McTighe ch. 51 Reproductive System

Section 2

Eggs form in ovaries. Meiosis reduces the chromosome number in eggs to 23. Eggs are about 75,000 times larger than sperm are.

Section 2

In the follicular phase, FSH causes a follicle to grow. Estrogen produced by the follicle causes an egg to mature and the uterine lining to build up.

Section 2

In the luteal phase, the follicle becomes a corpus luteum. The corpus luteum secretes progesterone, which stimulates further buildup of the uterine lining

What changes occur in a fetus during the third trimester of pregnancy?

In the third trimester, the fetus grows quickly and undergoes changes that will enable it to survive outside the mother. The fetus can see light and darkness through the mother's abdominal wall, and it can react to music and loud sounds. During the last half of this trimester, the fetus develops fat deposits under its skin. These fat deposits, which make the fetus look rounded and lass wrinkled, insulate the body so that it can maintain a steady body temperature.

What is the function of the uterus?

It is where the fertilized egg will develop

How are eggs and sperm similar, and how are they different?

Similar: egg formation occurs through meiosis. Each mature egg/sperm cell has 23 chromosomes (the haploid number) Different: sperm - four functional sperm result from each cell that begins meiosis egg - egg formation results in one functional egg from each cell that begins meiosis

ovary

an organ that produces eggs

embryo

an organism in an early stage of development of plants and animals; in humans, a developing individual from the second through the eighth week of pregnany

How is a zygote formed?

After a sperm enters an egg, the egg completes meiosis II, and the sperm's nucleus fuses with the egg's nucleus. The diploid cell that results from this fusion is called a zygote.

Describe a mature sperm.

An elongated cell with three distinct parts (a head, a midpiece, and a tail), all of which are enclosed by a cell membrane

chorionic villus

fingerlike projections of the chorion that extend into the uterine lining

Describe the path that sperm take in exiting the body.

from seminiferous tubules in the testes => epididymis => vas deferens => abdominal cavity, where it loops around the urinary bladder and merges with the urethra => exits through the urethra.

seminiferous tubule

one of the many tubules in the testis where sperm are produced

trimester

one of the three equal periods of about 12 weeks into which the human gestation period is divided

bulbourethral gland

one of the two glands in the male reproductive system that add fluid to the semen during ejaculation

seminal vesicle

one of two glandular structures in male vertebrates that hold and secrete seminal fluid

labium

one of two pairs of folds of skin and mucus membranes of skin and mucous membranes that cover and protect the openings of the vulva

Summarize the changes in a mother's body during pregnancy.

primary germ layers and 4 embryonic membranes form, placenta develops, umbilical cord, placenta begins to secrete a hormone called human chorionic gonadotropin, uterus enlarges.

menstruation

the discharge of blood and discarded tissue from the uterus during the menstrual cycle

ejaculation

the expulsion of seminal fluids from the urethra of the penis during sexual intercourse

vulva

the external part of the female reproductions organs

menstrual cycle

the female reproductive cycle, characterized by a monthly change of the lining of the uterus and the discharge of blood

vagina

the female reproductive organ that connect the outside of the body to the uterus and that receives sperm during reproduction

semen

the fluid that contains sperm and various secretions produced by the male reproductive organs

uterus

the hollow, muscular organ in which a fertilized egg is embedded and in which the embryo and fetus develop

epididymis

the long, coiled tube that is on the surface of a testis and in which sperm mature

penis

the male organ that transfers sperm to the female reproductive tract during sexual intercourse and that carries urine out of the body

luteal phase

the menstrual stage in which the corpus luteum develops

blastocyst

the modified blastula stage of mammalian embryos

cervix

the neck of the uterus

Identify the main female reproductive organs

the ovaries

pregnancy

the period of time between implantation and birth

testis

the primary male reproductive organs, which produce sperm cells and testosterone

labor

the process by which the fetus and the placenta come out of the uterus

implantation

the process by which the newly fertilized egg in the blastocyst stage embeds itself in the lining of the uterus

gestation

the process of carrying young from fertilization to birth

ovulation

the release of an ovum from a follicle of the ovary

afterbirth

the remains of the placenta and the membranes, which are expelled from the mother's body following birth

amniotic sac

the sac formed by the amnion

scrotum

the sac that contains the testes in most male mammals

follicular phase

the stage in which an immature egg completes its first meiotic division

placenta

the structure that attaches a developing fetus to the uterus and that enables the exchange of nutrients, wastes, and gases between the mother and the fetus

umbilical cord

the structure that connects an embryo and then the fetus to the placenta and through which blood vessels pass

What is the corpus luteum?

