Chapter 28: The Reproductive Systems Flashcards

1
Q

What is sexual reproduction?

A

The process by which organisms produce offspring by making germ cells called gametes

After fertilization - when the male gamete (sperm cells) unites with the female gamete (secondary oocyte) - the resulting cell contains one set of chromosomes from each parent

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2
Q

Define gonads

A

Testes in males and ovaries i females produce gametes and secrete sex hormones

Various ducts the store and transport the gametes, and accessory sex glands produce substances that protect the gametes and facility their movement

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3
Q

Define the scrotum and the following components: raphe, scrotal septum, dartos muscle, cremaster muscle

A

The scrotum is the supporting structure for the testes, consists of loose skin and underlying subcutaneous layer that hands from the root (attached portion of the penis)

The raphe is a median ridge that separates the single pouch into lateral portions

Scrotcal septum divides the scrotum internally into two sacs, each containing a single testis

Dartos muscle is a muscle tissue which is composed of bundles of smooth muscle fibers that makes up the septum

Cremaster muscle is assorted with each testis and is a series of small bands of skeletal muscle that descend as an external of the internal oblique thought the spermatic cord to surround the testes

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4
Q

Define the testes and the following components: tunica vaginalis, tunica albuginea, lobules, seminferous tubules

A

The testes (testicles) are paired oval glands in the scrotum - they develop near the kidneys and begin their descent into the scrotum through the inguinal canals during the latter half of the 7th month of fetal development

tunica vaginalis - serous membranes which is derived from the peritoneum and forms during the descent of the testes, partially covered the testes

tunica albuginea - internal to the tunica vaginalis and is a dense irregualar connective tissue that extends untoward, forming a septa that divide the testes into series of internal compartments called lobules

lobules - each of the 200-300 lobules contains 1-3 highly coiled tubules, the seminiferous tubules, where sperm are produced

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5
Q

Define spermatogenesis

A

The production of sperm from seminiferous tubules

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6
Q

What are the 2 types of seminiferous tubules?

A

Spermatogenic cells - sperm-forming cells

Sustentacular cells (sertoili cells)- have several function in supporting spermatogenesis and extend from the basement membrane to the lumen of the tubule

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7
Q

Define spermatogonia (spermatogonium)

A

Stem cells that service from primordial germ cells that areas form the yolk sac and enter the testes during the 5th week of development

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8
Q

Where is a sperm cell (spermatozoon) released?

A

Once formed, it is released into the lumen of the somniferous tubule

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9
Q

What is the blood-testis barrier?

A

The junction of neighbouring sustentacular cells, referred to as a barrier because substances must first pass through the sustentacular cells because they can reach the developing sperm

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10
Q

What are interstitial cells of leydig cells in the testicles?

A

They are spaces between adjacent seminiferous tubules which secrete testosterone, the most prevalent androgen

An androgen is a hormone that promotes the development of masculine characterietics

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11
Q

Describe the process of spermatogenesis

A

Take 65-75 days and begins with the spermatogonia, which contain the dipped number of chromosomes

Spermatogonia are types of stem cells; when they undergo mitosis, some spermatozoa remain near the basement membrane of the seminiferous tubules in an undifferentiated state and the rest squeeze through the tight junctions of the blood-testis barrier, undergo developmental changes and differentiate into primary spermatocytes

Shortly after formed, each primary spermatocyte replicates it DNA and meiosis beings (46 chromosomes)

The two cells formed by meiosis I are called secondary spermatocytes - each chromosome has two chromatids

The 4 haploid cells resulting from meiosis II are called spermatids

The final stage is sperminogensis, the development of haploid spermatids into sperm

No cell division occurs in spermiogensis each spermatid becomes a single sperm cells where spherical spermatids transform into elongated, slender sperm and are released from there connections to sustenacular cells, and event known as spermiation

Sperm enters the lumen of the seminiferous tubule

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12
Q

Define the following compoentners of sperm: head, nucleus, acrosome, tail, neck, middle piece, principal pieces

