Intoduction to Psychology (Module 6)

Question 1

Unique for its role in human reproduction, a ______ is a specialized sex cell carrying ____________—one half the number in body cells. At the time of fertilization, the chromosomes in one male gamete, called a ______(or ______), combine with the chromosomes in one female gamete, called an ______. The major function of the reproductive system is to ensure ______ of the species. Other systems in the body, such as the ______ and ______ systems, work continuously to maintain ____________for survival of the individual. An individual may live a long, healthy, and happy life without producing offspring, but if the species is to continue, at least some individuals must produce offspring.

Answer 1

gamete, 23 chromosomes, fertilization, sperm, spermatozoon, oocyte, survival, endocrine, urinary, homeostasis

Question 2

1. Every child is genetically related to one _____ and one _____ parent.
2. A female’s reproductive system does not begin producing eggs until she reaches _____ _____.
3. Both males and females begin to lose the ability to _____ after age ___.
4. Millions of sperm fertilize _____ _____.
5. A developing fetus’ heart does not begin to beat until ____________________.
6. The _____ _____ and _____ supply the fetus with _____ and _____ from the mother’s _____.
7. A mother’s use of _____ or _____ can lead to _____ _____ for her child as the child grows and develops.

Answer 2

male, female
sexual maturity
reproduce, 54
one egg
after 24 weeks of development
umbilical cord, placenta, oxygen, nutrients, blood
drugs, alcohol, health problems

Question 3

The Female Reproductive System includes:

Answer 3

1. External Genitalia
   A. Vulva and its structures
2. Internal Genitalia: three-part system of ducts.
   A. Uterine tubes
   B. Uterus
   C. Vagina

Question 4

This system of ducts connects to the ______, the __________________. The ovaries produce ___ _____ and release them for ______. Fertilized eggs develop __________________.

Answer 4

ovaries, primary reproductive organs, egg cells, fertilization, inside the uterus

Question 5

The female reproductive system is designed to carry out several functions. It produces the female egg cells necessary for ________, called the ___ or ________. The system is designed to transport the ___ to the __________________. Conception, the fertilization of an egg by a sperm, normally occurs in the ________ _____. The next step for the fertilized egg is to implant into the ___________________, beginning the initial stages of pregnancy. If fertilization and/or implantation does not take place, the system is designed to __________(the monthly shedding of the uterine lining). In addition, the female reproductive system produces ________________ that maintain the ____________ ______.

Answer 5

reproduction, ova, oocytes, ova, site of fertilization, fallopian tubes, walls of the uterus, menstruate, female sex hormones, reproductive cycle

Question 6

Ovaries
Resemble large ___________
Attached to __________ in the ______ _____ on each side of the ________
Ovarian follicles — contain an ______, which is an _________________ (about ______ at birth)
About _____-_____ mature follicles _______ during the ___________ __________ of most women

Answer 6

almonds
ligaments, pelvic cavity, uterus
oocyte, immature sex cell, 1 million
300 – 500, ovulate, reproductive lifetime

Question 7

The ovaries are two almond-shaped structures that sit on either side of the _____, connected to the _____ _____. They produce _____ (egg cells), as well as _____, _____, and other _____. _______________, or _____, begins with the _____ _____. As girls reach _____, each ovary contains thousands of these follicles, and each follicle contains a _____ _____. When follicles mature, some primary oocytes become _____ _____. By the time of _____ there is only one mature follicle remaining. The rest of the follicles _____. During ovulation (about once a month), the dominant follicle _____ and releases its secondary oocyte. The oocyte travels into the _____ _____, where it can be _____.

Answer 7

uterus, uterine tubes, oocytes, estrogen, progesterone, hormones, egg cell production, oogenesis, primordial follicles, puberty, primary oocyte, secondary oocytes, ovulation, deteriorate, bursts, uterine tube, fertilized

Question 8

Uterine tubes (also called __________ ______ or ________)
The uterine tubes (also called Fallopian tubes or oviducts) connect the ovaries to the uterus. The walls of each tube have an external ________ _____, a ________ ________ ________, and an ________ ________ ________ that is continuous with the inner lining of the uterus. Each uterine tube can be divided into three parts: The ________ is open to the abdomen. A constricted section called the ________ connects with the uterus. Finally, an intermediate, dilated portion, the ________, curves over the ovary. ____ ________ usually occurs in the ampulla. The eggs then travel through the ________ into the uterus.

