Ch.16: The Reproductive System Flashcards
1
Q
What are gonads?
A
- Primary sex organs
- Testes in males
- Ovaries in females
2
Q
Gonads produce _____ and secrete _____.
A
- Gametes (sex cells)
- Hormones
- Sperm—male gametes
- Ova (eggs)—female gametes
3
Q
What is the anatomy of the male reproductive system?
A
- Testes
- Duct system
- Accessory organs
- External genitalia
4
Q
The duct system in the male reproductive system includes:
A
- Epididymis
- Ductus (vas) deferens
- Urethra
5
Q
The accessory organs of the male reproductive system include:
A
- Seminal glands (vesicles)
- Prostate
- Bulbourethral glands
6
Q
The external genitalia of the male reproductive system include:
A
- Penis
* Scrotum
7
Q
Each testis is connected to the trunk via the spermatic cord, which houses:
A
- Blood vessels
- Nerves
- Ductus deferens
8
Q
Coverings of the testes include:
A
- Tunica albuginea
* Septa
9
Q
What is the tunica albuginea?
A
Capsule that surrounds each testis
10
Q
What are septa?
A
Extensions of the tunica albuginea capsule that extend into the testis and divide it into lobules
11
Q
Each lobule contains _____ to _____ seminiferous tubules
A
- One
- Four
- Tightly coiled structures
- Function as sperm-forming factories
- Empty sperm into the rete testis
12
Q
Sperm travels from the _____ to the _____.
A
- Rete testis
* Epididymis
13
Q
_____ in the seminiferous tubules produce _____ such as testosterone.
A
- Interstitial cells
* Androgens
14
Q
The duct system transports sperm from the body and includes:
A
- Epididymis
- Ductus deferens
- Urethra
15
Q
What is the epididymis?
A
- Highly convoluted tube 6 meters (20 feet) long
- Found along the posterior lateral side of the testis
- First part of the male duct system
- Temporary storage site for immature sperm
- Sperm mature as they journey through the epididymis
- During ejaculation, sperm are propelled to the ductus deferens
16
Q
What is the ductus (vas) deferens?
A
• Runs from the epididymis via the spermatic cord through the inguinal canal and arches over the urinary bladder
*Ampulla
*Ejaculatory duct
• Moves sperm by peristalsis into the urethra
• Ejaculation
• Vasectomy
17
Q
What is the ampulla?
A
End of the ductus deferens, which empties into the ejaculatory duct
18
Q
What is the ejaculatory duct?
A
Passes through the prostate to merge with the urethra
19
Q
What is ejaculation?
A
Smooth muscle in the walls of the ductus deferens create peristaltic waves to squeeze sperm forward
20
Q
What is a vasectomy?
A
Cutting of the ductus deferens at the level of the testes prevents transportation of sperm (form of birth control)
21
Q
What is the urethra in the male reproductive system?
A
- Extends from the base of the urinary bladder to the tip of the penis
- Carries both urine and sperm
- Sperm enters from the ejaculatory duct
22
Q
What are the regions of the male urethra?
A
- Prostatic urethra—surrounded by prostate gland
- Membranous urethra—prostatic urethra to penis
- Spongy (penile) urethra—runs the length of the penis to the external urethral orifice
23
Q
Ejaculation causes the internal _____ to close.
A
- Urethra sphincter
- Prevents urine from passing into the urethra
- Prevents sperm from entering the urinary bladder
24
Q
What are the seminal vesicles of the male reproductive system?
A
• Located at the base of the bladder
• Produce a thick, yellowish secretion (60% of semen) that contains:
*Fructose (sugar)
*Vitamin C
*Prostaglandins
*Other substances that nourish and activate sperm
• Duct of each seminal vesicle joins that of the ductus deferens on each side to form the ejaculatory duct
25
What is the prostate in the male reproductive system?
• Encircles the upper (prostatic) part of the urethra
• Secretes a milky fluid
*Helps to activate sperm
*Fluid enters the urethra through several small ducts
26
What are the bulbourethral glands in the male reproductive system?
