Compendium Review Seven -- Reproduction

Katie Meyers

Compendium Review Seven – Reproduction

Human Life Cycle

• Overview of events in human life cycle
• Aging

Reproductive Organs (Genitals)

• 5 functions
• Male reproductive system
• Overview of male reproductive organs
• Steps of male reproductive system
• Ejaculation
• Testes
• Female reproductive system
• Organs
• External genitals
• Meiosis
• Female hormones
• Uterine cycle – non-pregnant
• Ovarian cycle – non-pregnant
• Uterine and ovarian cycles – pregnant
• Menopause

Birth Control Options, Infertility, and STDs

• Birth Control – some examples
• Infertility
• STDs – sexually transmitted diseases
• Viral
• Bacterial
• Prevention

Fetal Development at Birth

• Fertilization
• Implantation
• Processes of Development
• Extraembryonic membranes
• Development stages
• Pre-embryonic development
• Embryonic development
• Fetal development
• Genital development
• Pregnancy and birth
• Parturition
• Placenta
• Mother/fetus blood never mixes
• Umbilical cord
• Maternal changes in female anatomy
• How mother can prevent birth defects
• Birth
• 3 stages
• Many different approaches

Human Life Cycle

• Overview of events in human life cycle (in order)
• Meiosis
• “Reduction division”
• Occurs only in sex organs
• Fertilization
• Fetal Development
• Birth
• Childhood/Adolescence
• Puberty – when a child becomes, by a series of event, a sexually competent adult
• Reproductive system does not fully function until puberty is complete
• Occurs…
• 11 – 13 in females
• 14 – 16 in males
• Adulthood

• (found on slide 4 of Reproduction – BIO 156 PowerPoint presentation)
• During this stage, adults’ sex organs perform meiosis in preparation of having children
• Aging
• Death
• Changes to each of these stages is due to the aging process

Reproductive Organs (Genitals)

• 5 functions
• 1)
• Males – produce sperm within testes
• Females – produce eggs within ovaries
• 2)
• Males – nurture, transport, and eject sperm
• Females – transport eggs to uterus
• 3)
• Males – penis delivers sperm to…
• Females – …vagina – takes in sperm, ejects menstrual fluid, is birth canal
• 4)
• Females – uterus allows fertilized egg to develop and be nourished within a female
• Females – breasts provide nourishment after birth
• 5)
• Both – testes/ovaries produce respective sex hormones
• These hormones bring about masculinization/feminization
• Females – allow pregnancy to continue
• During sexual intercourse, both male and female will ideally experience orgasms
• Male Reproductive System
• (Overview of) Male Reproductive Organs

• (found on slide 6 of Reproduction – BIO 156 PowerPoint presentation)
• Testes – produce sperm and sex hormones; primary sex organ; plural (there are two)
• Millions of sperm in just a few drops of testicular fluid
• Scrotum – sacs that suspend testes (two of them)
• Epididymides – ducts; store sperm; this is where sperm also matures
• Vasa deferentia – conduct and store sperm
• Seminal vesicles – contribute nutrients and fluid to semen
• Prostate gland – contributes fluid to semen
• Urethra – conducts sperm
• Bulbourethral glands – contribute fluid containing mucous to semen
• Penis – sexual intercourse organ
• Prepuce – part of penis; removed during circumcision
• Steps of the male reproductive system
• Sperm is produced in left and right testes
• The vas deferens (left, right) carry it up into the abdominal cavity
• At base of penis, it (sperm) joins with urethra
• Semen produced by prostate and seminal glands at the penis’s base
• Ejaculation occurs
• When sperm travel from testes, are joined by semen, and ejected through erect penis
• At time of ejaculation, sperm leaves penis by means of semen
• 3 types of vesicles/glands add secretions to seminal fluid (see above: seminal vesicles, prostate gland, bulbourethral glands)
• Seminal fluid
• Each component is different and has a particular function
• Basic solution (more viable)
• Sugar fructose (provide sperm with energy)
• Prostaglandins (chemicals that contract uterus, moving sperm toward egg)
• Testes
• Begin developing inside abdominal cavity, descend into scrotal sacs during last two months of fetal development
• Scrotum regulates their temperature by holding them closer/farther from body, depending on their current temperature and the environment
• Each composed of…

• (found on slide 7 of Reproduction – BIO 156 PowerPoint presentation)
• Lobules
• Contain one to three seminiferous tubules
• Packed with cells undergoing spermatogenesis (production of sperm) by meiosis
• Seroti cells support, nourish, and regulate spermatogenesis
• Sperm not ejaculated is reabsorbed by testicular tissue
• It takes approximately 74 days for sperm to develop from spermatogenesis into sperm
• Mature sperm (spermatozoa) – 3 parts
• Head – nucleus covered by acrosome (which stores enzymes to penetrate egg)
• Middle piece – has mitochondria that provide energy for tail movement
• Tail – flagellum
• Do not live more than 48 hours in female genital tract
• Interstitial cells
• Live between seminiferous tubules
• Secrete sex hormone
• Most important sex hormone is testosterone

