Chapter 5 Reproduction Questions

What is the path that each egg travels in the female reproductive tract?

(Oogenesis of mature eggs in the ovaries ->movement through an oviduct during ovulation ->uterus)

What is the path that each sperm travels in the male reproductive tract?

(Spermatogenesis in the testes -> maturation in the epididymis ->release through the vas deferens and the urethra in the penis)

Know the route that sperm travel inside the female reproductive tract

(Vagina -> cervix -> uterus -> oviduct for fertilization to occur)

Does a fetus represent a significant challenge to its mother's homeostasis?

???? The mother's breathing rate, blood volume, nutrient needs, and kidney function (with the kidneys processing 50% more blood each hour than normal) all increase

Why is it a better "idea" (evolutionarily-speaking) to curtail female reproductive capacity at an earlier age than male reproductive capacity?

After a long period of adult life in which we are reproductively mature, both males and females enter a time of declining sexual function. Menopause refers to the decline and cessation of reproductive function in females. Males also experience a decline, although reproductive function may not stop completely. This period is called the male climacteric.

Do all organisms reproduce using sexual reproduction?

All organisms reproduce, but not all have sex. Some types of organisms reproduce asexually, without sex.

what is menopause triggered by?

lower estrogen and progesterone levels than were present during the reproductive period.

What sort of cell division produces an embryo?

mitosis

Are females "fertile," with mature eggs of optimal age for fertilization, all of the time?

no menopause is a *****

What are the advantages of asexual reproduction?

Asexual reproduction offers the advantage of reproduction with out the requirement of finding a mate. By producing offspring that are genetically identical to one another, it also yields more of the same; more organisms that are as well adapted for survival and reproduction in the existing environment as the parent was.

Know that many chemical (hormonal) signals control the ability of cells to express the genes that they contain, and that such signals will guide the differentiation of cells into different tissues in a developing organism.

Differentiation occurs as different groups of cells receive chemical (often hormonal) signals to express some parts of their genome and not others. During the first two weeks of development, the small sphere of cells divides further and cells begin to differentiate into layers that will have distinct functions in the fully-developed organism.

Are the reproductive systems of humans formed prior to birth or at puberty?

During prenatal development, some reproductive structures are built, but these remain relatively inactive during childhood. During puberty, our reproductive systems become functional and we develop secondary sex characteristics.

Why is toxin exposure a concern in the first few weeks of pregnancy? (What body system is forming at this stage?)

During the first two weeks of development, the small sphere of cells divides further and cells begin to differentiate into layers that will have distinct functions in the fully-developed organism. The nervous system of the embryo begins to develop during the first few days after fertilization, and toxin exposure is a major concern at this stage

Know that FSH and LH work to stimulate gamete and sex hormone production by gonads, which also leads to the development of secondary sexual characteristics.

FSH and LH exert their function directly on the gonads, stimulating production of gametes (sperm or eggs) and sex hormones (testosterone or estrogen and progesterone). Although males and females secrete different sex hormones, these hormones exert similar effects of the gonads and other organs of both males and females. Secretion of GnRH and sub sequent secretion of GSH, LH, and the sex hormones in the body results in increasing reproductive ability and the development of secondary sexual characteristics.

How do the hypothalamus and pituitary gland work together to "turn on" reproductive function?

In both males and females, the central regulatory organ in reproduction is the hypothalamus, a portion of the brain that secretes a hormone called Gonadotropin-releasing hormone (GnRH). GnRH is released from neurons within the hypothalamus and exerts its function directly on the pituitary gland. When GnRH reaches the pituitary, it stimulates the release of two pituitary hormones, also the same in males and females, called follicle stimulating hormone (FSH) and luteinizing hormone (LH).

What are the gonads and gametes present in the female reproductive systems?

In females the ovaries produce eggs

female hormones?

In females the ovaries produce eggs and the female sec hormones estrogen and progesterone.

male hormone?

In males the testes produce sperm and the male sex hormone, testosterone

What are the gonads and gametes present in the male reproductive system?

In males the testes produce sperm.

What are the three major stages of interphase? (Does the duplication of DNA take place during mitosis? NO. ☺)

Interphase= preparation for mitosis G1= growth stage (pre-synthesis gap) S= synthesis stage during which the genetic material of the cell is duplicated G2= post-synthesis gap

What happens to the egg and the endometrium in a female reproductive tract if fertilization does not occur?

It is shed through menstruation

do a majority of the sperm cells survive the journey to the oviduct?

NO

Are sperm completely mature before reaching the female reproductive tract?

No. Inhibitory molecules that had coated the outside of the sperm and had blocked the sperms ability to bind to other cells are washed away. And changes convert the previously weak flagella into a powerful whiplash motion.

What are the advantages of sexual reproduction?

One important benefit of sexual reproduction is that it produces offspring that are genetically different from their parents and from one another. We can see the importance of this variability by asking what happens to a group of genetically identical organisms when the environment around them changes. If the change is negative, there is some risk that all of the organisms in this group will die. Here, there is some chance that one or more of the organisms will not succumb to the now harsh environmental conditions and will survive or even thrive.

Are any contraceptive devices completely effective?

Only Abstinence.

What effects can genetic errors cause?

Some developmental errors are caused by inherited errors in the genetic information received by cells (Ex.=polydactyly in cats). Some types of errors can also be caused by environmental agents (Ex.= radiation, toxic chemical exposure during smoking, thalidomide exposure). In adult individuals, cancer can be caused by changes in a cell's activities due to a combination of environmental effects and genetic predisposition, but results in uncontrolled cell division (despite contact inhibition), resulting in an unwanted mass of cells= tumor - Malignant cancer is due to affected cells that release enzymes that allow them to invade additional tissues or the bloodstream to propagate new tumors - Benign cancer is due to affected cells that remain in one area

How do the contractions that lead to the birth of an infant provide a good example of a positive feedback loop?

The hormone oxytocin (created by the hypothalamus and released by the pituitary gland) increases the force of contractions in a positive feedback loop that will lead to birth. Contractions happen more and more often so that the baby eventually comes out and the mother can return back to her homeostatic state.

Why are multiple births often caused by fertility drugs?

These can block negative feedback loops between estrogen levels and FSH and LH production, increasing the number of eggs that will be released at one time (increasing the chance of releasing viable eggs, but also increasing the chance of multiple births)

How does a developing embryo "tell" the mother's body that it is present? (What is the purpose of human chorionic gonadotropin hormone?)

When a sperm cell reaches an egg, it burrows inside and merges its genetic material with that of the egg cell, and the egg cell becomes impenetrable to other sperm cells. Within 24 hours, the first cell division occurs, and, by day 5, a hollow, fluid-filled sphere of cells has developed. By this time, the sphere has reached the uterine wall (at day 5 or 6 of development), has become attached to an area that will become the placenta, and has begun to secrete HCG (human chorionic gonadotropin) hormone, which mimics the activity of LH in the body (causing the ovaries to secrete estrogen and progesterone), and stimulating the body to maintain the lining of the uterus

Is in vitro fertilization sexual reproduction?

Yes. The definition of sexual reproduction focuses on the fusion of specialized cells to produce one genetically new cell. Thus, even reproduction accomplished by simply adding sperm to an egg in a laboratory dish is sexual reproduction.

Remember that chromatids are copies of the same chromosome, and that they are held together at centromeres to form a pair.

chromotid chromotah

Know that the components of semen will provide sperm with food, will neutralize the acidic pH of the female reproductive tract, and will assist in making sperm move more efficiently.

did ya know that????

Know that a fertilized egg will move into the uterus, attach itself to the endometrium, and begin formation of a placenta.

good to know