesis: FSH stimulates meiosis I in primary spermatocytes (producing haploid (n = 23) secondary spermatocytes)
- Oogenesis: FSH stimulates follicular growth and stimulates estrogen secretion from follicles
LH (luteinizing hormone):
- Spermatogenesis: LH stimulates Leydig cells in the testes to produce testosterone
- Oogenesis: LH surge causes ovulation and causes development of corpus luteum
5
Q
Know the role of testosterone in the process of spermatogenesis and in the development of male sex characteristics.
A
- Testosterone stimulates meiosis II in secondary spermatocytes (producing 4, haploid (n= 23) spermatids) and stimulates Sertoli cells
- Note: Testosterone also causes development of male genitalia during embryonic development, causes development of secondary sex characteristics during puberty, and maintains male sex drive throughout lifetime
- Testosterone causes prenatal development of male genitalia, it aids in sperm production (meiosis II), it aids in development of male secondary sex characteristics (body hair, deepening voice, muscle development etc.), and it helps to maintain libido
6
Q
Know the roles of estrogen and progesterone in the menstrual cycle/ oogenesis, in the development of female sex characteristics, during pregnancy, and during parturition (birth).
A
Oogenesis:
- During the follicular phase of oogenesis: the secondary oocyte (“follicle”) secretes estrogen (to inhibit FSH - negative feedback - so only one follicle matures at a time, and to stimulate the lining of the uterus (endometrium) to “repair”/ grow and develop new tissues rich in blood vessels – to nourish an embryo if fertilization occurs)
- During the ovulation phase of oogenesis: rising levels of estrogen stimulate LH (luteinizing hormone) and some FSH (in lesser amounts) to be released in a “surge” from the anterior pituitary (positive feedback). This “surge” of LH stimulates ovulation of an “egg”
- During the luteal phase of oogenesis: high levels of both estrogen and progesterone in the bloodstream act as a negative feedback mechanism on the pituitary (no FSH and no LH = no more mature follicles produced during this time)
- During menstruation: without estrogen and progesterone, the endometrial lining cannot be maintained and it sloughs off (menstruation/ a woman’s period)
Development of female sex characteristics:
- Estrogen and progesterone cause prenatal development of female reproductive organs, they aid in monthly development and ovulation of an egg and preparation of a woman’s body for pregnancy (post-puberty), and they aid in development of female secondary sex characteristics (breast development, body hair, fat deposition etc.)
Pregnancy:
- Estrogen and progesterone maintain the highly vascularized endometrium, thicken the cervix, and prevent FSH and LH from releasing more follicles)
- Estrogen and progesterone maintain the highly vascular endometrium and prevent release of FSH and LH from the anterior pituitary
- Progesterone prevents uterine contractions by inhibiting oxytocin and causes development of breast tissue
- Estrogen stimulates growth of uterine muscles and development of mammary glands (but it inhibits the milk producing cells from releasing milk - these are stimulated to grow by prolactin during pregnancy)
Parturition:
- Extreme stretching of the uterine walls (baby takes up ALL space) triggers release of estrogen (estriol) from placenta
- Estrogen increases sensitivity of uterine muscles to oxytocin and inhibits progesterone
- Oxytocin released from pituitary (as progesterone levels drop, oxytocin release and contractions of uterine muscles no longer inhibited by progesterone)
- Oxytocin targets cells of the uterus, causing muscles to contract (it also inhibits progesterone)
- Oxytocin triggers lactation/ contraction of muscles in breast tissue (milk secretion/ breastfeeding); Prolactin no longer inhibited by estrogen, so triggers milk-producing cells to secrete milk
7
Q
Compare and contrast the processes of spermatogenesis and oogenesis.