• (found at http://www.andrologyaustralia.org/images/pageContentImages/MI_Image_Jul2005_04.jpg)
• Hypothalamus controls testes’ sexual function
• Secretes hormone gonadotropin – releasing hormone (GnRH)
• 2 types
• Follicle-stimulating hormone (FSH)
• Luteinizing hormone (LH)
• Used in negative feedback relationship; maintains fairly constant production of sperm and testosterone
• Female Reproductive System
• Organs

• (found on slide 9 of Reproduction – BIO 156 PowerPoint presentation)
• Ovaries – produce eggs (oocytes) and sex hormones (estrogen and progesterone)
• Site of initial meiosis, where unfertilized eggs are produced
• Oviducts – conduct eggs; location of fertilization in uterine/fallopian tubes specifically; lined with cilia
• Uterus (womb) – houses developing fetus
• Placenta – sustains development of embryo/fetus
• Cervix – contains opening to uterus
• Hysterectomy – removal of cervix; a form of sterilization
• Vagina – receives penis during sexual intercourse
• Birth canal
• Exit for menstrual flow
• Acidic environment
• External genitals
• Collectively known as the vulva
• 2 labia majora (folds of skin)
• Mons pubis
• Labia minora – similar to labia majora, just closer to vagina
• Urethra and vagina openings inside labia minora
• Glans clitoris
• Hymen – partially closes vagina; ring of tissue (virginity)
• Meiosis
• Occurs in ovaries
• Phase One
• Occurs in fetal ovary
• One egg per month (ovulation part of menstrual cycle) matures and bursts from ovarian wall and taken up into the fallopian tube
• Phase Two
• Occurs moment egg is fertilized, if that even happens
• Possibly very large gap between phases
• Female hormones
• Ovaries’ production of hormones

• (found on slide 10 of Reproduction – BIO 156 PowerPoint presentation)
• Primary follicles – produce estrogen
• Secondary follicles – produce estrogen and some progesterone
• Corpus luteum – produces progesterone
• Hypothalamus – same function in females as in males
• Hormone secretion (GnRH, FSH, LH) not constantly present, but secreted at different rates during menstrual cycle
• Estrogen – responsible for secondary female sex characteristics, e.g. body hair, fat distribution
• Estrogen and progesterone both required for breast development
• Uterine cycle – non-pregnant – average 28-day cycle
• Menstruation – days 1-5
• Endometrium breaks down
• Proliferative phase – days 6-13
• Endometrium rebuilds
• Secretory phase – days 15-28
• Endometrium thickens
• Glands become secretory
• Ovarian cycle – non-pregnant – average 28-day cycle (occurs simultaneously with uterine cycle)
• Follicular phase – days 1-13
• Follicle maturation occurs
• Estrogen secretion prominent
• Ovulation – day 14
• LH spike occurs
• Luteal phase – days 15-28
• LH secretion occurs
• Corpus luteum forms
• Progesterone secretion prominent
• Here is a picture of both the uterine and ovarian non-pregnant cycles

• (found on slide 11 of Reproduction – BIO 156 PowerPoint presentation)
• Here is a picture of both the uterine and ovarian pregnant cycles – unlike non-pregnant cycle, progesterone does not drop (because it helps maintain uterus wall in preparation of pregnancy)

• (found on slide 12 of Reproduction – BIO 156 PowerPoint presentation)
• Menopause – when ovarian cycle stops
• Begins between the ages of 45 and 55

Birth Control Options, Infertility, and STDs

• Birth Control – some examples

• (found on slide 13 of Reproduction – BIO 156 PowerPoint presentation)
• Abstinence – most reliable
• Prevents transmission of STDs
• Family planning – on of the least effective options
• 70% family planners succeed with the program
• Specifically female
• Contraceptives – medications, e.g. birth control pills
• Contraceptive implants – capsule that utilizes synthetic progesterone, prevents ovulation
• Contraceptive injections – either progesterone only or a progesterone/estrogen mix
• From a few weeks to three months between shots
• Contraceptive vaccines – immunize woman to hormones associated with egg production, e.g. HCG
• “Morning-after pills” – emergency contraception
• Intrauterine device (IVD) – small molded plastic piece inserted into uterus by physician
• Mostly inhibits fertilization
• Makes implanting impossible
• Diaphragm – soft latex cup with flexible rim
• Lodges behind pubic bone, fits over cervix
• Individually fitted
• Used with spermicidal jelly or cream
• Put in no more than two hours before sexual activity
• Remove at least six hours after sexual activity
• Female condom – large polyurethane tube
• Open end has ring that covers external genitals
• Considered a barrier method
• Renewed interest in STD protection possibility
• Tubal ligation – cuts and seals oviducts
• Brings about sterilization
• Should be considered permanent
• Specifically male
• Male condom – latex sheath goes over erect penis
• Better form of protection if used with spermicide
• Same as female condom in that it is considered a barrier method
• Renewed interest in STD protection possibility
• Vasectomy – cuts and seals vas deferens