• Pea-sized glands inferior to the prostate
• Produce a thick, clear mucus
*Mucus cleanses the spongy (penile) urethra of acidic urine prior to ejaculation
*Mucus serves as a lubricant during sexual intercourse
27
What is semen?
Milky white mixture of sperm and accessory gland secretions
28
What are the components of accessory gland secretions?
* Liquid portion acts as a transport medium to dilute sperm
* Sperm are streamlined cellular “tadpoles”
* Fructose provides energy for sperm cells
* Alkalinity of semen helps neutralize the acidic environment of vagina
* Semen inhibits bacteria
29
What is the scrotum in the male reproductive system?
* Divided sac of skin outside the abdomen that houses the testes
* Viable sperm cannot be produced at normal body temperature
* Maintains testes at 3°Celsius lower than normal body temperature
30
What is the penis?
Male organ of copulation that delivers sperm into the female reproductive tract
31
What are the regions of the penis?
• Shaft
• Glans penis (enlarged tip)
• Prepuce (foreskin)
*Folded cuff of skin around proximal end
*Often removed by circumcision
• Internally there are three areas of spongy erectile tissue around the urethra
• Erections occur when this erectile tissue fills with blood during sexual excitement
32
What are the chief roles of the male in the reproductive process?
* Produce sperm
| * Produce a hormone, testosterone
33
Sperm production begins at _____ and continues throughout life.
* Puberty
| * Millions of sperm are made every day
34
Sperm are formed in the _____ of the testis.
* Seminiferous tubules
* Spermatogonia (primitive stem cells) begin the process by dividing rapidly
* During puberty, follicle-stimulating hormone (F S H) is secreted in increasing amounts
35
Concept Link 1
Recall that F S H is a tropic hormone that, in males, targets the testes and stimulates sperm production (Chapter 9, p. 317).
36
Each division of a spermatogonium stem cell produces:
* Type A daughter cell, a stem cell, that continues the stem cell population
* Type B daughter cell, which becomes a primary spermatocyte, destined to undergo meiosis and form four sperm
37
What is meiosis in spermatogenesis?
* Special type of nuclear division that differs from mitosis
* Occurs in the gonads
* Includes two successive divisions of the nucleus (meiosis I and II)
* Results in four daughter cells (gametes)
38
Gametes are spermatids with __ chromosomes.
* 23
* 23 chromosomes are half the usual 46 found in other body cells
* 23 is known as the haploid number (n)—half the genetic material as other body cells
39
Union of a _____ (23 chromosomes, n) with an _____ (23 chromosomes, n) creates a _____ (2 n, or 46 chromosomes).
* Sperm
* Egg
* Zygote
40
What is spermiogenesis?
* Spermatids are nonmotile and not functional as sperm
* A streamlining process is needed to strip excess cytoplasm from a spermatid and modify it into a sperm
* A sperm has three regions: head, midpiece, tail
* Acrosome sits anterior to the sperm head (nucleus)
* The entire process of spermatogenesis, including spermiogenesis, takes 64 to 72 days
41
During puberty:
* Follicle-stimulating hormone (FSH) begins prodding seminiferous tubules to produce sperm
* Luteinizing hormone (LH) begins activating the interstitial cells to produce testosterone
42
What is testosterone?
```
• Most important hormonal product of the testes
• Stimulates reproductive organ development
• Underlies sex drive
• Causes secondary sex characteristics
*Deepening of voice
*Increased hair growth
*Enlargement of skeletal muscles
*Increased bone growth and density
```
43
What is the anatomy of the female reproductive system?
* Ovaries
* Duct system
* External genitalia
44
The duct system in the female reproductive system includes:
* Uterine (fallopian) tubes
* Uterus
* Vagina
45
What are ovaries?
Produce eggs (ova) and hormones (estrogen and progesterone)
46
Each ovary houses ovarian follicles consisting of:
* Oocyte (immature egg)
| * Follicle cells—layers of different cells that surround the oocyte
47
What are ovarian follicles?
* Primary follicle—contains an immature oocyte
* Vesicular (Graafian) follicle—growing follicle with a maturing oocyte
* Ovulation—the follicle ruptures when the egg is mature and ready to be ejected from the ovary; occurs about every 28 days
* The ruptured follicle is transformed into a corpus luteum
48
What supports the ovary?
