CH 28 Packet (BIO 181-171) Flashcards
What are gametes
the cells that are produced by each parent
What does it mean when we say that gametes are haploid
– Each gamete contains half of the genetic material of each parent
– n = a single set of 23 chromosomes
What is a zygote and it is diploid or haploid
the new cell that is produced from the combining of genetic material of the egg and sperm
– Zygotes are Diploid (46 chromosomes)
» 44 autosomes, 2 sex
Differentiate between the X an the Y chromosome
- X chromosomes are found in males and females
- Contains genetic material that is essential for life
- Y chromosomes are found only in males
- Contains genetic material that is essential for developing into male
- Thus, every individual must inherit at least one X chromosome
What is gametogensis
Production of gametes from a pool of undifferentiated germ cells
Differentiate between mitosis and meiosis
• Mitosis = normal cell division – DNA replicated once – Cells undergo division once • Meiosis = cell division that produces gametes – DNA replicated once – Cells undergo division twice
What is the end result of meiosis II
4 new cells that contain single copies of 23 chromosomes
What are the basic components of the male and female reproductive systems
- Gonads: organs that produce gametes and hormones
- Ducts: receive and transport gametes
- Accessory glands: secrete fluids into ducts
- Perineal structures: collectively known as external genitalia
- The Reproductive Tract: includes all chambers and passageways that connect the ducts to the exterior of the body
What are the gonads of the male and female and what are their function
– Male gonads: testes – Female gonads: ovaries – Gonads have two major functions – Produce gametes (sprematazoa and ova) – Secrete sex hormones – Testes secrete androgens – Ovaries secrete estrogens and progesterone – Although males have more androgens and females have more estrogens and progesterone, all of these hormones are found in BOTH sexes
What structures make up the spermatic cord
– Ductus deferens (Vas deferens) – Blood vessels – Nerves – Lymphatic vessels - Testis
What is the function of the semineferous tubules
sperm production
What are the two types of cells in the testis and what is their functions?
– between seminiferous tubules Leydig cells (interstitial cells) that Secrete testosterone
– Within seminiferous tubules are: Sertoli cells or Nurse cells (epithelial cells) that Support sperm development
Differentiate between the corpora cavernosa and the corpus spongiosum
- The Corpora Cavernosa (Two large, cylindrical masses of erectile tissue)
• Located under the anterior surface
• Separated by thin septum
• And surrounds a central artery - The Corpus Spongiosum (Relatively slender erectile body that surrounds penile urethra)
– Extends from urogenital diaphragm to tip of penis and expands to form the glans
What is the scrotum?
a fleshy pouch that houses the testes
What is the cremaster muscle and what is its function
– Is a layer of skeletal muscle deep into dermis
– Tenses scrotum and pulls testes closer to the body
– Important in temperature regulation (for sperm development)
Map out the pathway of spermatozoa starting from the semineferous tubules to the urethra
?
What are the functions of the epididymis?
- Monitors and adjusts fluid that is produced by the seminiferous tubules
- Recycles damaged spermatozoa
- Stores and protects spermatozoa
What is capacitation?
when sperm become motile
What does it mean when we say that the spermatozoa are in a state of suspended animation?
?
What are the three male accessory glands?
– Seminal glands
– Prostate gland
– Bulbo-urethral glands
What are the four major functions of the male accessory glands?
- Activating spermatozoa
- Providing nutrients that spermatozoa need for motility
- Propelling spermatozoa and fluids along the reproductive tract (Mainly by peristaltic contractions)
- Producing buffers (To counteract the acidity of urethral and vaginal environments)
Which accessory gland produces most of the semen volume
• Seminal vessicles
How much semen volume does the seminal gland contribute
60%
What type of fluid is secreted by the bulbo uretheral gland and what is its function
– Secrete thick, alkaline mucus
– Helps neutralize urinary acids in urethra
– Lubricates the glans (penis tip)
What three hormones govern male reproductive function
– Gonadotropins
– Androgens (testosterone)
– Gonadotropin releasing hormone (GnRH)
Differentiate between the targets and the actions of LH and FSH
– Gonadotropins, FSH and LH are secreted by anterior pituitary and target the gonads (in response to GnRH secretion by the hypothalamus)
– FSH Stimulates sperm production (spematognesis) by acting on sertoli (nurse) cells
– LH Stimulates androgen (testosterone) secretion by acting on leydig cells
What does inhibin do?