Answer 8

fallopian tubes, oviducts, serous layer, middle muscular layer, internal mucous layer, infundibulum, isthmus, ampulla, egg fertilization, isthmus

Question 9

The Uterus expands as an _______ becomes a _______

Answer 9

Embryo, fetus

Question 10

Generating Eggs: Ovaries are the _______ _______

Answer 10

female gonads

Question 11

__________: a pear Introduction -shaped organ located in the pelvic cavity

Answer 11

Uterus

Question 12

The uterus is a pear-shaped organ located in the pelvic cavity between the _______ and the _______. It is a hollow organ with thick, muscular walls. The uterine tubes lead from the ovaries into the upper part of the uterus (one tube on each side). The lower part of the uterus constricts into a segment called the _______, which leads to the vagina. During _______, the _______ _______ of the uterus is _______. When a woman becomes pregnant, however, the fertilized egg _______ itself in the uterine wall and menstruation is _______. The uterus expands dramatically as the egg develops into an _______ and then a growing _______.

Answer 12

bladder, rectum, cervix, menstruation, inner lining, shed, embeds, prevented, embryo, fetus

Question 13

The Vagina: A Tunnel with:

Answer 13

Three Core Functions

Question 14

The ______ is an elastic, muscular canal with a soft, flexible lining that provides ______ and ______. The vagina connects the uterus to the outside world. The ______ and ______ form the entrance, and the cervix of the uterus protrudes into the vagina, forming the interior end. The vagina receives the penis during sexual intercourse and also serves as a ______ for menstrual flow from the uterus. During childbirth, the baby passes through the vagina (______ ______). The ______ is a thin membrane of tissue that surrounds and narrows the vaginal opening. It may be torn or ruptured by ______ ______ or by ______.

Answer 14

vagina, lubrication, sensation, vulva, labia, conduit, birth canal, hymen, sexual activity, exercise

Question 15

*___________: Inflammation of the vagina, commonly from a yeast infection or bacterial overgrowth. Itching, discharge, and change of odor are typical symptoms. Vaginitis is treated with ________ or ________ ________.

Answer 15

Vaginitis, antibiotics, antifungal medication

Question 16

*_______________: Involuntary spasm of the vaginal muscles during sexual intercourse. ________ _________ about sex, or medical conditions, can be responsible. Depending on the cause, it can be treated with _______, _______ or some other types of _______.

Answer 16

Vaginismus, Emotional distress, medicine, counselling, therapy

Question 17

*_______ _______: ______ _______may affect the vulva, vagina, and cervix. Treatments can remove vaginal warts, which are caused by ____________ _____________ (HPV).

Answer 17

Genital warts, human papillomavirus

Question 18

*___________: Infection of the vagina by a microscopic parasite called trichomonas. Trichomoniasis is transmitted by ___ and is easily _______.

Answer 18

Trichomoniasis, sex, curable

Question 19

*_______ ________ (BV): A disruption in the balance of healthy bacteria in the vagina, often causing odor and discharge. __________, or ___ with a new partner can cause BV. BV is treated with __________.

Answer 19

Bacterial vaginosis, Douching, sex, antibiotics

Question 20

*________ ________ _______ (HSV): The herpes virus can infect the vulva, vagina, and cervix, causing small, painful, recurring blisters and ulcers. Having no noticeable symptoms is also common. The virus is transmitted _________. It can be treated, but not _____.

Answer 20

Herpes simplex virus, sexaully, cured

Question 21

*_________: This sexually transmitted bacterial infection most often infects the cervix. Half the time, there are no symptoms, but vaginal discharge and itching may occur. It can cause ________ ___________ _________ and __________. It is treated with antibiotics.

Answer 21

Gonorrhea, pelvic inflammatory disease, infertility

Question 22

*__________: The bacterium Chlamydia trachomatis causes this sexually transmitted infection. Only half of women will have symptoms, which may include __________ __________ or __________ in the vagina or __________. It can cause __________ __________ __________ and __________. Chlamydia is treated with __________.

Answer 22

Chalmydia, vaginal discharge, pain, abdomen, pelvic inflammatory disease, infertility, antibiotics

Question 23

*_______ ________: Cancer of the vagina is extremely rare. Abnormal vaginal __________ or __________ are symptoms.