• (found on slide 8 of Reproduction – BIO 156 PowerPoint presentation)
• Form of sterilization
• Should be considered permanent
• Infertility
• Definition – failure of a couple achieving pregnancy after one year of effort (unprotected, regular intercourse)
• Estimated 15% of couples infertile
• 40% -- males; low sperm count or much abnormal sperm
• 40% -- females; body weight
• 20% -- both
• Assisted reproductive technologies
• Artificial Insemination by Donor – sperm placed into vagina by physician
• In Vitro Fertilization – conception in lab glassware
• Gamete Intrafallopian Transfer – similar to IVF
• Eggs removed and reintroduced in same procedure/time period
• Surrogate mothers – paid women bring stranger’s baby to term
• Intracytoplasmic sperm injection
• Used in sever male fertility problems
• One sperm directly injected into egg
• STDs – sexually transmitted diseases
• Viral – none curable yet
• HIV infection – fatal
• Genital warts
• Caused by human papillomavirus (HPV)
• Genital herpes
• Caused by herpes simplex virus
• Type One – cold sores, fever blisters
• Type Two – genital herpes
• Above two very common and uncomfortable
• Hepatitis
• Infects liver by failure, cancer, or death
• Easily transmittable
• No immediate consequences
• ABCDEG
• A – not sexually transmitted; fecal to mouth
• BCDEG – transmitted by…
• Sexual contact
• Contaminated blood
• B – most common sexually transmitted hepatitis; can lead to liver failure
• CDEG – liver cancer possibilities; no vaccines yet available
• Bacterial – curable with antibiotics
• Chlamydia
• Gonorrhea – 40% strains now resistant to antibiotic therapy
• Syphillis – 3 stages
• Bacterial vaginosis (BV)
• Responsible for about 50% of vaginitis in American women
• “Caused by a disruption of the normal flora in the vagina leading to an overgrowth of certain bacteria” (from slide 16 of Reproduction – BIO 156 PowerPoint presentation)
• Candida albicans
• Overgrowth of normal yeast in vagina
• Characterized by – tissue that is red, inflamed, itchy; with, curdy discharge sometimes too
• Women using birth control hormones/antibiotics more prone
• Trichomonas vaginalis
• Caused by a type of protozoan
• Causes – frothy discharge, foul smell, itching
• Common cause of vaginitis
• Ways to prevent STD transmission
• Abstinence
• Long-term monogamous relationship(s)
• Be aware of partner’s STD history and risky (STD-wise) behavior
• Practice safe sex

Fetal Development and Birth

• Fertilization – union of sperm and egg resulting in zygote

• (found at http://www.bio.davidson.edu/Courses/Molbio/MolStudents/spring2005/Dresser/sperm%20and%20egg%20fusion.jpg)
• Flagellum on sperm finds (swims towards) egg
• Sperm head only (nucleus) fuses with egg’s nucleus
• Zygote receives cytoplasm and organelles from mother only
• Approximately one week from fertilization to implantation
• During that week, only mitosis occurs
• Implantation
• Normally in uterine wall
• Ectopic pregnancy – when a fertilized egg implants before getting to uterine wall, e.g. oviduct
• Can be dangerous, lead to hemorrhaging
• First step to take if pregnancy is suspected – find where zygote implanted
• Processes of Development
• Cleavage – occurs during mitotic cell division of the zygote
• Growth – cell division accompanied by daughter cells becoming larger
• Morphogenesis – shaping of the embryo
• First evident when some cells move/migrate compared to the other cells – such movements make embryo assume various shapes
• Differentiation – when cells take on specific structure and/or function
• Extraembryonic membranes

• (found at http://img.tfd.com/dorland/thumbs/amnion.jpg)
• Outside embryo
• 4 types
• Chorion – develops into fetal half of placenta
• Allantois – extends away from embryo
• Deal with kidneys/urinary tract and has umbilical blood vessels
• Yolk sac – first to appear of the four
• Contains many blood vessels – first site of blood cell formation
• Amnion – enlarges relative to embryo/fetus
• Contains cushioning fluid to protect embryo/fetus
• Overview of early embryonic development (about first month)
• “Basic body plan laid down”
• “No organs formed”
• “Placenta develops”
• “Very little growth, fetus still tiny”
• Above quotes from slide 20 of Reproduction – BIO 156 PowerPoint presentation
• Development Stages
• Pre-embryonic development
• Contains the events of the first week
• Zygote division while traveling down oviduct to uterus