A

head - the flattened, pointed head contains a nucleus with 23 highly condensed chromosomes

acrosome - caplike vesicle filled with enzymes that covers 2/3 if the nucleus and helps a sperm to penetrate a secondary oocyte to bring about fertilization

tail - subdivide into 4 parts:
1. neck: the constricted region just behind the head that contains centrioles

  1. Middle piece: contains mitochondria arranged in a spiral, which provide the energy (ATP) for locomotion of sperm to the site of fertilization and for sperm - - metabolism
  2. principal piece : longest portion of the tail
  3. end piece: the terminal, tapering proton of the tail
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13
Q

Describe how the following hormones affect testicular function:

Gonadotrophin-releasing hormone (GnRH)
Luteinizing hormone (LH)
Follicle-stimulating hormone (FSH)
Inhibin

A

Gonadotrophin-releasing hormone (GnRH) - stimulates gonadotrophs in the anterior pituitary to increase their secretion of the gonadotropins:

  • Luteinizing hormone (LH) - stimulates interstitial cells located between seminiferous tubules, to secrete testosterone (steroid hormone synthesized from cholesterol in the testes and principal androgen)
  • Follicle-stimulating hormone (FSH) - stimulates spermatogenesis acting synergistically with testosterone on sustentacular cells to simulate secretion of androgen-binding protein into the lumen which binds to testosterone kepis its concentration high

Inhibin is released by sustentacular cells once degree of spermatogenesis is required which inhibits FSH release

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14
Q

Describe the ducts of the testis

A

Pressure generates by the fluid secreted by systentacular cells pushes sperm and fluid along the lumen of the seminiferous tubules and then into a series of very short functs called straight tubules

These tubules lead to a network of ducts in the testis called the rate testis

Sperm then moves into a series of coiled efferent ducts in the epidemic that empty into a single tube called the ductus epididymis

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15
Q

What is the function of sterocilia on the ductus epididymis?

A

Increases SA for reabsorption of degenerated sperm

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16
Q

Define sperm maturation

A

Epididymis is the site for sperm maturation, the process by which sperm squires motility and the ability to fertilize an ovum

This occurs over a period of about 14 days and the epidemic propels sperm into the ductus defers during sexual arousal by peristaltic contraction of its smooth muscle and also stores stem, which remains viable up to several months

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17
Q

Describe the location and function of the ductus defers

A

A duct that is long and ascends along the posterior border of the epididymis through the spermatic cord and then enters the pelvic cavity where it lips over the ureter and passes over the side and down the posterior side of the urinary bladder

The terminal portion is the ampulla

Functionally, it conveys sperm during sexual arousal from the epididymis toward the uretra and can also store sperm

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18
Q

What is the spermatic cord?

A

A supporting structure of the male reproductive system that ascends out of the scrotum and consists of the ductus deferent as it ascends through the scrotum, testicular artery, veins that drain the testes & carry testosterone into circulation, autonomic nerves, lymphatic vesicles, and the cremaster muscle

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19
Q

Describe the ejaculatory duct

A

Formed by the union of the duct from the seminal vesicle and the ampulla of the ductus deferens

The short ejaculatory ducts form just superior to the base of the prostate and they terminate in the prosthetic urethra, where the eject sperm and seminal vesicle secretions just before the release of semi of the urethra to the exterior

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19
Q

Describe the ejaculatory duct

A

Formed by the union of the duct from the seminal vesicle and the ampulla of the ductus deferens

The short ejaculatory ducts form just superior to the base of the prostate and they terminate in the prosthetic urethra, where the eject sperm and seminal vesicle secretions just before the release of semi of the urethra to the exterior

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20
Q

Describe the urethra and 3 subdivisions: prostatic ureetha, membranous uretra, and spongy urethra

A

The urethra is the shared terminal duct of the reproductive and urinary systems; it serves as a passageway for both semen and urine

Prostatic urethra - 2-3cm long and passes through the prostate and continues inferiorly

Intermediate (membranous) uretha - 1cm longhand passes though the deep muscles of the perineum