* Suspensory ligaments secure the ovaries to the lateral walls of the pelvis
* Ovarian ligaments anchor ovaries to the uterus medially
* Broad ligaments, a fold of peritoneum, enclose and hold the ovaries in place
49
What are the uterine (fallopian) tubes?
* Form the initial part of the duct system
* Receive the ovulated oocyte from the ovaries
* Provide a site for fertilization
* Empty into the uterus
* Little or no contact between ovaries and uterine tubes
* Supported and enclosed by the broad ligament
50
What is the uterine (fallopian) tube structure?
Infundibulum
• Distal, funnel-shaped end
Fimbriae
• Fingerlike projections of the infundibulum
• Receive the oocyte from the ovary
• Cilia located inside the uterine tube transport the oocyte
51
What is the function of the uterus?
* Situated between the urinary bladder and rectum
* Size and shape of a pear, in a woman who has never been pregnant
* Receives, retains, nourishes a fertilized egg
52
What supports the uterus?
* Broad ligament suspends the uterus in the pelvis
* Round ligament anchors the uterus anteriorly
* Uterosacral ligament anchors the uterus posteriorly
53
What are the regions of the uterus?
* Body—main portion
* Fundus—superior rounded region above where uterine tube enters
* Cervix—narrow outlet that protrudes into the vagina
54
What are the layers of the uterus?
* Endometrium
* Myometrium
* Perimetrium (visceral peritoneum)
55
What is the endometrium of the uterus?
* Inner layer (mucosa)
* Site of implantation of a fertilized egg
* Sloughs off if no pregnancy occurs (menstruation or menses)
56
What is the myometrium of the uterus?
The middle layer of smooth muscle that contracts during labor
57
What is the perimetrium (visceral peritoneum) of the uterus?
The outermost serous layer of the uterus
58
What is the vagina?
* Passageway that extends from cervix to exterior of body and is located between urinary bladder and rectum
* Serves as the canal that allows a baby or menstrual flow to leave the body
* Female organ of copulation
* Receives the penis during sexual intercourse
* Hymen—partially closes the vagina until it is ruptured
59
The female external genitalia, or vulva, includes:
* Mons pubis
* Labia
* Clitoris
* Urethral orifice
* Vaginal orifice
* Greater vestibular glands
60
What is the mons pubis?
* Fatty area overlying the pubic symphysis
| * Covered with pubic hair after puberty
61
What is the labia?
```
• Skin folds
• Labia majora
*Hair-covered skin folds
*Enclose the labia minora
*Also encloses the vestibule
• Labia minora—delicate, hair-free folds of skin
```
62
What is the vestibule in the female reproductive system?
* Enclosed by labia majora
| * Contains external openings of the urethra and vagina
63
What are the greater vestibular glands of the female reproductive system?
* One is found on each side of the vagina
| * Secretions lubricate vagina during intercourse
64
What is the clitoris?
• Contains erectile tissue
• Corresponds to the male penis
• The clitoris is similar to the penis in that it is:
*Hooded by a prepuce
*Composed of sensitive erectile tissue
*Swollen with blood during sexual excitement
• The clitoris lacks a reproductive duct
65
What is the perineum?
Diamond-shaped region between the anterior ends of the labial folds, anus posteriorly, and ischial tuberosities laterally
66
The total supply of eggs is determined by:
The time a female is born
67
Ability to release eggs begins at _____ with the onset of the _____.
* Puberty
| * Menstrual cycle
68
Reproductive ability ends at:
Menopause (in female’s fifties)
69
What is oogenesis?
The process of producing ova (eggs) in a female
70
What are oogonia?