Answer 23

Vaginal cancer, bleeding, discharge

Question 24

______________ ______________: Due to weakened pelvic muscles (usually from childbirth), the rectum, uterus, or bladder pushes on the vagina. In severe cases, the vagina ___________ out of the body.

Answer 24

Vaginal prolapse, protrudes

Question 25

The Vulva Comprises the _________ _________ __________

Answer 25

External Female Genitalia

Question 26

The structures of the vulva facilitate sexual intercourse and provide the entrance to and outlet for the internal genitalia. They include the _______ _______ and _______ _______, the _______ _______, the _______, the _______ _______ _______, and the _______ of the vagina. The vestibule includes two openings: the smaller _______ _______ allows urine to exit (as part of the urinary system). The _______ _______ _______ is the entrance to the vagina.

Answer 26

labia minora, labia majora, mons pubis, clitoris, greater vestibular glands, vestibule, urethral orifice, larger vaginal orifice

Question 27

The female reproductive anatomy includes parts inside and outside the body. The function of the external female reproductive structures (the genitals) is twofold: ________________________________________________________________________________________. The main external structures of the female reproductive system include:

Answer 27

To enable sperm to enter the body and to protect the internal genital organs from infectious organisms.

Question 28

* ________ ________: This enclose and protect the other external reproductive organs. Literally translated as "________ ________," the labia majora are relatively large and fleshy, and are comparable to the ________ in males. The labia majora contains ________ and ________-________ ________. After puberty, the labia majora are covered with ________.

Answer 28

Labia majora, large lips, scrotum, sweat, oil-secreting glands, hair

Question 29

* _______ _______: Literally translated as "_______ _______," the labia minora can be very small or up to 2 inches wide. They lie just inside the labia majora, and surround the openings to the _______ (the canal that joins the lower part of the uterus to the outside of the body) and _______ (the tube that carries urine from the bladder to the outside of the body).

Answer 29

Labia minora, small lips, vagina, urethra

Question 30

* _________ ________: These glands are located beside the vaginal opening and produce a _________ (______) _________.

Answer 30

Bartholin's glands, fluid (mucus) secretion.

Question 31

* ________: The two labia minora meet at the clitoris, a small, sensitive protrusion that is comparable to the penis in males. The clitoris is covered by a fold of skin, called the ________, which is similar to the foreskin at the end of the penis. Like the penis, the clitoris is very sensitive to ________ and can become ________.

Answer 31

Clitoris, prepuce, stimulation, erect

Question 32

The internal reproductive organs in the female include: * _________: The vagina is a canal that joins the _________ (the lower part of uterus) to the outside of the body. It also is known as the _________ _________. * _________ (_________): The uterus is a hollow, pear-shaped organ that is the home to a _________ _________. The uterus is divided into two parts: the _________, which is the lower part that opens into the vagina, and the main body of the uterus, called the _________. The corpus can easily expand to hold a developing baby. A channel through the cervix allows sperm to enter and menstrual blood to exit. * _________: The ovaries are small, oval-shaped glands that are located on either side of the uterus. The ovaries produce _________ and _________. * _________ _________: These are narrow tubes that are attached to the upper part of the uterus and serve as tunnels for the ____ (egg cells) to travel from the ovaries to the uterus. Conception, the fertilization of an egg by a sperm, normally occurs in the fallopian tubes. The fertilized egg then moves to the _________, where it implants into the lining of the _________ ____.

Answer 32

Vagina, cervic, birth canal Uterus (womb), developing fetus, cervis, corpus Ovaries, eggs, hormones Fallopian tubes, ova, uterus, uterine wall

Question 33

Females of reproductive age experience cycles of _________ _________ that repeat at about one-month intervals. With every cycle, a woman's body prepares for a potential pregnancy, whether or not that is the woman's intention. The term menstruation refers to the _________ _________ of the _________ _________. (Menstru means "_________.‘’) The average menstrual cycle takes about __ days and occurs in phases: the _________ phase, the _________ phase (ovulation), and the _________ phase.

Answer 33

hormonal activity, periodic shedding, uterine lining, monthly, 28, follicular, ovulatory, luteal

Question 34

There are four major hormones (chemicals that stimulate or regulate the activity of cells or organs) involved in the menstrual cycle: ______-_______ _______, _______ _______, _______, and _______.