Spongy urethra - the duct passes through the corpus spongiosum of the penis that ends at the external urethral orifice

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21
Q

Describe the following accessory sex glands:

Seminal vesicles
Prostate
Bulbourehtral glands

A

Seminal vesicles - paired vesicles or seminal glands are convoluted pouch like structures, lying posterior to the base of the urinary bladder and anterior to the rectum; secretes seminal fluid that helps neutralize the acidic environment, fructose used for ATP production, prostaglinds contribute to motility and viability

Prostate - single, doughnut-shaped gland about the size of a golf ball; slowly increases in size from birth to puberty and then rapidly expands after 30 and then again at 45

Bulbourehtral glands - about the size of peas that are located on either size of the membranous urethra and secrete an alkaline fluid into urethra that protects the passing sperm from urine during sexual arousal

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22
Q

Describe semen

A

Semen is a mixture of sperm and seminal fluid, a liquid that consists of the secretions of the seminiferous tubules, seminal vesicles, prostate, and bulbourethral glands

Has an alkaline pH of 7.2-7.7

Ejaculation is typically 2.5-mlM with 50-150 million sperm/mL; if the number falls between 20 million/mL

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23
Q

Describe the penis and the following components: corpora cavernous penis, corpus spongiosum penis, erecitce tissue, glans penis, external urethral orfice, and prepuce (foreskin)

A

The penis contains the urethra and is a passageway for the ejaculation of semen and the excretion of urine - it consists of a body, glans penis and a roots

The body of the penis is composed of 3 cylindrical masses of tissues - the two dorsolateral masses called the corpora cavernous penis
- The smaller midvental mass, the corpus spongiosum penis, contains the spongy urethra and keeps it open during ejaculation

erectile tissue is composed of numerous blood sinuses lined by endothelial cells and surrounded by smooth muscle and elastic connective tissue

glans penis - the distal end of the corpus spongisium that is slightly enlarged acorn-shaped region

external urethral orfice - terminal slitlike opening

prepuce (foreskin) - covers the glands in an uncircumcised penis

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24
Q

Define erection

A

Parasympathetic fibers from the sacral portion of the spoinal cord imitate and maintain an erection, the enlargement stiffening of the penis

The parasympathetic fibers nitric oxide (NO) which causes smooth muscles of arterioles supplying erectile tissue to relax, which allows these blood vessels to dilate

This causes large amounts of blood to enter the erectile tissue of the penis and causes smooth muscles within the erectile tissue to relax, resulting in widening of the blood sinuses which results in an erection

25
Q

Describe ejaculation

A

Powerful release of semen from the urethra which is a sympathetic refelx coordinated by the lumbar portion of the spinal cord

The smooth muscle sphincter at the base of the urinary bladder closes, preventing using from being expelled during ejaculation and semun from entering the urinary bladder

Even before ejaculation occurs, peristaltic contractions in the epididymis, ductus defers, seminal vesicles, ejaculatory ducts, and prostate propel semen into the penialte portion of the utretal, which leads to emission (pre-cum)

Once stimulation of penis has ended, arterioles suppling the erecticel tissue construct and the smooth muscle contracts, making the blood sinuses smaller relieving pressure and the penis returns to its flaccid state

26
Q

Define the ovaries and the following components: germinal epithelium, tunica albuginea, ovarian follicles, mature folic, and corpus luteum

A

Ovaries are paired glands that are homologs to the testes - they produce gametes and release female sex hormones

germinal epithelium - layer of simple epithelium that covers the surface of the ovary (does not five rise to ova)

tunica albuginea - whitish capsule of dense irregulation connective tissue located immediately deep to the germinal epithelium

ovarian follicles - located in the cortex and consist of oocytes in various stages of development, plus the cells surrounding them

  • When the surrounding cells form a single layer they are called follicular cells
  • Later when they form several layers, they are referred to as granulose cells

mature (graafian) follicle - a large, fluid-filled follicle that is ready to rupture and expel its secondary oocyte, a process known as ovulation

corpus luteum - contains the remnants of a mature follicle after ovulation - produces progesterone, estrogens, relaxin, and inhibin until it deaerates into a fibrous scare tissue called the corpus albicans

