Reproductive system

Question 1

Sexual reproduction involves the combination of the __ ___ of two organisms to result in a genetically ___ ___. It requires the production of __ ___ ___ or gametes by ___ organisms, the union of these cells (____/___) to form a zygote, and the development of the zygote into another adult, completing the ___.

Answer 1

genetic material, unique offspring, functional sex cells, adult, conjugation/fertilization, cycle

Question 2

The male gonads, the ____ produce sperm in the tightly coiled ___ ___. The female gonads, the ____, produce ____. Some species are ____ which possess both functional male and female gonads. These include the ___ and the ___.

Answer 2

testes, seminiferous tubules, ovaries, oocytes, hermaphrodites, earthworm, hydra

Question 3

The production of functional sex cells

Answer 3

gametogenesis

Question 4

Sperm production

Answer 4

spermatogenesis

Question 5

egg production

Answer 5

oogenesis

Question 6

occurs with terrestrial vertebrates and provides a direct route for sperm to reach the egg cell

Answer 6

internal fertilization

Question 7

In internal fertilization, the chance for fertilization success ___, and females produce ___ eggs.

Answer 7

increases, less

Question 8

If the early development of the offspring occurs ____ the mother’s body, ___ eggs will be produced to increase the changes of offspring survival. Additionally, species that ___ their young more produce ___ eggs.

Answer 8

outside, more, parent, less

Question 9

The testes are located in the ___, an external pouch that maintains the testes temperature at ___ °C lower than body temperature, a condition essential for sperm survival. Sperm pass from the testes through the __ __ to the __ __ and then to the ___. The passes through the penis until it terminates with an external opening at the ___ of the penis. In males, the urethra is a common passageway for both the reproductive and ___ systems. The testes are also the sites of production of ____, which regulates __ __ __.

Answer 9

scrotum, 2-4, vas deferens, ejaculatory duct, urethra, glans, excretory, testosterone, secondary sex characteristics

Question 10

In spermatogenesis, ___ cells called ___ differentiate into ___ cells called primary ____, which undergo ___ __ to yield two ___ ___ ____of equal size. A second meiotic division produces ___ __ ___ of equal size. Afterwards they undergo a final series of changes that increase their ___, resulting in mature sperm, or ___.

Answer 10

diploid, spermatogonia, diploid, spermatocytes, meiotic division, haploid secondary spermatocytes, four haploid spermatids, mobility, spermatozoa

Question 11

the mature sperm is an __ cell with a __, neck, body and ___. The head consists almost entirely of the ___. The tail or ___ propels the sperm. ___ in the neck and body provide energy for ___. A caplike structure called the ____, derived from the __ ___, develops over the anterior half of the head. This cap contain enzymes needed to penetrate the touch outer covering of the ___. After a male has reached sexual maturity, ~___ million primary spermatocytes begin to undergo spermatogenesis per day

Answer 11

elongated, head, tail, nucleus, flagella, mitochondria, locomotion, acrosome, golgi apparatus, ovum, 3

Question 12

The ovaries are found in the __ ___ below the digestive system. They consist of thousands of ___ that produce ___. Approximately once a month an __ __ is released from the ovary into the abdominal cavity and drawn by ___ into the nearby ___, also known as the __ ___.

Answer 12

abdominal cavity, follicles, estrogen, immature ovum, cilia, oviduct, fallopian tube

Question 13

A multilayered sac of cells that contains, nourishes, and protects an immature ovum

Answer 13

follicle

Question 14

Each fallopian tube opens into the __ __of a muscular chamber called the ___, the site of ___ development. The lower, narrow end of the uterus is called the __, which connects to the __ ___, which is the site of __ __ during intercourse and is also the passageway through which a baby is expelled during childbirth

Answer 14

upper end, uterus, fetal, cervix, vaginal canal, sperm deposition

Question 15

Oogenesis occurs in the __ __. At birth, most of the immature ova, known as __ __ that a female will produce during her lifetime have already formed. These are ___ cells that form by mitosis in the ovary. After ___, one primary oocyte per ____ completes __ __, yielding two daughter cells of __ size. It consists of a __ ___ and a small cell known as a __ ___.

Answer 15

ovarian follicles, primary oocytes, diploid, menarche, month, meiosis I, unequal, secondary oocyte, polar body

Question 16

Meiosis II does not occur until ___. The oocyte cell membrane is surrounded by two layers of cells, the inner __ ___ __ and the outer __ ____ ___. Meiosis II is triggered when these layers are penetrated by a __ __, yielding two ____ cells, a ___ ___ and another polar body. The mature ovum is a large cell containing ___, __, ___ and ___ needed by the developing embryo. When polar bodies are formed, they lack these resources and rapidly ___

Answer 16

fertilization, zona pellucida layer, corona radiata layer, sperm cell, hapolid, mature ovum, cytoplasm, RNA, organelles, nutrients, degenerate

Question 17

The ovaries synthesize and secrete female sex hormones including __ and ___. The secretion of these are regulated by ___ __ and __ __ __ which in turn are regulated by ____.