A
SIMILARITIES:
Both form haploid gametes, both use FSH and LH, both involve mitosis/ growth and meiosis, and differentiation
DIFFERENCES:
Spermatogenesis:
- Location: Occurs entirely in testes
- Meiotic divisions: Equal meiotic division of cells
- Germline epithelium: Is involved in gamete production
- Gamete number produced: Four
- Size of gametes: Sperm are smaller than spermatocytes
- Duration: Uninterrupted process
- Onset: Begins at puberty
- Release: Continuous
- End: Lifelong (but reduces with age)
Oogenesis:
- Location: Occurs mostly in ovaries
- Meiotic divisions: Unequal division of cytoplasm
- Germline epithelium: Is not involved in gamete production
- Gamete number produced: One (plus 2 - 3 polar bodies)
- Size of gametes: Ova larger than oocytes
- Duration: In arrested stages
- Onset: Begins in foetus (pre-natal)
- Release: Monthly from puberty (menstrual cycle)
- End: Terminates with menopause
8
Q
Outline the genetic and hormonal control of the development of male and female sexual characteristics (prenatal).
A
Male:
- In males, the 23rd pair = XY
- The Y chromosome carries a gene called SRY (Sex Determining Region Y) which codes for a protein called TDF (testis-determining factor)
- TDF causes the embryonic gonads to develop into testes (which produce testosterone).
- Testosterone causes prenatal development of male genitalia, it aids in sperm production (meiosis II), it aids in development of male secondary sex characteristics (body hair, deepening voice, muscle development etc.), and it helps to maintain libido
Female:
- In females, the 23rd pair - XX
- No Y chromosome = no SRY = no TDF = embryonic gonads develop into ovaries (which produce estrogen and progesterone).
- Estrogen and progesterone cause prenatal development of female reproductive organs, they aid in monthly development and ovulation of an egg and preparation of a woman’s body for pregnancy (post-puberty), and they aid in development of female secondary sex characteristics (breast development, body hair, fat deposition etc.)
9
Q
Identify the hormones involved in the menstrual cycle on graphs showing their concentrations on different days during the menstrual cycle (and know the origin of each - either the anterior pituitary gland or the ovaries). Be able to DIAGRAM the levels of these hormones (in a graph of their concentrations over time) as well.
A
LOOK AT NOTES - Reproduction Part 1 slide 15: https://docs.google.com/presentation/d/1H5COb6j3ZBREd87cYH0rPdVy_ZUaIbUZxkG8GOz98Rw/edit#slide=id.p14
- FSH is secreted from the Anterior Pituitary
- Estrogen is secreted from the Ovaries (developing follicle/ secondary oocyte in follicular phase and corpus luteum in luteal phase)
- LH is secreted from the Anterior Pituitary
- Progesterone is secreted from the Ovaries (corpus luteum)
10
Q
Know the roles (and concentrations - in general, I mean are levels higher/ increasing or lower/ decreasing) of oxytocin, estriol (a type of estrogen), and prostaglandins in the positive feedback mechanisms of birth.
A
Estriol (Estrogen):
- Extreme stretching of the uterine walls (baby takes up ALL space) triggers release of estrogen (estriol) from placenta
- Estrogen increases sensitivity of uterine muscles to oxytocin and inhibits progesterone (so oxytocin can be released)
- Concentration gets higher at the start of birth
Oxytocin:
- Oxytocin targets cells of the uterus, causing muscles to contract (it also inhibits progesterone so more oxytocin can be released)
- Muscle contractions in the uterus stimulate more oxytocin to be released (causing more uterine contractions, causing more oxytocin to be released etc. – this is a POSITIVE feedback mechanism - it reinforces or AMPLIFIES the response/ change)
- Oxytocin triggers lactation/ contraction of muscles in breast tissue (milk secretion/ breastfeeding)
- Concentration gets higher as birth goes on
Prostaglandins:
- Fetus becomes increasingly cramped by contractions and releases prostaglandins, which stimulate more uterine contractions
- Concentration gets higher in the midst of contractions
11
Q
Know the roles (and concentrations) of progesterone, prolactin, and oxytocin in the processes of breast development, milk production, and lactation.