27
Q

Describe oogenesis and follicular development up until the secondary follicle

A

Oogenesis is the formation of gametes that occurs in fetal development - primordial gem cells migrate from the yolk sac to the ovaries where the differentiate into oogonia (diploid stem cells)

Even before brith most of these germ cells degrease in a process known as atresia, however some will develop into primary oocytes the enter prophase of meiosis I but do not complete their phase until after puberty

During the arrested stage, each primary oocyte is surrounded by a single layer of flat follicular cells and the entire structure is called a primordial follicle

After puberty (and every month after) gonadotrophin (FSH and LH) stimulate the development of primordial follicles where they start to grow developing into primary follicles

As it developed it forms a glycoprotein called the zona pellucidq between the primary oocyte and granulose cells and basement membrane begins to form an organized layer called the theca folliculi

A primary follicle develops into a secondary follicle

28
Q

Define granulosa cells

A

low-columnar cells that surround the primary oocyte in the later stage of development

29
Q

Describe follicular development following the maturation into a = secondary follicle

A

In a secondary follicle the innermost layer of granulose cells becomes firmly attached to the zona pelucidia and is now called the corona radiata

The secondary follicle becomes larger, turning into a mature follicle and just before ovulation the diploid primary oocyte completes meiosis I, producing 2 haploid cells of unequal size (each 23 chromosomes)
- the smaller cell is the first polar body which is essentially a packed of discarded nuclear material and the larger cells is known as the secondary oocyte and receives most of the cytoplasm

Once a secondary oocyte is formed meiosis II begins but then it stops it metaphase and the mature (graafian) follicle ruptures and releases its secondary oocyte, a process known as ovulation

After fertilization, meiosis II results and the oocyte splits into an ovum (mature egg) and a second polar body

The nuclei of the sperm cell and ovum then inutile, forming a diploid zygote

30
Q

Define infundibulum

A

The funnel shaped portion of the uterine tube (fallopian tube) that is close to the vary but is open to the pelvic cavity

It ends in a fringe of finger-like projections called frimbriae

31
Q

Define the ampulla and ishthmus of the uterine tube

A

Ampulla - the widest longest portion of the tube making up about the lateral 2/3 of its length

Isthmus - the more medial, short, narrow, thick-walled portion that joints the uterus

32
Q

What are the 3 anatomical subdivisions of the uterus ?

A
  1. Fundus - dome-shaped portion superior to uterine tubes
  2. Body - tapering central portion
  3. Cervix - inferior narrow portion that opens into the vagina
33
Q

The interior of the body of the uterus is called the _______ and the interior of the cervix is called _______

A

Uterine cavity; cervical canal

34
Q

What are the 3 layers of tissue in the uterus?

A
  1. Perimetrium (outer) or serosa - is part of the visceral peritoneum and is composed of simple squamous epithelium and areolar connective tissues
  2. Myometrium (middle) consists of 3 layers of smooth muscle fibers that are thickest in the fundus (circular) and thinnest in the cervix (longitudinal)
  3. Endometrium (inner) - highly vascularized and is divided into 2 layers:
    - straum functionalis (functional layer) lines the uterine cavity and sloughs off during menstruation
    - straum basales (deeper) is permanent and gives rise to a new stratum functionalism after each menstruation
35
Q

Describe uterine arteries and spiral arterioles

A

Uterine arteries are branches of the internal iliac artery that supplies blood to the uterus

Spiral arterioles supply the stratum funcitonalis and change markedly during menstrual cycle

36
Q

Define cervcial mucous

A

A mixture of water, glycoproteins, lipids, enzymes, and inorganic salts

during reproductive years, females secrete 20-60 mL of cervical mucous per day - it is much more hospital to sperm at or near the time of locution because it is then less viscous and more alkaline