Answer 34

follicle-stimulating hormone, luteinizing hormone, estrogen, progesterone

Question 35

How Many Eggs Does a Woman Have? The vast majority of the eggs within the ovaries steadily die, until they are depleted at menopause. At birth, there are approximately _ ________ to _ ________ eggs; by the time of puberty, only about _______ remain. Of these, only about _____ will be ovulated during a woman's reproductive lifetime. Any remaining eggs gradually die out at ________.

Answer 35

1 million, 2 million, 300,000, 500, menopause

Question 36

MALE REPRODUCTIVE SYSTEM The testes are the primary reproductive organs and generate sperm cells through a process called ______________. The glands of the male reproductive system produce _____ and _____ _____. The _____ _____, the _____ _____, and the _____ _____ contribute seminal fluid to semen, which _____ and _____ the sperm. During sexual intercourse, semen moves through a series of _____ to deliver the semen directly into the female reproductive system.

Answer 36

spermatogenesis, sperm, seminal fliuid, prostate gland, seminal vesicles, bulbourethral glands, carries, protects, ducts

Question 37

The function of the male reproductive system is to produce sperm and transfer them to the female reproductive tract. The paired testes are a crucial component in this process, as they produce both ______ and ______ (group of hormones that play a role in male traits and reproductive activity), hormones that support male reproductive ______. In humans, the most important male androgen is ______. Several accessory organs and ducts aid the process of ______ ______ and transport the sperm and other seminal components to the penis, which delivers sperm to the female reproductive tract. Here, we examine each of these different structures, and discuss the process of sperm production and transport.

Answer 37

sperm, androgens, physiology, testosterone, sperm maturation

Question 38

The Testes Produce Millions and Millions of Sperm Each Day The testes (or testicles) are the ____ ______and sit below the penis within a sac called the _______. They are _______ long, _______ in diameter, and covered with two _________ ______, the _____ __________ and the _____ __________. The testes generate sperm, the male sex cells, as well as testosterone and other sex hormones. The production of sperm is constant and occurs within numerous _____ in each testis. First, structures called _____ _____ generate _____ _____. These cells, the _____, divide into _____, and then divide further to become _____. The process is called _____. Spermatids move from the _____ to the _____ and mature into sperm.

Answer 38

male gonads, scrotum, 4-5 cm, 2-5 cm, membranous layer, tunica albuginea, tunica vaginalis, lobules, seminiferous tubules, stem cells, spermatogonia, spermatocytes, spermatids, spermatogenesis, testis, epididymis

Question 39

The _________, ___ _________, _________ _____, and _________ form a four-part transportation system. The epididymis sits directly on top of each testis. Sperm from the testis mature as they move through the _________ ____ of the epididymis. During _________ _________ and _________, they are expelled into the ___ _______. The vas deferens pushes the sperm up over the _________ and down toward the _________ _____. There, the vas deferens joins the ends of the _________ _________ (accessory reproductive glands) to form the _________ ______. The ejaculatory ducts receive ________ ____ from the vesicles, pass through the prostate, and move semen into the __________. The male urethra extends from the bladder, through the prostate, to the _______ ______ at the end of the penis. It receives additional _______ ________ from the prostate before it expels semen out of the body.

Answer 39

epididymis, vas deferens, ejaculatory ducts, urethra, coiled duct, sexual intercourse, ejacilation, vas deferens, bladder, prostate gland, seminal vesicles, ejaculatory ducts, seminal fluid, urethra, external orifice, seminal fluids,

Question 40

__________ ___________ _____________ Add Seminal Fluid to Semen

Answer 40

Accessory Reproductive Glands

Question 41

Semen Mixture of sperms and seminal fluid ___% from seminal vesicles, ___% from prostate Slightly _______, ____ _______ and _______ Contains _______, _______ _______ & an _______ to protect the sperms Typical ejaculate is __.__ to __mL in volume Normal sperm count is __________________ - Actions of many sperm are needed for one to enter - If less than _____________________

Answer 41

60, 30, alkaline, milky, sticky, nutrients, clotting proteins, antibiotic, 2.5, 5, 50 to 150 millions/mL 20 millions/mL sterile

Question 42

Sperm cells depend on ________ ______ to keep them moving and alive. This fluid is produced during ________ by ________ ________: the ________ ________, the ________, and the ________ ________. The seminal vesicles, two saclike structures, sit close behind the bladder and extend toward the ________. There they each join one of the vas deferens to form the ________ _____. The vesicles secrete a ________________ fluid containing ________, ________, and other substances that makes up ________ of the semen volume. The prostate, located under the ________ and above the start of the penis, contains the ________ _____ and the ________ ________. As semen enters the urethra, the prostate secretes ________ that help activate the sperm. The bulbourethral glands (or ________ ________) are pea-sized, with single ducts that connect to the urethra where it emerges from the prostate. These glands add ________ that helps with sperm ________.