– Suppresses secretion of GnRH by the hypothalamus
– Inhibits FSH production by the anterior pituitary gland*
What is the most important androgen in males and what are its functions
– Stimulates spermatogenesis
– Affects CNS function
– Stimulates metabolism
• Establishes male secondary sex characteristics
• Maintains accessory glands and organs of male reproductive tract
What is spermatogenesis and where does it begin
– Is the process of sperm production
– Begins at outermost cell layer in the seminiferous tubules
What are the three integrative processes that are involved in spermatogenesis
– Mitosis = normal cell division
– Meiosis = cell division that produces gametes
– Spermiogenesis=Formation of MATURE sperm
Name the five cells that will be produced during spermatogenesis in their proper order, form least developed to most developed
- Spermatogonia (stem cells) divide by mitosis to produce two daughter cells
- Primary spermatocytes begin meiosis and form secondary spermatocytes
- Secondary spermatocytes differentiate into spermatids (immature gametes)
- Spermatids
- Spermatozoa
During spermatogenesis, what is happening during meiosis I
– Primary spermatocyte produces two secondary spermatocytes
– BOTH are haploid (Each has 23 chromosomes)
What is happening during meiosis II of spermatogenesis?
– Each secondary spermatocyte produces two spermatids = for a total of FOUR SPERMATIDS
– All spermatids are Haploid (Each has 23 chromosomes)
What is spermatogenesis and what is its end result
– End result of spermiation = Spermatids differentiate into mature spermatozoa (highly specialized cells)
Where do the spermatozoa acquire motility
• Spermatozoa Acquire motility in the epididymis
What are the major functions of the nurse (sertoli) cells
- Maintain blood–testis barrier
- Support mitosis and meiosis
- Support spermiogenesis
- Secrete inhibin
- Secrete androgen—binding protein (ABP)
- Secrete Müllerian—inhibiting factor (MIF)
What is the function of inhibin that is secreted by the nurse cells?
• Pituitary production of FSH
• Hypothalamic secretion of GnRH
– The end result of the regulation of FSH and GnRH by Inhibin (Gives nurse cells feedback control of spermatogenesis)
Describe what happens in the presence of the srY gene
– Testosterone AND Müllerian-inhibiting substance (MIS)
– These hormones stimulate development of Wolffian ducts and degeneration of Müllerian ducts → male reproductive structures
Describe what happens in the absence of the srY gene
– Hormones are absent → causes Wolffian ducts regress, and Müllerian ducts develop → female reproductive structures
Give three characteristics of the female reproductive system
- Cyclic changes in activity
- Restricted periods of fertility
- Limited gamete production
What are the three main functions of the ovaries
– Production of immature female gametes (oocytes)
– Secretion of female sex hormones (estrogens, progestins)
– Secretion of inhibin, which is involved in feedback control of pituitary secretion of FSH
What are the structures of the female reproductive tract
uterine tubes, uterus, and vagina
What transports the oocyte from the ovary to the uterus
• Uterine Tubes
Give some characteristics of the myometrium
– Smooth muscle
– Thickest layer
– Comprises 90% of uterine mass
Which layer of the uterus contains the uterine glands
– Endometrium
What are the functions of the vagina
- Passageway for elimination of menstrual fluids
- Receives spermatozoa during sexual intercourse
- Forms inferior portion of birth canal
What is the vulva and what structures make up the vulva
– Structures that comprise the external genitalia • Mons pubis • Labia majora/minora • Vestibule • The Clitoris
What is oogenesis
process of ova development from oogonia (undifferentiated germ cells)
When does the process of meiosis begin in the female
in the first three months of embryonic life
When is meiosis completed in the female
prior to ovulation
Describe what is happening during the first three months of a female’s embryonic life
- Oogonia (diploid) undergo mitosis to yield 2-4 million clones from which all ova are derived
- Oogonia differentiate into primary oocytes
- Primary oocytes begin meiosis I and replicate their DNA
- At this point, meiosis stops and primary oocytes enter a state of suspended development called meiotic arrest
- Primary oocytes remain in meiotic arrest until just before ovulation
- Thus, at birth, a female’s eggs are in the form of primary oocytes in meiotic arrest: (state of suspended development)
What does it mean when we say that the oocytes are in a state of meiotic arrest, and how long doe the oocytes remain in meiotic arrest?