* Female stem cells found in a developing fetus
* Oogonia undergo mitosis to produce primary oocytes that are surrounded by cells that form primary follicles in the ovary
71
Primary oocytes are inactive until:
Puberty
72
_____ causes some primary follicles to mature each month.
Follicle-stimulating hormone (FSH)
73
In the female reproductive system, meiosis starts inside:
* The maturing follicle
* First meiotic division produces a larger secondary oocyte and a smaller first polar body
* A vesicular follicle contains a secondary oocyte (maturation from a primary follicle takes about 14 days)
* Ovulation of a secondary oocyte occurs with the release of luteinizing hormone (LH)
* Secondary oocyte is released and surrounded by a corona radiata
74
Meiosis is completed after ovulation only if:
* Sperm penetrates the oocyte
* Ovum is produced
* Two additional polar bodies are produced
* Once ovum is formed, the 23 chromosomes can be combined with the 23 chromosomes of the sperm to form the fertilized egg (zygote)
* If the secondary oocyte is not penetrated by a sperm, it dies and does not complete meiosis to form an ovum
75
What is produced by meiosis?
* Males—produces four functional sperm
| * Females—produces one functional ovum and three tiny polar bodies
76
What is the size and structure of sex cells?
* Sperm are tiny, motile, and equipped with nutrients in seminal fluid
* Egg is large, is nonmotile, and has nutrient reserves to nourish the embryo until implantation
77
Estrogens are produced by follicle cells and cause secondary sex characteristics, such as:
* Enlargement of accessory organs of the female reproductive system
* Development of breasts
* Appearance of axillary and pubic hair
* Increase in fat beneath the skin, particularly in hips and breasts
* Widening and lightening of the pelvis
* Onset of menses (menstrual cycle)
78
Progesterone is produced by the:
• Corpus luteum
• Production continues until LH diminishes in the blood
• Does not contribute to the appearance of secondary sex characteristics
• Other major effects
*Helps maintain pregnancy
*Prepares the breasts for milk production
79
Cyclic changes of the endometrium are about __ days in length.
* 28
* Regulated by cyclic production of estrogens and progesterone by the ovaries
* FSH and LH, from the anterior pituitary, regulate the production of estrogens and progesterone by the ovaries
* Ovulation typically occurs about midway through cycle, on day 14
80
What are the stages of the menstrual cycle?
* Menstrual phase
* Proliferative stage
* Secretory stage
81
Days 1–5 of the menstrual phase:
* Functional layer of the endometrium is sloughed
* Bleeding occurs for 3 to 5 days
* Ovarian hormones are at their lowest levels
* By day 5, growing ovarian follicles are producing more estrogen
82
Days 6–14 of the proliferative stage:
* Regeneration of functional layer of the endometrium
* Endometrium is repaired, thickens, and becomes well vascularized
* Estrogen levels rise
* Ovulation occurs in the ovary at the end of this stage
83
Days 15–28 of the secretory phase:
• Levels of progesterone rise and increase the blood supply to the endometrium, which becomes more vascular
• Endometrium increases in size and readies for implantation
• If fertilization does occur:
*Embryo produces a hormone that causes the corpus luteum to continue producing its hormones
• If fertilization does Not occur:
*Corpus luteum degenerates as LH blood levels decline
*The phases are repeated about every 28 days
84
What are mammary glands?
• Present in both sexes, but function only in females
*Modified sweat glands
• Function is to produce milk to nourish a newborn
• Stimulated by sex hormones (mostly estrogens) to increase in size
85
What are the parts of the mammary gland?
* Areola—central pigmented area
* Nipple—protruding central area of areola
* Lobes—internal structures that radiate around nipple
* Lobules—located within each lobe and contain clusters of alveolar glands
* Alveolar glands—produce milk when a woman is lactating (producing milk)
* Lactiferous ducts—connect alveolar glands to nipple
* Lactiferous sinus—dilated portion where milk accumulates
86
What is mammography?
X-ray examination that detects breast cancers too small to feel
87
The American Cancer Society recommends mammography annually for women between __ and __ years old and every __ years thereafter if the results are normal.
* 45
* 54
* 2
88
Breast cancer is often signaled by:
A change in skin texture, puckering, or leakage from the nipple
89
What is a conceptus?
* Developing offspring
* Embryo—period of time from fertilization until week 8
* Fetus—week 9 until birth
90
What is the gestation period?
From date of last period until birth (approximately 280 days)
91
An oocyte is viable up to __ hours after ovulation.
24
92
Sperm are viable up to __ hours after ejaculation.