Answer 42

seminal fluid, ejaculation, accessory glands, seminal vesicles, prostate, bulbourethral glands, bladder, ejaculatory ducts, whitish brown, sugars, prostaglandins, two-thirds, bladder, ejaculatory ducts, prostatic urethra, enzymes, Cowper's gland, mucus, motility

Question 43

________________________ Is Key to the Reproductive Function of the Penis

Answer 43

Spongy Internal Tissue

Question 44

The penis is part of the male _______ ________, suspended from the body at the front and sides of the pubic arch. Internally, the penis consists of three connected columns of tissue. The _______ _______ _______ extends together from the root of the penis through the body. The _______ _______ runs along the underside of the cavernosa. It contains the spongy urethra and expands past the body of the penis to form the glans penis (the tip). The tissue of the corpora cavernosa and the corpus spongiosum is sponge-like in structure. During _______ and _______, the spaces in the tissue fill with blood. The penis _______. Now it can penetrate the vagina to deliver semen directly into the female reproductive system.

Answer 44

external genitalia, paired corpora cavernosa, corpus spongiosum, arousal, intercourse, sitffens

Question 45

*fertilization: The act of _________ or _________ animal or _________ _________. *_________: A step spermatozoa undergo in the female reproductive tract that renders them capable of fertilizing an oocyte. *implantation: The embedding of the _________ _____ into the _________ _____. *Nondisjunction: Nondisjunction is the _________________ or _________ to separate properly during cell division. *zygote: A _________ ____ _____.

Answer 45

fecundating, impregnating, vegetable gametes capacitation fertilized ovum, uterine wall failiure of homologous chromosomes, sister chromatids fertilized egg cell

Question 46

The fertilized egg, known as a _____, then moves toward the _______, a journey that can take up to a week to complete until implantation occurs. Through fertilization, the egg is activated to begin its ____________ _______ (progressing through meiosis II), and the ________ ______ of the two gametes come together to form the ________ of a new diploid organism. Nondisjunction during the _________________ or problems with early cell division in the zygote to _______ stages can lead to problems with implantation and __________ _________.

Answer 46

zygote, uterus, developmental process, haploid nuclei, genome, completion of meiosis, blastula, pregnancy failure

Question 47

_______ ________: The sperm and ovum unite through fertilization, creating a zygote that (over the course of 8–9 days) will implant in the uterine wall, where it will reside over the course of __ _______. The process of fertilization occurs in several steps and the interruption of any of them can lead to failure. At the beginning of the process, the sperm undergoes a series of changes, as freshly ejaculated sperm is unable or poorly able to fertilize. The sperm must undergo _______ in the female’s reproductive tract over several hours, which increases its _______ and destabilizes its _______. By destabilizing the membrane, the sperm prepares for the _______ _______, the _______ penetration of the egg’s tough membrane, the zona pellucida. The sperm and the egg cell (which has been released from one of the female’s two ovaries) unite in one of the two fallopian tubes.

Answer 47

Human fertilization, 9 months, capacitation, motility, membrane, acrosome reaction, enzymatic penetration, zona pellucida,

Question 47

_______ ________: The sperm and ovum unite through fertilization, creating a zygote that (over the course of 8–9 days) will implant in the uterine wall, where it will reside over the course of __ _______. The process of fertilization occurs in several steps and the interruption of any of them can lead to failure. At the beginning of the process, the sperm undergoes a series of changes, as freshly ejaculated sperm is unable or poorly able to fertilize. The sperm must undergo _______ in the female’s reproductive tract over several hours, which increases its _______ and destabilizes its _______. By destabilizing the membrane, the sperm prepares for the _______ _______, the _______ penetration of the egg’s tough membrane, the zona pellucida. The sperm and the egg cell (which has been released from one of the female’s two ovaries) unite in one of the two fallopian tubes.