37
Q

Define the fornix

A

a recess that surrounds the vaginal attachment to the cervix

38
Q

Describe the mucousa of the vagina

A

It is continuous with that of the uterus and consists of non-keratinized stratified squamous epithelium and areolar connective tissue that lies in a series of transverse folds called rugae

39
Q

Describe the muscularis of the vagina

A

Composed of an outer circular layer and an inner longitudinal layer of smooth muscle that can stretch considerably to accommodate the penis during sexual intercourse and during birth

40
Q

Define the hymen

A

A thin fold of vascularized mucous membrane the forms a border around and partially closes the inferior end of the vfainal opening to the exterior, the vaginal orifice

After its rupture only the remnants of the hymen remains

41
Q

Describe the vulva and the components that make it up:

mons pubis 
labia majora 
labia minora 
clitoris 
vestibule
bulb of the vestibule
A

mons pubis - an elevation of adipose tissue covered by skin and coarse pubic hair that cushions the pubic symphysis

labia majora - two longitudinal folds of skin that are covered by pubic hair and contain an abundance of adipose tissue, sebaceous glands, and apocrine sudoriferous glands (scrotum)

labia minora - two smaller folds of skin that are devoid of pubic hair and fat and have few sudoeiferous glands but contain many sebaceous glands (urethra)

clitoris - small cyndrical mass composed to two small erectile bodies; the prepuce of the clitoris is a layer of skin formed at the point where the labia minor unites and covers the body of the clit and the exposed portion is the glands clitoris (glands penis in men)

vestibule - the region between the labia minor which contains the hymen, vaginal orifice, the external urethral orifice, and the openings of ducts on glands

bulb of the vestibule - consist of 2 elongated masses of erectile tissue just deep to the labia on either side of the vaginal orifice; becomes encouraged during sexual arousal

42
Q

Define the greater vestibular glands

A

They are on either side of the vaginal orifice, which open by ducts into a groove between the hymen and labia minora

They produce a small quantity of mucous during sexual arousal that adds to cervical mucous that provides lubrication

43
Q

What is the perineum?

A

the diamond shaped area medial the the thighs and buttocks of both males and females

It contains the external genital and anus

44
Q

What are the ducts of the nipple called?

A

lactiferous ducts, where milk emerges

45
Q

Why is the areola rough?

A

It contains modified sebaceous oil glands

46
Q

what is a mammary gland?

A

A modieif sudoriferous (sweat) gland that produces milk

It consists of 15-20 lobes (or comparemtns), seperated by a variable amount of adipose tissue

In each lobe are smaller comparemtnes called lobules, composed of grape-like clusters of milk-secreting glands termed alveoli

47
Q

Describe how myoepithelial cells are involved in milk production and excretion

A

Contraction of the myoepithelial cells surrounding the alveoli helps propel milk toward the nipples

When milk is being produced, it passes from he alveoli into a series of secondary tubules and then into the mammary ducts

Near the nipple, the mary ducts expand slightly to form sinuses called lactiferous sinuses, where some milk may be stored before draining into a lactiferous duct

Each lactiferous duct typically carries milk from one of the lobes to the exterior

These functions collectively are referred to as lactation

48
Q

What is the uterine cycle?

A

A concurrent series of changes in the endometrium of the uterus to prepare it for the arrival of a fertilized ovum that will develop there until birth

49
Q

What does the female reproductive cycle encompass?

A

The ovarian and uterine cycles, the normal changes that regulate them, and the related cyclical changes in the breasts and cervix

50
Q

Describe the function of each of the following hormones in the uterine and ovarian cycles: GnRH, FSH, LH

A

Gonadotrophin-releasing hormone (GnRH) is is secreted by the hypothalamus and stimulates the release of FSH and LH from the anterior pituitary

FSH initiates follicular growth and androgens under the influence of FSH are taken up by the granulose cells of the follicle and converted into estrogens

LH stimulates further development of ovarian follicles, stimulates the theca cells of a developing follicle to produce androgens, and triggers ovulation

both FSH and LH stimulate the ovarian follicles to secrete estrogens

51
Q

Describe the function of each of the following hormones in the uterine and ovarian cycles: estrogens, progesterone, relaxin and inhibin.