Answer 17

estrogen, progesterone, luteinizing hormone, follicle stimulating hormone, GnRH

Question 18

Estrogens are steroid hormones necessary for normal female ___. They stimulate the development of the female __ __, contribute to the development of __ ___ characteristics and influence ___. Estrogens are also responsible for the thickening of the ____. Estrogens are secreted by the ovarian follicles and the __ ___.

Answer 18

maturation, reproductive tract, secondary sexual characteristics, libido, endometerium, corpus luteum

Question 19

Progesterone is steroid hormone secreted by the __ __ during the __ phase of the menstrual cycle. This stimulates the development and maintenance of the ___ in preparation for ___.

Answer 19

corpus luteum, luteal, endometrium, implantation

Question 20

The hormonal secretions of the __, __ and _ __ play important roles in the female reproductive cycle. From puberty through ___, interactions with these hormones result in a monthly cyclical pattern known as the __ __.

Answer 20

ovaries, hypothalamus, anterior pituitary, menopause, menstrual cycle

Question 21

The follicular phase begins with the cessation of __ __ from the previous cycle. During this phase, ___ from the anterior pituitary promotes the development of the ___, which grows and begins secreting __.

Answer 21

menstrual flow, FSH, follicle, estrogen

Question 22

Midway through the cycle, ___ occurs, a mature ovarian follicle ___ and releases an ___. This is caused by a surge in ___ that is preceded and in part caused by a peak in ___ levels

Answer 22

ovulation, bursts, ovum, LH, estrogen

Question 23

Women ovulate approximately once every ___ weeks, except during __ and ____, until menopause, which typically occurs between the ages of __ and __. During this time, the ovaries become less sensitive to the hormones that stimulate __ ____ (LH, FSH), and eventually ___. The remaining follicles disappear, estrogen and progesterone levels greatly ___, and ovulation ___. The profound changes in hormone levels are often accompanied by physiological and _____ changes that persist until a new ___ is reached.

Answer 23

4, pregnancy, lactation, 45, 50, follicle development, atrophy, decline, stops, psychological, balance

Question 24

After ovulation, LH maintains the remnant of the ruptured follicle called the _ ___, which secretes ___ and ____. The latter causes the ___ of the ___ to mature and produce secretions that prepare it for the implantation of an embryo.

Answer 24

corpus luteum, estrogen, progesterone, glands, endometrium

Question 25

If the ovum is not fertilized, the corpus luteum ____. The resulting drop in progesterone and estrogen levels causes the endometrium with its superficial __ __ to slough off, giving rise to the __ __.

Answer 25

atrophies, blood vessels, menstural flow

Question 26

If fertilization occurs, the developing ___ produces ____ ___ ___, maintaining the __ __ as well as the supply of estrogen and progesterone that maintains the uterus. Eventually, the placenta will take over ____ of these hormones.

Answer 26

placenta, human chorionic gonadotropin, corpus luteum, production

Question 27

An egg can be fertilized during the ___ hours after ovulation. Fertilization most often occurs in the ___, ___ portion of the fallopian tube. Sperm must travel through the _ ___, __, __ and into the fallopian tubes to reach the ovum. Sperm remain ___ and capable of fertilization for ___ after intercourse.

Answer 27

12-24, widest, lateral, vaginal canal, cervix, uterus, viable, 1-2

Question 28

The first barrier that the sperm must penetrate is the _ ___. ____ secreted by the sperm aid in this. The ____ is responsible for penetrating the zona pellucida. It releases enzymes that __ this layer, allowing the sperm to come into direct contact with the ovum __ ____. Once in contact, the sperm forms a tubelike structure called the __ ___, which extend to the cell membrane and penetrates it, ___ the sperm cell membrane with the ovum cell membrane, The sperm __ now enter’s the ovum’s ____. The ovum completes __ ___

Answer 28

corona raiata, enzymes, acrosome, digest, cell membrane, acrosome process, fusing, nucleus, cytoplasm, meiosis II

Question 29

The acrosomal reaction triggers a __ ___ in the ovum, causing ___ __ to be released into the cytoplasm. this initiates a series of reactions that result in the formation of the __ ___. This is a hard layer that surrounds the ovum cell membrane and prevents _ ___. The release of calcium also increases the ovum’s __ ___. This is followed by the fusion of the sperm nucleus with the ovum nucleus to form a __ __. The first ___ division of the zygote soon follows

Answer 29

cortical reaction, calcium ions, fertilization membrane, multiple fertilizations, metabolic rate, diploid zygote, mitotic

Question 30

Monozygotic twins result when a single zygote splits into _ ___. If the splitting occurs at the ___ stage of development, the embyros will have separate ___ and separate ___. If it occurs at the ___ stage, the embryos will share both of these, and possibly an ___. Occasionally, the division is incomplete, resulting in the birth of ____ twins. Monozygotic twins genetically ___, and are the same sex, blood type and so on

Answer 30

two embryos, two-cell, placentas, chorions, blastula, amnion, conjoined, identical

Question 31

Dizygotic twins results when two ova are released in one __ ___ and are fertilized by two __ ___. The two embryos implant in the uterine wall ___, and each develop its own placenta, ___ and ___. The placentas may ___ if the embryos plant very close to each other. Fraternal twins share no more characteristics than any other ____.

Answer 31

ovarian cycle, different sperm, individual, chorion, amnion, fuse, siblings