Reproductive system Flashcards
Produce sex cells called sperm
Testes (male gonads)
Produce sex cells called ova (oocytes, eggs)
Ovaries (female gonads)
Sex cells have 1 set of genetic instructions on 23 chromosomes
compared to 2 sets on 46 chromosomes in other body cells
Sex cells are produced by a special type of division called
Meiosis
*Involves synapsis: Pairing of homologous chromosomes
*Crossover occurs: Exchange of genetic material between homologous chromosomes, to produce chromosomes with genetic information from both parents
Prophase I
- Chromosome pairs line up on midline of spindle
- Alignment is random, with respect to maternal or paternal origin
Metaphase I
*Homologous chromosome pairs separate, each replicated member migrating to a different pole
*Each daughter cell receives only 1 replicated member of each chromosome pair; this reduces the chromosome number by half
Anaphase I
*Cell divides completely, forming 2 new haploid daughter cells
*Each new cell contains 23 individual chromosomes with 2 chromatids
Telophase I
What begins after telophase I
Meiosis II
What are the four stages of meiosis II
Prophase II
Metaphase II
Anaphase II
Telophase II
*Chromosomes condense and reappear, still replicated
Prophase II
Replicated chromosomes attach to spindle fibers along midline
Metaphase II
Centromeres separate, and chromatids migrate to opposite poles
*Chromatids are now considered chromosomes
Anaphase II
Each of 2 cells produced in Meiosis I divides into 2 daughter cells
Telophase II
Primary sex organs (gonads) are the
2 testes
-Produce sperm cells, or spermatozoa
*Produce male sex hormones
Secondary (accessory) sex organs
*Other internal and external sex organs
*Secrete male sex hormones
*Transport sperm and secretions to outside of body
aids descent through the inguinal canal
Gubernaculum (fibrous cord)
contains the ductus deferens, blood vessels, and nerves
spermatic cord
Tough, fibrous capsule enclosing each testis
Tunica albuginea
Compartments in testis, separated by connective tissue septa
Lobules
*Highly coiled tubules inside lobules
*Lined with a special stratified epithelium containing spermatogenic cells that give rise to sperm cells
Seminiferous tubules
*Lie between seminiferous tubules
*Produce and secrete male sex hormones
Interstitial cells (cells of Leydig)
Channels that transport sperm from testis to epididymi
Rete testis
Coiled tube on surface of testis, that transports sperm from rete testis to ductus deferens
Epididymis
*Nurture and transport sperm cells
*Consist of epididymis, ductus deferens, ejaculatory duct, seminal vesicles, prostate gland, bulbourethral gland, urethra
Male internal accessory organs
*Narrow, tightly coiled tubes at top of each testis
*Connected to ducts in the testis
*Run between testis and ductus (vas) deferens
*Promote maturation of sperm cells
*Lined with pseudostratified columnar epithelium with nonmotile cilia
Epididymis (plural is epididymides)
*Narrow, tightly coiled tubes at top of each testis
*Connected to ducts in the testis
*Run between testis and ductus (vas) deferens
*Promote maturation of sperm cells
*Lined with pseudostratified columnar epithelium with nonmotile cilia
Epididymis (plural is epididymides)
*Muscular tubes, 45 cm long
*Part of the spermatic cord
*Each extends from the epididymis to the ejaculatory duct
*Lined with pseudostratified columnar epithelium
Ductus (vas) deferens (plural is ductus deferentia
*Each is attached to a ductus deferens near base of the urinary bladder
*Secrete alkaline fluid, which regulates pH in male and female tracts
*Secrete fructose and prostaglandins
*Contents empty into the ejaculatory duct
*Contributes most of volume of semen
Seminal vesicles (glands)
*Surrounds the proximal portion of the urethra
*Lies just inferior to urinary bladder
*The ducts of the gland open into the urethra
*Composed of tubular glands in connective tissue
*Also contains smooth muscle
*Secretes a thin, milky, alkaline fluid
*Secretion enhances sperm motility
*Contributes to volume of semen
Prostate gland
Also called Cowper’s glands
*Inferior to the prostate gland
*Secrete mucus-like fluid into urethra
*Fluid released in response to sexual stimulation
*Lubricates end of penis
Bulbourethral gland
Fluid transported by urethra to outside of body during ejaculation;
Contains sperm + various secretions of the accessory reproductive glands
Semen
Components of semen
Contains sperm cells from the testes
*Contains secretions of the seminal vesicles, prostate gland, and bulbourethral glands
*Slightly alkaline, pH = 7.5
*Contains prostaglandins and nutrients
*Volume is 2 to 5 mL per ejaculation
*Averages 120 million sperm cells per mL of semen
*Sperm begin to swim as they mix with secretions of accessory glands