Answer 47

Human fertilization, 9 months, capacitation, motility, membrane, acrosome reaction, enzymatic penetration, zona pellucida,

Question 48

_______ ________: The sperm and ovum unite through fertilization, creating a zygote that (over the course of 8–9 days) will implant in the uterine wall, where it will reside over the course of __ _______. The process of fertilization occurs in several steps and the interruption of any of them can lead to failure. At the beginning of the process, the sperm undergoes a series of changes, as freshly ejaculated sperm is unable or poorly able to fertilize. The sperm must undergo _______ in the female’s reproductive tract over several hours, which increases its _______ and destabilizes its _______. By destabilizing the membrane, the sperm prepares for the _______ _______, the _______ _______of the egg’s tough membrane, the ____ _______. The sperm and the egg cell (which has been released from one of the female’s two ovaries) unite in one of the two fallopian tubes.

Answer 48

Human fertilization, 9 months, capacitation, motility, membrane, acrosome reaction, enzymatic penetration, zona pellucida

Question 49

The process leading to pregnancy If pregnancy is considered to begin at the point of implantation, the process leading to pregnancy occurs earlier as the result of the female gamete, or oocyte, merging with the male gamete, or spermatozoon. In medicine, this process is referred to as ___________; in lay terms, it is more commonly known as ____________.

Answer 49

fertilization, conception

Question 50

After the point of fertilization the fused product of the female and male gamete is referred to as a _______ or ________ ___. For species that undergo ________ _________, such as humans, the fusion of male and female gametes usually occurs following the ________________________.

Answer 50

zygote, fertilized egg, internal fertilization, act of sexual intercourse

Question 51

However, the advent of ________ __________ and in ____ _________ have made achieving pregnancy possible without engaging in _______ ____________. This approach may be undertaken as a voluntary choice or due to ________.

Answer 51

artificial insemination, vitro fertilization, sexual intercourse, infertility

Question 52

Egg Cells from the Ovaries Move through the _______ _______

Answer 52

uterine tubes

Question 53

Sperm Morphology Adapted for reaching and fertilizing the egg Head contains ___ and the ________ with _________ for penetrating the egg Midpiece contains ________ to form ___ for _______ Tail is _________ used for __________

Answer 53

DNA, acrosome, enzymes, mitochondria, ATP, energy, flagellum, locomotion

Question 54

Milk production and secretion -_______ develop the ducts system in the breasts -_______ develop the milk-secreting glands which are called _______ -_______ stimulate ____ _______ in the alveoli -_______ stimulate ____ _______ from the alveoli

Answer 54

Estrogen, Progesterone, alveoli, Prolactin, milk synthesis, Oxytocin, milk ejection

Question 55

A _________ is simply a picture of a person’s chromosomes. In order to get this picture, the chromosomes are _________, _________, and _________ under the microscope. Most often, this is done using the chromosomes in the _____ ______ ____. A picture of the chromosomes is taken through the microscope. Then, the picture of the chromosomes is cut up and rearranged by the chromosome’s size. The chromosomes are lined up from largest to smallest.A trained _________ can look for missing or extra pieces of chromosome.

Answer 55

karyotype, isolated, stained, examined, white blood cells, cytogeneticist

Question 56

Extra or missing chromosomes, or abnormal positions of chromosome pieces, can cause problems with a person's ______, ________, and ____ _________.

Answer 56

growth, development, body functions

Question 57

Chromosomes There are __ numbered pairs of chromosomes called _________. The ____ pair of chromosomes are the ___ ___________. They determine an ______ ___. Females have two X chromosomes, and males have an X and a Y chromosome.

Answer 57

22, autosomes, 23rd, sex chromosomes, indivdual's sex

Question 58

Each chromosome has been assigned a number based on its size. The largest chromosome is chromosome __. Therefore chromosome ___ is one of the _______ chromosomes in humans.

Answer 58

1, 18, smallest

Question 59

Chromosome abnormalities often happen due to one or more of these: *Errors during __________________ (_________) *Errors during ________________________ (_________) *Exposure to _________________________ (____________)

Answer 59

dividing of sex cells (meiosis), dividing of other cells (mitosis), substances that cause birth defects (teratogens)