• (found on slide 19 of Reproduction – BIO 156 PowerPoint presentation)
• Embryonic development

• (from slide 20 of Reproduction – BIO 156 PowerPoint presentation)
• Goes from second week to end of second month
• Week two – embryo begins implanting in uterus
• Gastrulation occurs
• Turns inner cell mass into embryonic disk
• An example of morphogenesis
• At completion, there is…
• 3 primary germ layers

• (found on slide 21 of Reproduction – BIO 156 PowerPoint presentation)
• Ectoderm
• Mesoderm
• Endoderm
• Embryonic disk has become embryo
• Week three – two important organ systems appear
• Nervous system
• Heart (both third and fourth weeks)
• Week four – body stalk (future umbilical cord) connect embryo to chorion; limb buds (flippers) appear
• Week five – head enlarges; sense organs gain prominence; visual development (possible to see) of eyes, ears, and nose
• Week six to week eight – embryo changes into recognizable human being; head achieves normal relationship with body; neck region develops; nervous system responsive (to reflex actions); all organ systems established
• Fetal development – fetus is recognizably human
• Month three – fingernails appear; gender distinguishable by ultrasound
• Month four – skeleton visible; hair begins appearing; cartilage begins being replaced by bone
• Month five – heartbeat heard; vernix caseosa (cheesy protective coating) begins being deposited; mother begins feeling movment – pregnancy obvious
• Month six – body covered with lanugo (fine hair); wrinked and reddish skin
• Month seven – testes descend into scrotum; eyes are open; possible for baby to survive if born now
• Month eight – body hair begins disappearing; depositing of subcutaneous fat begins
• Month nine – fetus ready for birth and about 20 ½ inches long and 7 ½ pounds
• Male and female development of genitals

• (found at http://www.mie.utoronto.ca/labs/lcdlab/biopic/fig/41.13.jpg)
• Development of gonads and ducts, development of external genitals
• Sex of fetus determined at fertilization
• Males – XY
• Male XX syndrome
• Females – XX
• Female XY syndrome
• Both syndromes result in ambiguous sex determination
• Gonads do not start developing until the seventh week
• At six weeks, males and females have same types of ducts
• At fourteen weeks, primitives testes/ovaries are located deep inside abdominal cavity
• Pregnancy and birth
• Parturition – process of birthing offspring
• Placenta – source of progesterone and estrogen during pregnancy
• 2 sides
• Fetal side – contributed by chorion
• Maternal side – consisting of uterine tissue
• Placental hormones cause…
• Fluctuations in energy levels
• Uterus relaxation
• Pulmonary values to increase
• Stress incontinence
• Decreased venous return
• Edema
• Varicose veins
• Stretch marks (Striae gravidarum)
• Peptide hormone (from placenta) brings about pregnancy-induced diabetes
• Mother/fetus blood never mixes

• (found at http://images.main.uab.edu/healthsys/ei_0181.gif)
• Umbilical cord – fetus’s lifeline
• Contains umbilical arteries and vein
• Maternal changes in female anatomy
• Shift in organs
• Bladder and rectum pushed superiorly and squeezed, resulting in changes in urination and defecation patterns
• Stomach is compressed, making the mother eat more often, but less at every meal
• Appetite change due to immune response changing to avoid possible poisons for the fetus’s sake
• “Postural changes to compensate for anterior weight” (found on slide 22 of Reproduction – BIO 156 PowerPoint presentation)
• Breasts enlarge because of milk production
• First milk production begins around the sixth month of pregnancy
• How mother can prevent birth defects
• Get a physical exam
• Have good health habits
• Avoid…
• Drinking alcohol
• Smoking cigarettes
• Taking illegal drugs
• Taking medications not approved by your physician
• Exposure to environmental toxins and radiations
• Help prevent conditions associated with birth
• Birth
• 3 stages

• (found at http://www.scienceclarified.com/images/uesc_02_img0089.jpg)
• Stage One
• Effacement – taking up the cervix – done by uterine contractions
• Amniotic membrane ruptures, if it has not already
• First stage of parturition ends once cervix is completely dilated
• Stage Two
• Beings when uterine contractions occur every one to two minutes and last about one minute each
• Mother has desire to push, or bear down
• As soon as head is delivered physician may hold head and guide it downward
• After birth, umbilical cord is cut and tied once baby is breathing normally and functioning independently
• Stage Three
• Afterbirth (placenta) is delivered about 15 minutes after delivery
• Many different approaches to the birthing and the child-raising processes