A
Progesterone:
- Progesterone causes development of breast tissue
- Inhibits oxytocin to prevent uterine contraction and lactation until birth (when estrogen inhibits progesterone)
Prolactin:
- Prolactin stimulates milk producing cells to grow during pregnancy
- Prolactin, once uninhibited by estrogen at the end of birth, triggers milk-producing cells to secrete milk
Oxytocin:
- Oxytocin triggers lactation/ contraction of muscles in breast tissue (milk secretion/ breastfeeding)
12
Q
Explain the process of fertilization (including the acrosome reaction), and including the mechanisms that prevent polyspermy (the cortical reaction). Know that fertilization takes place in the oviduct/ fallopian/ uterine tubes too.
A
- Millions of sperm cells are ejaculated into female’s vagina (sexual intercourse)
* * Note: Sperm absorb fructose from the seminal fluid to “power” their mitochondria (to make ATP for swimming – it’s a LONG journey). Seminal fluid is also slightly alkaline to protect sperm from the female’s acidic vagina. - Upon entering the female reproductive tract, biochemical changes occur to sperm in the final part of its maturation (capacitation) - chemicals in the uterus dissolve cholesterol coat around sperm (improves motility) and destabilize acrosome cap (for acrosome reaction once sperm meets egg)
- Sperm travel (“swim”) from the vagina, through the cervix, up through the uterus and into the fallopian tubes (oviducts) where, hopefully, an “egg” will be waiting! FERTILIZATION OCCURS (usually) IN THE OVIDUCT!!!
* * Note: Chemical signals from the egg (secondary oocyte) attract sperm toward it (chemotaxis) - Sperm cells that reach the egg begin working their way through (“digging into”) the follicle cells surrounding the “egg” (secondary oocyte)
- Acrosome vesicles on sperm cells that penetrate the follicle cells bind to receptors on the zona pellucida of the “egg” and release hydrolytic enzymes from their acrosome to digest through it (acrosome reaction)
- Once a sperm is through the zona pellucida, it binds to “docking proteins” on the egg membrane. Following this, the membranes of the sperm and “egg” fuse and the sperm nucleus (and centrioles) enters the egg.
- Calcium ions are released in the egg, triggering the final meiotic division in the egg nucleus (and polar body creation)
- Calcium ions (within milliseconds) also stimulate the cortical reaction (to prevent polyspermy – more than one sperm entering the egg) Vesicles (called cortical granules) are stored in the egg cytoplasm just inside the plasma membrane
Vesicles fuse with the plasma membrane
Vesicle fusion releases enzymes (exocytosis) that destroy the sperm-binding proteins on the “egg” plasma membrane and harden it (no more sperm shall bind/ pass!) – creates a “fertilization membrane/ envelope” - Within 24h, the two haploid (n) nucleii (sperm and egg) fuse, creating a one-celled zygote (fertilized egg) that is diploid (2n) – AKA, “Your eggo is preggo!”
13
Q
Know that a fertilized egg is called a zygote, and that 2-5 (ish) days post-fertilization the cells inside of it undergo rapid mitotic divisions to form a functional blastocyst that will implant in the endometrial lining of the uterus.
A
KNOW IT! (I don’t even want to hear it, Rylee)
14
Q
Know the function and the origin of the hormone hCG.
A
Function: Maintains the corpus luteum, which maintains high levels of estrogen and progesterone, maintaining the endometrium for implantation and embryo growth/ development
Origin: Secreted by the embryo if fertilization occurs
15
Q
Outline the structure and function of the placenta.
A
Structure:
- A disc-shaped structure (half fetal tissue, half mother’s tissue) that will nourish the embryo/ fetus and secrete hormones to maintain the pregnancy after the corpus luteum degrades
- The placenta connects to the fetus through blood vessels in the umbilical cord
- The umbilical vein delivers oxygen-rich, nutrient-rich (glucose, amino acids, water, vitamins, minerals, antibodies, lipids) blood to the fetus: this blood also contains hormones and it may contain viruses, alcohol/ drugs/ nicotine (depending on mom during pregnancy)
- A pair of umbilical arteries carry carbon dioxide-rich blood (with urea, water, and hormones – like hCG) from the fetus to the placenta
Function:
- Nourishes the embryo/ fetus
- Secretes estrogen and progesterone to maintain the pregnancy after the corpus luteum degrades