* 48
* For fertilization to occur, sexual intercourse must occur no more than 2 days before ovulation and no later than 24 hours after
93
Sperm cells must make their way to the _____ for fertilization to be possible.
* Uterine tube
| * Sperm cells are attracted to the oocyte by chemicals
94
Concept Link 2
Recall the concept of chemotaxis, in which cells move toward or away from a stimulus (positive and negative chemotaxis, respectively) (Chapter 12, p. 406).
95
When sperm reach the oocyte:
* Enzymes break down the follicle cells of the corona radiata around the oocyte
* Sperm undergo an acrosomal reaction
* Membrane receptors on the oocyte pull in the head of the first sperm cell to make contact
* Oocyte undergoes second meiotic division to produce an ovum and a polar body
96
Fertilization occurs when the genetic material of a _____ combines with that of an _____.
* Sperm
| * Oocyte
97
What is a zygote?
* First cell of a new individual
* The zygote is the result of the fusion of DNA from sperm and egg
* The zygote begins rapid mitotic cell divisions, known as cleavage, 24 hours after fertilization
* The zygote journeys down the uterine tube, moving toward the uterus
98
What is cleavage?
* Rapid series of mitotic divisions that begins with the zygote
* 3 days after ovulation, the embryo reaches the uterus and floats as a morula, a ball of 16 cells
99
What is a blastocyst (chorionic vesicle)?
* Hollow, ball-like structure of 100 cells or more
* Secretes human chorionic gonadotropin (h C G) to induce the corpus luteum to continue producing hormones, preventing menses, until the placenta assumes its role
100
What are the functional areas of the blastocyst?
* Trophoblast—large fluid-filled sphere
| * Inner cell mass—cluster of cells to one side
101
By day __ after ovulation, the blastocyst has attached to the endometrium.
7
102
Inner cell mass of blastocyst develops into:
Primary germ layers
• Ectoderm—outside layer, which gives rise to nervous system and epidermis of skin
• Endoderm—inside layer, which forms mucosae and associated glands
• Mesoderm—middle layer, which gives rise to everything else
103
After implantation, the trophoblast of the blastocyst develops:
* Chorionic villi (projections)
| * Chorionic villi combine with tissues of the uterus to form the placenta
104
Once the placenta has formed, the _____ is attached to the placenta by an _____.
* Amnion
* Umbilical cord
* Amnion is a fluid-filled sac that surrounds the embryo
* Umbilical cord is a blood vessel–containing stalk of tissue
105
What is the placenta?
* Forms a barrier between mother and embryo (blood is not exchanged)
* Delivers nutrients and oxygen
* Removes wastes from embryonic blood
* Becomes an endocrine organ and takes over for the corpus luteum (by end of second month); produces estrogen, progesterone, and other hormones that maintain pregnancy
106
What are the events of embryonic and fetal development?
* All organ systems are formed by the end of the eighth week
* Activities of the fetus are growth and organ specialization
* The fetal stage is one of tremendous growth and change in appearance
107
What are the anatomical changes associated with pregnancy?
* Enlargement of the uterus
* Accentuated lumbar curvature (lordosis)
* Relaxation of the pelvic ligaments and pubic symphysis due to production of the hormone relaxin
108
How is the gastrointestinal system affected during pregnancy?
* Morning sickness is common and is due to elevated progesterone and estrogens
* Heartburn is common because of organ crowding by the fetus
* Constipation is caused by declining motility of the digestive tract
109
How is the urinary system affected during pregnancy?
* Kidneys have additional burden and produce more urine
| * The uterus compresses the bladder, causing stress incontinence
110
How is the respiratory systemaffected during pregnancy?
* Nasal mucosa becomes congested and swollen
* Vital capacity and respiratory rate increase
* Dyspnea (difficult breathing) occurs during later stages of pregnancy
111
How is the cardiovascular system affected during pregnancy?
* Blood volume increases by 25% to 40%
* Blood pressure and pulse increase
* Varicose veins are common
112
What is labor?
* The series of events that expel the infant from the uterus
* Rhythmic, expulsive contractions
* Operates by the positive feedback mechanism
113
What is false labor?