the structure that forms from the ruptured follicle in the ovary after ovulation

corpus luteum

the structure that forms from the ruptured follicle in the ovary after ovulation; it releases hormones

menopause

the termination of the menstrual cycle

Which structures in a male produce fluids that mix with sperm to form semen?

the three exocrine glands (seminal vesicles, prostate gland, bulbourethral gland)

What is the function of the vas deferens?

to help move sperm along as they exit the body

Section 1

A mature sperm consists of a head, which contains the nucleus and chromosomes; a midpiece, which contains mitochondria; and a tail, which contains of a flagellum

Section 3

During childbirth, contractions of the uterus initiated by prostaglandins and oxytocin push the baby from the mother's body through the vagina

Summarize the changes in a mother's body that take place during birth.

During childbirth, contractions of the uterus initiated by prostaglandins and oxytocin push the baby from the mother's body through the vagina. The placenta, amnion, and uterine lining, called afterbirth, are expelled shortly after the baby is born.

Section 3

Fertilization occurs in a fallopian tube. Pregnancy begins when a blastocyst implants itself in the lining of the uterus.

Section 1

Fluids that are secreted by various exocrine glands are mixed with sperm to produce semen

Section 3

For the first eight weeks of pregnancy, the developing human is called an embryo. From the eighth week until birth, a developing human is known as a fetus

Section 2

Menstruation occues at the end of the menstrual cycle, when a corpus luteum stops secreting hormones.

Explain why the testes are found in the scrotum and not inside the male body.

Normal body temperature is too high to allow sperm to complete development. The slightly cooler temperature of the scrotum is necessary for the development of normal sperm.

Section 3

Nutrients, gases, and other substances pass through the placenta by diffusion from the mother to the fetus

How can alcohol affect a fetus?

Nutrients, gases, pathogens, drugs, and other substances can pass from the mother to the embryo through the placenta. Alcohol use by women is the leading cause of birth defects, such as fetal alcohol syndrome (FAS).

Section 2

Ovulation occurs midway through the ovarian cycle, when LH causes the follicle to rupture and release its eggs

Section 1

Sperm form in the seminiferous tubules of the testes. Meiosis reduces the number of chromosomes in sperm to 23

Section 1

Sperm take the following path to exit the body; seminiferous tubules of the testes => epididymis => vas deferens => urethra

Section 2

Starting at puberty, the ovarian and mentrual cycles occur approximately every 28 days

How is a fetus nourished during development?

The chrorionic villi and the portion of the uterine lining that they invade form a close-knit structure called the placenta. The placenta is the structure through which the mother nourishes the embryo.

How do high levels of estrogen and progesterone during the luteal phrase of the ovarian cycle affect the uterus?

The corpus luteum begins to secrete large amounts of progesterone and estrogen. Progesterone stimulates growth of blood vessels and storage of fluids and nutrients in the lining of the uterus during the menstrual cycle. This stimulation causes the uterine lining to become thicker.

Section 2

The female reproductive structures include two ovaries, two fallopian tubes, the uterus, the cervix, the vagina, two labia, and the vulva

Section 1

The male reproductive structures include two testes, two epididymides, two vasa deferenta, the urethra, and the penis

Section 2

The ovarian cycle consists of three phases: follicular phase, ovulation, and luteal phase

What is the process of implantation?

The process in which the blastocyst burrows and embeds itself into the lining of the uterus

What role does luteinizing hormone (LH) play in the ovarian cycle?

The sharp rise in the LH level that occurs midway through the ovarian cycle causes the follicle to rupture and release its egg.

Section 1

The testes are contained in the scrotum, where the cooler temperature allows normal sperm development

Section 3

The three primary germ layers -- the ectoderm, mesoderm, and endoderm -- form early in embryonic development. Four membranes -- the amnion, yolk sac, allantois, and chorion -- also form early in embryonic development

Section 3

Unnecessary drug use can negatively affect an embryo or fetus

fetus

a developing human during the period from the eight week after fertilization until birth

vas deferens

a duct through which sperm move from the epididymis to the ejaculatory duct at the base of the penis

prostate gland

a gland in males that contributes to the seminal fluid

human chrorionic gonadotropin

a hormone that is secreted by the placenta and that stimulates ovulation and secretion of progesterone and testosterone

ovum

a mature egg cell

ovarian cycle

a series of hormone-inducing changes in which the ovaries prepare and release a mature ovum each month

follicle

a small, narrow cavity or sac in an organ or tissue, such as the ones on the skin that contain hair roots or the ones in the ovaries that contain the developing eggs

fallopian tube

a tube through which eggs move from the ovary to the uterus