*Sperm cannot fertilize egg until they go through capacitation in female tract, which weakens acrosome (cap over sperm head)
What are the external male reproductive organs
Scrotum and penis
Pouch of skin and subcutaneous tissue, located behind penis
*Subcutaneous tissue lacks fat
Scrotum
Smooth muscle in subcutaneous tissue
*Contracts and relaxes in response to temperature changes, to keep testes at optimal temperature for sperm production and survival (about 5oF below body temperature)
*Medial septum divides the scrotum into 2 chambers:
*Each chamber is lined with a serous membrane
*Each chamber houses a testis and epididymis
Dartos muscle
Conveys urine and semen through urethra to outside of body
Specialized to become erect for insertion into the vagina during sexual intercourse
Penis
Body (shaft) contains 3 columns of erectile tissue
*2 corpora cavernosa
*1 corpus spongiosum, which surrounds urethra
distal enlargement of corpus spongiosum
Glans penis
is covering of glans penis; removed during circumcision
Prepuce
During sexual stimulation, parasympathetic nerve impulses release nitric oxide, which dilates arteries of penis
*Pressure of arterial blood compresses veins
*Blood accumulates in the erectile tissues
*Penis swells and elongates
Erection
Culmination of sexual stimulation
*Pleasurable feeling of physiological and psychological release
*Accompanied by emission and ejaculation
Orgasm
is the movement of semen into the urethra
Emission
is the movement of semen out of the urethra
*Dependent on sympathetic nerve impulses
Ejaculation
(Part of sperm cell) Nucleus contains 23 chromosomes
*Acrosome: Cap over the nucleus, which contains enzymes that penetrate layers around oocyte during fertilization
Head of sperm cell
(Part of sperm cell). Contains many mitochondria ,which provide ATP for swimming
Mid-piece (body) of sperm cell
(Part of sperm cell) Contains many microtubules enclosed in extension of cell membrane
*Lashing movement propels sperm toward egg
Tail (flagellum) of sperm cell
*Male sex hormones
*Interstitial cells of testes produce most of them, but small amounts are made in the adrenal cortex
Androgens
most important androgen
*Secretion begins during fetal development and continues until several weeks after birth, after which secretion nearly stops during childhood
Testosterone
*Androgen derivative of testosterone
*Acts on cells in prostate gland, seminal vesicles, external accessory organs
Dihydrotestosterone (DHT)
Specialized functions of the female reproductive organs
*Produce female sex cells (egg cells, or oocytes)
*Transport oocytes to site of fertilization
*Provide favorable environment for developing offspring
*Transport offspring to outside the body
*Produce female sex hormones
Primary female sex organs (gonads) are
Ovaries
Ovary attachments
Broad ligament: Largest ligament; holds ovary in place, and is also attached to the uterine tubes and uterus
*Suspensory ligament: Holds the ovary at the upper end
*Ovarian ligament: Rounded, cord-like thickening of the broad ligament; attaches lower end of ovary to uterus
Tubular organ that transports ovulated egg cell from ovary to uterus
*End near ovary is funnel-like infundibulum with extensions called fimbriae
Peristaltic contractions help move secondary oocyte down uterine tube
*Fertilization occurs in uterine tube
Uterine tubes (fallopian tube)
Hollow, muscular, pear-shaped organ
Receives the embryo and sustains its development
Uterus
Layers of uterus
Endometrium (mucosa)
*Myometrium (muscle layer)
*Perimetrium (serosa)
Fibromuscular tube that runs between uterus and outside of body
Conveys uterine secretions, receives the penis during intercourse, and provides a passageway for offspring during birth
Vagina
Recesses between upper vaginal wall and cervix
Fornices
Partially enclosed by hymen, a thin layer of connective tissue and stratified squamous epithelium
Vaginal orfice
Layers of vagina
Inner mucosal layer of stratified squamous epithelium
*Middle muscular layer
*Outer fibrous layer
*Rounded folds of adipose tissue and skin
*Enclose and protect the other external reproductive organs
*Merge to form a rounded elevation over symphysis pubis, mons pubis
Labia majora
*Flattened, longitudinal folds between the labia majora
*Well supplied with blood vessels
*At anterior end, they form a hood-like covering around clitoris
Labia minora
*Small projection between labia minora, at anterior end of vulva
*Corresponds to male penis; composed of 2 columns of erectile tissue
clitoris
*Space between labia minora; encloses the vaginal and urethral openings
*Vestibular glands secrete mucus into vestibule during sexual stimulation
vestibule
Erectile tissues in clitoris and around vaginal entrance respond to sexual stimulation