state of suspended development
remain in meiotic arrest until just before ovulation
At birth, what is the state of a female’s eggs?.
meiotic arrest
With respect to oogenesis, what happens when a female reaches puberty?
When female reaches puberty, one primary oocyte per month continues to meiosis I
What happens just prior to ovulation with respect to oogenesis and what is the end result
Just prior to ovulation, a primary oocyte completes meiosis I to yield two daughter cells possessing 23 replicated chromosomes each (n x 2)
•One daughter cell = secondary oocyte
•The other daughter cell = first polar body
When does meiosis II occur in the female?
Meiosis II only occurs if the secondary oocyte is fertilized
What does meiosis II yield when fertilization occurs?.
If fertilization occurs, meiosis II yields
•One ovum (which recieves most of the cytoplasm)
•One second polar body (which degenerates and dies)
What is the total number of chromosomes of a fertilized egg?
46 chromosomes (2n)
Differentiate between the ovarian cycle and the uterine cycle
• The Ovarian Cycle
– Includes monthly oogenesis
• The Uterine Cycle (or menstrual cycle)
– Is a repeating series of changes in the endometrium of the uterus
What are the two phases of the ovarian cycle
1. Follicular phase – Menstruation → ovulation – ~14 days 2. Luteal phase – Ovulation → before menstruation – 14 days
Where in the ovaries would you find the developing oocytes?
cortex of the ovaries
Name the fluid filled cavity that develops as the follicle continues to develop
antrum
With respect to the ovarian cycle, what happens during ovulation?
• Wall of Graafian follicle ruptures during ovulation with respect to the ovarian cycle
The ruptured follicle forms into what structure?
Ruptured follicle forms into the corpus luteum
What hormone is secreted by the corpus luteum?
Corpus luteum secretes progesterone, which prepares the uterus for pregnancy
What happens after the degeneration of the corpus luteum
there is a decrease progesterone which leads to menstruation (end of luteal phase)
The uterine cycle involves changes in which part of the uterus
endometrium
What are the three phases of the uterine cycle? And how do they coincide with the phases of the ovarian cycle?
– Menstruation and proliferative phase
» Occur during ovarian follicular phase
– Secretory phase
» Occurs during ovarian luteal phase
What happens during menstruation?
– Is the process of endometrial sloughing and shedding of the uterine lining
When does the secretory phase of the uterine cycle begin, and what is happening during this phase?
– Endometrial glands enlarge, increasing rate of secretion
– Begins at ovulation and persists as long as corpus luteum remains intact
– Peaks about 12 days after ovulation
– Generally lasts 14 days
When does the uterine cycle end?
• The Uterine Cycle ends when the corpus luteum stops producing stimulatory hormones
What are the primary hormones involved in the female reproductive system
– GnRH – FSH – LH – Estrogen – Progesterone – Inhibin
What is the end result of the LH surge in the female
LH surge causes ovulation
What is the function of inhibin that is secreted by the developing follicles?
– Inhibits any further secretion of FSH
What are the five functions of estrogen?
- Stimulates bone and muscle growth
- Maintains female secondary sex characteristics
- Affects central nervous system (CNS) activity
- Maintains functional accessory reproductive glands and organs
- Initiates repair and growth of endometrium
Describe the autonomic innervation that is occurring during erection and ejaculation in males.
– Erection = innervated by the parasympathetic nervous system
– Ejaculation = innervated by the sympathetic nervous system
What is emission in the male sexual response?
– Neural activity starts to shift from parasympathetic control to sympathetic control