Braxton Hicks contractions are weak, irregular uterine contractions
114
During the initiation of labor:
* Estrogen levels rise
* Uterine contractions begin
* The placenta releases prostaglandins
* Oxytocin is released by the pituitary
* Combined effects of rising levels of hormones—oxytocin and prostaglandins—initiates contractions and forces the baby deeper into the mother’s pelvis
115
Concept Link 3
Remember the concept of the feedback loop (see Chapter 1, p. 19). A stimulus triggers a receptor, the information is sent to the brain for processing, and a signal is sent to an effector with instructions for a response. Most of the feedback in the body is negative feedback, in which the response decreases the initial stimulus. Labor, however, involves positive feedback: The response (stronger contractions) actually increases the initial stimulus (oxytocin release) until the child is born.
116
What is dilation?
* Cervix becomes dilated
* Full dilation is 10 centimeters
* Uterine contractions begin and increase
* Cervix softens and effaces (thins)
* The amnion ruptures (“breaking the water”)
* Longest stage, at 6 to 12 hours
117
What is expulsion?
* Infant passes through the cervix and vagina
* Can last as long as 2 hours, but typically is 50 minutes in the first birth and 20 minutes in subsequent births
* Normal delivery is head-first (vertex position)
* Breech presentation is buttocks-first
118
What is the placental stage of labor?
* Delivery of the placenta
* Usually accomplished within 15 minutes after birth of infant
* Afterbirth—placenta and attached fetal membranes
* All placental fragments should be removed to avoid postpartum bleeding
119
Gender is determined at:
* Fertilization
* Males have XY sex chromosomes
* Females have XX sex chromosomes
120
Reproductive system structures of males and females are _____ during early development.
Identical
121
Gonads do not begin to form until:
The eighth week
122
The presence or absence of _____ determines whether male or female accessory reproductive organs will form.
Testosterone
123
The reproductive system is _____ during childhood.
Inactive
124
Reproductive system organs do not function for childbearing until:
Puberty
125
Puberty usually begins between ages __ and __.
* 10
| * 15
126
What signals the onset of puberty?
Males
• Enlargement of testes and scrotum signals onset of puberty (often around age 13)
Females
• Budding breasts signal puberty (often around age 11)
• Menarche—first menstrual period (usually occurs about 2 years later)
127
What is menopause?
• A whole year has passed without menstruation
• Ovaries stop functioning as endocrine organs
• Childbearing ability ends
Hot flashes and mood changes may occur
• There is a no equivalent of menopause in males, but there is a steady decline in testosterone
128
What is contraception?
Birth control
129
What is the birth control pill?
* Most-used contraceptive
* Relatively constant supply of ovarian hormones from pill is similar to pregnancy
* Ovarian follicles do not mature, ovulation ceases, menstrual flow is reduced
130
What is the morning-after pill (MAP)?
* Taken within 3 days of unprotected intercourse
| * Disrupts normal hormonal signals to the point that fertilization is prevented
131
Other hormonal birth control devices that cause cervical mucus to thicken include:
* Minipill (tablet)
| * Norplant (rods placed under the skin)
132
What is an intrauterine device (IUD)?
* Plastic or metal device inserted into uterus
| * Prevents implantation of fertilized egg
133
What is sterilization?
* Tubal ligation (females)—cut or cauterize uterine tubes
| * Vasectomy (males)—cut or cauterize the ductus deferens
134
What is coitus interruptus?
Withdrawal of penis prior to ejaculation
135
What is rhythm (fertility awareness)?
* Avoid intercourse during period of ovulation or fertility
* Record daily basal temperature (body temperature rises after ovulation)
* Record changes in pattern of cervical mucus
136
What are barrier methods?
* Diaphragms
* Cervical caps
* Condoms
* Spermicidal foams
* Gels
* Sponges
137
What is an abortion?
Termination of pregnancy
138
What is a miscarriage?
Spontaneous abortion is common and frequently occurs before a woman knows she is pregnant
139
What is RU486?
* “Abortion pill”
| * Induces miscarriage during first 7 weeks of pregnancy
