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BIOEXCEL 192 - Animal Reproduction

Animal Reproduction

____.) Define the following:
a) fertilization -
b) parthenogenesis -
c) gonads -
d) gametes -
e) zygote -
f) external fertilization -
g) internal fertilization -
h) hermaphrodite -
i) sequential hermaphrodite -
j) protandrous sequential hermaphrodite -
k) protogynous sequential hermaphrodite -

____.) Define asexual reproduction and describe three types of asexual reproduction.

____.) Imagine you have two populations of earthworms, one that reproduces sexually and one that reproduces asexually. Suppose a devastating disease were introduced into these populations. Which would have a greater chance of surviving and why?

____.) What are some of the requirements for external fertilization? Why is it sometimes considered an inefficient mode of fertilization?

a) What are two components of the testes and what do they produce?
b) Trace the path that sperm takes through the male reproductive system to the external environment starting from the testes.
c) Name three accessory glands associated with the male reproductive system. What does each of these glands produce?

____.) Draw and label a spermatazoa. Use the following terms: tail, plasma membrane, mitochondria, middle piece, head, nucleus, acrosome.

a) What are the primary and secondary effects of androgens such as testosterone in males?
b) Androgens can then, via a negative feedback mechanism, inhibit the release of _________________________ from the hypothalamus as well as the release of FSH and LH from the _________________________.
c) What does FSH promote in males?
d) What does LH promote in males?

____.) Match the terms to the correct description:
___Tunica albuginea
___Seminiferous Tubules
A. White outer capsule of testis consisting of dense connective tissue
B. Compartments of the testis containing seminiferous tubules
C. Layer of dense connective tissue which separates lobules
D. Location where blood vessels enter the testis
E. External structure found in some male mammals consisting of a testis in a scrotum
F. Functional unit of the testis
G. Male gonad

____.) The overall process of making sperm is called ____________________. The first step in this process is ______________________ which involves mitosis of stem cells called __________________ which produces _____________________ and __________________. The second step is ______________ during which diploid _______________________ divide into __________ secondary spermatocytes. Via meiosis II secondary spermatocytes become haploid ____________. At this point, cell division ends, so the last step of sperm formation called _____________________ involves cytodifferentiation where a ________________ becomes _________________.

____.) List the 4 steps of cytodifferentiation:

____.) List the types of cells you would find as you move form the basement membrane of the seminiferous tubule toward the lumen. If you prefer, you can answer this question with an illustration.

____.) What forms the blood-testis barrier? Why is the blood-testis barrier important?

____.) List the functions of the Leydig cells and the Sertoli cells. Which cell produces testosterone?

____.) In males, the _________________________ releases GnRH (gonadotropin-releasing hormone) which stimulates the _________________________ to release _________________________ and _________________________ . _________________________ promotes sperm production whereas _________________________ promotes testosterone production. Testosterone suppresses the actions of the _________________________ and the _________________________ in a negative feedback manner. Furthermore, inhibin is produced by _________________________ cells which inhibits the _________________________ from producing _________________________ and _________________________ via a ______________________ feedback manner.

a) Why are the testes located outside the body cavity?
b) Describe ways in which temperature regulation is achieved for the testes.

____.) Match the following structures with their appropriate function.
A. seminal vesicles
B. penis
C. prostate
D. epididymis
E. bulbourethral glands
F. seminiferous tubules
G. vas deferans
H. ejaculatory duct
____________ i) produces 30% of seminal fluid
____________ ii) contains mostly smooth muscle involved in movement of sperm and ejaculation
____________ iii) adds enzymes and prostaglandins that stimulate sperm motility and enhances viability
____________ iv) characterized by 2 large corpora cavernosa and a smaller corpus spongiosum
____________ v) is usually the structure that is cut during a vasectomy
____________ vi) produces lubricating substances as well as alkaline mucus to allow sperm to survive in the acidic environment of the vagina
____________ vii) produces 60% of seminal fluid
____________ viii) main storage site of sperm
____________ ix) is really just a continuation of the vas deferans as it joins with the urethra
____________ x) provides fructose as an energy source for sperm
____________ xi) are considered accessory glands (more than one answer)
____________ xii) males normally have only one of these (more than one answer)
____________ xiii) males normally have two of these (more than one answer)
____________ xiv) site of sperm and testosterone production

____.) Describe the following components of the ovarian follicle structure:
a) oocyte:
b) granulosal cells:
c) zona pellucida:
d) thecal cells:
e) basement membrane:

____.) Compare and contrast spermatogenesis and oogenesis

____.) What is the name of the fluid-filled cavity that contains the oocyte prior to ovulation?

____.) What is the term given to the layer of granulosal cells that stick to the oocyte prior to ovulation?

____.) How do ectopic pregnancies occur?

____.) How does the fallopian tube (oviduct) move the egg to the uterus?

____.) In thecal cells, ______________ is converted to _______________ which is converted to a weak ______________. In ____________________, weak androgens are converted to _____________.