A

Estrogens - secreted by the ovarian follicles and have several important functions:

  • promote development and maintenance of female reproductive structures, feminine secondary sex characteristics, and breast
  • increase protein anabolism
  • lower cholesterol
  • moderate levels inhibit release of GnRH, FSH, and LH

Progesterone - secreted by cells of the corpus letus and functions by:

  • works with estrogens to prepare endometrium for implantation
  • prepares mamary glands to secrete milk
  • Inhibits release of GnRH and LH

Relaxin - produced by corpus luteum during each monthly cycle:

  • inhibits contraction of uterine smooth muscles
  • during labor, increases flexibility of pubic symphysis and dilates uterine cervix

Inhibin - secreted by granulose cells of growing follicles and by the corpus lutem after ovulation:
- Inhibits secretion of FSH and to a lesser extent LH

52
Q

List the 4 phases of the female reproductive cycle

A
  1. Menstrual phase
  2. Preovulatory phase (proliferative phase)
  3. Ovulation
  4. Postovulatory phase
53
Q

What events occur in the ovaries and uterus during the menstrual phase?

A

Menstrual phase - first 5 days of the cycle

Ovaries - Under the influence of FSH, several primordial follicles develop into primary and then into secondary follicles (however, the follicles that develop may not reach maturity until several cycles later)

Uterus - menstrual flow caused by shedding of the endometrium that occurs because the declining levels of progesterone and estrogens stimulate release of prostaglandins that cause uterine spiral arterioles to constrict and the cells become oxygen deprived and start to die

54
Q

What events occur in the ovaries and uterus during the proliferative (preovulatory) phase?

A

The time between the end of menstruation and ovulation (days 6-13)

Ovaries - secondary follicles begin to secrete estrogens and inhibin and one secondary follicle outgrows the other and becomes the dominant follicle and the others stop growing and undergo atresia

Uterus - estrogens stimulate the repair of the endometrium; cells of the straum basal undergo mitosis and produce a new stratum functionalism

55
Q

Describe the events that occur during ovulation

A

The mature follicle ruptures and the secondary oocyte is released into the pelvic cavity (day 14)

High levels of estrogens from almost mature follicle stimulate release of more GnRh and LH

GnRH promotes release of FSH and more LH

LH surge brings about ovulation and the oocyte is swept into the uterine tube

56
Q

What events occur in the ovaries and uterus during the postovulatory phase?

A

The time between ovulation and onset of next menses (14 days long)

Events in 1 ovary - the mature follicle collapses, the basement membrane and the internal breaks down and a blot clot forms from the minor bleeding of the ruptured follicle; the luteal phase absorbs the blood clot and secreted estrogen, progettone, relaxin, and inhibin

  • If the oocyte is not fertilized, the corpus luteum has a life span of only 2 weeks. Then, its secretory activity declines, and it degenerates into a corpus albicans
  • If the secondary oocyte is fertilized and begins to divide, the corpus luteum persists past its normal 2-week life span. It is “rescued” from degeneration by human chorionic gonadotropin (hCG) (detected in pregnancy tests)

Events in uterus - progesterone and estrogens promote growth and coiling of the endometrial glands, vascularization, and thickening of the endometrium; phase is referred to as secretory phase as endometrial glands begin to secrete glycogen

57
Q

Define vasectomy and tubal ligation

A

sterilization procedures:

vasectomy - a portion of each ductus deferent is removed
tubal ligation - both uterine tubes are tied closed and then cut

58
Q

Define non-incisional sterilization

A

Alternative to tubal ligation where a coil is inserted into each uterine tube that stimulates scar tissue, blocking the uterine tubes

59
Q

Define spermicides

A

Substances that make the vagina and cervix unfavourable for sperm survival and are available without prescription - placed in vagina prior to sex

60
Q

Define the rhythm method of brith control

A

Abstaining from sexual activity on the days that ovulation is likey to occur