*Nitric oxide dilates arteries in erectile tissue, expanding vagina
Erection
Sexual stimulation causes vestibular glands to secrete mucus into vestibule
*Mucus lubricates vestibule and vagina, to aid in intercourse
Lubrication
Clitoris responds to sexual stimulation
*Sexual stimulation ends with orgasm, pleasurable feeling of physiological and psychological release
*Muscles of perineum, uterus, and uterine tubes contract rhythmically, which helps transport sperm toward uterine tubes
Orgasm
Process of maturation of an oocyte
*Beginning at puberty, some primary oocytes continue meiosis (Meiosis I), resulting in cells having half as many chromosomes as in parent cells
Oogenises
is a future ovum (egg cell), which may be fertilized by a sperm in the future
Secondary oocyte
resulting in a tiny second polar body and a zygote (fertilized egg)
Secondary oocyte undergoes meiosis II if it is fertilized
allow for the formation of an egg cell with large amounts of cytoplasm and organelles, and a haploid number of chromosomes
Polar bodies
releases the secondary oocyte and first polar body from mature antral follicle
Ovulation
triggered by surge of LH released from anterior pituitary gland
Ovulation
Secreted by ovaries, adrenal cortices, and the placenta (during pregnancy)
Estrogens and Progesterone
Stimulate enlargement of accessory reproductive organs
*Stimulate thickening of the endometrium
*Develop and maintain female secondary sex characteristics:
*Breast and mammary gland duct development
*Increased adipose tissue in breasts, thighs, buttocks
*Increased vascularization of skin
Estrogens
Stimulates uterine changes during menstrual cycle
*Affects mammary glands
*Regulates secretion of gonadotropins
Progesterone
Secreted by adrenal cortex
*Cause growth of pubic and axillary hair at puberty
Androgens
Characterized by regular, recurring changes in the endometrium of the uterus, which culminates in menstrual bleeding (menses)
Menstraul cycle
1st reproductive cycle
Menarche
The stopping of the menstrual cycles for 1 year
*Usually occurs in the late 40s or the early 50s
*Ovaries no longer produce as much estrogens and progesterone as they did previously
*Some female secondary sex characteristics may disappear
*Increased loss of bone matrix (osteoporosis) may occur
*50% of women experience hot flashes
*Migraine headaches, backaches, and fatigue occur in some women
Menopause
Accessory organs of the female reproductive system
*Specialized to secrete milk following pregnancy, to nourish baby
Mammary glands
Voluntary regulation of the number of offspring produced and the time they are conceived
Birth control
Practice of withdrawing the penis from the vagina before ejaculation, preventing entry of sperm cells into the female reproductive tract
*Not very effective, since sperm can leave urethra before ejaculation
Coitus interruptus
Requires abstinence from sexual intercourse 2 days before and 1 day after ovulation;
*Not very effective, since it is difficult to predict the exact time of ovulation
Rhythm method
Prevent sperm from entering female tract during sexual intercourse
*Examples: Male and female condoms
Mechanical barriers
Spermicides in form of creams, foams, and jellies
*Most effective when used with a mechanical barrier
Chemical barriers
Deliver estrogen and progesterone to prevent pregnancy
*Contain synthetic chemicals that function like estrogen and progesterone
*Disrupt normal FSH and LH secretion, which prevents follicle maturation and ovulation
*Also thicken cervical mucus to prevent sperm passage
*Various methods are used to deliver hormones
Combined Hormone Contraceptives
An intramuscular injection of medroxyprogesterone acetate protects against pregnancy for 3 months
*Prevents maturation and release of a secondary oocyte
Other Hormone Contraceptives
Small, solid object implanted in uterine cavity
*Causes inflammation that is toxic to sperm and oocytes; prevents pregnancy
Intrauterine Device (IUD)
Morning-after pill can be taken 3 to 5 days after intercourse
*Works by temporarily stopping ovulation
*Prevents pregnancy, but does not work if ovulation have already occurred
Emergency contraceptive
Surgical procedures that permanently prevent pregnancy
Sterilization
Removal of a small section of ductus deferens, and cut ends are tied
*Prevents sperm from leaving epididymis
Vasectomy
Uterine tubes are cut, and ends are tied
*Prevents sperm from reaching oocyte
Tubal ligation
Burning sensation during urination
* Pain in the lower abdomen
* Fever or swollen glands in the neck
* Discharge from the vagina or the penis
* Pain, itch, or inflammation in the genital or the anal area
* Sores, blisters, bumps, or rashes
* Itchy, runny eyes
Symptoms of STI