____.) Draw and label the following stuctures of the human female reproductive anatomy: ovaries, oviducts, uterus, vagina, and cervix

____.) When a female is born, it is theoretically possible to determine exactly how many eggs she will produce in her lifetime based on the state of her reproductive tissues at that moment. How is this so? How does this compare to the male reproductive system?

____.) What is the difference between the menstrual cycle of humans vs. dogs, rats, and sheep? What is the official name for the latter?

____.) The Menstrual Cycle - THE PHASES
a) In regards to the Ovarian Cycle (pertaining to the ovum):
Days 1 through 14 correspond to the _________________________ phase.
At Day 14 _________________________ occurs.
Days 14 to 28 correspond to the _________________________ phase.
b) In regards to the Uterine Cycle (pertaining to the uterine endometrial lining):
Days 1 through 5 correspond to the _________________________ phase.
Days 5 through 14 correspond to the _________________________ phase.
Days 14 to 28 correspond to the _________________________ phase.

____.) The Menstrual Cycle - THE HORMONES
a) What hormone causes follicular recruitment?
b) What hormone does the developing follicle produce as it matures?
c) A surge of what hormone causes the breakdown of the ovary wall for ovulation to occur as well as leads to the subsequent formation of the corpus luteum?
d) What hormones are produced by the corpus luteum itself?
e) What hormones build and maintain the endometrium?
f) What hormone maintains the corpus luteum assuming no fertilization occurs?
g) What hormone does the developing embryo produce that maintains the corpus luteum in the event that fertilization does occur?

____.) The Menstrual Cycle - THE FEEDBACK MECHANISMS
a) A slow rise in estrogen levels _________________________ secretion of FSH and LH. This is an example of a _________________________ feedback mechanism.
b) A steep rise in estrogen levels _________________________ secretion of FSH and LH. This is an example of a _________________________ feedback mechanism.
c) Estrogen PLUS Progesterone _________________________ secretion of FSH and LH. This is an example of a _________________________ feedback mechanism.

*****Be sure you understand the diagram showing how both cycles are coordinated with each other and with the rise and fall of FSH, LH, estrogen, and progesterone during one 28-day period.*****

During the _________________________ phase, follicle cells are stimulated to grow and mature by _________________________ secreted by the anterior pituitary. The follicle secretes _________________________ at low levels which inhibits the release of _________________________ and _________________________ from the anterior pituitary in a negative feedback fashion. As the follicle continues to mature, things change radically as the follicle secretes great amounts of _________________________, which _________________________ production of FSH and LH in a _________________________ feedback manner. Eventually, there is surge in levels of _________________________ that causes _________________________ to occur on Day 14. Also, the _________________________ from the growing follicle _________________________ the thickening of the endometrium. In terms of the endometrium, this corresponds to the _________________________ phase. After the egg is expelled, the _________________________ phase begins and the emptied follicle transforms into the _________________________ , which produces _________________________ and _________________________ . Production of both these two hormones _________________________ the secretion of LH and FSH as well as continues the thickening of the endometrium. At this point, the endometrium has entered the _________________________ phase. As _________________________ levels decline, the corpus luteum disintegrates. It therefore halts in the production of estrogen and progesterone and _________________________ and _________________________ are no longer inhibited. Also, the decline in ovarian hormones causes the endometrial tissue to slough off. Menstruation, or the _________________________ phase, results as the _________________________ continues to disintegrate and levels of _________________________ and _________________________ continue to drop. Finally, levels of _________________________ and _________________________ are able to rise again. And the cycle begins again!!

____.) If fertilization does take place, _________________________ produced by the embryo (which is the substance theat preganancy tests are designed to detect) maintains the _________________________ because it mimics the action of _________________________ .

a. What structure produces progesterone for the first trimester?
b. What structure produces progesterone after the first trimester?

____.) During which trimester does each of the following take place?
a) organogenesis -
b) rapid growth to about 3kg and 50cm in length -
c) all major structures present -
d) heart starts beating -
e) starts to becomes active -

a) What are the functions of oxytocin and prostaglandins during birth?
b) Outline the stages of birth and parturition.
c) Birth control pills are usually a combination of _________________________ and _________________________. Birth control pills act via a negative feedback mechanism to stop the release of GnRH and FSH (due to the effect of _________________________ ) as well as LH (due to the effect of _________________________ ).

____.) Designate the following occurrences with the proper trimester (1,2,or 3) of pregnancy:
___ secretion of progesterone by placenta
___ period of most radical change in the embryo
___ formation of the placenta
___ stimulation of placenta to secrete prostaglandins
___ development of the body organs

____.) What is unusual about the natural phenomenon known as Menopause? What is a hypothesis of why it occurs?

2002-2003 Kevin Hong